Gains from a Multiangle valve job
the reason for the 70 60 45 30 15 , is the 70degree is almost like a back cut into the head (like a small porting job) it blends the port and the seat together, now the x-tra 15 is to remove a sharp spot out of the cylender (sharp spots create hot spots). as i stated, i have tested my theory more than one time. on average i ran .2 quicker. the reason alote of machinists go with a 3 angle is time. time is money. those extra 2 angles are well worth the hassle. its just like porting, u want smooth transitions not sharp ones.
o there is no doubt that u can have a decant 3 angle setup. but i will bet money anytime u have a 5 angle that extra time and money wil be worth it in the end. myself personley i like to use the cutter, and finish by hand with the stones, then lap in all of the valves. when i vacuum test the lapped in valves always seal just a tad better.
o there is no doubt that u can have a decant 3 angle setup. but i will bet money anytime u have a 5 angle that extra time and money wil be worth it in the end. myself personley i like to use the cutter, and finish by hand with the stones, then lap in all of the valves. when i vacuum test the lapped in valves always seal just a tad better.
If you want to know details on what TSP's or PRC's valve job entails, you should call or PM one of their reps to ask. Most head porters would consider the angles proprietary, along with most other details. The likelyhood of getting any hard data from them posted here is very low.
I'm sure there are several schools of thought on what makes a good breathing cylinder head, so any answer they gave here would likely be the subject of much debate. Asking for key details of a cylinder head is probably the same as asking the Colonel for the secret recipe for KFC - you might actually get the primary ingredients, but getting the knowledge/technique to execute it the same way is still required to get the end result.
I'm sure there are several schools of thought on what makes a good breathing cylinder head, so any answer they gave here would likely be the subject of much debate. Asking for key details of a cylinder head is probably the same as asking the Colonel for the secret recipe for KFC - you might actually get the primary ingredients, but getting the knowledge/technique to execute it the same way is still required to get the end result.
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I did my own 5 angle valve job, its a lot of work especially if you are using stones and have to gridn them all to size by hand. I spent probably 20 hours in the valve job alone, but I don't do this all the time, I did make it perfect though. Blended the seats and lapped the valves when I was done. Air does not like to turn much more than 15 degrees. Your top cut is pretty critical and it can also help out fuel economy if you get it right. I would like to thank Bret Bauer though because he provided me with all the critical info, helped me along whole way and we matched everything with a cam that performs great.
Edit: The stock gm valve job is a joke. The valve seats are not concentric at all! At a bare minimum everyone should atleast lap there valves in on a stock valve job. Go ahead and check it for yourself, some valves were on touching on one side of the seat.
Edit: The stock gm valve job is a joke. The valve seats are not concentric at all! At a bare minimum everyone should atleast lap there valves in on a stock valve job. Go ahead and check it for yourself, some valves were on touching on one side of the seat.
Last edited by Nitroused383; Aug 30, 2009 at 04:16 AM.
Teching In
Joined: Mar 2009
Posts: 43
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From: Florida
A mass production valve job is what it is, it ain't perfect. Add to that what happens to a new casting after many heat cycles, the seats move around. Whether an LS1, LT1, BMW, Harley Davidson, a good 'blueprinted' valve job will always pick up HP. The # of angles have nothing to do with longevity, done properly, more make for a better, smoother transition, more flow. Back cutting the valves works well also.
[QUOTE=Nitroused383;12147998]I did my own 5 angle valve job, its a lot of work especially if you are using stones and have to gridn them all to size by hand. I spent probably 20 hours in the valve job alone, but I don't do this all the time, I did make it perfect though. Blended the seats and lapped the valves when I was done. Air does not like to turn much more than 15 degrees. Your top cut is pretty critical and it can also help out fuel economy if you get it right. I would like to thank Bret Bauer though because he provided me with all the critical info, helped me along whole way and we matched everything with a cam that performs great.
Edit: The stock gm valve job is a joke. The valve seats are not concentric at all! At a bare minimum everyone should atleast lap there valves in on a stock valve job. Go ahead and check it for yourself, some valves were on touching on one side of the seat.
How in the hell did you cut that by hand? my **** would be so wack if i did that lol. and in that last port is it me or does it looked cracked?
Edit: The stock gm valve job is a joke. The valve seats are not concentric at all! At a bare minimum everyone should atleast lap there valves in on a stock valve job. Go ahead and check it for yourself, some valves were on touching on one side of the seat.
How in the hell did you cut that by hand? my **** would be so wack if i did that lol. and in that last port is it me or does it looked cracked?
That's incorrect. 100% of our cylinder head business is done in house (minus the pouring of our aftermarket casting obviously).
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Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!
COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
the reason for the 70 60 45 30 15 , is the 70degree is almost like a back cut into the head (like a small porting job) it blends the port and the seat together, now the x-tra 15 is to remove a sharp spot out of the cylender (sharp spots create hot spots). as i stated, i have tested my theory more than one time. on average i ran .2 quicker. the reason alote of machinists go with a 3 angle is time. time is money. those extra 2 angles are well worth the hassle. its just like porting, u want smooth transitions not sharp ones.
