Low compression

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Schurkey

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IF I suspected a ring stuck in the piston by deposits, I wouldn't put solvents in the gas tank, or in the oil pan. At least, not as a first procedure.

Water down the intake manifold works wonders to remove carbon from the combustion chamber. Might work to remove carbon from the top ring...maybe.

If this were in MY driveway, I'd warm the engine, pull the spark plug on the low-compression cylinder, and dump 4 oz of GM Top Engine Cleaner into the cylinder. Rotate the crank a time or two by hand, leaving THAT piston at TDC. Put the plug back in, loosely, to keep debris from falling in. Leave it overnight.

Next day, pull the plug, crank the engine with the starter to assure it won't hydro-lock. Put the plug back in, start the engine, warm it up...and repeat the entire procedure.

If the Top Engine Cleaner doesn't solvent-clean the ring groove with those two applications, it's going to have to come apart. But you could try the Seafoam or whatever in the oil 'n' gas.
 

Erik the Awful

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If this were in MY driveway, I'd warm the engine, pull the spark plug on the low-compression cylinder, and dump 4 oz of GM Top Engine Cleaner into the cylinder. Rotate the crank a time or two by hand, leaving THAT piston at TDC. Put the plug back in, loosely, to keep debris from falling in. Leave it overnight.

Next day, pull the plug, crank the engine with the starter to assure it won't hydro-lock. Put the plug back in, start the engine, warm it up...and repeat the entire procedure.

If the Top Engine Cleaner doesn't solvent-clean the ring groove with those two applications, it's going to have to come apart. But you could try the Seafoam or whatever in the oil 'n' gas.
Back in my RX-7 days we'd use this procedure to clean up stuck apex seals (the rotary engine equivalent of piston rings), but we'd use ATF. It worked extremely well, and you'd get rid of all the mosquitos in the neighborhood for a day or so.
 
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