How to Repair a Stuck Engine

By Staff
article image

While “barn fresh” engines are still appearing into the hobby, more enthusiasts are tackling the more serious restorations of engines which have stood outside in the elements for years or been through fires. A subject which comes up on the Stationary Engine Mailing List with regularity is how to free a stuck engine:

“On Saturday I picked up a McCormick Deering M 1.5 HP engine that will be a birthday present for my dad. While it’s being given to him to restore, I would like to get a few things done to it before I give it to him, mainly getting the stuck engine freed up. The connecting rod is disconnected, and I have the head off. I turned it on end and have been soaking it in Kroil. I’ve given it a few whacks using a hammer and a chuck of lumber, but it doesn’t seem to be moving. I know patience is probably the best tool for a job like this, but it’s not a tool I’m very familiar with! Has anyone had any success using Kroil for this? I know it works wonders on everything else. I’ve also thought about making a steel plate to bolt on where the head goes and putting a block of wood in the cylinder and tightening it down to put constant pressure on it, but I’m afraid of cracking these holes out. Anyone have any ideas or tricks to share?”

I had a stuck engine a few years ago and it took about a month to get my rustbuster to finally leak through. I was using Gibbs-it. Great stuff! I had my stuck engine blocked up and would go out and give it a good rap everyday. After about a month there was fluid running down below the engine and I was able to pound it out without damage. I thought about taking it to my favorite machine shop and pressing it out with his 12 ton hydraulic press, but because of design of those engines it would be hard to block up under the ram without possible damage. I realize it’s a gift for your dad, but sometimes haste can ruin a good engine.

I had a similar problem with an M. Since it is a sleeved engine you can remove the piston/sleeve assembly. That will make it a little easier to work with. I tried soaking it for over a year in Kroil. I heated the sleeve red hot with a torch several times and hammered it with a wood block. Nothing would move it. I finally made a slug that fitted over the head of the piston and pressed it out. Once it moved initially it was easy to move the rest of the way.

Patience, patience, patience! If you are not familiar with this, you need to learn to be if you are to play with the old engines. Without it you have the great potential to turn your engine into a piece of scrap metal and break parts that are expensive to replace. Depending on how bad your piston is stuck will dictate how long it takes to get out.

Since your stuck engine has a pressed in sleeve, I would suggest soaking as you are doing till it starts to creep through the rings. You may tap on it once in a while with a hammer and block to fit the piston. If you use too much force, you are going to end up with the sleeve and piston on the floor. Many of us soak engines for months to a year! I would not heat it due to the seals in the sleeve.

A puddle of burning, boiling diesel on top of the piston isn’t bad either -just remember there’s an O-ring on that sleeve. So what are we left with? Soaking for a long time and whacking it every day, soaking, whacking and then using the jack plate you mentioned, or pushing it out with grease (after a long soak under prressure, with a bit of whacking in between).

I’ve had fairly good luck using rubbing alcohol. I havn’t tried it on anything stuck really bad.

I tried several methods (including lots of burning) when I was freeing up my 2 HP Stover KA engine. It was one of the most stuck engines I have ever seen. I ended up using the “grease method.” Since your engine is sleeved, this method may not work, but you may be able to clamp in the sleeve. The grease gun method is pretty much sure fire, if it doesn’t get the piston out, the piston probably won’t come out in one piece. It does take some time to set up correctly, but it is definitely worth it.

The M’s sleeve won’t come out through the crankcase. It has a flange at the head end and must be pushed out from below, by hammering on a wooden block pushed against the base of the sleeve. The notch at the head end of the sleeve at the top center is for inserting a prybar once it’s started.

I left the 2B Buzacott soaking for 15 years! It still took a lot of effort with the big hammer to get the piston out. But the patience was worth it as the engine is now running with original piston, two of the three original rings and the bore was fine after a light hone.

How about using candle wax? Melt candles on top of the piston until there is a large accumulation of wax on top, then warm the wax gently with a blow torch, until the wax melts and runs down all the small cracks. Then use the block of wood and a large hammer.

I still believe in the good ole heat method. When removing the piston from the Leader we did it with a furnace fan blowing into the engine while using a bag of charcoal. It turned orange then we doused it with water. She released!

Other means to try: Always soak the piston first for some time to get fluid to creep through rings.

1. Use wooden block and sledgehammer

2. Use loose rod bearing bolts to rock the flywheels back and forth to use the mass of the flywheels to jar the piston loose.

3. Use a hydraulic press.

4. Build a plate to take the place of the head with a fitting for a grease gun. Bolt on plate with a gasket, fill space between plate and piston with oil/grease, then use the hydraulic pressure of your grease gun to force the piston to move.

5. Build a plate to take the place of the head, place wooden block between piston and plate, then alternately tighten head bolts to force block to move piston.

As the engine is a tank cooled version, with a water jacket, I filled the top of the piston and the water jacket with diesel. The diesel in the water jacket is separate from the diesel on top of the piston, and can be set alight. After an hour or so of burning this heats up the casting all the way down to the cylinder, allowing the diesel to penetrate between the piston and cylinder and free up the piston. This worked really well and with a little battering with a rubber mallet the piston came out.

So, if you have a stuck piston which needs to be freed, the three best tools in your toolbox will be patience, heat, and force, applied in various quantities over a period of time.

Contact Helen French at http ://

Gas Engine Magazine
Gas Engine Magazine
Preserving the History of Internal Combustion Engines