Compression Check

Posted by Joe Hall On 2014/9/15 22:26:18

Its been awhile since I have posted here, but often lurk. Today, thought I'd submit the following, for anyone who enjoys playing with numbers on our cars.

I recently changed the plugs in my Golden Hawk's 352, which I last rebuilt in the late 1990s. While the plugs were out, decided to do a compression check. The heads are fresh, with 4000-5000 miles on them, but the rings have about 95,000 miles on them.
Two cylinders were at 175 psi; two others were 150, and the remaining four were in between, with an average of 162.5 psi.

For comparison, records of a freshly rebuilt 352 back in 2002 revealed 170-195 psi, with an average of 188 psi. However, that motor was tight, with EGGE pistons, and ran borderline hot for the first 20,000 miles or so, but had cooled down nicely by the time I sold it at 41,000 miles on the rebuild.

So this 352 is getting a little tired, but runs nice and cool. However, oil consumption is up to about 1000 miles per quart. A freshly rebuilt 352 usually gets around 5000 per quart for the first 50,000 to 75,000 miles. But its not ALL about oil mileage, IMHO.