What's sad about all this is that GM never recalled and fixed this issue. Every Z06 has this problem. Good call on checking them and addressing the issue.
Robet Fletcher hell yeah that has to clear things up for many folks. Haven't seen a video like yours addressing that issue anywhere. And we'll done, loved the tools you used.
Not every. Mine has 61,302 miles on it and just had American heritage check mine when it hit 62k. They said all are perfect still but one but is still Within specs. At 63k I will have them replaced only cause I want it cammed. 7gran it will cost total. That's heads with polish slight port, cammed and dyno tuned.
@@huskymoto9207 Hi guy. Sounds like it'll be an awesome motor. I have a couple suggestions, based on owning a C5 with a transplanted LS7 for 20,000 miles/4 years. Personally, I've found these heads flow like a hurricane. Improving on them is difficult, and a VERY poor return on the bang for the buck scale. Unless you're going for every last horsey, it's not a cost effective mod. If you eliminate this one mod, it should knock a couple Gs off that $7,000 figure, and you'll never see/feel the difference. I'm not sure where the bill justifies another $5,000. WCCH usually charges around 2Gs to rebuild the heads. A good dyno tune shouldn't cost over $700 MAX. That leaves $2,300 for the cam install. That seems a little high. But hey, I don't know have an itemized list. I'm just trying to save you a few bucks. I had a 427 Darton sleeved LS1 before the LS7 came out. I had AFR 225 heads, a FAST intake, and several other things done. My cam was fairly mild. With the LS7 motor in it now, with LS7 heads, I've picked up 40 rear wheel hp. That's only 5hp per cylinder. Sure, it matters if you're racing. But 95% of the time, or more, I'm not at the strip racing. The first engine was a much better street engine, and I honestly can't tell any difference in power. Just sayin........
Disagree on every Z06 having the problem. Agree that WAY TOO MANY DO!! I've talked to guys who had never raced their car and their motors were completely stock. Some still had the original plugs in them. Some were just tooling down the freeway at 1,800-2,000 RPM!!! Many also did it just after the factory warranty expired. No excuse for it. GM lost a LOT of customers over this, for sure. There's a good reason GM dropped this motor from the Corvette and Camaro. In the Corvettes case, maybe they finally figured out most people don't wanna lay out $90,000.00, or MORE, for a car that grenades it's own engine......
I appreciate the math, attention to detail, and explanations. Thinking about my next sports car and C6Z06 is one option. I wrench as much as possible so appreciate your effort. Keep it up! Subscribed.
you're a great man. thank you for taking the time to prove this conspiracy true* I love your install videos. I have a 12 Grandsport and your LS information is priceless.
This was an outstanding commentary and procedure done on the ZO6 valve had problem. The wiggle check works as long as you have the proper gauges. Outstanding documentary I have thirty-eight hundred miles on my ZO6 and you just proved to me what I have to do before I go out and beat on my vehicle.
How does that work? What is included in that deal? I think I read that you can pay a core charge and then send your heads back? Do they send you a complete part that you can install and get on your way?
Legitimately one of the most thorough, intelligent CZcams DIY car videos I’ve ever watched. Picked up a c6z a month ago. This helped quite a bit. Thank you 🍻
@@southfloridagearheads6504 I absolutely will. One thing I wasn’t sure of - when using that tester, does that require the 12 degree angle? Or does buying that more expensive style tester negate the need to angle it properly?
@@Mopar_Roc The test indicators can handle much more acute angles. The dial indicator needs to be almost perpendicular to the valve stem. Which isn't possible in this application so the test indicator is required.
Great video. Good to see someone actually knows what their talking about. I do believe this issue was on a certain years of LS7s due to head manufacturer who used a bad guides. So find out the years with bad guides and get the heads redone for LS7. Its cheaper to do that then to replace the engine. Other than that LS7 is an outstanding motor. Good luck Z06 owners.
Awesome vid man, much appreciated. I’m considering a C6 Z06 with the LS7 and this came up as a known fault during my research. Glad I ran across your video since I too am a DIY kind of person and I wanted to see what I was in for.
@@southfloridagearheads6504 Except the issue comes back even after the heads are reworked. If I'm you I'd be checking these every 10k miles because unfortunately this doesn't fix the issue completely
@@southfloridagearheads6504 From what I've read / heard it sounds like no one knows what causes these issues. There's a CZcams user that goes by chadyellowz06 or something along those lines. He ports heads etc for a living and has more info than I. According to him and others he has personally seen where after doing bronze guides and SS valves the problem comes back. I believe he went threw 3 sets of LS7 heads before switching to a LS3 head on his personal Z06. Not trying to scare you just info I've heard. This issue has turned me off from buying a C6 Z06. I recommend checking out his videos here on CZcams and deciding for yourself. Good luck with the car.
@@southfloridagearheads6504 I've been watching all of these LS7 head videos (thank you by the way, I'll be pulling mine in the next few weeks also) and would be VERY interested to see a wiggle test performed in the same way as you did before.
Very nice video. I like that you took your time and the diagram was a graphical example. The dial indicator angle at 12 deg was perfect. I was taught that angle should never exceed 15 deg.
As a tech with 30yrs wrenching when you said wiggle test, I wrote a comment saying it was nuts ,and just better to pull the heads as as I thought you meant just wiggle with the springs on as you were saying, lol..good job..and your correct it’s only a certain build yr which are effected buy the lock,and guide failures.
Wow! It was a good thing you did that test while you still could! She would have blown sooner than later. I have been looking at C6 ZO6's, and I found a nice clean 2008 with only 12,000 miles on it. Apparently, the milage doesn’t matter with this issue.. if I get one,, I am not wasting any time or taking any risk.. I am just going to replace the heads with a well known rebuilt head and take the worry out of it.. If you do the test and they all check out okay, they could wear out in the next 10,000 miles anyway. Then you blow it up and get stuck with a HUGE engine bill. If you want to drive a ZO6, you are best off just doing this and getting it out of the way.
Great garage setup, man. 👍 WoW, you have a lot of patience to do all that. I'm starting to look at getting a 2008/2009 C6Z06 as a track toy, but this Valve guide issue is making me second guess my choice.
I watched a video last night where the dude spent $16,000 on his "upgrade save." Good grief, I bought my 08 for 51k. Only had 6k miles. I just enjoy the car. There's Always something that will outrun ya!
I've been watching a bunch of videos the last few days from a company that does tuning on these engines and race setups. They talk about this and evidently send the heads out for the work or replacing them. But you are the first to show this problem more precisely and demo the testing for it. What I want to know is what the stock guides are made of that causes them to wear so excessively and also I understand the exhaust valve stems are hollow, sodium filled, so is it the exhaust valves that usually break and go into the cylinder.
Great video, just a small correction when you measure 12 thousandth rocking the valve back and forth you need to halve that measurement to get the stem-to-guide clearance because the clearance basically means the "gap" all round the valve, which you measure twice by rocking back and forth.
Great video! Overall, GM never talked about why this issue really happened. Excessive rocker ratio (I.e. bad valve train geometry = bad design), sub-par material selection (bad design), and dynamic valve train instability (again bad design) are the real issues here…design issues from the factory. GM blamed a “quality spill” on their valve guide suppliers over and over, which of course is a cop out. (I guess the engineers’ smoke and mirrors worked.) If you have an LS7, get the heads reworked using quality materials ASAP, use quality aftermarket rocker arms too (factory roller trunnions are crappy band-aids) and go out and have fun with this high rev engine! But if you’re running up to redline often, you’ll still want to check your valve-to-guide clearances once in a while. LS7 is a great race engine, lol. If you want a far more reliable and lower maintenance street option, go with a supercharged LS3 and keep the stock redline. Essentially that was the lesson learned before the C7Z was born. High rpm’s = cost + commitment and not always worth it depending on your goals. I love Corvettes, but GM should have done better here! I sold my ‘09 C6Z after 12k miles, without failure, and it was fun for sure!
Corvette owners are hilarious. You make 12,000 miles sound like an achievement. GM always denied responsibility on their poor designs. They blamed LS7 failures on a batch of bad valve guides in a limited production run, but ALL heads and valve train need to be replaced. Then there was piston slap in some LSs (this is normal!), the chronic wheel cracking, the cylinder deactivation failures... List goes on and on, as does the list of class action suits. You can forgive that at the price point of the C6, but now Corvettes are >$150-200k cars after dealer gouging and GOOD LUCK with a DCT and 4 valve flat plane motor made in Kentucky. But it looks like a real sports car.
Also it would be super helpful if you could include links to all of the tools you used in the description of the video so that we could buy them too. Thanks a lot for the great video!! Very helpful.
I have been in three of the zo6 top ends and buddy you caught that one at the right time she was one foot peddle from finding the valve in the intake or pan
I've been thinking about buying one of these C6 Z06's but this makes me have 2nd thoughts. So if I do I'm gonna just have the heads done immediately just for piece of mind. Either that or I'm gonna just buy the C7 and avoid the issue all together. Its a damn shame GM didn't take care of this issue this car is one of the best bang for the buck values out there.
I’ve backed off looking at them as well. Too much money for a car I have to pull the heads to spend a couple months to correct an issue instead of tracking it out of the box.
The valve drop issue is one reason it's such a good bang for the buck deal. These cars would probably be worth another 10G if this problem didn't exist!! The LS7 with dished Forged pistons and heavier rods has shown to be capable of around 1,000 reliable hp with a small amount of boost. If ya didn't have to worry about the heads, you could have a 1,000hp supercar for under 50Gs!!!
@@milojanis4901 Worth another 10G? I don't know about that, a decent say 2009-2012 C6 Z06 from I've been seeing is mid 30s low 40's. Another 10G and that's C6 ZR1 territory. And when it comes to putting boost on a LS7 I'd be careful with that one too. GM opted to not use a boosted version of that motor in the ZR1 because of the thin cylinder walls.
MrWicked98 True but if the Z06 didn’t have that problem and were worth more, I am sure the ZR1’s would be worth more too compared to what they are worth now to even things out
@ Milo Janis I’m not so much concerned about added horsepower, my main concern is that it seems to have too many issues ( expensive ones at that ) to be just a daily driver for what it is now
Excellent and thorough presentation....well prepared and organized...and a BIG thank you ! A minor suggestion would be to drop the music....it interferes with the flow of information. thanks, Tim
Great video, thanks for the information. Did your engine exhibit any valve train noise? I have an 08 with 43k on it. No obvious noise, but perhaps by the time you hear valve train noise the days are numbered and you’ve been lucky. If the original exhaust valves were solid, not hollow sodium, filled, they would have tolerated a lot of wear and not broke. I might be better off trading it back in on a new mid engine C8. Ha.
WOW in 40 years as mechanic that is the most play i have ever seen in a valve no gauge needed for that it looked like hot it would be..020 . GM used snap off parts on that model happily you can laugh now at that now.I LAUGHED AT THE WIGGLE TEST IN YOUR TITLE BUT IT IS REAL.
In the video you said that you went with stainless steel exhaust valves, why did you go with those over titanium or just use new stock valves? Aren’t the stainless steel ones heavier than stock?
hands down, the most thorough and accurate video regarding this topic, bar none. I watched another video of a guy measuring his valve movement at the top of his valve stem, with a dial indicator, and he got a deflection of about 12 thousanths, but did not do the trigonometry calculations you clearly laid out. He moved on to replace his heads based on his numbers, when you extract out the correct numbers for the movement at the base of the valve stems, his valves were most likely IN SPEC. LOL I much respect your effort to lay out the difference in the two measurement techniques and recommending the TEST Indicator. I feel bad for you, that exhaust valve had a lot of movement...wow. Either bad metalurgy on that set of valve guides, as I've read was one of the problems, depending on year, and/or your valve guide holes were machined out of spec, off center, not concentric to the valve seats...which is the other technical explanation I've seen for the premature wear on these valve guides. People who are supposed to have technical expertise get on youtube here and tell you to replace your valves with solid titanium ones and that the stems are stronger and will prevent the valves from breaking, while they have no idea whats actually wrong. I'm about to do the wiggle test, with the gear you laid out here, on my '07 Z06....mine has 30,350 miles on it and these LS7's make a lot of valve train noise to begin with, but now I try to listen for extra noises and I'm just getting paranoid. Gonna stop driving it until I get this test done, and decide whether to go with the big power cam and heads package now, or later on...depending on my results. The extra 100+ wheel horsepower is going to happen, sooner or later :)
Thank you for the comment. I struggled myself to find the correct information online so that is why I decided to put together the video. I have since done the heads, big cam, headers etc. and have racked up about 10k more miles on the car since I did the work. She runs great and I feel confident in the engine now. Check out some of my other videos if you plan to tackle the heads/cam yourself. hope they help out. cheers!
Texas Speed did the heads. new exhaust valves, polished intake valves, bronze guides, dual springs, ported and milled. the rest of the build and others is on my CZcams page
@@valleypivot you can't measure anything with a dial indicator being parallel to your work. a dial indicator needs to be 90 degrees or perpendicular to the work. that is why I'm using a test indicator because it can accurately measure at a more acute angle than 90 degrees. I explain the math at the end of the video.
Quick question bud! Just got a 2008 Z06 with cams, intake, exhaust and headers done. Also exterior and interior work done but that’s besides the point. I talked to the previous owner and he mentioned the original owner was not cheap about anything on the car, (which is obvious.) However, he nor I are exactly sure if they heads have been touched. Considering the motor was already out and opened due to the installation of cams and how much has been done to the car, would it be safe to assume the heads were worked on as well? How much do you think it’d be for a shop to check them out?
I would expect the heads have been done if it has a cam in it. No way to know for sure though. Unless they are aftermarket heads with the company logo on the front side. Factory fixed heads are hard to identify from the outside. Im suprised with that amount of work you didnt get a build sheet or receipts. I save all the receipts for the stuff on my car. No plans to sell it but im sure a new owner would like to know whats done buying a modified car. Im not sure who in your area would check them or even know how to do it properly.
Don't always assume it's the guide, although it is the weaker link of the two. Checking a BBC (heads off) I found one valve out of spec. I switched a valve that checked good on it's home guide and it checked good in the out of spec. unit. Mic'ed the stem and it was undersize. So in this odd situation it was the valve stem and not the guide. FYI
Did you go with an aftermarket head, or just install new valves and guides? I want to get my 2012 Z done, but have read that some feel that fixing the stock heads may not be a permanent repair. Let us know what you have done, what parts you used, and if you had any excessive clearance return? Thank you!!
You can watch more of the build here. czcams.com/video/6wb0qL4uTWY/video.html I had texas speed rework my heads. about 10k miles on them now. plan to recheck them soon to see if the fix is permanent.
I am about perform this test on my Z06 and was curious as to why you disconnected the air pressure after removing the springs and retainers. Isn't the point of the air prssure to prevent the valve from dropping once the retainer is removed? Thanks!
if you put the piston at TDC the valve can't really drop valve will just sit on top of piston. and you need to allow the valve to come down a small amount off the valve seat to "rock or wiggle" the valve. so you can't do that with the air on.
Can you redo the test measuring at the wrong (higher) point as compared to the correct location and tell us the difference and also post the conversion formula for those who measure at the higher point?
I have plans for another wiggle test video. The car almost has 10k miles on the reworked heads now so I will do another check on the guides and see if this is a perm fix or not. i will include the measurements for the wrong position to compare.
I have read that GM admitted that they got badly machined heads from 2008 to 2011, where the valve seat inserts were not concentric with the valve guides. This misalignment might have caused excessive lateral forces on the ends of the valve stems with corresponding wear and then valve wobble. I could see the resultant exhaust valve leaking causing valve overheating and then failure, especially being a hollow sodium-filled valve. Whenever I've done valve jobs I've always lapped the seats and used a dye, like Prussian blue, to view the seating ring on the valve seat. I have to wonder about GM's QA practices where this would not have been detected during the engine assembly. A misaligned valve seat insert and valve guide would have shown up as a nonuniform dye ring on the valve seat.
yes that is what I have read about the issue. I have blue checked valve seats/discs after lapping on old navy steam ships! But who knows what kinda QA checks went on. And the problem would only get worse over time as the guides wear and there is more play.
Here is the best write up on how to do it. Basically what I followed during this test. www.corvetteactioncenter.com/specs/c6/corvette-ls7-engine/ls7-engine-valve-wiggle-test-1.html
Thanks for your vid, very helpful! Do you think an ls7, that surived a higher mileage without blowing up increases the chance of not having the valve drop issue? My `10 Z06 now has about 50000 on it without ever being inspected.
I ended up going with AHP heads and replacing them on my Z28. I didn’t want to take any chances. I kept my original heads. I might send it to them to have them reworked.
It's also sad that GM never owned up to the problem. A class action lawsuit brought by C6 Z06 owners has been ongoing for about four years but seems to be going nowhere, which is too bad for all involved. On the plus side, you're definitely giving your car a new lease on life! I myself am driving an 08 LS3 car at present and may sell it to pick up a base '14 or '15 C7 a couple years from now.
just watched your video and now i'm concerned about my 06' z06 with 20k miles. not sure if this question has been addressed, but I heard there was a batch of guides that were done correctly (diff material) at the factory and won't develop the issue. have you heard this? i need to check the factory with my VIN to see if I have the lucky batch. do you have any info on this? thanks.
correct the problem does not exist with all heads. problem is there is no info on which heads/years/ vin it effects. or at least GM wont release the info.. because that would mean they would need to admit they did something wrong...
@@southfloridagearheads6504 It affects every year, its a ls7 design flaw, gm put out that bs to cover the ass that it was only the 2006 its every year. They wiggled out of having to do a full recall and redesign
Just assume your heads are jacked up from the factory and have them replaced. The failures are just to sporadic to pin point. I’ve seen 10k-80k and everywhere in between. If you keep rolling the dice. You eventually will roll snake eyes. And in this case snake eyes = 18k in damage.
It’s worse than that, because every time someone buys and sells one of these you need to do the test because are you going to take the sellers word he fixed it? Or it was done right
Sounds great! That's totally stock? If so they sound much better than the other models! I am in the market for upgrading my Camaro 2SS to a C6 and tempted on going with a Z06 and guess I will be adding head / valve upgrade to my purchase. Such a shame, but be nice to get that 7.0 :) nice ride and great walk through!
So what would be the specific parts needed to fix the issue on a Z06? Not sure if it would be worth doing the work myself, once having all the necessary tools and two, it will be my daily driver. The big plus for the Z06 is all of them are manuals and that seems to be a hard to find with my searches. About 3/4 of the ones I have seen are Autos. Wouldn't be a show stopper, but would prefer the manual.
Yeah, once I get it the only things I plan on doing to it is headers and exhaust, a CAI and a Tune. That will be plenty of fun for my DD. I love the Camaro 2SS, but I miss the vette, had C4 in the 90s. So the only tool I would need is the valve compression tool? Or would I need that if I just take the heads off and take to a shop just have them fix everything and then bolt back on. IF that is the stock exhaust I am not sure i would need to do anything to the car actually. That sounds like a Vette should. Guess the finally let the Z06 breath compared to the base Corvette. Would you happen to know if the Grand Sport sounds better than the base?
The stock powdered metal guides just don't work with 1.8 rockers. The ls7 1.8 is just to much. My ls3's don't get even close to that bad with 1.7's. Even with a roller cam and .700 lift springs. When I go to an ls7 head Ill be running roller tip rockers.
@@paisley2342 no, this car is still together 10k miles or so since the work was done. I've built a few others since then. the last one had AI heads from RPM.
@@southfloridagearheads6504 I cant see in the vid but if you are taking the measurement at the tip of the stem and the stem is sticking out of the guide the measurement will be way high. Checking on the spring end is kinda bogus anyway. If you measure side to side at the tip of the stem with the tip barely sticking out of the guide you did a great job, measuring stem to guide clearance at the very top of the guide....The part that matters is the head of the valve. That vid i linked, the top of the guide clearance was out of factory spec by a thou or 2 but the guides were worn on the other end. was the stem/guide clean and dry when you took the measurement? Oil film makes a difference. You said you could not feel anything on one of the valves? Clean and dry, if you cant feel anything you need to have your feeler checked...i can "feel" down to .0008. GM says the problem is bad machine work...the engineers at gm are plenty smart, i was a gm service tech for 15 years...they are not always truthful. A crooked valve guide can cause a head to break off? Ya, maybe if the valve is not quite as good as it should be..Your car fall within the build numbers that gm says might have the problem, fix it...outside..i wouldnt worry. You have any starter problems? my buddy has a 13 zo6 and the starter shit the bed at 6k miles..we live in lake havasu, hotter than hell in summer, gm mounted a cat 2" from the starter and cooked it, new starter wrapped with insulator and a heat shield. I made a hard run to parker and back, got it good and hot. it was 115* and i let it idle with the ac on..no problem....and if you ever push the clutch pedal to the floor and then the pedal doesnt work send me a message, i tell ya how to fix it...
@@blackbirdxx928 This is the proper way to check the valve clearance so i'm confident in my findings. This is the write up I used during the test. Maybe this will answer some of your questions. www.corvetteactioncenter.com/specs/c6/corvette-ls7-engine/ls7-engine-valve-wiggle-test-1.html This video is also almost 3 years old at this point. I had the heads re-machined about 10k miles ago and put a cam in there while I had the car apart. Never had any starter related issues and the car runs long tube headers with no cats. Also no issue with the clutch sticking. Factory clutch with 30k miles.
@@southfloridagearheads6504 The proper way is to remove the valve, measure the stem, measure the id of the guide with a bore gauge and do the math. That is how its measured as per GM service manual...But it doesnt really matter...loose valve guides dont break valves...aint gona happen....and GMs story about poor machine work...like how can the seat not be aligned with the guide if the guide is used as the center line of the tool? Understand that i have a bit of experience with this stuff...i usually do shortblock assembly, big inch blown/turbo offshore stuff but if the boss is busy i am perfectly capable of replacing guides and seats on the $60k sunnen.....i did make a few calls to some people....yep, valves dont break...except for those....poor quality....why, after all these years could gm forget how the make a valve. Its the last part that you want to break...much more damage than a broke rod bolt...the answer? outsourcing parts...no need to say where..other than not canada or mexico...back in those days a lot of aftermarket crankshafts came from there...stuff that never failed before was having problems...passable machine work but who spends $3500 on a crank and sends it out to see if the 4130 stamp is real....yep, real stamp, not real 4130....GM will never admit it, they cant...you guys with vetts would eat them alive...at least GM is able to track what cars they put the junk valves in, i have a buddy with a 13 zo6 with 7000 miles and was scared to drive it...i double checked and it wasnt a problem build...he is old guy, drives like grandpa..has no idea how hard the car runs..told him. i brake, i fix..you buy parts...the rubber from the rear tires has been there for a year...anyway. your car, your way...i know all about corvette owners, i worked at a shop in the mid 80s all we did were vetts...15 years GM service tech, 5 of them at Cadillac. Fussy people..all of ya...lol...now i do boat motors...most everthing that goes out is show quality outside, best money can buy inside...you familiar with oakland roadster show? years ago my boss won...with a boat..and it wasnt a show boat it was a full on 240mph drag boat..
@@blackbirdxx928 yes, but the measurements come out the same. Ive done valve guide ID with a bore gauge and valve stem OD, and the clearance comes out to the same value as the "wiggle test" value. Ive done this same trial on numerous different heads and manufactures. And the valve stems are hollow sodium filled so they would fail easier then a solid stainless valve. Maybe that was their big problem. Trying to get fancy with a hollow stem valve for better heat transfer but they were not made well enough to stand up to 7k redline. Big boat guy here. I run a marine diesel shop in fort lauderdale. thanks for the comments and idea sharing.
Get your engine oil analyzed for titanium. Earliest alert to engine grenade potential. No teardown. If you own a C6 Z06, Send oil samples to Blackstone Labs $35. Cheap engine insurance. I did, from 18,000 to 22,000 Titanium increased significantly. Blackstone suggested I get the heads checked. GMPP would not pay for inspection. I authorized the removal at my expense. GMPP then paid for new heads, valves. Gaskets and labor. No kaboom LS7!
Oil Analysis is a great tool to use to see what is going on inside your engine without opening it up. Especially if you have enough data to establish a base line and have a trend to look at. That is great you got the issue fixed under GM's dime. Although, new factory heads would not hold up with the plans I had for the car. So catching the problem early enough and sending the heads out to be re-worked was the best action. I got my heads ported, milled, bronze guides, new SS exhaust valves, dual springs, TI retainers, viton seals.
Dennis Murphy. Oil analysis is a good tool, but it wont help on the exhaust guide/valve stem wear. Because only the intake valves are made of titanium. From my experience, the exhaust side fails more often than the titanium intakes do, although the intake valves also drop. Nobody has a definite cause, as there are a lot of variables. When I do mine, I'm going with Ferrea exhaust valves. Pricey, but one of the best.....
Milo. I can tell you, my oil analysis was recommended by my tuner. The analysis folks reported elevated titanium. It was a signal, I heard noise valves after a hard run had the oil retested and titanium was way up. I had to agree to pay if the teardown didn't show any problems but I was confident with the noise which they could not hear and the oil testing that it needed to turn down. Its saved me and gave me proof of the part failure going on. It may not be perfect or catch it all, but for $30 it's a great tool and knowledge set to have on a Corvette engine. My repair was $7,000 on GMPP. I paid an extra $900 to drop the oil pan and pull out the rocker roller bearings as well. D
It is a shame of GM to sell such a misconstruction to the customer...:-( I would like to buy a z06 here in Germany and I hope that I find one, where everything is already done... :-)
@@jamesreeves4600 from my experience they are great cars. Ive owned mine for 5+ years. It's very modified now and I still have driven it from FL to NY straight without any issues ( just a few stops for gas) Only thing ive had go wrong is the key fob transmitter went out so I have to put the key in the slot in the glove box. I love the car and would never get rid of it.
@@jamesreeves4600 Check out some of the newer videos if you are curious about the c6z. we have tons of engine work, clutch swaps, etc. Thanks for the comment!
Personally I do not, I do however inform the buyer of this issue so there are no surprises. I get buyers that want to buy these stock so they can decide exactly what head work they want to go with and I get buyers who want it already done regardless of what head work the prior owners went with.
texas-speed did my heads. Port, mill, bronze guides, new SS exhaust valves, recut and polish intake valves, dual spring kit, TI retainers, viton seals around $1200. you can go more agressive on the porting or milling, upgraded valves, etc for more money. check out the install video czcams.com/video/6wb0qL4uTWY/video.html
Im not sure about the years. I remember back when I was doing research on this GM claimed to have fixed the manufacturing issue with machining the valve guide concentric to the valve seat but I don't recall if they published a date. Might have to dig through the old corvette forums. If it were me and I was buying another c6z, I would pull the heads and have them done.
@@southfloridagearheads6504 nice, I got a 08 c6z, pretty much all stock besides muffler delete and tune, previous owner had a new motor installed by the dealer under warranty, due to the value guide issues. He even gave me the receipt for the work done, the thing is I'm not sure if they fixed the guide issue on the new motor, or just a simple motor swap, what do you think? Btw the receipt didn't say much about what was done to it...
@@southfloridagearheads6504 it was like almost $8000,according to the receipt. So I'm guessing just fixing the problem without doing a complete swap, I've always liked the chops from a big cam, I'm from California the bay area to be exact, so far I haven't found any shops around here that can get h/c , done. There's a shop in Livermore California but it's like over an hr away from me. Man I wish you were in ca so you can get it done for me lol
I’m currently looking for a c6 z06 and it’s pretty hard to find one for a fair price considering that I’ll just go ahead and upgrade the heads. How much would a heads and cam swap cost in just labor?
Don’t buy replacement GM heads. If you have a reputable competent aftermarket specialist like Lingenfelter rebuild your heads with superior aftermarket parts the issue won’t come back.
It seems like you didn't watch the whole video. this was simply an inspection to see if there was any issue with the valves or guides. obviously, with my measurements, the guides were out of spec. the heads were pulled in the next video and sent out to Texas speed for machine work.
If I bought another 6cz Id just pull the heads and have them done from the start. Not even worth the time to take the measurements IMO. Just have them done from the beginning
Sorry to hear that. This was one of the first videos I made and filmed with my phone. The audio could certainly use some work. Hope you are able to find a better ls7 valve guide video to help you out. Cheers!
What's sad about all this is that GM never recalled and fixed this issue. Every Z06 has this problem. Good call on checking them and addressing the issue.
Robet Fletcher hell yeah that has to clear things up for many folks. Haven't seen a video like yours addressing that issue anywhere. And we'll done, loved the tools you used.
Mine went at 23000 miles on it!
Not every. Mine has 61,302 miles on it and just had American heritage check mine when it hit 62k. They said all are perfect still but one but is still Within specs. At 63k I will have them replaced only cause I want it cammed. 7gran it will cost total. That's heads with polish slight port, cammed and dyno tuned.
@@huskymoto9207 Hi guy. Sounds like it'll be an awesome motor. I have a couple suggestions, based on owning a C5 with a transplanted LS7 for 20,000 miles/4 years. Personally, I've found these heads flow like a hurricane. Improving on them is difficult, and a VERY poor return on the bang for the buck scale. Unless you're going for every last horsey, it's not a cost effective mod. If you eliminate this one mod, it should knock a couple Gs off that $7,000 figure, and you'll never see/feel the difference. I'm not sure where the bill justifies another $5,000. WCCH usually charges around 2Gs to rebuild the heads. A good dyno tune shouldn't cost over $700 MAX. That leaves $2,300 for the cam install. That seems a little high. But hey, I don't know have an itemized list. I'm just trying to save you a few bucks. I had a 427 Darton sleeved LS1 before the LS7 came out. I had AFR 225 heads, a FAST intake, and several other things done. My cam was fairly mild. With the LS7 motor in it now, with LS7 heads, I've picked up 40 rear wheel hp. That's only 5hp per cylinder. Sure, it matters if you're racing. But 95% of the time, or more, I'm not at the strip racing. The first engine was a much better street engine, and I honestly can't tell any difference in power. Just sayin........
Disagree on every Z06 having the problem. Agree that WAY TOO MANY DO!! I've talked to guys who had never raced their car and their motors were completely stock. Some still had the original plugs in them. Some were just tooling down the freeway at 1,800-2,000 RPM!!! Many also did it just after the factory warranty expired. No excuse for it. GM lost a LOT of customers over this, for sure. There's a good reason GM dropped this motor from the Corvette and Camaro. In the Corvettes case, maybe they finally figured out most people don't wanna lay out $90,000.00, or MORE, for a car that grenades it's own engine......
I appreciate the math, attention to detail, and explanations. Thinking about my next sports car and C6Z06 is one option. I wrench as much as possible so appreciate your effort. Keep it up! Subscribed.
Thank you! check out the newer builds on the channel we just finished up a sweet black C6Z with a RPM heads/cam package
Great video! Explained and showed in a very precise manner that we all can understand. Look forward to seeing future vids. Thank you
Thank you. This video is pretty old, check out some of the newer stuff and builds!
you're a great man. thank you for taking the time to prove this conspiracy true* I love your install videos. I have a 12 Grandsport and your LS information is priceless.
Great video, the attention to detail and the math excellent. You’re a fine young man and thank you for your service. Boo to GM
thank you!
Very informative video. I've been researching these cars for a few months now and have come across this potential issue. Thanks for the explanation.
Glad the video helped you out!
This was an outstanding commentary and procedure done on the ZO6 valve had problem. The wiggle check works as long as you have the proper gauges. Outstanding documentary
I have thirty-eight hundred miles on my ZO6 and you just proved to me what I have to do before I go out and beat on my vehicle.
thanks for the comment, glad the video helped you out. Enjoy the car!
Great vid. No longer have corvette fever, but still like to sneak a peek from time-to-time.
Great job on the video. I have my AHP heads waiting to be installed this spring.
How does that work? What is included in that deal? I think I read that you can pay a core charge and then send your heads back?
Do they send you a complete part that you can install and get on your way?
Legitimately one of the most thorough, intelligent CZcams DIY car videos I’ve ever watched. Picked up a c6z a month ago. This helped quite a bit. Thank you 🍻
Thank you! hope you will enjoy some of the other videos on the c6z builds
@@southfloridagearheads6504 I absolutely will. One thing I wasn’t sure of - when using that tester, does that require the 12 degree angle? Or does buying that more expensive style tester negate the need to angle it properly?
@@Mopar_Roc The test indicators can handle much more acute angles. The dial indicator needs to be almost perpendicular to the valve stem. Which isn't possible in this application so the test indicator is required.
@@southfloridagearheads6504I thought that was what you meant, just wanted to clarify. Thank you!!
Love your garage! Nice work.
thank you!
Great video. Good to see someone actually knows what their talking about.
I do believe this issue was on a certain years of LS7s due to head manufacturer who used a bad guides. So find out the years with bad guides and get the heads redone for LS7. Its cheaper to do that then to replace the engine. Other than that LS7 is an outstanding motor. Good luck Z06 owners.
yes, it is an amazing engine. Just have the heads done and your good to go.
Great video and awesome garage
Awesome vid man, much appreciated. I’m considering a C6 Z06 with the LS7 and this came up as a known fault during my research. Glad I ran across your video since I too am a DIY kind of person and I wanted to see what I was in for.
@@southfloridagearheads6504 Except the issue comes back even after the heads are reworked. If I'm you I'd be checking these every 10k miles because unfortunately this doesn't fix the issue completely
@@southfloridagearheads6504 From what I've read / heard it sounds like no one knows what causes these issues. There's a CZcams user that goes by chadyellowz06 or something along those lines. He ports heads etc for a living and has more info than I. According to him and others he has personally seen where after doing bronze guides and SS valves the problem comes back. I believe he went threw 3 sets of LS7 heads before switching to a LS3 head on his personal Z06. Not trying to scare you just info I've heard. This issue has turned me off from buying a C6 Z06.
I recommend checking out his videos here on CZcams and deciding for yourself. Good luck with the car.
@@southfloridagearheads6504 I've been watching all of these LS7 head videos (thank you by the way, I'll be pulling mine in the next few weeks also) and would be VERY interested to see a wiggle test performed in the same way as you did before.
Very nice video. I like that you took your time and the diagram was a graphical example. The dial indicator angle at 12 deg was perfect. I was taught that angle should never exceed 15 deg.
Thanks Mike, Im glad you enjoyed the video!
Great job..I learned a lot.
Thank you.
Great video. Keep putting videos like this and your channel will be great
Thank you for your comment! stay tuned
As a tech with 30yrs wrenching when you said wiggle test, I wrote a comment saying it was nuts ,and just better to pull the heads as as I thought you meant just wiggle with the springs on as you were saying, lol..good job..and your correct it’s only a certain build yr which are effected buy the lock,and guide failures.
Wow! It was a good thing you did that test while you still could! She would have blown sooner than later. I have been looking at C6 ZO6's, and I found a nice clean 2008 with only 12,000 miles on it. Apparently, the milage doesn’t matter with this issue.. if I get one,, I am not wasting any time or taking any risk.. I am just going to replace the heads with a well known rebuilt head and take the worry out of it.. If you do the test and they all check out okay, they could wear out in the next 10,000 miles anyway. Then you blow it up and get stuck with a HUGE engine bill. If you want to drive a ZO6, you are best off just doing this and getting it out of the way.
thats the smart play for sure
Great garage setup, man. 👍
WoW, you have a lot of patience to do all that.
I'm starting to look at getting a 2008/2009 C6Z06 as a track toy, but this Valve guide issue is making me second guess my choice.
When you cam it might as well fix the issue you know.
I watched a video last night where the dude spent $16,000 on his "upgrade save." Good grief, I bought my 08 for 51k. Only had 6k miles. I just enjoy the car. There's Always something that will outrun ya!
I've been watching a bunch of videos the last few days from a company that does tuning on these engines and race setups. They talk about this and evidently send the heads out for the work or replacing them. But you are the first to show this problem more precisely and demo the testing for it. What I want to know is what the stock guides are made of that causes them to wear so excessively and also I understand the exhaust valve stems are hollow, sodium filled, so is it the exhaust valves that usually break and go into the cylinder.
thats good to hear a race shop is doing the same!
Excellent video
Great video, just a small correction when you measure 12 thousandth rocking the valve back and forth you need to halve that measurement to get the stem-to-guide clearance because the clearance basically means the "gap" all round the valve, which you measure twice by rocking back and forth.
excellent demonstration
Loved the show
Great video! Overall, GM never talked about why this issue really happened. Excessive rocker ratio (I.e. bad valve train geometry = bad design), sub-par material selection (bad design), and dynamic valve train instability (again bad design) are the real issues here…design issues from the factory. GM blamed a “quality spill” on their valve guide suppliers over and over, which of course is a cop out. (I guess the engineers’ smoke and mirrors worked.) If you have an LS7, get the heads reworked using quality materials ASAP, use quality aftermarket rocker arms too (factory roller trunnions are crappy band-aids) and go out and have fun with this high rev engine! But if you’re running up to redline often, you’ll still want to check your valve-to-guide clearances once in a while. LS7 is a great race engine, lol. If you want a far more reliable and lower maintenance street option, go with a supercharged LS3 and keep the stock redline. Essentially that was the lesson learned before the C7Z was born. High rpm’s = cost + commitment and not always worth it depending on your goals. I love Corvettes, but GM should have done better here!
I sold my ‘09 C6Z after 12k miles, without failure, and it was fun for sure!
Corvette owners are hilarious. You make 12,000 miles sound like an achievement. GM always denied responsibility on their poor designs. They blamed LS7 failures on a batch of bad valve guides in a limited production run, but ALL heads and valve train need to be replaced. Then there was piston slap in some LSs (this is normal!), the chronic wheel cracking, the cylinder deactivation failures... List goes on and on, as does the list of class action suits.
You can forgive that at the price point of the C6, but now Corvettes are >$150-200k cars after dealer gouging and GOOD LUCK with a DCT and 4 valve flat plane motor made in Kentucky.
But it looks like a real sports car.
Also it would be super helpful if you could include links to all of the tools you used in the description of the video so that we could buy them too. Thanks a lot for the great video!! Very helpful.
Robert Fletcher awesome thanks!!
I have been in three of the zo6 top ends and buddy you caught that one at the right time she was one foot peddle from finding the valve in the intake or pan
yes, just in time could have been buying a new long block
Thanks Robert for the video. My C6Z has 19,000 on the odo, I’m getting nervous about the valves. Maybe time to pull them.
I've been thinking about buying one of these C6 Z06's but this makes me have 2nd thoughts. So if I do I'm gonna just have the heads done immediately just for piece of mind. Either that or I'm gonna just buy the C7 and avoid the issue all together. Its a damn shame GM didn't take care of this issue this car is one of the best bang for the buck values out there.
I’ve backed off looking at them as well. Too much money for a car I have to pull the heads to spend a couple months to correct an issue instead of tracking it out of the box.
The valve drop issue is one reason it's such a good bang for the buck deal. These cars would probably be worth another 10G if this problem didn't exist!! The LS7 with dished Forged pistons and heavier rods has shown to be capable of around 1,000 reliable hp with a small amount of boost. If ya didn't have to worry about the heads, you could have a 1,000hp supercar for under 50Gs!!!
@@milojanis4901 Worth another 10G? I don't know about that, a decent say 2009-2012 C6 Z06 from I've been seeing is mid 30s low 40's. Another 10G and that's C6 ZR1 territory. And when it comes to putting boost on a LS7 I'd be careful with that one too. GM opted to not use a boosted version of that motor in the ZR1 because of the thin cylinder walls.
MrWicked98 True but if the Z06 didn’t have that problem and were worth more, I am sure the ZR1’s would be worth more too compared to what they are worth now to even things out
@ Milo Janis
I’m not so much concerned about added horsepower, my main concern is that it seems to have too many issues ( expensive ones at that ) to be just a daily driver for what it is now
I was in Subic Bay Phillipines multiple times 1987-1990 MSSG-15 with 15th MEU!!!!!
awesome! subic is a great port. good times there.
Great video!
Wonderful video, thank you
Excellent and thorough presentation....well prepared and organized...and a BIG thank you ! A minor suggestion would be to drop the music....it interferes with the flow of information. thanks, Tim
Thanks for watching and the comment! This was one of the first videos I had made so i hope they have come a little way since then!
Great video. Sorry to see those results but at least it is not a motor. You people with the Z06 motor take heed.
Great video, thanks for the information. Did your engine exhibit any valve train noise? I have an 08 with 43k on it. No obvious noise, but perhaps by the time you hear valve train noise the days are numbered and you’ve been lucky. If the original exhaust valves were solid, not hollow sodium, filled, they would have tolerated a lot of wear and not broke. I might be better off trading it back in on a new mid engine C8. Ha.
That is a crazy amount of valve to stem clearance for such a low mileage car. Yes you dodged the bullet.
WOW in 40 years as mechanic that is the most play i have ever seen in a valve no gauge needed for that it looked like hot it would be..020 . GM used snap off parts on that model happily you can laugh now at that now.I LAUGHED AT THE WIGGLE TEST IN YOUR TITLE BUT IT IS REAL.
Thanks for the vid!
In the video you said that you went with stainless steel exhaust valves, why did you go with those over titanium or just use new stock valves? Aren’t the stainless steel ones heavier than stock?
Thanks for the video
hands down, the most thorough and accurate video regarding this topic, bar none. I watched another video of a guy measuring his valve movement at the top of his valve stem, with a dial indicator, and he got a deflection of about 12 thousanths, but did not do the trigonometry calculations you clearly laid out. He moved on to replace his heads based on his numbers, when you extract out the correct numbers for the movement at the base of the valve stems, his valves were most likely IN SPEC. LOL
I much respect your effort to lay out the difference in the two measurement techniques and recommending the TEST Indicator.
I feel bad for you, that exhaust valve had a lot of movement...wow. Either bad metalurgy on that set of valve guides, as I've read was one of the problems, depending on year, and/or your valve guide holes were machined out of spec, off center, not concentric to the valve seats...which is the other technical explanation I've seen for the premature wear on these valve guides.
People who are supposed to have technical expertise get on youtube here and tell you to replace your valves with solid titanium ones and that the stems are stronger and will prevent the valves from breaking, while they have no idea whats actually wrong.
I'm about to do the wiggle test, with the gear you laid out here, on my '07 Z06....mine has 30,350 miles on it and these LS7's make a lot of valve train noise to begin with, but now I try to listen for extra noises and I'm just getting paranoid. Gonna stop driving it until I get this test done, and decide whether to go with the big power cam and heads package now, or later on...depending on my results.
The extra 100+ wheel horsepower is going to happen, sooner or later :)
Thank you for the comment. I struggled myself to find the correct information online so that is why I decided to put together the video. I have since done the heads, big cam, headers etc. and have racked up about 10k more miles on the car since I did the work. She runs great and I feel confident in the engine now. Check out some of my other videos if you plan to tackle the heads/cam yourself. hope they help out. cheers!
Great video! What was the outcome and shop used for the guide work? Replacements all stock or upgraded heads?
Texas Speed did the heads. new exhaust valves, polished intake valves, bronze guides, dual springs, ported and milled. the rest of the build and others is on my CZcams page
They do make dial indicators that have longer reaches, so that you can check for movement down into that base of the valve guide. Great video though!
longer reach isn't the problem, it's the angle. dial indicator needs to be at 90 degrees. you can't achieve that angle. it's too acute.
@@southfloridagearheads6504 I own some that work at a parallel angle as well. Been a machinist for 40 years. They do exist!
@@valleypivot you can't measure anything with a dial indicator being parallel to your work. a dial indicator needs to be 90 degrees or perpendicular to the work. that is why I'm using a test indicator because it can accurately measure at a more acute angle than 90 degrees. I explain the math at the end of the video.
Glad you caught it before it Blew up...
Still running strong 2+ years later
Great video and info.I don't think I'd take the chance, good or not,I'd have the work done,,,can't trust the factory hardware.
yes best to pull them and send them to be reworked
Quick question bud!
Just got a 2008 Z06 with cams, intake, exhaust and headers done. Also exterior and interior work done but that’s besides the point. I talked to the previous owner and he mentioned the original owner was not cheap about anything on the car, (which is obvious.) However, he nor I are exactly sure if they heads have been touched.
Considering the motor was already out and opened due to the installation of cams and how much has been done to the car, would it be safe to assume the heads were worked on as well? How much do you think it’d be for a shop to check them out?
I would expect the heads have been done if it has a cam in it. No way to know for sure though. Unless they are aftermarket heads with the company logo on the front side. Factory fixed heads are hard to identify from the outside. Im suprised with that amount of work you didnt get a build sheet or receipts. I save all the receipts for the stuff on my car. No plans to sell it but im sure a new owner would like to know whats done buying a modified car. Im not sure who in your area would check them or even know how to do it properly.
Don't always assume it's the guide, although it is the weaker link of the two. Checking a BBC (heads off) I found one valve out of spec. I switched a valve that checked good on it's home guide and it checked good in the out of spec. unit. Mic'ed the stem and it was undersize. So in this odd situation it was the valve stem and not the guide. FYI
Good point it can be the stem. I have not come across that but good point. Regardless, new valves and guides would be the smart play.
Did you go with an aftermarket head, or just install new valves and guides? I want to get my 2012 Z done, but have read that some feel that fixing the stock heads may not be a permanent repair. Let us know what you have done, what parts you used, and if you had any excessive clearance return?
Thank you!!
You can watch more of the build here.
czcams.com/video/6wb0qL4uTWY/video.html
I had texas speed rework my heads. about 10k miles on them now. plan to recheck them soon to see if the fix is permanent.
Great video what heads you going with ?
I am about perform this test on my Z06 and was curious as to why you disconnected the air pressure after removing the springs and retainers. Isn't the point of the air prssure to prevent the valve from dropping once the retainer is removed? Thanks!
if you put the piston at TDC the valve can't really drop valve will just sit on top of piston. and you need to allow the valve to come down a small amount off the valve seat to "rock or wiggle" the valve. so you can't do that with the air on.
Can you redo the test measuring at the wrong (higher) point as compared to the correct location and tell us the difference and also post the conversion formula for those who measure at the higher point?
I have plans for another wiggle test video. The car almost has 10k miles on the reworked heads now so I will do another check on the guides and see if this is a perm fix or not. i will include the measurements for the wrong position to compare.
I have read that GM admitted that they got badly machined heads from 2008 to 2011, where the valve seat inserts were not concentric with the valve guides. This misalignment might have caused excessive lateral forces on the ends of the valve stems with corresponding wear and then valve wobble. I could see the resultant exhaust valve leaking causing valve overheating and then failure, especially being a hollow sodium-filled valve. Whenever I've done valve jobs I've always lapped the seats and used a dye, like Prussian blue, to view the seating ring on the valve seat. I have to wonder about GM's QA practices where this would not have been detected during the engine assembly. A misaligned valve seat insert and valve guide would have shown up as a nonuniform dye ring on the valve seat.
yes that is what I have read about the issue. I have blue checked valve seats/discs after lapping on old navy steam ships! But who knows what kinda QA checks went on. And the problem would only get worse over time as the guides wear and there is more play.
Toast..... also the .0035 how does gm call for the way the stem to guide measurement is taken
Here is the best write up on how to do it. Basically what I followed during this test. www.corvetteactioncenter.com/specs/c6/corvette-ls7-engine/ls7-engine-valve-wiggle-test-1.html
Thanks for your vid, very helpful! Do you think an ls7, that surived a higher mileage without blowing up increases the chance of not having the valve drop issue? My `10 Z06 now has about 50000 on it without ever being inspected.
@@southfloridagearheads6504 Yeah I think you`re right. I´ll better get the heads checked and replaced if necessary. Thanks for the advice
I ended up going with AHP heads and replacing them on my Z28. I didn’t want to take any chances. I kept my original heads. I might send it to them to have them reworked.
How much all the cost and labor for purchasing and installing these heads if you don’t mind me asking..
About $5200.00
HOW have the AHP heads held up?
Did you need to make sure that the piston was up so that the valve does not drop down too far?
@@southfloridagearheads6504 Thank you!
Does this apply to the current LS7 crate engines GM is selling? I just purchased an LS7 yesterday for a project car.
I think its possible with all ls7 engines.
Robert... Any idea what percentage of C6 Z06s have this issue?
It's also sad that GM never owned up to the problem. A class action lawsuit brought by C6 Z06 owners has been ongoing for about four years but seems to be going nowhere, which is too bad for all involved. On the plus side, you're definitely giving your car a new lease on life! I myself am driving an 08 LS3 car at present and may sell it to pick up a base '14 or '15 C7 a couple years from now.
Nice video I am just buying a C6 Z06 with 40k on the engine, so worried.
How did it work out ? Did you have any issues ?
I like that specification sheet,metric or english
i think it has both listed. LS7 service manual
just watched your video and now i'm concerned about my 06' z06 with 20k miles. not sure if this question has been addressed, but I heard there was a batch of guides that were done correctly (diff material) at the factory and won't develop the issue. have you heard this? i need to check the factory with my VIN to see if I have the lucky batch. do you have any info on this? thanks.
correct the problem does not exist with all heads. problem is there is no info on which heads/years/ vin it effects. or at least GM wont release the info.. because that would mean they would need to admit they did something wrong...
@@southfloridagearheads6504 It affects every year, its a ls7 design flaw, gm put out that bs to cover the ass that it was only the 2006 its every year. They wiggled out of having to do a full recall and redesign
21,000 miles. I am at like 13K. Love the attention to details
Thanks! She is up to about 30k now. Running good with the new set up.
After you fix the valve issue the first time how often after do you have to keep fixing or is it a one time fix..
one time fix
@@southfloridagearheads6504 how much was to fix that in your Ls 7 including the part?
Just assume your heads are jacked up from the factory and have them replaced. The failures are just to sporadic to pin point. I’ve seen 10k-80k and everywhere in between. If you keep rolling the dice. You eventually will roll snake eyes. And in this case snake eyes = 18k in damage.
It’s worse than that, because every time someone buys and sells one of these you need to do the test because are you going to take the sellers word he fixed it? Or it was done right
Thanks this made me skip out on z06 such a pos game for this reason only 40k used and need to spend more money to fix engine !!
Sounds great! That's totally stock? If so they sound much better than the other models!
I am in the market for upgrading my Camaro 2SS to a C6 and tempted on going with a Z06 and guess I will be adding head / valve upgrade to my purchase. Such a shame, but be nice to get that 7.0 :)
nice ride and great walk through!
So what would be the specific parts needed to fix the issue on a Z06? Not sure if it would be worth doing the work myself, once having all the necessary tools and two, it will be my daily driver. The big plus for the Z06 is all of them are manuals and that seems to be a hard to find with my searches. About 3/4 of the ones I have seen are Autos. Wouldn't be a show stopper, but would prefer the manual.
Yeah, once I get it the only things I plan on doing to it is headers and exhaust, a CAI and a Tune. That will be plenty of fun for my DD. I love the Camaro 2SS, but I miss the vette, had C4 in the 90s.
So the only tool I would need is the valve compression tool? Or would I need that if I just take the heads off and take to a shop just have them fix everything and then bolt back on.
IF that is the stock exhaust I am not sure i would need to do anything to the car actually. That sounds like a Vette should. Guess the finally let the Z06 breath compared to the base Corvette. Would you happen to know if the Grand Sport sounds better than the base?
To buay something like this is like self-torture to count.
What you should of done was check the guides when you bought it, and had the dealer cover the costs ..
Where are you located in Palm beach? I’m in lake worth....
this is an old video from my old house. im in Fort Lauderdale now
The stock powdered metal guides just don't work with 1.8 rockers. The ls7 1.8 is just to much. My ls3's don't get even close to that bad with 1.7's. Even with a roller cam and .700 lift springs. When I go to an ls7 head Ill be running roller tip rockers.
Whats heads did you end up going with? Debating on going with Katech or RPM
this build was Texas speed. last build I did was RPM spec done by AI. can also do Frankenstein
@@southfloridagearheads6504 Last build? Did the A.I. heads fail? RPM swears by them.
@@paisley2342 no, this car is still together 10k miles or so since the work was done. I've built a few others since then. the last one had AI heads from RPM.
@@southfloridagearheads6504 what heads seem the mkst reliable? I am looking myself.
@@paisley2342I really like Frankenstein. I would go with them if they are in your budget.
Are you measuring side to side movement at the tip of the stem with the stem hanging out of the head? If so...cant do it that way..
Not sure what you are asking, but its pretty clear in the video how I took the measurements.
@@southfloridagearheads6504 I cant see in the vid but if you are taking the measurement at the tip of the stem and the stem is sticking out of the guide the measurement will be way high. Checking on the spring end is kinda bogus anyway. If you measure side to side at the tip of the stem with the tip barely sticking out of the guide you did a great job, measuring stem to guide clearance at the very top of the guide....The part that matters is the head of the valve. That vid i linked, the top of the guide clearance was out of factory spec by a thou or 2 but the guides were worn on the other end. was the stem/guide clean and dry when you took the measurement? Oil film makes a difference. You said you could not feel anything on one of the valves? Clean and dry, if you cant feel anything you need to have your feeler checked...i can "feel" down to .0008. GM says the problem is bad machine work...the engineers at gm are plenty smart, i was a gm service tech for 15 years...they are not always truthful. A crooked valve guide can cause a head to break off? Ya, maybe if the valve is not quite as good as it should be..Your car fall within the build numbers that gm says might have the problem, fix it...outside..i wouldnt worry.
You have any starter problems? my buddy has a 13 zo6 and the starter shit the bed at 6k miles..we live in lake havasu, hotter than hell in summer, gm mounted a cat 2" from the starter and cooked it, new starter wrapped with insulator and a heat shield. I made a hard run to parker and back, got it good and hot. it was 115* and i let it idle with the ac on..no problem....and if you ever push the clutch pedal to the floor and then the pedal doesnt work send me a message, i tell ya how to fix it...
@@blackbirdxx928 This is the proper way to check the valve clearance so i'm confident in my findings. This is the write up I used during the test. Maybe this will answer some of your questions.
www.corvetteactioncenter.com/specs/c6/corvette-ls7-engine/ls7-engine-valve-wiggle-test-1.html
This video is also almost 3 years old at this point. I had the heads re-machined about 10k miles ago and put a cam in there while I had the car apart.
Never had any starter related issues and the car runs long tube headers with no cats. Also no issue with the clutch sticking. Factory clutch with 30k miles.
@@southfloridagearheads6504 The proper way is to remove the valve, measure the stem, measure the id of the guide with a bore gauge and do the math. That is how its measured as per GM service manual...But it doesnt really matter...loose valve guides dont break valves...aint gona happen....and GMs story about poor machine work...like how can the seat not be aligned with the guide if the guide is used as the center line of the tool? Understand that i have a bit of experience with this stuff...i usually do shortblock assembly, big inch blown/turbo offshore stuff but if the boss is busy i am perfectly capable of replacing guides and seats on the $60k sunnen.....i did make a few calls to some people....yep, valves dont break...except for those....poor quality....why, after all these years could gm forget how the make a valve. Its the last part that you want to break...much more damage than a broke rod bolt...the answer? outsourcing parts...no need to say where..other than not canada or mexico...back in those days a lot of aftermarket crankshafts came from there...stuff that never failed before was having problems...passable machine work but who spends $3500 on a crank and sends it out to see if the 4130 stamp is real....yep, real stamp, not real 4130....GM will never admit it, they cant...you guys with vetts would eat them alive...at least GM is able to track what cars they put the junk valves in, i have a buddy with a 13 zo6 with 7000 miles and was scared to drive it...i double checked and it wasnt a problem build...he is old guy, drives like grandpa..has no idea how hard the car runs..told him. i brake, i fix..you buy parts...the rubber from the rear tires has been there for a year...anyway. your car, your way...i know all about corvette owners, i worked at a shop in the mid 80s all we did were vetts...15 years GM service tech, 5 of them at Cadillac. Fussy people..all of ya...lol...now i do boat motors...most everthing that goes out is show quality outside, best money can buy inside...you familiar with oakland roadster show? years ago my boss won...with a boat..and it wasnt a show boat it was a full on 240mph drag boat..
@@blackbirdxx928 yes, but the measurements come out the same. Ive done valve guide ID with a bore gauge and valve stem OD, and the clearance comes out to the same value as the "wiggle test" value. Ive done this same trial on numerous different heads and manufactures. And the valve stems are hollow sodium filled so they would fail easier then a solid stainless valve. Maybe that was their big problem. Trying to get fancy with a hollow stem valve for better heat transfer but they were not made well enough to stand up to 7k redline. Big boat guy here. I run a marine diesel shop in fort lauderdale. thanks for the comments and idea sharing.
Get your engine oil analyzed for titanium. Earliest alert to engine grenade potential. No teardown. If you own a C6 Z06, Send oil samples to Blackstone Labs $35. Cheap engine insurance. I did, from 18,000 to 22,000 Titanium increased significantly. Blackstone suggested I get the heads checked. GMPP would not pay for inspection. I authorized the removal at my expense. GMPP then paid for new heads, valves. Gaskets and labor. No kaboom LS7!
Oil Analysis is a great tool to use to see what is going on inside your engine without opening it up. Especially if you have enough data to establish a base line and have a trend to look at. That is great you got the issue fixed under GM's dime. Although, new factory heads would not hold up with the plans I had for the car. So catching the problem early enough and sending the heads out to be re-worked was the best action. I got my heads ported, milled, bronze guides, new SS exhaust valves, dual springs, TI retainers, viton seals.
Dennis Murphy. Oil analysis is a good tool, but it wont help on the exhaust guide/valve stem wear. Because only the intake valves are made of titanium. From my experience, the exhaust side fails more often than the titanium intakes do, although the intake valves also drop. Nobody has a definite cause, as there are a lot of variables. When I do mine, I'm going with Ferrea exhaust valves. Pricey, but one of the best.....
Milo. I can tell you, my oil analysis was recommended by my tuner. The analysis folks reported elevated titanium. It was a signal, I heard noise valves after a hard run had the oil retested and titanium was way up. I had to agree to pay if the teardown didn't show any problems but I was confident with the noise which they could not hear and the oil testing that it needed to turn down. Its saved me and gave me proof of the part failure going on. It may not be perfect or catch it all, but for $30 it's a great tool and knowledge set to have on a Corvette engine. My repair was $7,000 on GMPP. I paid an extra $900 to drop the oil pan and pull out the rocker roller bearings as well. D
Mine were out of spec with 16xxx miles on my car
It is a shame of GM to sell such a misconstruction to the customer...:-( I would like to buy a z06 here in Germany and I hope that I find one, where everything is already done... :-)
Great Video! Thank you!!!
Yes that's true! The Z06 is a great car and I can not wait to finally buy it... :-)
What exhaust setup are you running here?
Just a Corsa sport axle-back and a K&N intake
@@southfloridagearheads6504 Wow, sounds great for just an axle back!
Does the problem keep appearing after heads are changed? Or is it gone?
I will let you know, plan to check them again at 10k miles on the new heads
@@southfloridagearheads6504 are the heads the only issue with the car? Or are there others
@@jamesreeves4600 from my experience they are great cars. Ive owned mine for 5+ years. It's very modified now and I still have driven it from FL to NY straight without any issues ( just a few stops for gas) Only thing ive had go wrong is the key fob transmitter went out so I have to put the key in the slot in the glove box. I love the car and would never get rid of it.
@@southfloridagearheads6504 Thank you for the replies, keep posting!
@@jamesreeves4600 Check out some of the newer videos if you are curious about the c6z. we have tons of engine work, clutch swaps, etc. Thanks for the comment!
Question....will most used car dealers perform this important work on an 07 corvette if asked?
I would take it to a corvette shop that knows the proper procedure.
@@southfloridagearheads6504 thanks dude.
Personally I do not, I do however inform the buyer of this issue so there are no surprises. I get buyers that want to buy these stock so they can decide exactly what head work they want to go with and I get buyers who want it already done regardless of what head work the prior owners went with.
@@fb6_avery912 thank you so much for honesty, sir.
So how much does it cost to repress the guides?
texas-speed did my heads. Port, mill, bronze guides, new SS exhaust valves, recut and polish intake valves, dual spring kit, TI retainers, viton seals around $1200. you can go more agressive on the porting or milling, upgraded valves, etc for more money. check out the install video czcams.com/video/6wb0qL4uTWY/video.html
@@southfloridagearheads6504 that’s not bad at all
Is it true after 2011 they were good?
Im not sure about the years. I remember back when I was doing research on this GM claimed to have fixed the manufacturing issue with machining the valve guide concentric to the valve seat but I don't recall if they published a date. Might have to dig through the old corvette forums. If it were me and I was buying another c6z, I would pull the heads and have them done.
What city and state are you located?
@@southfloridagearheads6504 nice, I got a 08 c6z, pretty much all stock besides muffler delete and tune, previous owner had a new motor installed by the dealer under warranty, due to the value guide issues. He even gave me the receipt for the work done, the thing is I'm not sure if they fixed the guide issue on the new motor, or just a simple motor swap, what do you think? Btw the receipt didn't say much about what was done to it...
@@southfloridagearheads6504 it was like almost $8000,according to the receipt. So I'm guessing just fixing the problem without doing a complete swap, I've always liked the chops from a big cam, I'm from California the bay area to be exact, so far I haven't found any shops around here that can get h/c , done. There's a shop in Livermore California but it's like over an hr away from me. Man I wish you were in ca so you can get it done for me lol
@@southfloridagearheads6504 nice, looking forward to the new video 😎
This WORRY me
I’m currently looking for a c6 z06 and it’s pretty hard to find one for a fair price considering that I’ll just go ahead and upgrade the heads. How much would a heads and cam swap cost in just labor?
Robert Fletcher what would the cost for parts be? I’m assuming about 5k?
Just looked at the Lingenfelter 630hp package... $12,046. Heads, cam, intake port match, long tube headers, tuning. Very tempting to DIY!
What spoiler is that?
its called the zr1 extended. got it from c7 carbon
WHATS THE SYMPTOM SMOKING?
no symptoms from my car. ran fine, no abnormal noises or smoking. Really hard to tell when is going on without taking the measurements.
Can someone tell me the operating temperature on a car like this?
195 is normal temp
I believe c6 and c7 have the same ENGINE. Can tell me.
SHELL I buy the c7 zo6
What rear spoiler do you have on the vette
It's call the zr1 extended spoiler. c7Carbon is where I got all the aero stuff for the car.
@@southfloridagearheads6504 thanks. It looks great on there. Beefy but not to much either. Well done
cant blame you because the ls7 is a 15 thousand dollar motor just being stock
not worth the gamble
Your lucky that thing is still in one piece.
Really pisses me off GM never fessed up to this issue.
yes I agree!
Don’t buy replacement GM heads. If you have a reputable competent aftermarket specialist like Lingenfelter rebuild your heads with superior aftermarket parts the issue won’t come back.
You should blow that carbon monoxide outside the garage, NOT inside.
Bring money no problem.
Until you take the heads off and you say "well while im in there" and start racking up the parts haha
Hi that not the answer you have to pull the heads do the valves and valves guides to do it right other wise it’s $22,000 good luck
It seems like you didn't watch the whole video. this was simply an inspection to see if there was any issue with the valves or guides. obviously, with my measurements, the guides were out of spec. the heads were pulled in the next video and sent out to Texas speed for machine work.
That does not work. Have them redone do not take a chance. It happened to me no more GM products
What "does not work"?
Also , put i the title, if you're going to wiggle test then just rebuild your heads...
If I bought another 6cz Id just pull the heads and have them done from the start. Not even worth the time to take the measurements IMO. Just have them done from the beginning
Disliked because its impossible to hear you talking and then you put super loud music in it
Sorry to hear that. This was one of the first videos I made and filmed with my phone. The audio could certainly use some work. Hope you are able to find a better ls7 valve guide video to help you out. Cheers!