GapxGuy

I have a set of 85mm JE pistons for my B20. For you guys with JE pistons in your B20, what's the piston to deck height? I called JE and they said the piston to deck height measures at 0.00 instead of the normal 0.03 for B18/B20. They said that these pistons will yield at 10.5:1 CR, but using the C-Speedracing CR calculator, with a pistons to deck height of 0.00, would give me 11.4:1 CR.

This is critical because it will determine whether I will mill my head or not.

Use the C-Speedracing Calcutor and help me if you can.http://www.c-speedracing.com/howto/c...c/compcalc.php

Block: 85mm pistons and 89mm stroke
Head: Unmilled B16a
Piston: -1.7
Head gasket: stock (0.029)
Piston to deck height: ?????????????

This is crucial to me because I will either end up with 11:1 CR or 12:1 CR. I wouldn't mind 12:1 CR, but CA only offers 91 octane. If I do end up with 12:1 CR, would I be able to get away with running on 91 octane?

Please help, thanks.

GapxGuy

Jeff C

I hate to say it, but clay it...that should tell you. Surely it would not be 0.00 though, that sounds impossible. There has to be some tolerance. It was always my understanding that the b16 head added .2 to the compression. :shrugs:

I too have the 10.5 JE's for my b20, but they are 84mm. I would also like to know the answer.