What exactly is a 3-angle valve job?
#11
Re: What exactly is a 3-angle valve job?
Originally Posted by fc735
three angles on the seat instead of the standard 1. better flow of air of course, due to the smoother air transition.
not gonna do much on a street car, unless other things are done to improve airflow also.
not gonna do much on a street car, unless other things are done to improve airflow also.
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Re: What exactly is a 3-angle valve job?
Originally Posted by fc735
what kind of head? was this a performance shop?
It had been open for 80 years when I started working. Two of the machinists had been there for nearly 40 years.
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Re: What exactly is a 3-angle valve job?
Something interesting that I've never seen before, Z1 motorsports offers a rediculous 14 angle radius cut valve job on their stage 4 motors, here's the link... http://www.z1motorsports.com/product...products_id=58
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Re: What exactly is a 3-angle valve job?
Originally Posted by BigBake
It comes stock on a factory LS1 style head, I don't know how much more street you can get than that. You are correct that the airflow dictates the use of such small details.
GM started using it on production heads on the Vortech's in 94+, i figured they would use it on the LS's.
Originally Posted by greygti
They did it on nearly all their heads. The shop was not a performance shop. The did do some performance work (porting and sleeving)
It had been open for 80 years when I started working. Two of the machinists had been there for nearly 40 years.
It had been open for 80 years when I started working. Two of the machinists had been there for nearly 40 years.
damn. my shop does a standard one angle on most unless i ask
Originally Posted by MGBRaceman
Something interesting that I've never seen before, Z1 motorsports offers a rediculous 14 angle radius cut valve job on their stage 4 motors, here's the link... http://www.z1motorsports.com/product...products_id=58
#16
Re: What exactly is a 3-angle valve job?
Royalty,
Since no one really answered your question properly, I joined this site to help out.
This is what a 3-angle valve job is....
A 3 angle valve job is the process of machining the contact area of the underside of the valve, so that the mating surface is smaller or sharper, and making the seat angle greater. This allows the valve to seal faster and more tightly. This also increases port turbulence, which increases air speed, allowing more air into the mix.
One reason why it is important to have a good machinist is that by changing the angles and size of the valve contact patches, you can change the “agressivenes” of the valve job. A more drastic valve job will have higher gains, but at a cost. Valves dissipate heat during their closed state. When the valve is closed, it is in contact with the cylinder head, and the heat is transfered. This issue with heat transfer is why titanium valves were introduced. Titanium valves provide ultimate thermal protection, and decreased maliability under stress.
Another thing to consider when doing any kind of cylinder head modifications is that entire valve train is designed to work as a system. The tolerances, valve lashes, spring tensions, etc, are all designed so that everything runs on harmony. When changing any part, you need to be careful and make sure that everything is compatible. I personally recommend the all or nothing approach. Many street cars will be just fine with stock head work. If you’ve got a spare head, and want to bring your car to the next level, i say go for it. But you can’t just throw in super aggressive cams, or get a 3 angle valve job by itself.
The best thing to do is make friends with a local machine shop. They will have more knowledge than you will know what to do with!
Hope this helps.
Be fast and true,
Mike
Since no one really answered your question properly, I joined this site to help out.
This is what a 3-angle valve job is....
A 3 angle valve job is the process of machining the contact area of the underside of the valve, so that the mating surface is smaller or sharper, and making the seat angle greater. This allows the valve to seal faster and more tightly. This also increases port turbulence, which increases air speed, allowing more air into the mix.
One reason why it is important to have a good machinist is that by changing the angles and size of the valve contact patches, you can change the “agressivenes” of the valve job. A more drastic valve job will have higher gains, but at a cost. Valves dissipate heat during their closed state. When the valve is closed, it is in contact with the cylinder head, and the heat is transfered. This issue with heat transfer is why titanium valves were introduced. Titanium valves provide ultimate thermal protection, and decreased maliability under stress.
Another thing to consider when doing any kind of cylinder head modifications is that entire valve train is designed to work as a system. The tolerances, valve lashes, spring tensions, etc, are all designed so that everything runs on harmony. When changing any part, you need to be careful and make sure that everything is compatible. I personally recommend the all or nothing approach. Many street cars will be just fine with stock head work. If you’ve got a spare head, and want to bring your car to the next level, i say go for it. But you can’t just throw in super aggressive cams, or get a 3 angle valve job by itself.
The best thing to do is make friends with a local machine shop. They will have more knowledge than you will know what to do with!
Hope this helps.
Be fast and true,
Mike
#17
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Re: What exactly is a 3-angle valve job?
I know this is a thread bump from 2005, so I'm closing the thread but leaving the post intact for now if someone can get some knowledge from it. Normally that would get an infraction or warning for bumping a 7 year old thread.
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Re: What exactly is a 3-angle valve job?
Oh, and titanium valves aren't used for their "ultimate thermal protection". They're used for their low mass. There are much better alloys for difficult thermal problems. There are special high temp Ti alloys, but they're used for the combination of weight and decent temp characteristics, not temp characteristics alone. There are a lot of nickel-based alloys with higher temp resistance.
Last edited by Fabrik8; 01-05-2012 at 11:23 AM.
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