Cam timing for REAL power and the automatic cam degree wheel
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- čas přidán 29. 08. 2024
- In this, episode 73, DV goes into the techniques he uses for getting the cam timing right for max power and that is rarely what the cam companies recommend. There is cam advice in this video that DV has learned from literally thousands of test, This means there will be tech info for pro's as well as home builder enthusiasts. Miss out on this and you will loose what can be described as universally applicable cam timing tech.
I was today years old when I heard of:
A) "spark scatter"
B) "tolerance stacking"
Anyone else feel like your caring relative is teaching you like a dad or granddad when he looks right at the camera?
Thanks, David Vizard!
Back in the day David's 2L Ford/Pinto book was my bible.... I thought he was a yank. Turns out he is a pommie grandfather expert. Kudos and love to DV.
I've worked out that I'm different from every other engine builder. The very first component that I put into the cylinder block, is the cam. I always put it in with the block upside down, or vertical, so I can control both ends of the cam at the same time. After that, I put the crankshaft in etc.
A cam install tool and a coated wire works from the top😁.
Cam in first is technically "by the book"! (I guess it depends on the book, but it was in my basic engine building book years ago). Cam first is the way to go. I haven't tried it on the ground yet, but I've heard of other guys doing it that way and I imagine the fastest way to get it in without scarring any cam bearings.
Yes that's definitely the way to go.
Corvair engine blocks have two halves with direct gear drive. No chain. Assembly step 1? Crank & cam go in together, gears must be in perfect sync or you'll tear it all apart later.
Cam first and block upside down is usually how I assemble.
Almost every shop I worked for always had a crotchety old timer working there. I found those are the ones you can really learn from. They know things no school can teach.
David, I have been a heavy diesel fitter for over 45 years and I just took a master class in cam timing. never to old to learn.
That comment is out of utmost respect and gratitude of Mr. Vizard. His informative and knowledgeable videos are irreplaceable. I would be honored to meet David Vizard . Thank you sir for your library of knowledge.
David, I have several of your performance books over the last 50 years. You have taught me many engine building tips. Your books are my Bible and my go to. ( I am religious and do read my Bible) also. I have enjoyed many hours of your videos and you will continue to entertain me :)
That "double decker" timing wheel is pretty slick. 👍
Thanks Mr.Visard, again you confirmed that I have been doing it correct for many years. I build 10 to 12 custom engines a year, and even though I am using top quality parts, I still find 30+% of the time I need to make corrections just to get the cam timing where it's a good starting point. The rest of them typically come with in half a degree. I have been helping a couple of long time friends with their engines and when they see the time involved and the effort it takes to make parts work together that are engineered to work together but don't, they are starting to get a bigger picture. I give you some of the credit because of your books I had a jump start on many, and also because my Father instilled in me the desire for excellence and detail, my engines generally perform above expectation. Thanks.
This was an interesting video and i did enjoy it. However, as others have stated, the outer degree wheel was at 88 degrees, not the stated 92 degrees. At 29:31 the 88 degree mark on the outer wheel was aligned with the 91 degree mark on the inner wheel (remember, the inner wheel is 1/2 degrees per graduation). The entire wheel is then rotated to the 130 degree mark on the outer wheel. While the wheel is being rotated, notice that at 29:45 the outer wheel 88 degree mark is now aligned with the inner wheel 90 degree mark. The inner wheel had been moved relative to the outer wheel. When i first watched the video, I couldn't make the numbers reconcile (the outer wheel advanced 42 degrees while the inner wheel advanced 20 degrees, somehow ending up at 111 degrees to match the math done earlier in the video), but this explains everything to me. The lobe center line is at 109 degrees, so now i can sleep tonight:)
The dual degree wheel seems cool at first, but it only appears to do the simple math of adding the two degrees and dividing by 2. If the guy who built the wheel can't make it work, how will we mere mortals do so without error?
Good catch and explanation.
8:00 - - as a SBC lover I can hardly watch while people cram the camshaft into the block.....I tip the motor and stand over on it's back and glide it in vertical with no fuss or banging.
I've learned MUCH from you David, thanks !!
Same here. I let gravity work with me. Not against me.
I have been reading your books and articles since I raced Mini's 30+ years ago, thank you David for putting the effort in and producing these videos, simply the BEST information available...
We have found a differance in degrees between a dial indicator and a solid piston stop , so we use the solid stop.
When using a dial indicator, you still have to go to either side of TDC and find the average, just like you do with a stop. This is because the piston will dwell (without moving) for many degrees at TDC (during the connecting rod rollover) although the crank is still rotating. Using one that way, a dial indicator is just as accurate.
The bumper on the piston stop needs to be in the center of the piston to avoid piston rock messing up the distances.
I have a Milodon gear drive for my build. The idler gear is to the side for adjustment of backlash. The cam gear is slotted for timing adjustment. If an engine get align bored and the center to center distance between the can and crank centerlines, this set up will adjust for it. It comes with a Torrington bearing, case and all hardware. Not an inexpensive unit. Harmonics issues are supposed to be more than with the used of a chain but the timing is spot on and no cam stretch. Milodon claims it can handle high rpm.
A friend uses one in his 5.90ET blown BBC dragster. Revs to 8500 every pass
Thank you so much David for sharing your years of knowledge and making these videos for us all to learn from.
How many of us have heard
"I bought xxx off the shelf cam and it didn't make the power promised"?
Is this the reason?
Even with custom cams having the chance to be off even a little, makes perfect sense why any decent engine builder talks about timing their cams on their instead of trusting the card.
Hey DV I hate to point this out but the degree wheel reading was 88 NOT 92 and both scales are reading in the same direction. So the ICL was actually 109 NOT 111.
Thanks for pointing this out! I had thought it was just me imagining things!
Man, I had to watch this so many times over and over and I still don't quite it. I'm a hands on guy, so probably after a few times of performing it..? I also do not believe you gave us enough information at the end on what to adjust the gears to. You keep telling us things like - it will be in the next video, but then it comes too much later, and I have forgotten.
If one had a rotary table, you could use that on your mill, and with a milling / sanding bit, and could remove a few thousandths out of each crotch on the crank gear. That way you could really dial in how much "slop" in the chain one wants.
Rather than using a hammer to offer the gear on the crankshaft snout, I've found it much more gentle to use the crank bolt or a press, accounting it has plenty of threads to grab in the snout and pending press tolerances for fitment. Same goes for removing the timing gear - a puller is a must for not damaging the cam with a hammer.
Please keep up the GREAT videos!
Yes to Zoom. We all want to learn from the man who made a career out of having fun.
That's awesome 👍 I love to have one I've been battling by ear and smell for years tuning cars always new that there was a perfect spot to set the timing got close but never dead on that's pretty neat 👍
You probably have forgotten more about horsepower than most will ever learn. I'm more into gaining hp on a old Triumph motorcycle..... but this was a GOOD vid
I have a 67 BSA Lightning that I would love to hop up!
@@alleyoop1234 Going to try to apply this to my Bonneville....
@@kevinsmith1044
triumph twins are readily tuned
and sweet when balanced
i had a greenwood 1950s iron motor t110 very quick and uncanily smooth , lightened polished , 10mm centre plugs single 32mm amal on long tapered manifold
Still as confused as ever..
I'm sorry, do you have a even simpler explanation of the cam timing?
I must be missing something.
I grateful to have this lesson from a legend.
Timing a cam using intake center line is good, I also use the valve open and close timing to set my timing of the cam.
Unless you time the cam in on the dyno you are ony useing the less than inspire guess of the cam manufacture.
I gotta say, I really enjoy watching and learning, but the more I do, the LESS I want to try and mess with my engines because I realize I don't have the right equipment and I truly don't know what the heck I am doing! It feels like leaving it stock is the best bet!
Boost your stock engine
@@Ws6Ms Yeah, but then I gotta worry about tunes and all that. It really feels like a hassle. I have factory turbo engines and I love them. My truck is the one that is N/A and as I analyze my use of it and what I need...it just doesn't feel like it's worth messing with.
Probably a good call however if your feeling spendy, there is the old Paxton style units that lend a helping hand while towing up a hill. I have NA diesels that I wish to add turbo to; not because I want to rock my world but in that they just work better with any kind of boost and especially at higher altitudes. I’ve head the story of the backpack blower added to an old 2 stroke diesel to get it over the mountain passes 😆, sounds plausible.
I have done builds, the first two were within 1 degree.. the last one I did on an LT was 5deg off.. So your right, used to think it wasn't worth the time, but I was wrong..
I've read books from the early 60's, the late 60's and the 70's, with different theories on cam timing and power. They knew early on that advancing a cam would increase cylinder pressure. The oldest theory I could find thought that a cam had maximum power potential if installed straight up and this was back with lobe separation was usually fairly wide. Then they could didn't know why power often increased with the cam advanced. The next theory in history tightened lobe separation, but still held that straight up could produce the most power. The close lobe separation often did make powder, but when straight up, the intake lobe is closer to the ideal position, compared to wider separation. So a 112 LS straight up would put it at 112 degrees and 108 LS would put it at 108 degrees. Still often advancing the cam would often still increase power. The final theory from the late 1970's I found was, the intake lobe at 106 degrees made the most powder and at 102 degrees made the most torque, REGARDLESS OF LOBE SEPARATION. If power was better retarded, the cam duration would be considered smaller than ideal for maximum power and it required being advanced more than 102 degrees, the duration is larger than ideal. That late 70's theory often still holds up well.
We use a phillips head screw driver in one bolt hole to move cam slightly to line up gear with cam then install bolts.
Good job! That is why I always degree my cams
i usually timing my cams to inlet lift @tdc first. All cam grinders have that spec on their cards. Then check away.
Excellent video thank you for sharing your knowledge
I once forgot the loctite on a Ford 302 cam bolt. I assembled two engines back to back, and of course the one I messed up was the one in my car. Driving along and it quit. No spark. Finally figured out the distributor wasn't turning, pulled the cover and the chain and gear were just laying in there.
id rather that happen to my engine, then a customers.
@@northernlits425 oh absolutely, didn't stop me from feeling like a dumbass though. Few years later I pulled the cam for an upgrade and 5 lobes had deep grooves plowed in them from the roller not rolling. They cracked at the roller axle when the cam slid back and the neighboring lobe smashed into the side of the lifer. At least it explained why the engine had gotten so noisy. New lifters, new roller rockers, and proper length pushrods made it happy.
I always tell people that I just met that im a firm believer that a man has a right to say what he is capable of doing or what he knows without someone saying he is a bragger! As long as what he is saying is accurate or he can pull off what he said he could. If his word didn't pan out that is unexceptable! But if he fell short after giving his best i can overlook that due to the fact he tried his best and he is only a man and i myself have come up short of what I thought I was capable of.And a good man won't beat you over the head with your short comming. 😉
Love that cam wheel! I have a big blue single wheel.
Well done, as in every video! Thanks !
I am working on a vintage 1991 Chrysler 3.3 L V6 build. It uses a Cam Sensor that senses notches in the cam sprocket for ECM injector timing. If I change the angular relationship between the cam sprocket and the camshaft, the cam sensor will still read the same timing notches, but the cam will change the valve timing. I am guessing that would not work. I will have to do the timing changes by cutting additional keyways on the crankshaft gear similar to the Comp Cams gear David uses in this video.
I'm cringing when you're calling a 91 Chrysler 3.3 a vintage engine. Now I'm feeling old LOL
Unless it's direct injection, injection timing is not all that sensitive. I had a customer running an engine on a dyno with a mechanical injection pump 180 degrees out. They said correcting it made no difference. I think it might have had better transient response but they weren't looking for that
Your very good at this thank you for sharing 😊
I have a 85 stock 302 f150. About 20 years ago I installed a comp cams 270° at .51 lift. Nowadays I see nobody using a cam with much less duration. Have I got the right hidrolick flat tappet cam? Is mine old incorrect tech? Should I advance the cam 4°? Oh its 040 over if that makes any difference besides it being a 308ci.
Excellent lesson. Thank you.
I was lucky to be led to D V when a friend turned me on to the Vizard street ram in I think 1980.
It’s great that you’re sharing all this knowledge I remember my mini days & anything from Vizard was the golden rule. Can you do a video like this for twincam engines & compare any differences between chain & belt drive??
Twin cam engines use all the same principles, the difference is you have the ability to advance or retard the intake and exhaust centerlines independently, which could be used to affect lobe separation angle and valve overlap without having to get another cam. As for chain vs belt, a chain is stronger and requires less maintenance, but it makes more noise, requires lubrication, costs more, has more rotating mass, and transfers more harmonics between the valvetrain and the rotating assembly and vice-versa; a belt is quieter, transfers less harmonics, has less rotating mass, doesn't require lubrication, and is cheaper but requires more frequent maintenance and isn't as strong.
Good explanation.
I'm all in for a Zoom that suits Australian users in Australia. I mentioned it on the old channel to ask if you would do it.
same here count me in Sunshine Coast QLD
Sounds very possible.
Plus to that.
Plus to that. Melbourne Australia
It seems to me that David avizard is not using metric sizes.
Thank you David
If I want to buy a comp cam with one of your designs/specs, how do I do that ?
Can I buy a cam from you or how does it work ?
Also I know that the 128 formula is only correct for just one csb combination.
I assume you will not share the whole comlex formula that this came from. But I work with so many totaly different setups so It would be fantastic to get recomendations on LSA for a given setup. Just now I work on ported TBI swirl heads for a heavy truck that need best torque and power and I have no clue what LSA to use.
What if you do a cam recomendation calculator on your website ?
One that give a good recomendation on camspecs and also mayby recomends a existing grind, or if no cam is good enough, print out camspecs that can be sent to a cam manufacturer.
You cold charge for this service. Or even better, order the cam and sell it to customers after calculating from customers need.
To bad I could not go to your seminars. I live in Sweden so it was a dream not possible to achieve.
I have a Moroso 20 in. degree wheel bought it back in the early 90’s
It's time to find a flow bench DIY kit. I did do some searching but until now no kits could be found.
- Are kits on sale somewhere?
- Are the right parts needed known.?
Performance Trends' *"EZ Flow System"* probably does what you're looking for.
David, when I looked closely at your degree wheel (approx 33:06 mins into the video) you were talking about 92deg but your cam wheel was reading 88deg. The pointer was 2 notches on the 80 side of 90 on the outer ring.
I’m new to cam timing, so I’m not trying to correct you but I can’t figure out if I’m reading something wrong or did you just make a mistake there?
Averaging 88 and 130 would then give an intake peak position of 109? Still off but not as bad as first thought. Have I got that right?
Richard
You are correct
Thanks for the video, although I feel we only received have of the procedure. You didn’t show how to adjust to the correct degree. I can figure it out but some people may be lost.
He did by using the keyway in the crank gear and using the adjustable cam gear to get it where it truly needs to be.
please discuss Dynamic compression
Static comp is the CC of air the piston pushes up the bore to tdc..WITHOUT RUNNING (just math) with static, it can, say be less with bleed-off from a big cam with alot of overlap/headers, open plenum intake, big carb, etc..CHANGE to a smaller carb, header, cam overlap & dynamic comp (spinning engine at rpm) will increase.. Smaller cam/carb headers makes more torque at lower rpm. You can make the same numbers(probably more) with bigger cam/carb etc BUT at a higher rpm. Maybe someone can explain it better. Basically if you can put more air into the engine it'll have more compression.. the vacuum signal an engine pulls into the cylinder will have less Dynamic compression at 2000 rpm than say 5 grand.. air pulled into the cylinder likes to pull more air with it.
As soon as i started watching i could tell you know your shit with this subject and subscribed.
Im attempting to build my first LS1 engine in my 2001 VX GTS300 Commodore callaway engine equipped sedan could you do a cam timing video the ls1 engine please .. thanks mate from Australia. 👍
Decreeing in cams is easy and very essential for a performance application! Cams and gears are never ground 100% perfect.
Love the channel very interesting points question to you is what are your thoughts and experience on gear Drives
Greg Anderson how we do it. Sheet metal intake manifold. 260 260 SUMMIT
Using a roller chain for least noise? A Spock would say "this does not compute"
David,
Please do another video and go a little more in depth on the degree wheel and dual degree wheel.
When you said you are at 92 degrees on outer wheel it looks like 88 degrees to me. Then yousaid you set the inner wheel at 92 but it looks to me like you set the inner at 91. Since there is 20 ticks on inner wheel each tick is half at degree?
Thanks.
Thank you Mr David
I have searched for " dummy lifters " and cannot find any. Does anyone have any information on these ? Thanks.
Great job explaining how to find the camshaft centerline and how to change where the valve timing starts. But this does not explain how to figure out what the particular number is that you need. So, this is only half the equation.
I would love to know how much difference in cam timing the stretched chains made. I've also recently had trouble finding timing chain sets that are nice and snug like they used to be before everything moved to China.
Snug is a problem dv has a video talking about it
It wouldn't make any difference if you're degreeing in the cam, because you always take the slack out by coming to your number in the direction the engine actually rotates while running. If you have to rotate the engine backwards, you go past your number and then come back to it in the forward direction as he did a few times in this video, he just didn't explain it. So effectively there is no slack in the system when you time your cam, whether the chain is stretched or not.
Well Done!
Thank you for all the great videos have learned alot from you i usually time mine in at .050 you set this in at .080 what is the difference
In this case it doesn't matter, he just picked an arbitrary number (.080" was .020" down from max lift) to use on either side of max lift so as to find the intake center line by averaging the crank degree readings, from the same point on either side of max lift. As long as it's the same amount on either side of max lift, the actual number doesn't matter, you're just finding the center line.
Why don't they manufacture the camshafts with an extended leading edge taper on the journal to make installation easier?
Hi David 👍 check out the Aussie made Higgins cyl heads. Beautiful things. Cheers old son 👍🥃🇦🇺
That is slick!!!
Lady's and gentelmen may I present the amazing master of the internal combustion engine David Vizard the Wizard.
THANK YOU DAVID
Was the Adjustable Timing Gear set at "zero"? Also was the .02 for valve lash ? Thanks
Im trying to learn about building Ford FE 428 stock dish piston rebuild. The cams I see all list that they work in 360 low compression engine and also the high compression 428. See this at summit and other retailers. I sent a cam core to a custom regrinder for his recomendation. When I got the cam back the notes said static compression no more than 9 to 1. Well I told them it was for a stock 428 rebuild.. The cam I got intake valve closes at 38 deg abdc. Works for a 360 not for a 428 stock engine. Just pisses me off that All the google searches on people saying they build with high compression engines and run on pump gas. So much bad info out there. 99% of it is bad. FE sites on facebook are telling new engine builders to go 0 deck and flat top pistons. Just venting. I have a 390 I built last year with flat tops and now going to pull it apart and put stock dish pistons it. The cam will work in that engine. Retired now and wanted to build some of the FE blocks I have collected over the years. Just venting as I watch and learn
I would love to hear your input on boosted applications and camshaft lsa adjustments if any.
Chris - will get to that as soon as I can.
Asymmetrical cam? BVVC if you are trying for seat timing chk w/ camgrinder if .050 timing is used instead of max lift.
I'm a yes for the Zoom seminars.
I'm missing something but for the likes of me I can't seem to figure it out. I've purchased 2 of these adjustable timing sets but neither will bolt to my hydraulic roller cam. The bolt pattern is different. I called both places I purchased timing set from (jegs & sumit) and both said they don't have an adjustable set for a hydraulic roller. I will say that was after they sold me the timing sets saying that they would fit. Is there a part number for a set that will fit a hydraulic roller cam? It will be much appreciated if you do. The engine is sbc 350 (the vortec iteration, 880 block number. Cam is a melling hydraulic roller)
Dave , your deg. Wheel is reading 88 deg. Not 92. Then you set your inner deg wheel to 92. I think you messed up?
Is it me or is half the audio just static? Missed tons of info from the video 😕
how would this apply to a bmw inline 6 for example and S52 single vanos engine?
That’s what i want to build with all your insights. Thanks David. Loving all your videos
How can I check this timing on an already together engine ?
i would like to purchase you timing wheel
i line the dots up and thats about it,i guess i have been loosing hp.i would like to have a degree wheel,never had one
maybe, maybe not as DV pointed out sometimes things line up in your favor. I use the Cloyes 9way Timing sets and they have degreed in with less slop in both the chain and keyway than Comp timing sets (in Oldsmobiles anyway). My last "Dot to Dot" cam was 3* advanced when the card said 4*, that 1* is good enough for me, every other event was verified as what was indicated on the cam card (or very close to it). If you get a degree wheel get a BIG one, the small ones are harder get accurate readings, I use the Moroso one, you can make your own too with cardboard.
Did somebody build your degree wheel, May I have the contact info,and if nobody offered I would be interested ,
my eyes arent the best but i saw 88 degrees not 92....
88 is 4 degrees off, actual would put it at 107, which is right where David wants it. Unless I missed something with the dual degree wheel?
@edwardspaccarelli5944 107° is the LSA he was after during cam selection. During cam installation, he was looking for 102° for the intake center line for cam timing, two totally different things. Additionally, 88+130÷2=109, not 107. Although 88 is 4 less than 92, you have to average the numbers to get the center.
I thought this was going to be a video about Harold Brookshire.
What size tires and wheels are those
Damn, due to time differences, I'll be working. Gutted!!! Will have too watch it later whilst I'm having lunch.
Lunchtime now. Great stuff David
Im still confused on how we would fix the timing from the 109° to the correct 102°
Hey love you videos.. quick question just building a 383 sbc using a hydraulic Rolla Howard 110265-12 cam, WITH A 1.60 rocker ratio it should have 565/585, @.050" 237/244 ,scat 9000 crank. H beam eagle rods, single plane Team G Manifold, 850 quick fuel carby. 1.58 pipes Pacmakers, Dart pro1 heads 200cc/64cc 23° Aluminium Cylinder Heads, cfm 277 compression is around 10.80. how much power do you think this combo will make???
Probably real close to 575 hp if you hit 7,000 rpm
I thought you said let’s get too it?
You don't ever want to use a used chain on new gears or new chain on used gears chain and sprockets wear as a set.
And they will wear as a set eventually whatever combo is used.
That isn't as true on roller chains as it was for the older inverted tooth type of chains.
I find this was a poor explanation of what you're actually measuring here. From your description sounds like you are measuring intake centreline position relative to ????
Yep, intake centerline is what you use to phase (degree) a cam; so in this case, he was looking for the intake centerline to be installed at 102° of crank rotation.
Tell me about peat Jackson gear drive l know koud be bad on Harleys because of out of round on crank
ZOOM YES!
Moroso still makes it. I just bought one through summit and they drop shipped it to my house.
you shoud make them i bet you not verry many people wont know how to youse it.
where do I get the cam program?
Nice
I think a dyno is the best way to time a cam.
why do you use the thrust button on a flat tappet cam?
As the cam wears it could eventually walk towards the timing cover also erratic spark , less power, chain wear
The comp 252 cam (202 @,050) has more torque below 3000 rpm compared to a 268 given same lca which is a marketing, stocking consideration not performance. Compression was not optimized for each cam for this test. Difference is considerable
what valve over lap ?
The exhaust valve is still shutting when the intake starts opening - - both valves are slightly open at the same time causing exhaust to be sucked up the intake OR some intake charge (air-fuel) to be sucked out the exhaust.
I would like to know where exactly valve timing comes in dynamically even when compared to a perfect static unloaded measurement. How many degrees could be expected when accounting for deflection of parts under load? A couple of crank degrees?
wouldn't it be better to return the defective cam shaft?
I think the idea here is that even though the installed centerline spec is off he trusts that the lobes are the correct shape and that the lobe lift figures are correct. That’s why he measured lobe lift as .327 and when the spec was .326 he was satisfied with it. Returning a part might end up giving you better tolerances on one measurement but learning how to compensate for manufacturing tolerances means you can proceed to make the power you should and in a more reasonable time.
I would like to buy the rights to your wheel.
Zoom - Yes please