compression and leak down results

[sekifoce]

compression and leak down results
Did a comprehensive health check on the motor in my newly acquired 87 325is. Nice one owner car with 180k miles. Not sure if this motor has had any major work done to it.
Run smooth, no noises or smoke.
Cosmetically and mechanically well maintained

Would like any opinions on whether to rebuild/refresh this or go with it as is.

Here are the results of compression and leak down:
#1 165 15%
#2 145 14%
#3 150 11%
#4 155 11%
#5 150 18%
#6 145 8%
All leak down results are valve related except 2 & 3 valve w/slight compression loss.
Planning a few mild performance upgrades- lightened fly wheel, exhaust header and free flow exhaust system, ECU chip (any addl. recommendations appreciated).
Thanks!

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[Zambuzan]

Nice, mine was also a 1 owner car at 210k. I also need to do a compression/leak down test...

Some mild e30-specific upgrades off the top of my head:

- "OEM" short shifter (25117527252) with new shifter bushings (some companies have poly options as opposed to soft rubber)
- e46 steering rack (much faster ratio than e30), this is basically plug-n-play
- Soft-Poly suspension bushings

I'd recommend going to FCPEuro.com and flipping through their catalog. They have a good selection of replacement and upgraded parts.

[ZeKahr]

Those compression numbers are within spec for a healthy M20 according to the Bentley manual.

[ForcedFirebird]

Those are OK numbers. Fine for a street driven e30, power will be just slightly down from fresh.

There was just a thread about this a few days ago....

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/9939897-compression-and-leak-down-results

And as I stated there:

Did you note where the leakage was? The skewed numbers could be rings, or valve sealing. When doing a leak down, we typically note where the air is escaping. During the test, the throttle body should be opened, smoke in the tailpipe, and the dipstick checked. If air comes out the exhaust or intake, it needs a valve job, if it comes out the dipstick, that cyl ring set is compromised.

If you are fin with it, then it's not "out of spec" with there being an ~8% difference across the board. If you do a valve job, the engine will wake up a bit. I dyno'd a tired m20b25 that had 145psi across the board and it still managed to make 145whp. When they have a fresh valve job they are closer to 155, and will see 180-ish psi cranking..

EDIT: Wait, the first post in that thread, as well as this one is exactly the same. Someone have dual memberships?

[SteveG]

That was my post, have no idea how it got reposted by "sekifoce"...