how can you tell if oem pistons are reusable? ive seen them reused. i know sometimes they are sometimes they arent depending on how the rods are taken off. i can say, the wristpins still move pretty freely in them, all the ringlands are intact and t hey are generally clean. i take it the only way they wouldnt be is if the press used distorted them at all. is there a way i can tell without actually sticking them in an 81mm bore and running a feeler gauge all the way around? can a machine shop tell? thanks.

 

have them run a dial bore guage to see how out of round the cylinder is. if its not out of round or out of spec throw some new rings on there and call it a day.

 

well its an 81mm ls block. if the pistons are reusable im goign to jsut get it alignhoned and use the pistons. they are p72s. if the pistons are facked im going to go to 82mm and get 82mm itr pistons from rsmachine.


whats the CR in an lsv with p72 pistons? and being as they are pistons from a vtec motor i should not have valve to piston issues with a cam with less than 12mm of lift correct?

id even consider dragging the pockets on ls pistons and milling the hell otu of the head to get a decent mid 11:1 CR....just toying with ideas, i know i want to use the flattest piston i can get. have all the parts laying around. i dont feel like asking around too much about it becuase there are very few truly helpful people around anymore.

 

9.98CR w/ B16 head
10.1CR w/ GSR head is what i get assuming its never been decked etc.

 

so i could probably take .025 off a pr3 head and be at 11.7:1ish?

what exactly is the math on that? and whats the math on how much to take out of the valve pockets for say a cam with 11.8mm of lift? i dont want the measurements, just curious as to how to get them. i have my crayola and napkin ready to figure this all out.

 

i dont know the exact math for milling the head cause that changes combustion chamber volume. keep this post on page 1 and im sure someone will answer that.
my friend took his valve pockets i think .020 deeper than stock when he got his RM cams.

 

yea these gsr pistons look super flat. these and a shitload off the head should make a good running motor.

 

nobody? i used to gt good info in here....whered everyone go?

forget it ill figure it out. just dont ask how.