I'm at school reading a mag and all the internet is blocked except yahoo. So i'm trying to figure out what the diff is between 3 angle versus 5 angle valve jobs.
2 Valve, 1 Exhaust Valve; 3 Valve, 2 Exhaust Valves. Faster Exhaust Removal, More Intake air/Fuel Mixture, Higher Power.
The object of the valve angles is to produce a smooth transition to help air flow. So a 5 angle valve job is done to make a series of angles that are closer to a even radius or even parabolic. For street use, you not see that much difference. But when you are at the top levels of competition that little bit might be the difference between an also ran and a winner (read winnings).
Cylinder ports flow better with a fancy four or five angle valve job. If you look at most standard valves there is only one contact point all the way around the valve face that actually seals on the valve seats. The width of this surface in multi-angle valve jobs is just as it sounds. Instead on one 45 - 46 degree angle. the valve will have two to three additional angles toward the valve stem under the valve head to smooth out the intake flow of fuel and air into the combustion chambers. there also may one to two additional angles above the sealing surface of the valve for the same reason. The actual part valve of the valve face that sits on the valve seat may be very narrow 3/32 to .060 This is especially true of the intake valves. Not so true of the exhaust valves. The exhaust valves need all the cooling they can get and the valve seat is the only saving grace of cooling them off. Therefore the faces of the valves are a bit wider. The narrowed up intakes however are constantly bathed by cool air and fine droplets of gasoline.
Im not familliar with a 3 valve per cylinder but it either has two intake valves and one exaust valve or vice versa. IN this case it should have nothing to do with speed. I hope this helps
