924Board.org

[levans924]

i just purchased a 78 924 but before i bought it had a compression test done.
these were the results

1-170
2-173
3-169
4-175

is this good?

[numbers]

Very.

[Smoothie]

I'd say it's very good that the numbers are so close to one another - small percentage of difference between cylinders. Not sure if they're a little high though - maybe indicating some carbon build up? (REALLY not sure about that, so; don't worry about it - they're probably just real good numbers.)

[ This Message was edited by: Smoothie on 2002-03-23 04:41 ]

[Cbass]

Those are quite high indeed. Ask the previous owner what sort of work was done to the engine.

[Smoothie]

If you do ask the previous owner - also ask (if the head was off) what part # head gasket was used. I realise this might be an obscure question, but; he might just happen to know. A thinner head gasket might account for higher compression readings.

[ This Message was edited by: Smoothie on 2002-03-23 04:49 ]

[ricomartinez]

Yeah, if everything is stock, I'd either just be happy they are so close or get another gauge to very the first gauge is good.

[Smoothie]

Somewhere over the years I read that it's ok to have high readings - most important is that they all be about equal (within something like 10% of each other). Might just be getting a few more HP out of it. If detonation is a problem, as can happen with higher compression, try higher octane gas. If detonation is still a problem and the high compression is due to carbon buildup, there are ways to get some of that out without dismantling the engine.

[ This Message was edited by: Smoothie on 2002-03-23 10:30 ]

[Cbass]

Try using 87 octane gas. Punch the throttle, release quickly, run at high rpm, the usual. If you get any significant detonation, then you know you have high compression.

[Smoothie]

levans924 -
Is that a US spec car, Europe or something completely different?

[Roger Hall]

rejoice and be happy

those are great readings