suggestions for freeing up a locked motor

[ReycleBill]

Fill each cylinder with vinegar if the pistons are stuck. Once the vinegar is inside the crankcase you'll be good! It'll take at least three days. It will also clean the cylinders.

I was thinking, I have some of that stuff that is used to "pickle" galvanized before painting. I can't remember what it's called but it also treats rust and like vinegar, it's a reactive alkaline. Never tried it or vinegar but I can see how either might work.

 

[Beau]

My buddy has been trying to free up his Ford flathead. I told him many times to use vinegar and he wouldn't. He tried a bunch of different things.

When he finally used vinegar, it cleaned the cylinder to bare metal. He was amazed. After a couple weeks he was able to get them out.

 

[ReycleBill]

My buddy has been trying to free up his Ford flathead. I told him many times to use vinegar and he wouldn't. He tried a bunch of different things.

When he finally used vinegar, it cleaned the cylinder to bare metal. He was amazed. After a couple weeks he was able to get them out.

Rinse, lather, repeat, Rinse, lather, repeat, Rinse, lather, repeat, Rinse, lather.... I can see where vinegar might work. Or perhaps it was the bunch of different things... who knows?

This guy ( http://en.wikipedia.org/wiki/Bob_Welborn ) and his younger brother were friends of my Daddy. Daddy and Bob are gone now but Bob's younger brother, Edgar, has a shop right down the road from me and specializes in Flathead Fords. I'm sure he deals with lots of stuck engines. He brings me his scrap metals. Next time I see him I'll ask how he gets them unstuck.

 

[MacMcMacmac]

All this talk of pressurizing the cylinders won't do a thing if either/any of the valves happen to be open.

And what if a crank or rod bearing is the reason the engine is locked?

As for the molassis trick-- I can't say one way or the other but because of the potential damage, after using the molassis, I would want to pull the engine apart and vat it before cranking it. Then again, if I have to unstick it then it's getting a complete teardown anyway.

MacMcMacmac Did you mean 100psi instead of 1000psi ?

The number 1 tool for freeing siezed engines is, always has been, remains, and always will be, patience.

I meant 1000psi. It's pretty easy to do with a grease gun. Peak combustion pressure must be near or higher than that. I am seeing over 2500psi for a gasoline engine during the power stroke from cursory surfing on the subject. I'd pull the camshafts to ensure the valves were closed first (if they move that is).

I use an iron tee fitting, a reducer with a grease nipple and a pressure gauge to set pressure switches when they are over a couple of hundred psi. Put the gauge on one outlet, the switch on another, and the grease nipple on the third, after filling it with a light oil. You have to be very careful though, you will bury a 1000psi gauge with less than a stroke. What is really neat is how much the pressure changes just by backing out the grease nipple with a wrench a thread or so. You can get amazingly fine control over the pressure, just perfect for setting up cut in and cut out pressures.

I have heard of people using ammonia to free up stuck fasteners as it eats up a bit of the aluminum around the threads. I don't know if that would work on a piston, as they are real aluminum, not the mazak, zamak stuff used on the cases.

 

[SSPPIITT]

I have a question regarding this topic. I started a tear down of my 1980 XS650 becasue of a noticeable headgasket leak. Before I started the tear down I could kick over the motor. Now the motor is out of the frame and after followoing the tear down instructions for the cylinder head removal from the Haynes manual I have found the pistons rusted and seem to be seized. I have tried several chemicals but I still can not move the pistons. In this state are you guys saying that if I just place a block of wood on top iof one of the pistons and pound on it, I can free them up? Should I us ea sledge hammer, rubber hammer, regular hammer? If someone could please chime in I would really appreciate it. Thanks.

 

[Beau]

Spend $2 and fill the cylinders with vinegar. Let them sit for 24-36 hours and empty the cylinder. Tap with a small piece of wood and any old hammer lightly.

Get all the other lubes and whatnot out first though.

Hitting the piston hard can ruin the piston and also cause things to crack.

I swear nobody will ever listen to me about the FACT that vinegar will clean rusty parts. It just take a little time, but once you do it you will never buy chemicals again.

Before:

After-

 

[XSLeo]

The vinegar trick is worth a try. Can you lift the jugs any? If so block them up as high as you can with wedges cut from 2x4's Now with a piece of 2x4 and a hammer you can tap one one piston then the otherAs the pistons move down lift and wedge the cylinders. Eventually the cylinders will come up off the pistons. If you were careful and your hammer wasn't to big then you won't hurt the pistons.
Once you have it apart you can measure the cylinders to see how they are worn. Inspect the pistons. Measure for wear if the clearances are ok reuse them. If the wear is too much then you need new pistons and the cylinders bored.
Most machine shops can do the measuring for a small fee. Free if they get the work. I had mine done for $35 per hole.

 

[MrBillohnooo]

Make sure the cam chain isnt wadded up in the bottom of the crankcase causing the crank to not turn!

 

[SSPPIITT]

Make sure the cam chain isnt wadded up in the bottom of the crankcase causing the crank to not turn!

I already removed the cam and cam chain. I thought that was the original problem. I will let you guys know how it all turns out. Thanks for the help.

 

[gggGary]

I am late to this party but want to caution against putting pressure on just one piston. you don't know which side is stuck and I would hate to think of the forces transmitted to all the parts involved if you are beating on the "other" piston. So wood blocks on both piston tops (fit block fairly close to the cylinder walls, the center of the piston crown is thin) say a 2x4 on edge across both cylinders then some gentle taps with a heavy maul. It seems that pretensioning the system with a ratchet strap before the maul taps is a good idea. LIke rapping a flywheel puller with the bolt snugged up it helps get the force to where you need it.

 

[XSLeo]

I agree don't pound hard on just one piston. As I said tap one one piston then the other. One tap one one then one tap one the other.
Thats How I got the 82 engine that sat out for unknown years, no plug, open intake and exhaust. Pistons about half way down. Got the head off soaked it good with PB Blaster. The crank would turn so wedged the cylinders up and drove the pistons down. Lifted, wedged, drove. After enough time the cylinders came off.
The rings were seized right in the pistons, no coming out. If I ever use those cylinders I'll bore them out or get new sleeves.
As well as I like Mike's 750 kit I doubt I will Ever put one back to a 650.