Losening stuck piston rings

[Guffin]

Has anybody been successful loosening stuck piston ring by using oil additives? There are some oil additives on the market that are said to clean the engine inside and loosening up stuck piston rings. These additives are rather expensive so I wonder how effective they are.

Jan

[Charles2]

I would first confirm the diagnosis. Stuck rings aren't really that common and if they occur, it is usually the compression rings that stick. I don't think that oil additives would help much here. I have used them in the past for a variety of engne problems and have never had them help anyone but the additive manufacturer. I think you are due for at least a valve and ring job.

[Shop Rat]

My husband swears by a mix of old gasoline and oil mixed together. He says it works better than anything he has ever found. And he had to loosen every piston in a 1939 Dogdge engine after it had been "coked" and then sat for several years.

He also found a straight tree limb the exact size of the piston and cleaned all the bark off of it. Then he sanded and smoothed it up and made sure that the end that would come in contact with the piston was level as well as smooth to avoid pressure points. He let the gas/oil mix sit in chamber for a few days. Then each piston got the wood put on it and gently tapped until there was even the smallest amount of movement. Then they sat a day or two more to let the mix crawl into the new area. He finally got all of them out with damage to only one. And that, by his own admission, was his fault. He should have let it sit another day and instead he gave it an extra "whack" and broke it.

The wood idea came from a friend that works on Model T's and has for most of his life and knows lots of tricks on how to do stuff with cars.

[Guest stude8]

Guffin, are you talking about an engine that is still assembled and running or one with the cylinder heads removed for service? If you are talking about an engine that still runs but smokes bad the problem could be worn valve guides (Over head valve engines) that pass excess oil into combustion chamber. Problem there is not the rings. How did you evaluate it is "Stuck Rings" problem.

I have heard stories about pouring large amount of penetrating type oil into carburetor while engine is running at fast idle speed until the motor finally stalls. By this time it is saturated with the penetrating oil and after it sits a few days restart it and see if the rings have loosened after driving it a few miles. Stude8

[Guest BillP]

It looks like he's talking about rings gooed up & stuck, passing oil up and compression down.

Once, during a recurrence of my mad scientist phase, I tried that oil down the carb trick with Marvel Mystery Oil (love the smell of that stuff) in a grim but dreamy-eyed effort to unstick a stuck valve on a flathead Packard. Of course, it made a terrific blue cloud, the Packard continued to chug happily and it still had zero compression on that cylinder.

I thus re-learned the old saw about free lunches and tore the engine down for a proper rebuild.

[WireNut8]

Try using water to steam clean the internals. Be careful not to hydro lock. Works great to decarbon, might free up the rings. Otherwise dump some clean ATF in the fuel. It is a good detergent.

Good Luck

[Guffin]

Thanks for all help. I am talking about a running engine. I restored the cylinder head two years ago so I believe the oil is not coming from the valve guides. Unfortunately I did not check the rings at that time. The cylinders seemed not to be worn too much. The compression is good in two cylinders but poor in the rest (50 to 70 percent of the good ones)

The reason that I suspect stuck rings is that the previous owner put in new rings a long time ago but did not drive the car much. Especially the last three or four years it was mot use at all.

I have been driving the car for about 1,700 miles now with modern detergent oil. I was hoping something would happen to the rings but it takes as much oil now as when I started to use it.

Perhaps the only thing is to lift the top again and take out the pistons. If I do that, it will be next winter's project.

Jan

[Guest BillP]

Maybe the rebuild never broke in, that is, the rings & cylinders never became intimately familiar with each other. Before disassembling the engine again, what about running for a few thousand miles on straight 30 weight non detergent with changes (plus filter) every thousand. Don't abuse it, but don't baby it either. Put a load on it and run through the rev range. Chrome rings are especially prickly this way, don't know your type.

[Guest Roamiinrooster]

I have a 1939 Buick original 38,000 mile vehicle been in my family since new . Has been sitting now in my garage for 10 yrs . Seems as oil ring has stuck as oil on plugs in 2 cylinders and mis fires ! Any trick i can use to possibly free up without dis-asm ! 

[Rusty_OToole]

I would try using thin oil like 10W30  with an additive like Marvel Mystery Oil or Rislone. And some in the gas. Then take a few long trips, 100 miles per day. If it did not get any better then the only thing to do is tear it down for a ring and valve job.

 

Sometimes they free up and sometimes they don't. But short local trips won't do much, the engine has to get good and hot.

Edited April 26, 2017 by Rusty_OToole (see edit history)

[misterc9]

Years ago I had good luck using Rislone engine oil treatment.The full quart size worked best rather than the concentrate. I ran it about 500 or more miles to get results. The smoking eventually went away.

[cahartley]

In addition to detergent oil add a bottle of a detergent additive and beat the heck out of it.

Sitting around won't accomplish anything.

[C Carl]

Hey 'Rooster : Recycle whatever oil is in your crankcase (unless it is 10W/30 FULL synthetic) , and refill with 10W/30 FULL synthetic. FULL synthetic means at least Mobli 1. That means Castrol is out (unless they have improved their product in the last few years - I don't know). More synthetic yet is Amsoil , and I may be switching to the newest Penzoil synthetic which is made from natural gas. Lots of rumors persist about drawbacks of using synthetic oil in old engines. One of them had to do with provoking leaks. That did have some validity A FEW DECADES AGO when synthetic oil first came on the general market for public consumption. Synthetic oil has been around for longer than most people realize. Military use of synthetics goes back to WW 2 , I believe , and HAD to be used in extremely cold environments. "Modern" high altitude aircraft recip's needed synthetics because of the extreme temperature variations in the conditions they operated in. Of course turbine oil must be synthetic. But yeah , EARLY synthetic did find clever ways to drip on your driveway. The one drawback of changing to synthetic oil in very high mile old engines which IS valid might just work in your favor. Synthetic oil lubricates so well , and is so detergent , that carbon seals built up at the rings will disintegrate over time with synthetic. Give it a try. Get the old Bu' out on the road and don't baby it. It will be fun , too ! How are you tires ? Oh , also , keep running synthetic oil in your engines. Your '39 will in many respects be a 38,000 mile engine forever by doing so. 10W/40 might be right for the long run. Cheap insurance in the worst case. Good luck to you !  - Carl 

[Rusty_OToole]

I have only seen one engine with stuck rings that I know for sure what happened, because we tore down the engine in a shop I worked in. It was a 1970 Chevrolet six cylinder pickup truck that had been off the road and in storage for 10 or 12 years. A local carpenter bought it. He used it for a few years, all on local work and short trips to the lumber yard etc. It started and ran well but burned oil. After a couple of years he had us tear it down for a valve job. With the head off, you could see a ring of rust marks in each cylinder where the rings had been frozen to the cylinder. We took out the pistons, honed the cylinders with a bottle brush hone, and put it together with new rings and a rebuilt cylinder head. After that it ran like a dream and burned no oil. This truck had very low miles on it, I think it had 25000 or 30000 when the customer bought it.

 

Other engines with suspected stuck rings usually came around after some use. I think the reason the truck didn't was that it was used for short trips and never got thoroughly warmed up.

 

There was another case of a crazy Englishman named Derek Arnold. He liked to buy odd old cars. One time he was in California and bought an early fifties Morris Minor convertible in a junk yard. The carburetor was gone but he found one off a Ford Escort that would fit. Then he set out to drive it back to Ontario, a trip of 3000 miles or more. It burned oil like mad so he bought a case of oil and topped it up every time he stopped for gas. As he went along it burned less and less oil, by the time he got home it burned no oil at all. I can only figure that sitting in a junk yard for years with no carburetor rusted up the rings but over time the heat and oil made them come free.

 

I have seen other old cars that were out of commission for years. When they were revived they ran but not too well. But with some oil changes, tune up, and driving they soon freed up and ran well.