deafwish wrote:Hi all,
He quoted me around $1000 (Australian) to perform a 'multi angle valve cut' and a 'slight match porting'... Anyone care to explin in more detail WTF this is?!
Daz.
a multi angle valve cut is when the valve sealing edge is machined at (normally) three slightly different angles and is supposed to promote better valve sealing.
Port matching is where you "match" openings between intake and head so both openings are the same and there is no obstruction (or overlap) between the two openings.
I've done both (on car motors) before and the difference in power is barely enough to notice much difference (note - never dynoed)
Head flowing on the other hand
can make a lot of difference. It involves modifying ("porting") the combustion chamber area shape to change the way the air/fuel mixture and exhaust gasses flow.
As slow and wobbly said - this must be done on a flow bench by a good operator who knows what he's doing. As mentioned, it's easy to stuff this up and can actually make it worst.
Also remember that no matter what you end up doing when chasing horsepower, the whole engine, drive train ratios etc should be looked at as a whole so that everything complements everything else.
When building high performance car engines, I've always been taught to choose the cam that will best suit what you want, then build the whole motor, drive train etc around that cam.
Note - that's just my understanding of things. I'm only a back yard tinkerer so do lots of homework before spending the bucks