What temp to check compression?

bretto

Seaman
Joined
Sep 20, 2006
Messages
59
Do you check it when the engine is at full operating temp or cold. Does comression normally go up when after the engine is warm or visa-versa?
Thanks,
Brett
 

baxtr

Petty Officer 1st Class
Joined
Jul 16, 2006
Messages
387
Re: What temp to check compression?

you can check it cold, as your motor gets warmer, the rings do expand,that is why there is a gap in the ring, so they don't expand and get too tight in the cylinder.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,754
Re: What temp to check compression?

Warm is more consistent.
Do it cold if you can't warm it up.
Readings tend to be higher when the engine is warm.
 

bretto

Seaman
Joined
Sep 20, 2006
Messages
59
Re: What temp to check compression?

So I checked the compression last night cold and got all 3 at 115 or so #'s. So is it safe to assume that the compression will be more so when at full running temp? Are those good #'s? This is on a '83 Force 85 by the way. Also I sorta goofed and didnt ground out the plug wires when I did it, do you think I damaged the coils at all?
Thanks all,
Brett
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,754
Re: What temp to check compression?

Compression is fine.
Damage? don't know.
 
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