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JDM BPZE Compression Numbers

 
Old 02-04-2019, 02:13 PM
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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 ****?

Thanks,
Brian
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Old 02-04-2019, 02:16 PM
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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.
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Old 02-04-2019, 03:00 PM
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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".
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Old 02-04-2019, 03:06 PM
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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.
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Old 02-04-2019, 03:08 PM
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Perfect, thanks for the help. So 180+psi is healthy with less than a 5% spread between cylinders.
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Old 02-04-2019, 06:02 PM
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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?
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Old 02-04-2019, 07:53 PM
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Originally Posted by concealer404 View Post
Not all the JDM VVT motors had the 10.5 pistons.
JDM Rain Man strikes again
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