Topic: Compression Check Range?

[GlacierJim]

Looking at buying a motor with the miles unknown. They have run a compression check on it and I was told the following:

"MOTOR WITH 140-150 ON THE COMPRESSION, 25 PSI ON THE OIL PRESSER"

Can someone give me a link to show on a graph where this motor stands? Or give me some idea of what the normal compression range is @ with 25psi of oil presser?

This is for a 1995 YJ 2.5L

Thanks,

Jim

[Jeffy]

Well, that's pretty good compression.  Although I'd like to see each cylinder listed instead of a range.  If one's 140 and all the others are 150, I'd be wondering why it's lower.  Although it's got good compression.  Jeep recommends 120-150 as good.  Max variation is 30psi.

I'm not sure what's the deal with the oil pressure.  If they're doing a cylinder leak test they should be using around 80psi to replicate the engine's normal pressure.  For a compression test, I've never pumped up the oil pressure.  Although I was doing compression tests around 15 years ago.

[GlacierJim]

Jeffy,
  Once again you have the answers :)

Thanks and wish you happy holidays!!


Jim

[Tall Boy]

It'll only take you a little while to check it yourself though.