Compression?

[wylie coyote]

Just curious...I hear a lot of discussion about checking the cranking compression, but I have yet to see any numbers that should be considered within range for decent shape. What is considered reasonable? Of course, depending on altitude and so on. Thx

[fredintoon]

Just curious...I hear a lot of discussion about checking the cranking compression, but I have yet to see any numbers that should be considered within range for decent shape. What is considered reasonable? Of course, depending on altitude and so on. Thx

Hi Wylie,
150 psi on all 4 is real good. Note that all 4 should read within 10% of each other. Thus 120psi on all 4 shows a high mileage engine that's still good for several thousand miles more but 150-150-150-120 shows #4 is in trouble and needs work.

[BigRed]

Well, Fred, that makes me really excited 'cause I just checked on the weekend, and had 152-158 across all four. Didn't expect her to be in that good a shape!

[wylie coyote]

Here's a link for some altitude conversions I found regarding compression. I know some of us are pretty well up there.
I don't know if I pasted this in right, but you should be able to follow it by pasting it or whatever...(Hey- I tried)

http://www.pelicanparts.com/techarti..._rebuild-2.htm