we just installed B16 piston in ls block and its low compression i mean i read and i see in here about these pistons being great and give high compression better than the type r's my friends ls and he has the P73A0's and he is hitting 222 psi each cylinder but its giving me 160 psi each cylinder with these B16 pistons i mean whats going on and also its hitting the valves please help!!!!!!!! and oh yea i have a 2 layer head gasket and im using the ls rods and crank, its and all motor ls not ls vtec help!!!!!!!!

 

Did you hone the cylinders before putting the pistons in? My first guess as to why the compression is so low is that the rings are not sealing right. First off, make sure you're using the compression tester correctly. If you're getting 160psi across all of the cylinders, you may have a big problem. Are you sure that the valves are hitting the pistons? The dome on the B16 pistons is pretty tall, but if you're at stock deck height (minus 1 layer of the head gasket) I wouldn't think that it'd be a problem.

 

yea we honed the block not only that we also resurfaced the head to and we are using toda seals and rings.

 

are you shure the ring gaps are all positioned in realtion to each other the right way?

 

I not a wealth of information but if the pistons were hitting the valves would'nt that mean that they are open and perhaps that is why your getting low numbers? Also did you check your timing marks. I had a problem with my cams until I discovered that the guy I bought my JDM head off had sold it to me with US cams in it and they were off by several degrees causing the timing marks to be useless. Anyway im probably wrong sooo......