Cold compression test

[280ZED]

What is the difference in psi for a cold engine compared to a warm engine? I did a cold compression test on my 280Z 2+2(I haven't got my fuel system straightened out yet and was told it may have a dead cylinder) today and found 85-95 psi for all 6. Is this normal? Warm engines for a 280Z should be 170-180. How much more pressure will I get once I have my engine running and warm? :paranoid:

[Nissanman]

At least the compression readings are close to each other, that in itself is a good sign.

Try dosing the cylinders with a squirt of oil, to help seal the rings, and repeat your test.

The compression readings should increase.

If the lowest reading is 75% of the highest, chances are the rings and valves are OK.

Make sure the throttle butterfly are wide open when you do the test.

[280ZED]

That helps. I was scared that 85-95 psi cold was too low. I think the engine might need to be broken in again after 25 years of not going anywhere.(the previous owner did start it in 2000).