I saw that the Prelude Type S cylinder head has a 45 degree valve seat angle instead of the regular non-S spec H22a's, which have a 60 degree valve seat angle. How does this work better?

Thanks,
Mark

 

It would allow the valve/seat clearance to open faster with less lift. If you have a steep angle, there is still the top of the valve and lower portion of the seat to deal with. With a shallow angle, the top of the valve and bottom of the seat aren't as close to eachother at the same lift levels as the steeper angle. A picture would reveal much more, I just don't have one.

The negative effects of the shallower seat is less area for the valve to cool/seal against the seat. Good for NA, bad for turbos. Then again........ I'll take good low lift flow any day....

 

Thanks. Sounds interesting. I will probably have it done.

Regards,
Mark

 

I am pretty sure that valve work is among the more important aspects when head porting is done.