porting questions

[ametzzz]

I am sending my y8 head to a friend's machine shop for work... he has never worked on a honda only has done BMW stuff..... Anybody know exact measurements on porting

[civicmug]

i have been looking into this for myself recently... from what i have found out recently... it depends on what application you are looking for... if you go too wild/aggressive the powerband may be too high in the rev range for it to be functional for you... for the machine shops/machinists i have talked to each one seems to have their own 'philosophy' on their approach... measurements for the actual porting ... not so sure about that ... as for texture/roughness... exhaust side 100 grit... intake side 80 grit (make sure the area just after the injectors has some texture... also the part on the port floor just before the chamber goes down into the combustion chamber)... measurements for milling the head depend on what you want to do... if you want to just deck it to make sure its nice and flat before you put the head back on just take off enough to even it out... you can also mill off more to raise the compression of your engine...
(look at this to see what kind of compression you can get from milling different amounts http://www.knology.net/~jediklc/D.htm)... if you are not confident you may want to get someone with porting and polishing honda cylinder heads because depending on the 'mistake' you may not be able to 'fix' it...

also look at this resource...
http://www.d-series.org/viewtopic.php?t=2712&highlight=port+polish
if you insist on going with your friend's machine shop maybe you could print some of this info off and pass it on to him :p

...from what i have found i don't think there are any 'exact measurements' on porting... the castings from cylinder head to cylinder head are going to change slightly... as is the application

... oh yeah... make sure your friend does not mess around too much with the port floor on the intake or exhaust side... (more so on the intake side in my experience)...i have been told this by several people with PnP experience... the shape flows quite well coming from the factory (no real hard angles/edges)...

good luck!