Hi guys, i bought my car and it sat for 5 years without being started. The previous owner replaced the head gasket, and all of the valve seals and everything while it was sitting. I have the motor in and it seems to be running perfect.. I purchased a compression tester from harbor freight for 25 bucks.. i did the compression test and it was as follows: 140, 140, 145, 140.. it was consistent after checking each cylinder 3 times..

I've read people typically have 230 or higher. we did do the test cold and dry (we didn't drop any oil into the cylinder head) so i've read that the numbers are substantially less. From what i have read it is fine just because all of the numbers are the same..

Can anyone confirm this? I am far from a mechanic so putting this motor back in has been a learning experience for me. I have tried doing a ton of research and keep getting some mixed results so i figured i would hope someone knowledgeable could help me out. Thanks!

 

A compression test should be done on a warm/hot motor. That should raise those numbers a little.

 

IMO its too low, they are all pretty close, but try with the engine warm.

 

Did you do the test with WOT? (Wide Open Throttle)? Meaning when you crank it over, the pedal should be at the floor. I had low numbers like that when I didn't do WOT, and they all shot back up into the 240s after.

 

Yes we did it at WOT and without being on the pedal at all and the numbers were identical. I read somewhere that 130 is the minimum. I don't think i have anything to worry about just because it was cold and probably completely dry of oil. I plan on testing it warm tomorrow i just wanted to get some opinions and see if anyone else had similar results. Thanks guys

 

Post back with warm compression numbers. I did a cold test on my car last week though (hadn't been sitting 5 years though), and my lowest cold reading was 220. That's after 197k miles.

 

There's a very good chance that the numbers are low from a faulty tester. Is it the US General tester? I also bought a compression tester from Harbor Freight for around $25 and my numbers were about 170 consistent, on a warm engine on WOT. I was paranoid for over a month because of this, then I looked it up and just about everyone with that tester said it has a design flaw and reads really low. I went out and borrowed a OEM tester from autozone and got 210 with that. Just something to consider.

 

That's exactly what i was considering. I got the universal kit for 25 because the regular one was sold out. I'm going to try it again on a warm motor tonight hopefully. If it is still very low i'll try getting a new tester