JC951

What should the compression numbers be for a 1986 turbo? mine are between 125 and 135

potent951turbo

The last compression test I did on mine was around 145psi per cylinder, which is considered to be in good health from what I have read. I also helped test another 951 engine about a month ago which did around 140-145psi per cylinder.

LS1Porch

In general i think the most important thing is that they're all within ~5-10% of each other. Sounds like your motor might be a little more worn than some, but if it's not burning a ton of oil it's no big deal. Things like altitude affect the readings so i wouldn't say "if it's not ____ it's a problem".

Charles A. Toupin

I've been rebuilding my engine. Compression was 125 all over the board... eating oil like crazy (I'm DE'ing it though).

140 + is an engine in good shape.

c.

adrial

My engine was ~130 across the board before it blew a HG @ 90k and it was the same after the rebuild (after ~1k mile break-in). I never tried another compression gauge or used this one on a different engine, so I am assuming the gauge is a little off -- but who knows.

So long as it is even across the cylinders, you are in good shape IMO.

The typical "acceptable" range is 140-150 hot, with the throttle wide open.

spyder348

140. 15-50 mobil should help some.

Mike Lindsey

The compression ratio on the 951 in reality ranges from 7.5:1 to 8.5:1 so the numbers vary from
engine to engine, healthy or not. If you're above 125, and similar across the board, unless you have
a good reason to rebuild, just drive it.