JDM BPZE Compression Numbers
 

Hi All,

1st post here, looking to swap a JDM BPZE into my 97'. I know the JDM motor has .5 higher compression than USDM. What is a good PSI on 1st crank, highest and leak-down numbers?

Any other tips to ensure I am not buying a pile of shit?

Thanks,
Brian

Make sure they're even, that matters more. Not all the JDM VVT motors had the 10.5 pistons. Probably wont be able to tell for sure without a borescope.

I have one with below compression numbers:

1st number is 1st crank PSI, 2nd number is max PSI

Cylinder 1: 160 - 205
Cylinder 2: 120 - 190
Cylinder 3: 100 - 175
Cylinder 4: 100 - 175

Good? Bad? Average? Seems 3 and 4 are pretty low for a "less than 60k mile engine".

I would agree with your assessment. I would prefer to see within 5%, that engine dropped 8%, then 15% (x2). If he's measuring cylinder 1-4, he may have had a dead battery? Otherwise I'd consider it a reasonably strong rebuildable core.

Perfect, thanks for the help. So 180+psi is healthy with less than a 5% spread between cylinders.

When searching for a used motor, how should wet compression compare against dry?

Any preference for telling the true story about a motor between these?

JDM Rain Man strikes again