What's a good way to get a ring loosened up that has sat a while and rusted into the piston? Piston is removed from engine. I've had it soaking for some time then tried boiling it in RV antifreeze for heat in hope of loosing it up. hasn't worked. I was hoping to save it and not have to replace it. The external surface looks ok.

If you havent yet, leave it in the hot antifreeze for a couple of days.

I did it for a couple days with no appearent change. Is there something better to boil it in? I thought about using a propane torch but a little leary of getting it too hot. Was hoping to loosen it up and clean it up before assembly as to keep the crap from scratching the cylinder wall.
A lot of years ago we had an antique engine that the piston,cast, was stuck into the steel cylinder. We soaked it in different things for over a year and no luck. This was a big stationary engine with a bore of about 6". Used an old hydraulic cylinder ram and a 15 lb. sledge directly on the piston every month or so to no avail. Then an old wise man said to soak it in lacqer thinner. Did so for a month or so and tried the sledge again. It moved! Just enough to see it had. Some more soaking and hammering got it out. Later it did run. Same piston and rings. They just don't build like they use to. Sometimes that's a good thing.

Eagleflyer,you just answered your own question.Soaking the piston and ring in Lacquer thinner will indeed soften this carbon based gunge and make cleaning the ring and piston groove much easier.In alot of cases,the softer elements of the build up will merely dissolve on their own into the lacquer but some harder portions made indeed need some physical agitation with an old tooth brush to help remove.Just be patient when your doing it and jiggle and slide the ring back and forth a bit at a time allowing the the thinner to better penetrate all around the ring,especially behind it.Jusy remember to use soft tools when cleaning to avoid any uneccessary scratches.All the best in your endeavours.

soak it in creasote the kind for treating wood you can get it in quarts and gallon can , It will make the piston and ring look brand new and will not hurt the material . I have used this method on car engines and all sorts of engines that were froze up .

Don't get any creasote on your hands. It will chap them to no end.

Enjoy,

Jim

well you are supposed to use gloves ,I thought that should be common knoledge but it is a good point to bring up thanks

I used to use this as part of a cocktail to soften racing tires.. Use gloves and you should be fine.


exposure to creosote over time can cause skin problems, kidney and liver problems, possible birth defects, unconsciousness and death

If you get around hot creasote where the fumes are comming off, it will just eat you up. It'll seem to get the soft skin under your eyes first. As a young person, I helped build several piers with creasoted wood. The sawdust would get on your skin and give trouble.

Follow precautions and it will be fine.

Enjoy,

Jim