angled valves and head skim

[jamieccc]

how do you angle valves and skim a head? always talked about it and no what its for but never really understood how to do it! cheers

 

[frank]

jamie

3 angle seat,s are just like putting a shampfer on the valve seat really (making the seat thinner) and should really only be done to the inlet,s.
a machine shop will skim some material off the head face for you

 

[jamieccc]

jamie

3 angle seat,s are just like putting a shampfer on the valve seat really (making the seat thinner) and should really only be done to the inlet,s.

y only on the inlet's?

 

[Ed]

Frank not quite true.

Jamie, in order for air to get in and out of a head as easily as possible, you need to make any transition in direction of flow as smooth as possible. If you say force air along a pipe with a 9 deg bend but smooth that off into a 45deg (thats your one angle) then the transition is quite abrupt. If you further divide this with two more angles one before and one after the 45 ( 45 is the one the valve sits on) then the transition is smoother and flow more efficient.

MA heads are three angle inlets and single angle outlets. The inlets are more important than the outlets but both are important if looking for all available gains. There is a great deal of room for improvement on a MA head. Much of which I am looking to find for my ST.

Further to this head skimming just ensures that the deck is flat and a decent surface is present for the head gasket to seal against.

 

[frank]

y only on the inlet's?

jamie

the exhaust valve,s can get very hot, and a wider seat will transfer/soak up more of that heat

 

[Ed]

Frank its not a problem. You will never ever find a single valve exhaust seat on a high performance engine. Its simply as the MA head is not performance orientated, its cheaper to cut a single angle seat.