Hi,

I'm looking at a -6 that had on compression test on 7/24 and the results were:

1-160
2-170
3-155
4-150
5-170
6-110

That car has sat for quite a while but the owner says it runs well. He asked the same shop to test the compression on 7/31 and now cyl #6 is showing 140.

Can compression improve when taking a car out of storage and driving it? Or is this just sloppy work on the shop that did a PPI?

-Steve

Yes it can. rings could free up, valves seats can clear up, and more oil on pistons from cranking can increase pressure. valve clearances must be checked before performing compression test.

Yeah Steve, what he said.

maybe forgot to hold the throttle open for # 6 ?

Got it, thanks.

-Steve

Could have had a chunk of carbon holding a valve open.

Once it runs again, it can improve even more as everything " re-seats " and As Woody said, a chunk of carbon, acorn shell, mighty mouse terd, chopstick, etc could have fallen into the chamber and kept a valve from closing fully.