I did a compression test today and I thought I would post some numbers. The engine in question has about 80k on it. The first time I did the test it was on a cold engine cuz im a dumbass and i forgot to let it warm up so i did 2 of the 4 cylinders before i realized what i was doing. Anyway, this is what i got:

cyl 4: 28 psi
cyl 3: 93 psi
cyl 2: N/A
cyl 1: N/A

I started the engine up and let it get to operating temperature and then re-did the test:

cyl 4: 55 psi
cyl 3: 151 psi
cyl 2: 15 psi
cyl 1: 140 psi

wow...i put oil in cyl 4 and cyl 2 (the ones I had the most problem with) and this is what i got:

cyl 4: 115 psi
cyl 3: N/A
cyl 2: gauge did not register anything (shot up to about 30 and immediately went back down)
cyl 1: N/A

what do you guys think? Keep in mind I have stock compression and im running crower 2's. I will rebuild the engine REGARDLESS. One of the reasons i could attribute to such low numbers is that i had the cylinder head off the car for a couple of weeks cuz i was waiting for valve springs and the cams so the valve seals may have dry rotted...this is f'n ridiculous. No wonder the car is so slow; It doesnt help that it's non-turbo either...Also, you may believe it is just a bad compression tester, but how do you explain the huge fluctuation in numbers? It has to be the engine, there is not enough evidence to prove otherwise.

That blue car got me boobies once

I think you don't know how to do a compression test... unless your car is completely miss timed and your valves are completely open when they aren't supposed to be. Something to that effect is the only reason for that bad of compression. I still don't think you know how to do the test though.

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The wonders of 2gnt chat:

here is a link to the compression test writeup that i used when checking compression before doing my headgasket swap http://www.2gnt.com/www/corbin/comp.html

give it a good lookover also make sure you are disconnecting power and fuel relays first

those are the exact instructions i used. word for word

That blue car got me boobies once

Does your car idle like shit? I'm convinced that your timming is off, check your marks.

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yeah i agree with those numbers your car should not even run much less be slow? ? i seriously doubt bad rings would bring your compression down that low.

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i have crower 2's so the idle has a noticeable lope to it. The engine has no problem with maintaining idle either. It revs up to redline smoothly so i doubt the timing is off and ive put about 3000 miles on the car without issue and even though it is slow, it is still faster than my last eclipse which only had i/e. i will re-do the compression test today considering some of you are questioning my abilities. Im also still inclined to believe that the valve seals are the culprit. Info?

That blue car got me boobies once

just because your car holds idle and goes to redline is no indication that your timing is dead on. My car ran with the timing off 2 teeth. At first i thought it was a bad IAC or plug wires. Until i got home and checked the timing. Don't get stuck on "my timing is perfect" until you line up your marks and recheck it. About your abilities to check your compression, you may do the writeup correctly but if you have a shitty gauge whats the point. If you get the same results then get another gauge and try that. If your compression was seriously 0 then your car wouldn't run.

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The wonders of 2gnt chat:

I should probably add that I set up the timing with the engine out of the car and when i did, all three of the timing marks were dead on. like i said, ive driven the car for about 3000 miles without issue. And tell me, if your car is out of time does that mean it will run perfect in every rpm range except idle? I would think not. If your car was out of time, you would notice it at idle and throughout the entire rpm range. That is, if you knew what you were looking for.

That blue car got me boobies once

-Unplug motor fuse
-take out one spark plug
-put on compression checker
-go WOT
-crank the car until needle stops(don't go over 10 secs.)
-repeat on the rest of cylinders

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The wonders of 2gnt chat:

Your car should run like garbage with those numbers...

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if it makes you feel any better I often think my car is gay too, it goes from one problem right into the next

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Don't work for the system, Let the system work for you.

Maybe there's something down in the spark plug hole keeping the tester from sealing and registering good numbers?

My mustang had loads of shit down in the spark plug holes, I blew it out with the air compressor before pulling the plugs. So much shit came out of each one that I had to blow off the intake and valve cover each time also.

~Luke
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1969 Cougar - 11.91 - 380HP
2007 GSXR 750
1999 OZ - SOLD - 15.26 NA - 14.71 on 75 shot

Agreed this dude probably has multiple problems, but someone please explain to me how putting oil in a cylinder for a compression test and getting a higher number as a result is NOT the rings. It defies logic to think that putting oil in the cylinder will affect the valve seals. I am resisting the urge to get cocky in case I am missing something, because it just doesn't make sense to me. Also, when you labeled N/A on your charts, was that because you didn't do a compression test on those cylinders in that round of testing, or because the cylinders read 0? I can't possibly see how, with Crower 2's, you could have enough overlap to read 0, that'd take a level of incompetence that is beyond measure, and thus would go down in the hall of fame. There is definitely something odd about this engine though, I’m thinking that if you can't get anywhere with these posts, you may want to pull the head and check the cylinder walls for scuffing.

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Read what he wrote, the N/A means he didn't do it for that one.

As far as oil in the cylinder, I think it can show bad rings, but I think it will also show scarred cylinder walls, or over warn cylinder bore. It won't affect valve stem seals because they're on top of the head. I believe that if he put enough in there, it could help seal at the valve seat. But that's just my speculation, I don't think that would actually happen.

~Luke
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1969 Cougar - 11.91 - 380HP
2007 GSXR 750
1999 OZ - SOLD - 15.26 NA - 14.71 on 75 shot

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=5&topic_id=76483&mode=full

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hmmm. well, i havent checked the timing yet because im lazy but i might be forced to do something tommorrow. It appears that the general consensus is that my engine has a lot of problems. (thanks for putting things into perspective guys) it's right to believe that you can put oil in the cylinder to see if the rings are bad and its obvious that that is the case in that one cylinder. My car also burns oil like crazy. Seriously I can go through a quart each week. ive always wanted to build a motor and now i have an excuse to do so, but i think i will buy another compression tester and see what my compression is with that first. there's something i dont understand though: when i had my cylinder head off you could still see the cross hatching on the inside of the cylinder walls so i assumed that it was a good engine with little wear. I assumed that there was a direct relationship with the wear of the cylinder walls to the condition of the rings but maybe im way off. Do the rings wear independently of the walls?

That blue car got me boobies once

It's a safe bet that the rings aren't that bad.

Valve stem seals don't hold in compression - they hold out oil. If they failed, you would have smoke at idle and high-vacuum conditions.

Try another compression tester, blow out the cylinders with compressed air, and if you don't like what you see, try a leakdown test.

The tester is suspect already if it shot up to 30 PSI and came back down. A compression tester is supposed to have a checkvalve in it so that it holds at the peak pressure.