HELP! One piston ring is stuck but good.....need solution

During my teardown of my spare XJ550 engine (lower mileage that I was hoping to use to replace my high mileage one) the same cylinder #2 with the busted spark plug was giving me grief while removing the jugs. I managed to get the jugs off but saw the issue - the top piston ring was seized in the groove but good. So far, I've tried everything I can think of to remove it but no mas. 48 hour soaks with 100% acetone, 50/50 acetone/ATF, CLR, vinegar, penetrating oil, you name it. Even using hard steel tools in the gap to try to pry the ring out is fruitless. Of course all other rings on this engine are just fine. Anyone have this issue and have successfully resolved it, without wrecking the piston?

 

Do you suspect it’s stuck because of carbon or is it mechanically stuck??

if carbon, Berryman chem-dip is good at eating carbon. Or just plain gasoline.

 

Old fashion carburetor cleaner I think it was GUNK that advertised being the "carbon blaster".
The problem with carbon is when it builds up and gets jammed in the ring lands over time it also gets compressed during the contraction of the aluminum enough to effectively lock out any cleaning solvents, some heat might be in order here to expand the piston enough for solvents to penetrate. When I say heat I mean close to the running temp of the piston so on say an air cooled XJ I'm talking some 260+ degrees.

 

I think it is rust stuck - this was the same cylinder that had the rusty sparkplug that broke off trying to remove it. The cylinder walls had some slight discoloration but no surface rust or any pitting. IDK, it could be either rust, carbon, or mechanical. If I had to guess - mechanical, like really, really jammed on.

Soaked it in carb cleaner. Also tried brake parts cleaner. No mas.

 

Hate to say it but- there is always eBay. Or maybe someone around here might have one laying around

 

Rust stuck is a different game all together.

 

Would boiling the piston crown in water make any difference? Never tried it but if all else fails.

 

I don't see anything to lose.

 

Yes boil then cool and boil again see if they free up.

 

I’ve had good luck with CLR and evaporust for rust problems. Unfortunately, the cost to buy the stuff to soak it in might be throwing good money after bad.

 

Thanks for all the ideas. Right now it is just the top ring that is stuck, the others were all free. I just can't tell why it is so stuck, so I'm speculating that whatever moisture issues got into the plug threads also got into the top (and only the top) ring. Puzzling since the cylinder looks fine, so I'm thinking all corrosion happened after bike was parked. Many Ebay vendors with used parts will not ship to us here in Canuckistan, even if shipping and duty were reasonable $ (they are not, especially considering a 69 cent dollar). But I've got parts to trade/cash if anyone close to me has a 550 piston with rings to offer up. I'll keep trying things - maybe that water boil is next up on the list.

 

Jeez - I didn't realize that shipping to Canada was so expensive.

 

Have you tried heating the piston on inside behind the stuck ring? Mabe MAP gas would be best provided it doesn't damage the piston. Don't know if the boiling water will be hot enough.

 

It's the shipping cost, then the import duties, then the currency conversion, then - yes there's more - the 13% sales tax on ALL of that. A piston with rings in typical used condition being listed for $40 US would cost me $140 CAD just to get it to my door, one month or more after I placed the order.

 

Ya, its nuts. I checked the cost to send a 1 lb package with $10 declared value and it was like $140. What in the sweet fiddlers f$#%?? That sucks for you.

 

Shipping costs would decrease if Canada was our 51st state!

 

very true but then we’d have to give up all those extra genders

 

I'm close enough to the border where I could throw it over the fence.

 

So........It's toast. Not a chance this piston is salvageable. Even propane blowtorch and modified jeweller's screwdriver used as a chisel would not budge this friggin ring. This is now the only part preventing me from rebuilding this engine. I'll have to diagnose the original engine that has over 70,000 miles with a compression tester when it finally warms up here, but I suspect that engine is too far gone as well, even for parts. Will reach out to Hogfiddles, maybe I can come down to his place in June with the bike and spare engine, but this is a job likely too big for his carb clinic.

 

So what are the odds of using a piston from the 70,000 mile engine in the rebuild? This would be my first move.