i bought this from a guy who told me they are 12:1 but im not sure..going to be using them on a lsvtec b16 head...anybody know for sure what compression will they yield..? 81m4 is all they say and they are 81mm...

 

You'll need to contact JE for that information. Look underneath the pistons for numbers as well, JE will need that info to give you the correct info.

 

they dont have a part number...the only way to be sure is to send je 1 pistons and they charged liek 100 to tell u wat it is..i was hoping someone here who has seen them before would tell me...the only number is the forging number which is 81m4 and doesnt say anything about the piston..

 

well, the only other way you could do it is to install them in the block and cc them along with the combustion chamber to see what your compression will actually be but I'm sure that will cost you more than $100. The lesson here, is that it's never a good idea to not really know what you're buying especially when it comes to a part as important as pistons. I'd send it away and find out if I were you. You don't want to be isntalling pistons that aren't right for you as that will cost a lot more money than $100.

 

its a budget engine build if it blow up i dont really care...its only until my turbo block is ready..but thanks for ur help...i was gonna used itr cams to run them but if they are over 12:1 i thinks thats a mistake...im gonna have to used some blox c or sk2 s2..another question is will i do more damage if i used a .040 head gasket to lower my compression? since thats gonna also reduce my quench ones...

 

If you take the time to put your budget build together properly, you'll not only have a reliable engine to fall back on if something happens to your turbo build, you can also sell it to help pay for your turbo build. A .040 thinck head gasket would lower your compression slightly but would be of little value to you if you don't know where your compression ratio is to begin with. Unless you have money to burn, investing that $100 into identifying what your piston will give you compression wise, is worth it in the long run.