ReggieSD said:
i dunno maybe i just misunderstood..but i'll ask him again to get accurate info. if grinding the pistons screws everything up..then maybe it was teh valves...or does it mess it up too?
ls/b20 pistons dont have sufficient valve reliefs to clear the large lift of a vtec cam, and so unless you run gsr cams or run zero timing advance, there will be some measure of piston and valve contact. the valve reliefs can easily be ground out to sufficiently clear the valves, however, its a process that needs to be done by a pro, so that you dont risk grinding off too much and putting a hole in the piston, or even making it too thin and making a weak spot.
to everyone who keeps saying "sleeve a b20" that is really, really stupid. there is NO advantage to sleeving a b20 over an ls. when you sleeve a motor, you distroy the advantage the b20 has over the ls- the extra 3mm of bore. the ls and b20 are the same basic casting- once sleeved, they are pretty much identical, and you can bore either anywhere from 81-86+ mm. concidering that ls blocks are much cheaper to get than b20's, it makes no sense to sleeve a b20.