freeing stuck cylinders

[81xsproject]

Other than MMO and ATF, does anyone have any other little tricks for freeing stuck cylinders? A friend mentions some good old Coca-cola.

[prometheus578]

I seem to recall stories that WD40 and such loosen up rust. It's a little thinner than the two oils you mentioned.

[Dsxs11]

Well an off the shelf remedy is PB Blaster. Might not have it in CA not much use for a rust buster out there. My home brewed remedy and it's worked every time I've used it. gallon of diesel 2 liter of Classic Coke. half quart paint thinner. and pour it down the plug holes and let sit over night and KICK it over or use a breaker bar. DO NOT USE THE STARTER. Breaker bar on the crank end will work well and if you can rock it back and forth then keep going. If you try the starter you will probably burn it up before it moves.

[81xsproject]

We do have PB in CA (and I live on the coast, so there is TONS of us for PB). And, dsxs11, that sounds more like a bomb than a cleaner (We are all now being monitored by homeland security ) I will definitely try that one next.

[TopCatGr58]

Hey DsXS11,

Would that be DIET coke, vs. the sugar kind, don't think sugar is too good for the innards?
T.C.

[81xsproject]

I started googling different things like "frozen cylinder" and "froze engine" and found something VERY intriguing. It is a patent request of some kind. Read the description.

The device invented by the petitioner is a simple one-piece device made of durable steel measuring in length about 13/4 inches overall. Its purpose is to facilitate the introduction of lubricants under pressure into a combustion chamber of an internal combustion engine to free a cylinder immobilized by corrosion. The device would be useful only in cases where the corrosion has not physically damaged or changed the internal engine configuration in any way. This device closely resembles a conventional automotive spark plug minus the porcelain-sheathed electrode, but including on top a conventional grease fitting. Its design would allow it to be screwed or inserted into an engine block or head with a conventional wrench. To use the the spark plug or injector must be removed and replaced by the device, which must be fitted into the block in the same manner a replacement plug or injector would be inserted. Before inserting the device, a few ounces of penetrating oil must be poured into the combustion chamber to loosen the rust. Then, heavy (SAE 80 to 90 transmission or gear type) oil must be added to fill the combustion chamber up to the spark plug or injector hole. Before any oil is added, however, the intake valve for the seized cylinder must be seated tightly. With the device inserted in the spark plug or injector hole, a conventional hand or air pressure grease gun is adjusted to the fitting on top of the device. Then, grease under normal grease-gun pressure is added to the oil in the now sealed combustion chamber in an effort to force-saturate with lubricant all corrosion-affected metal to the point where the immobile piston will be freed. The pressure may also expand the cylinder wall to facilitate breaking the corrosion bond and allowing piston travel once again.

[81xsproject]

Oh, I also read that ATF was worked better than MMO, but who knows.

[jetmechmarty]

I knocked a spark plug apart and made a grease fitting for the spark plug hole. Just find the cylinder with the closed valves. A grease gun will bust it loose.

[prometheus578]

"What an interesting idea..."

Might want to pull the cams... all valves closed at the same time.
Obviously, only do cylinders #1 and #4(or #'s 2+3)

[jetmechmarty]

A friend of mine recently used the method on a Chevy V8 that was stuck for 20 years. It broke free applying pressure to just one cylinder!

I have another friend who plays with antique tractors. He uses a hydraulic press to free them. It's less cleaning than grease.

[mro]

Wonder what CLR would do???

I've had good results using an oil/laquer thinner mix.
(was what was in shop at the time)


mro

[Geezer]

Don't put any water based solutions (wd40) into the cylinders.

I've had very good luck with ATF in the cylinders then heating the engine so that the oil gets down the sides of the pistons.

I usually pull the tank and carbs then use a couple propane torches to warm up the cylinders. This time of year you can set the bike out in the sun for a couple hours to help get the warming process started.

When the cylinders are warmed up, put the tranny in high gear and rock the bike back and forth. I've freed many engines this way over the years.

Geezer

[81xsproject]

Thanks Geeze, I had no idea WD was water based. Is PB, too?

[2bhappy]

What if some of the valves are bent and will not fully seat? A tear down is almost always required in that situation. Not meaning to streal the thread, but what if the rings are rusted and glued to the pistons. How do you remove the rings????????

Marc

[TomB]

I've used the Coke method where nothing else would shift the pistons in an old Triumph.