Do Your Own 3-Angle Valve Seats!
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- čas přidán 8. 04. 2022
- In this video we cover how to do your own 3-angle valve job on a Mopar Slant 6 head, but really it's the same for any engine, from a lawnmower to a big block. Doing your own valve seats really is no more expensive than having a shop do them, and with the quality I see out of machine shops today, I trust my own work far more than theirs.
Links:
Source for Neway tools (not sponsored or affiliated):
www.cylinderheadsupply.com/
For a slant 6, I ordered Part #'s CU234 and CU205
If you have a different application, the size guidelines are here:
www.newaymfg.com/cutters
Marking fluid: amzn.to/3uoUD2M
Lapping compound: amzn.to/3E0VES2
Lapping tool: amzn.to/3E0VES2 - Auta a dopravní prostředky
Ffs, just send it to a good machine shop and have the seat width, depth & angles finished properly. Honestly, we don't mind doing these jobs and it'll cost you MORE if you proceed to fuck it up and then ask us to fix it. Sheesh...
Absolutely! No one should even attempt to do things themselves any more. I mean why did I even tear it apart or assemble it? I could have just had someone else do it. For that matter why do I even drive a car? I could always just call a Lyft. You've convinced me! I'm getting rid of all my vehicles, just have to find someone to sell them all for me.
Plus, we can see the work the professional machine shop did with the resurfacing. Taking it somewhere doesn't mean it will be done better. It seems more and more it means it will be done worse.
@@damnimcooltom1 I bought a set for myself after a machine shop fucked it up in the first place, they didn't use heat to remove the guides, snapped one, threw an old inlet in to the exhaust side and called it a day!
Why send it to a competent machine shop? CNC machining. Depth of all 3 angles correct to head joint face, concentric bore and k-line of valve guides and superior surface finish.
Money well spent, and I get a kick out of doing the job.
Maybe, just MAYBE that is not an option. Machine shops around Boise are 4 months out. 'qualified staff' shortages' ........ And, dissing someone who is showing an alternative and effective DIY, shows your character and arrogance.
FINALLY, SOMEBODY EXPLAINED HOW IT WORKS THE RIGHT WAY. THANKS A LOT, I'M GOING FOR IT.
I've been a small engine mechanic for thirty five years, and I've had my Neway valve seat cutters for thirty some odd years. I couldn't even hazard a guess as to how many valve jobs I've done with them. Expensive, but worth every penny. If you do enough of this type of work, they pay for themselves in just a handful of jobs. They've literally earned me tens of thousands of dollars over the years, maybe more.
Awesome video, well explained.
Tearing down my fzr250, im up against the challenge neway mentions on their site...
Basically...
"Save your money, the cutter BODY wont fit"
Looks like i gotta make custom cutters to do a 15mm exhaust valve...
Meh. At least if i tool up i will probably be the only person that can do them...
Do love my neways... when theres room!
Thats Rash, learning the hard way... is just part of living. I'd highly recommend learning to cut seats with this process long as the guides are in good condition to start.
By far, this is the best simplest way to rebuild cylinder head in your garage, Thanks for the tips
These are a great tool, I use them all the time. Machine shops are not what they used to be. There's a very small number of competent machinists out there.
THIS !
And the competent ones are booked out for 6-9 months!!!
Undoubtedly, simple tool , but, definitely, great in value
Excellent video! Not only great, calm presentation, but perfect audio and video quality. Thank you!
The 60 and the 30 cutters do give you a more progressive flow pattern but their main purpose is to give a vale seat its correct width and its correct position on the valve face that is why you must have the valves you are using with you when you cut the seats. it is also very important with cutters like these that the valve guide is well within wear tollerances or your seat will be out of center or tilted. You also need to keep an eye on valve depth as undercutting seats leads to uneven valve spring heights and tensions. This is also very important when using new valves and new valve seat inserts because with some engines if you leave the valve sitting to high and have shaved the head the valve may hit the piston. This is more of a problem on heads with no combustion chambers like with most diesel engines. Gas engines with multi valve systems at more acute angles can have this problem as well. The valve seat shown at the end is to wide and that will work against flow rate.
Need to do this job and I found your video well presented. Also very well explained and told in good detail. Very easy to understand. Best video on the subject outhere.
Excellent video on how to use the Neway cutter system..They're right down the road from me in Corunna Michigan..If you've got a problem, they are always willing to help..Great bunch of people..
Well done...the calm approach is very appropriate!
We're never better served than by ourself, thank you for this precise and very informative presentation. Cheers from Geneva Switzerland
I purchased does cutter set in 1980s. I paid $1600 US. I cut the seats at 45 degrees, and the valves face at 44 and half degrees for best sealing
The 46 deg angle on the valve and the 45 deg on the seat is so that the valves and seat will slap into a tight seal for mass production. When I was working on the old VW motors. When cutting valve seats you can slam the valve in hard or just seat the valve and give a gentle tap. The valve will get a fine line on it so you can get an idea of the seat position prior to lapping/ grinding the valve and seat. It saves time from going back and forward from cutting and lapping. I have had a set of Neway cutters for years, wouldn't be without them. They live on the shelf and they don't eat much. Kerosene is a good cutting fluid and don't drop the cutters. Cars, Lawnmowers, motorcycles and most anything they can be used on.
Excellent video thanks so much for posting. And I can't believe I am saying this, but, excellent comments from viewers too! No BS just actual valid discussion about valve cutting. Cheers from Canada!
Great video, well explained with good visuals. Thanks
I used to teach this and video is probably better in most respects than the official Neway training video. (plus it doesn't have the 1970's background music)
There are a few extra things to check, seat width as mentioned by 'Flinch', seat position on valve face plus valve installed height
Seat width around 0.040"~0.060" (1~1.5mm) on intakes is normal with 0.060"~0.080" on exhaust side (1.5~2mm)
There is a general formula to calculate seat width based on valve diameter but maximum and minimum is generally in the accepted range (unless your doing a 'race tuned' 35cc Honda weed-whacker or marine diesel with 3 to 4inch diameter valve heads.........LOL)
For 'ordinary' engines, centre of face is good as it will give maximum life before replacement or reconditioning.
For performance, move contact point closer to outer edge cut 45 to slightly larger diameter then reduce seat width with 60 degree cutter.
Although installed height is 'less critical' on engines with push-rods or adjustable rocker (or some form of non-shim adjustment) it can be very important and need the valve stem tips ground shorter to either get clearance (with OHC shim motors) or correct rocker arm geometry
I got one, love mine
Hey, your videos have helped me repair some small engines. Thanks for your content.
I've Been using the Neway Seat cutters since the early 80's on motorcycle,atv,and marine engines.They work great and it sure beats having to take stuff to a machine shop.
👍🇦🇺
I have these cutters, Its been a long time since I did a set of valves so watching this video as a refresher. Great video.
I have the cutter but I still use the valve machine and guides instead, been using it 60 years
Show the video
Run that 60 again: seat width is bigger than I-10 through Houston. Margin at the outer diameter [on valve] is good enough. Aim fpr about 0.045" seat width. Self cleaning and low lift flow will improve.
I don't know I-10 through Houston but agree.
@@1crazypj Houston, Texas has many 10 lane highways that are still packed with traffic. I am so glad I don't have to live there.
@@skylinefever Thanks for the explanation. I 'found' an old thumb drive today (from around 2010) with valve seat width information as percentage of valve head diameter.
@@skylinefever I live near i10 and work on 10 at the beltway on the west side of Houston . I-10 on the westside of Houston is 26 lanes wide. Remember every thing is bigger in Texas!!!
@@mlwakatholy 🐄
Awesome explanation ! I have the same set I’ve been using for many years, I love them…
Nice explanation, well done. Thanks for this video.
Great video ! While porting my DOVE heads for my 460 I slipped on the second to last port. I put a nice little nick on an exhaust valve seat. Hopefully I can clean the seat up with the cutter and save a ton of money. Its worth a try. All the machine shops in south central Texas are backed up for months. I been calling every where and seems to be 2-4 month wait to get the seat fixed. My 460 block has been at the engine shop for five months. I sent it to get bored .060 over, align honed, decked, new pistons and the whole thing balanced and short block assembled. Owner told me 8 to 10 months at least !
Thanks for this. I could do this all day!!!
Great video and excellent camera work, Thanks
Very good video and thank you for the link to cylinder head supply.
Got me to sub. I have 10 motors to build and was going to pay the machine shop for valve jobs. Not any more.
Thank you.
@Dartgame 340 cross that bridge when I get there.
I've used the Neway cutters on every thing from Briggs and Stratton to 455 Pontiacs including winning late model stock car engines. Never had any problems if you take your time.
Excellent video. Thanks YOSHI 👍
Great video bery well explained 👍
Thanks for a Great Learning Video.. Excellent work 👏 👍
Nice vid clear explanation. I have my Newey set from 19??, regularly used. However, I only use the 30/60 degree cutters to take the sharp edge off the main seat, v light cut. Making the 30/60 degree cuts any bigger is pointless, as if too wide, they quickly coke up, leaving you with one wide seat, roughly 45 degrees.
Great tutorial best I ever saw thanks
That was really good, thanks for sharing.
Amazing, never seen this done. TYVM for the video!
Cool tool. DIY is always great.
If I use new valves and the head is a wedge, easy to set seat depth all the same.
Well done. Thank you for sharing. Keep up the great work
Very good video and you did the valve job just right.
ShOcK & AWE... I haven't been this impressed since I stepped out of the shower dripping wet (sorry for that visual). Very COoL. I had not idea these tools exsisted. You RoCk! Cheers from So.CA.USA 3rd House On the Left
Great video very nice explanation thank you 😊 slowly and nice smooth
Very nice, this is good for most engine work 👍
Nicely done, thanks for sharing! Those look like some good tools!
I recognize a slant 6 head anywhere, lol
A really cool process
Excellent Video. Yes you can pay others to do it, but there's something to enjoy about doing these things yourself
Excellent video
Really appreciate this video!
Thanks alot. Great video! This took away a lot of the anxiety involved with taking my head to an understaffed machine shop
I started off rebuilding Air-cooled VW engines and was taught using Sioux stones which I have had ever since but I always wanted to get a Neway set for both a backup and in a pinch can use it on mobile jobs or when power is unavailable. Thanks for the video !
I've done plenty with a Sioux set as well, but I must say these won me over the first time I used them
I got it but it’s still brand new
Can’t stop using valve machine
🤦🏻♂️
Thank you!
Nice work!
I have had a set of Neway cutters and pilots for 40 years. Used them on industrial engines and they worked fine. I would still get a 3 or 5-angle valve job on a serious street bike or car.
excellent tutorial
the job is excellent except for a detail, your seat is a bit too wide, you should consider 1/16" to 3/32" max ( 1.5 to 2 mm ) otherwise, the valve will eventually seat on carbon and burns off due to lack of heat transfert capability
Great feedback. Thanks
Excellent, many thanks!
Not bad really. Pretty simple. Thanks.
Great video !! can't wait to my heads !!
Nice video! Didnt know that you can cut the valve seats on your own, so if I ever come across the need to get this done, now I know I can do it by myself! Thanks!
These are handy tools - Neway makes them. You can add an extra angle or two to an existing valve job if you like. I picked up a 75 degree to improve effective intake radius on a set of heads some time back. If the cut goes past seat register on aluminum heads, you probably need a light blend with a stone to smooth the transition. No big deal, but dissimilar materials under the same cutter don't always get the same bite. As he says, keep cutting force near center of carbide inserts - they will walk on you if don't [from side loading] and you could cut a groove instead of a clean angle face. They may chatter a bit on powdered metal seats [cutting by hand], and not sure if I would choose them for the 45 [or whatever the seat angle is going to be] in those cases.
So do I bro 🙏
innformativ ! Slowly and at all no stressing education ! Nice ! :-)
I have been reconditioning heads for almost fifty years using Rose cutters, stones and newway cutters although the set I used had 46 degree cutters and RVR machines. I would note that with some hardened seats it is a good idea to use some fine emery paper initially to remove the hardening as it can dull the cutters very quickly.
I highly recommend using a valve seat runout gauge from someone like Goodson Tools. It goes over the pilot rod and will tell you if the seat is concentric with the pilot. It will also let you know which side of the seat is higher and to press the cutter a little harder on that side. Valve seat runout plus valve face runout combined should be less than 0.002”. New valves out of the box can have as much as 0.005 runout and need to be trued up on a valve grinder like your friend has. /John
excellent recomendation
Using ink on the seat, and the new valve is a great way to see whether you have run out or not
It should be noted that the 30 and 60 degree angles are used to adjust the width of the 45 degree sealing surface. Too hide and the valve can actually run too cool. Too narrow can cause the valve to over heat. If I remember correctly a good width is 1mm. Also you need to avoid tool chatter when cutting and make sure the valve guides aren't worn.
wow, now i understand, thankyou
Good work
well done video
Too big the 45 angle for contact valve, usually are 1,2 mm tickness for the Inlet valve and 1,6 for the Exhaust valve.
YES!! Very important details overlooked by most.
Nice video!
Thanks you for the explenation, they are util for my project of rebuild on the engine of my Nissan 100 nx GTI (sorry i have a verry bad english😅).
Never seen or done seats without the valve to see where the margins are on the valve. Need to get some of those Nuway cutters.
you also can use the dychem to check where it is seating on the valve seat. by either coating the valve face or the seat and lightly seating the valve, this will also show you if the valve seat is inline with the valve. many times they are not even though the test you did will show it all looks fine...but may be AFU. especialy when guides have been instaled.
So how likely is it to cut to much and require a larger valve, or is that even possible. Very good video. Reason I ask is because I'm seriously considering buying a neway set, and actually do my own heads. Thank you, your input is appreciated
I have had valve jobs done by two different shops and after both cut the valves and seats the contact area was not acceptable. I also purchased these cutters and it does take time to properly cut the seats. I use new valves as they are cheep. I use an old valve to carefully lap the seat with fine compound just to clean up the seat of any very minor imperfections. I typically do not use the new replacement valve for lapping the seat (and yes its not really lapping) as if you over lap the valve it just screws up the valve face and if they are coated it can ruin the surface. Then I use the new valve with Dyekem to check the contact width. If I do lap with the new valve I use very fine compound. Its time consuming but I get it exactly what is specified.
After the 45° seat is cut, you do the 30° top cut to define seat O.D. then do the 60° undercut to define seat width.
Grinding paste never failed me .....just takes a fuck ton of time when its badly burnt.
I find the hand cutter makes it hard to get a good constant cut as you have to reposition your hands while cutting. I use a Milwaukee cordless in slow speed with 3/8 socket adapter and 1/2 inch deep socket. It cuts quickly and leaves a nice finish..
I have an old Black & Decker valve seat grinder from the 50s or 60s. I don't do very many valve jobs anymore, but I do think a ground seat is the way to go. Especially for hardened seats.
@@pb68slab18 Back in the 70s I had a snap-on valve seat and valve grinder. IIRC they were B&D rebadged. When I got out of mechanics professionally, I sold them. At the same time. the hand cutters came out. They did not produces as good a finish as the ground seats. Still using a drill motor real slow make the cutters work very well.. Still regret selling grinder but at the time I needed the money.
Start and stop of the hand cutter is not best.
Motor driven will be smoother.
When your done cutting, don"t forget to measure the seat to be within tolerance!
Good job on the video.
The Neway cutters are tricky to master using the hand t-wrench. I'll typically use (2) hands pushing downwards with my palms to balance the cut while rotating with some Windex for the cutting fluid. Using (1) hand typically produce an unbalanced cut that takes forever to cleanup, thus lighter cuts are better. A helper spring would have saved me from dulling the carbide cutters when the cutter head drops accidentally every so often so extra carbide blades are a good option. I've used 800 grit lapping compound to quickly lapp the valves in and nothing rougher. Then a wire wheel to remove the lapping compound off the valve face and seat. Not too hard to adjust the seat width according to the factory spec but it takes some practice for sure and I use a loop and caliper. Trick is removing just enough to avoid cutting the seat too deeply or at least keeping them all consistent so IMHO it's good to practice on another junk head to get the technique down. I believe the Neway powered head would be a huge improvement in cutting consistency and speed so that's probably my next upgrade. But otherwise with some skill you can definitely get some nice 3-angle valve jobs with these if you take the time and develop the feel for them. Most of the pros would probably recommend a Serdi, Sunnen, or Rottler but for the DYI folks these Neway are not too bad for the money.
Thx for the input bro, all this while I was thinking about the machine shops for this kind of jobs. I am awakened. 😁
Only ever used neway cutters on Lycoming and continental engines, always working on seats from the other end of the cylinder with a long extension must have helped keep things square as I never had issues applying even pressure. Agree cutting fluid is essential for decent results.
So many people don't understand this. Seat concentricity is so critical to longevity. Factors such as valve guide wear only compound the problem. Yeah, a monkey can make a seat that will seal for a while with a Neway. But to create a correct seat is much harder. The real issue for Neway is the finish of the cut (as you commented) and the lack of cut depth indication with a hand cutter. There is a powered track system for Neway type cutters but it dose not depth indicate. Runout is still an issue with any floating type of cutter like Neway And 3acut (ebay brand). By the time you have purchased all that you can buy a good used seat and guide machine like a Peterson 25 or a Winona and a basic Newen (not Neway) 3 angle system. The Newen has several knockoffs that are even cheaper than the brand name. Regardless quality application specific cutters are sold by cylinder head supply of Oregon, or Goodson, beam equipment. Silverline and many others. www.cylinderheadsupply.com/pr3vasecuki.html
@@bad406camaro Holy shit, someone who actually has a grasp of engineering principles. Well explained mate. But you know what they say.. " I can explain it to you, but I can't understand it for you"
Seems to be the overriding vibe here.
wow thank you sir for your totorial, yes I can see with old school V8 heads your 3 angle valve job method would be no drama, like you said go slow and do it right.
Usually a 3 angle valve job is done for performance, a single cut or 2 if seat is too wide is used in stock applications. You forgot to mention about seat width. The whole reason for a 3 angle valve job is to make the seat as small as possible and the other cuts is to make that width correct and to increase flow for performance. You had your valves reground, did you also have multiple angles cut on them to maximize airflow ? If spending that much to do seats I didn't see any porting done to the heads. I'd port them before doing seats as porting may damage seats and you would have to repeat doing them over again.
The maximum flow restriction of any head is the valve seat and valve.
A closed valve is very restrictive. 🤔
#1 thing is a good valve job.
#2 bowl shape
#3 port shape and size
Excellent.
Excellent
This is a great video! Thank you so much for making it. This will help immensely in the work on my old boat engine.
No it won't. You have no idea of the cost of these, do you? Cheaper to take to a shop and put the liability of a scew-up on them.
@@yeagermcbipper9008 Thanks for the feedback but Yes it did!
In Dr. Lynn Mosher's head rebuilding class at Cal Poly San Luis Obispo back in the late 70's we were taught to forget about lapping ,as it should have gone out with the model T. It seems as the valve heats up it gets longer and no longer seals at the nice frosty line from lapping that gave you a warm fuzzy feeling.I had lapped valves since high school like my ole man did once a year on his flathead Hudsons. I checked this out once and actually did it with a 170c.i.slant 6 with new valves and 0.030 larger stems like Chrysler recommends for worn guides. I step reamed the guides to the .030 as wellof course . I heated the exhaust valve in a lab oven to about 600 degees installed with dykem and proved the valve face did not hit the previously lapped area.
Great info!
Is exactly the way I have done it for50 yrs, never had a problem. Soon as I saw that pogo stik an paste come out,I could see an otherwise reasonable job being vandalised.
My saying, "lapped to crapped".
Also he only machined an intake with no insert straight cast iron "chocolate ", compared to some modern inserts.
I say, show us a job on a well used welltite inexhaust insert using these cutters. And show the actual outcome with the markings on the valve.
Adrian.
@@adriandines I've had Neway stuff for years, as well as an old flexible grinder with stones, but I made a mistake using the Neways using a T bar handle in an old air cooled engine with rock hard seats (same with sintered Kolbenschmiddt stuff). I eventually got out of the poor cutting results by using a slow speed cordless drill and ball joint driver, and learnt a lesson in the process. They did produce a good finish in the end, but the next engine I build I will definitely pre-finish the replacement seats in a lathe first to reduce the amount of material I need to remove.
My 90's cadillac service manual says that new valves should never be lapped. So I assume used valves can be lapped?
I think a light lap at least lets you know there is full contact around the valve and where it is seating. The engine running is going to pound that fuzziness flat in no time.
If the exhaust has hardened seats, it could become a little more difficult to get a cut...I would also add a spring under the cutter housing...
Thank you sir
The step before you started cutting the seats was to check valve stem to valve guide clearance with a dial indicator. If it was out of spec, the fix is to knurl the guides or install guide inserts. The clearance must be within specs before cutting the seats.
If after the lapping, it shows the valve face is not contacting the seat in the center of the valve seat, then you can adjust with the 30 or 60 degree stone to center contact area of valve face to seat. Finally measure width of contact area of valve face to verify that it is at least the minimum width.
Or use a tapered pilot ….
The FIX for out of spec guides it to REPLACE THEM. The cheap hack that might last a while before you get high oil consumption is to knurl them
With the cost and scarcity of tools, knurling probably isn't cheaper. But I do have access to a set of the tools, so now I think I might pull an old head off the shelf and knurl the guides. Could be fun and interesting, and as a bonus it will trigger a bunch of machine shop guys into telling me I'm doing it the wrong way.
cutting 30° and 60° is for air transition but also to give the seat the just contact width with de valve. To large => valve pressure on the seat is reduce, leaks can appear. To low => pressure to high. I think !
Really good helpful video....Maybe I missed it, but you seem to be Cutting the Seat Surfaces Dry without any Cutting Fluid.. Neway recommends using a certain type Cutting Oil on their Carbide Cutter & the Seat surface & some users use WD-40...Just wondering why you didn't use any Cutting Fluid ? ....Thx again for showing all the details on how to use this affordable tool.
A great question. Neway recommends lubricant for "soft seats." For automotive applications, this probably means anything before about 1974 when they started induction hardening seats from the factory.
thanks🔧🔧
Hi, would you know which Neway cutter set to get for Honda V6 J series- J35A7? Thanks. Nice video. So rare to see a video like this. Thanks again.
I've got a link in the description that has a size list. You'll have to look up or measure your valves
I didn’t realize this could be done at home. Thank you so much for the wonderful video.
How did you get the new seats in? Did the machine shop that skimmed the head do that for you?
I didn't put in new seats - just cut the ones that were already there. I put new guides in myself.
@@YoshimoshiGarage have you done a video showing the guide install?
yes. It's here: czcams.com/video/Ky4-238Hq3g/video.html
@@YoshimoshiGarage Thanks! I actually found it right after I ask. That was a great video as well.
I do SEVEN angle valve cuts on my motorcycle valves and seats. I learned from the late "Pops" Yoshimura. The 30% open flow is 50% GREATER, which is VERY important on my 1964 305 Honda SuperHawk twin two-valve engine. Yes, the flycutter cost nearly a thousand dollars and there is only one man in town I let use it-he also does the cylinder honing for me. He is an artist with the Sunnin honing machine. When he decides to retire, the lady that runs the machine shop says she'll probably close-up, because she can't get any young guys that will learn to do race engines and drag boat engines. REAL machinists are a dying breed, sadly. If you can install new bronze valve guides and ream them to fit the valve stems, you might have the makings of a machinist. Now when like my late Daddy, you can cut the taper for the pins that hold on the wings of a B-47 bomber (by hand!) you ARE a machinist! He also built the first and second stages of the Saturn V rocket booster for Rocketdyne. We ALL knew the astronauts PERSONALLY, so it wasn't "Just a job". I'm a klutz.
“The lady that runs the machine shop.”
WTF??
@@psychbomb7543
SMH
REAL engine machinists aren't a dying breed. Maybe you lack the ability to find them but they're still out there and new ones are coming along behind.
Sign me up I’ll do it, it’ll give me the extra kick in the ass I need to do the old Palmer in my sailboat
I do 9 angles on my honda c50
I’ve used nuway cutters for many years , Would never use the T-handle Because it induces inaccuracy in the cut. Nuway makes a electric drive motor that makes it effective for accuracy.I would always use a cutting lubricant on the top two seats Which is dishwashing soap ,water and a spray gun, it works flawlessly and it produces a chrome like finish .It also smells awesome when you hit it with the air gun…lol. in my opinion a good valve job does not need to be lapped in because it scrapesthe shit out of the seat and the valve. Valves need a period of time to seat them selves in ,Aftert that you’re good. Keep on rockin
What do you mean by saying "valves need a period of time to seat them selves in"? You don't hone them with compound and you just install them as it is from the factory, so they will become sealed after some time of working when the motor will running?
But if the valves doesn't seal before, how will this motor work?
Thanx
Great video - how do we find Dr. Torque???
He doesn't have a channel, but it a regular over on www.youtube.com/@MotorsandMischief
The surface finish on that valve after the lap seems not great I don't know that it matters but I'd lap it a little more
When I ran my shop i used to charge 5 bucks a port for a 3angle seat. I recently paid nearly 40. Times have changed!
Good informative video, very well explained. I remember growing up, hanging with some of my "motorhead" friends and them talking about this as part or a "performance" up grade when also adding a high performance cam, carburetor, and headers to a stock engine. How much HP does this add versus a regular valve job?
Well I can remember having seen a video given by David Vizard when tuning the A series engine of a mini cooper. But he put 2 angles on the valve seat which is a regular 45 degree and a 20 degree. The reason for cutting these angles is widely misunderstood as in this video which although is a great presentation and more of an engineering lesson. To understand why we bother to do the cuts one has to understand what is happening to the flow of the gas behind the valve in the inlet port and then one has to understand what happens to the flow of the gas when it has left the valve and entered the combustion chamber. So to clear up a myth so that we are both on the same page; We are not making the cuts to make a smoother run in for the gas to flow behind the valve. Its has nothing to do with it as does polishing the ports believing it will do the same when it doesn't and in some engines causes less power?? Surprised !! I always laugh at this point when people look at me with disbelief but its true? I cannot produce you a sketch of a valve and valve seat on this post but I would really like to and so I will attempt to just explain what happens?
Imagine we are both looking at a standard valve which has a standard 45 degree machined. And then we have a standard valve seat with a 45 degree machined. Imagine the valve is sat on the seat and in the closed position ok? Now imagine the valve is half a millimetre off its seat just as if it is in a partially open position? When you examine the gap between the valve face and the valve seat you can see the size or the room in which the inlet gas has to flow past and into the combustion chamber? Now imagine the valve is 1mm Off its seat ? When you look you can see a much bigger area or room for the inlet gas to flow past into the combustion chamber? Now obviously the more the valve opens the bigger the area for the gas to flow ok? Now lets take a valve which has Not the standard 45 degree machined But 20 degree machined on the same cylinder head of the same engine? Lets look at what happens? Firstly I want to explain before going any further that for creating more horsepower and torque the major gains are to be had at the Initial lift of the valve and Not at Full lift of the valve ok? Now i'm talking about the moment the Inlet Valve comes off its seat in the first few degrees of the cam duration cycle and not at say 108degrees of the crankshaft where the valve is fully open ok? So we are talking about when a cam commences to open the inlet valve at 40 degrees before top dead centre? And so we are talking about the events which are happening at initial lift of the inlet valve between when the cam is just kissing the inlet valve without opening it and when the cam is at 20 degrees before top dead centre ( 40 to 20 degrees BTDC) This say equates to Zero to 1mm lift only . Now for the important bit ? Because the piston acts like a suction pump? Plus we have on this cam as much as 80 degrees of valve overlap? The gains in power from using this force of both the piston sucking and the force or the PULL of the exhaust gasses leaving the exhaust can be exploited to force feed the inlet gas into the cylinder and get more of it in it because of the speed of the PULL? Now lets take a look at the 20 degree angle cut on the seat? At the beginning we spoke about the 45 degree machined ? We said that at 0.5mm lift and at 1mm lift we could see an area in both examples of say X and we noticed that the area got bigger for the gases to flow at 1mm? Now with the same valve machined to 20 degree cut lets take a look at the area beneath the valve for the same cylinderhead and for the same engine? At 0.5mm opening the area or the room which the inlet gas has to flow past the valve face is so much bigger?? Yes it really is and in Cubic Feet Per Minute the gases are 6 times the volume with this cut flowing into the combustion chamber and then at 1mm the volume of the gases is 36 times the CFPM than with the 45 cut? Amazing yes? It doesn't stop their? Now because of the speed of the PULL this increase in area at Initial LIft when the valve starts to open to a Lift of between 0.5mm and 1mm the flow speed or rate of the gases increases its velocity past the inlet valve by 3600 times? Now when you look at it like this with both a larger area and a greater speed being achieved you don't need a lesson in maths to know what happens next? So benefits are an increase in torque and horsepower but also throttle response because a bigger charge of gas fills the cylinder in a shorter time? Just as an example : The mini in standard trim was making 36 HP I think and the Cooper Works team rallied the 849cc for the Monte Carlo Rally and got 110 at the wheels? They all had 20 degree cuts and the inlet manifolds were rough? Very rough because that type of engine likes big drops of fuel and the rough pores in the inlet tract act like a WELL catching some of it and then it vapourizes it? I hope this helps? Lotus did the same thing?
@@giuseppegiacomoni7058
This is intriguing as can be to me. Any chance we could speak. I'm with you, but on the fence slightly. I would be happy to provide my email address if so. Please let me know. Thanks you! D.
@@giuseppegiacomoni7058
Getting ready to do a pinto head for a race boat.
@@chopsooy This engine can tune well and many performance parts are available. For a power boat you are wanting 100hp/litre and its also possible to source a twin cam BDA cylinderhead which will give the power you need? Lotus made a cylinder head also that fits to a Ford Block with a Big Valve Head
The neway instruction book states to cut the throat cut first then the top cut and the valve seat cut last.
Thats the way I've always done it.
Is it necessary to have the valves lapped with a coarse lapping compound for the best sealing surface? Bacause i would continue to use finer grits till i have a smooth finish. Just because my logic makes me think that would be better. Not because i know for sure. And thats why i am asking.
It's not necessary to use coarse at all. All you're checking for here is that the seat is concentric with the guide, so you're just lapping enough to remove the marker/marking fluid, not remove material.
Sorry i got it now lol. Thanks sir.