High crank case blow-by.---I have 87, EA82, 4wd, auto, wgn, 90k miles on clock. The guy I got it from said it had set for 4-yrs. He replaced the leaky water pump, got it smoged and sold it to me. The guy was a little flaky but it ran fine so I bought it anyway. Ran fine for 3-mo. It then started losing power after 5-miles drive. Got so bad it would just stop. I discovered a great amount of blow-by and oil from the PCV line. I replaced the PCV valve and found no change. The compression looks OK to me (120-125 on all 4). Any ideas?

 

Thanks…Jim

Thats not a good compression test result, the numbers are low. Thats a low compression. Do the test again, only this time squirt some oil in each cylinder and give us each number.

 

Sounds like to me the engine is tired.

 

nipper

The oil rings may be worn or frozen in the piston ring grooves. A leakdown test might yield some more information.

With that mayny few miles, and the description you gave-

 

stuck rings

tired rings

PO used some magical elixer to try to hide the problem?

 

nipper

Thanks...

It will ba awhile before I can recheck the compression since it's under 2-ft of snow and a long way from the shop. I guessed piston rings and tried some magic stuff down the spark holes with no luck.

 

I have another EA82 with blown HG. I was just starting to fix that engine when someone said I should join this site and ask first. This replacement engine is out of a manual shift. Is there any issue using it in an auto car?

 

---Jim

Compression isn`t that bad. Blowby isn`t going to stop the motor after a short drive.I`ve owned several w/much worse compression than that.They ran great until the oil rings got bad enough to foul the plugs.

 

Sounds more like a plugged cat.Put a vacuum gauge on the intake for verification.Plugged exhaust might make blowby worse.

 

If it sputters to a stop,check the fuel filer.

 

Blowby may improve after more driving.Could be a little rust on the cyl. walls after the long hibernation.

+1 Nipper, when these engines sit for long periods it is not abnormal for the rings to get stuck. Especially if it was a high carbon engine to start with. I have had success with marvel mystery oil , or atf. I just add a quart to the oil and run the engine at idle, or slightly above for an hour or so. Drain and refill with fresh oil and filter. It may or may not improve your engine, but it is inexpensive to try. I am sure that some other members will have some different methods also.

Compression isn`t that bad. Blowby isn`t going to stop the motor after a short drive.I`ve owned several w/much worse compression than that.They ran great until the oil rings got bad enough to foul the plugs.

 

Sounds more like a plugged cat.Put a vacuum gauge on the intake for verification.Plugged exhaust might make blowby worse.

 

If it sputters to a stop,check the fuel filer.

 

Blowby may improve after more driving.Could be a little rust on the cyl. walls after the long hibernation.

 

 

Hes been driving it for three months without a problem. So that rules out the rust issue.

 

Lets do a pood mans compression/leakdown test. Throw a vaucme gauge on it and tell us exactly what it reads and what the needle does.

 

Loosing power as the car warms up is very typical of bad rings. Once the oil thins out the oil that was acting as cylinder sealer thins out and can no longer assist in sealing the rings.

 

I too have ownbed cars with 90 psi compression, but they were slow and had lots of blowby. I am betting those numbers are cold compression numbers (in all seriousness who takes a hot compression test) and most likly drop significantly when the engine is hot.

 

A clogged cat would be also be a consistnat issue, not just when it was warmed up.

 

Yes there may have been rust in the cylinders, but that can wipe out the rings if it is deep enough.

 

nipper

Did your 90 psi cars stop?........Mine didn`t either.

 

A partially plugged cat might take a few miles of open road heavy throttle to build up significant backpressure.(hot or cold)Should be OK after a short stop though.

 

Splitting hairs,the complaint was power loss after driving,not after warm-up.

Thanks for the ideas. It sounds like I need to dig it out of the snow and check a few more things.

 

I tried the marvel mystery oil, half down the spark hole and half in the crank case, no luck.

 

I had thought about the cat but because it just passed smog I figured it was OK. I live in a small town and I now have reason to believe there may have been some monkey business going on with that. Is there an easy way to check out the cat?

 

It always seemed to have a lack of power even when it was running OK. This is my first suby and with a small engine and auto in a wgn, I thought that's just the way it is. I now have an 84 4-spd wgn and it has more power than the 87 automatic ever did, but I think it's lighter too.

 

I want to get this thing going. My wife is driving a Durango at 10mpg in 4wd and my 84 Suby can get down our driveway while the Durango gets stuck.

 

---Jim

A vacume gauge will tell us if the engine is weak, if the cat is clogged, and a few other things.

 

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

 

nipper