Is there a way to loosen up stuck piston rings without removing the pistons? Maybe pour some oil/cleaner down the spark plug holes and let it sit overnight and then remove the stuff by cranking the engine without the plugs in it, so that some of the stuff comes out?
By stuck I mean the compression rings are glued or sticking to their lands (grooves ) in the piston. That is bad, as they do not move and hence cannot accomodate for the expansion and contraction of the cylinder. (They are not stuck to the cylinder, that case is called seizing of the piston)
And so the result is compression loss especially at higher operating temperatures.
Ooooh... that seems like a tuffy. Just thinking about the physics of the situation, it sounds like you would have to pull the pistons to solve the problem. I know this doesn't help you solve this, but how did that happen? Dirty/old oil?
Well, pulling the pistons is the last thing I want to do right now. Too many logistics issues (dont have any other form of transport, not too confident of doing the massive job myself)
There are some methods like soaking the rings by pouring some miracle mystery oil / Tranny oil through the plug holes and let them sit for a day or two and then flush out as much oil as possible and crank up the engine. But I am concerned about the risks involved in spoiling the CAT, O2 sensors, more carbon due to more oil burning and so on... Need more wise ppls opinions before I dive.
After a great deal of me lurking about on automotive sites because of engine smoke (sticking rings...replaced valve stem seals)to find out how to get them freed up without removing them, I decided to come back here, register, and report my success.
Here's what I did that finally worked for me:
The engine is a vertical 4 double overhead cam. Initial compression test was 176-150-176-176 out of a possible 191 max. I did this compression test after a tune up when I discovered one discolored plug (#2 cylinder). The #2 cylinder compression tested low. Right away I added acetone, let it sit a bit, then fired it up. Compression jumped up to 176 from 150. I was now noticing smoking at high RPM with heavy throttle. I believe I was smoking before but didn't see it.
I knew I had a stuck second ring and oil rings likely. I tried every chemical that seemed it may work to clear all the rings up, but nothing was working. My only success was getting the top ring working again. But, here's where I had success: I tried B12 Chemtool
Here's what I did: I drained my oil and left drain plug removed. I put the offending cylinder at TDC and poured in B12. Then, using an air fitting I pumped in 120psi (most I could) air pressure forcing the B12 down through and around the piston. I repeated this several times. I allowed some time between each air shot for soaking to occur. I then returned motor oil and drove. Oil pan did not contain any B12.
After the above procedure, I was impressed with the smoke reduction I was experiencing at high RPM. So...I did it again. This time I bought 2 cans of B12 and was very thorough. I kept soaking and blowing it through. (I also put some B12 on the spot under my oil filler cap to see what it did to varnish. Wow...too bad this stuff is bad for seals and some gaskets.)
I almost forgot to mention I did WOT runs after treatments.
Anyway, now I'm smoke free and plan to treat the other 3 cylinders to match them all up clean wise. Sure would like to see a 180 all the way across. Kinda doubt I'll get much more compression since their all matched up up at 176.
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