how to loosen stuck motor

Depending on what you plan to do. After getting it unstuck are you going to tear it apart?? If so, I would pull the plugs and pour a cup full of Marvel Mystery oil, ATF, or a 50/50 mixture of Acetone and MMO into each cylinder and let it set for a day or so before trying to turn it over. Others may have other ideas. FWIW
Paul in CT
 
I have once made a plug that went into the spark plug hole with a grease fitting. Soaked the cylinders with atf, closed the valves and used a grease gun. The crank moved about one degree/pump

Rune Waltoft from Norway

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fill the cylinders with ATF and let it soak for a month or 6.........


set a crank handle at 3 pm and hang a cinder block on it.
 
After plug removal and oiling up all of the cylinders with Marvel Mystery Oil, release emergency brake and put the A into 3rd gear. By rocking the car back and forth will often break the engine loose. Or at least show you how loose your U joint is......

The A venders also sell an expensive gear type of tool that goes where the starter is to turn the engine with a socket breaker bar...
 
pull the head and valve cover .Oil the valves and cylinders and put a jack under the hand crank and leave it alone . ( Do not have car in gear )
 
1931 flamingo said:
Depending on what you plan to do. After getting it unstuck are you going to tear it apart?? If so, I would pull the plugs and pour a cup full of Marvel Mystery oil, ATF, or a 50/50 mixture of Acetone and MMO into each cylinder and let it set for a day or so before trying to turn it over. Others may have other ideas. FWIW
Paul in CT
Click to expand...

This has worked for me twice Acetone and MMO the only thing different I did two applications 3 days apart and I let it sit a week.
 
Kerosene poured through the spark plug holes and left to soak worked good for me . I usually come back and add more kerosene for a few days before trying to turn the engine . A stuck closed valve will lock up a model A engine . I always remove the manifolds and valve cover for better access . I spray kroil on the upper valve stems through the ports and through the valve spring openings in the valve chamber .
 
If all the suggestions above do not work, you sometimes have to take it apart. And sometimes if it is really stuck, you might have to use a BFH hammer to get the pistons out.
 

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I have always heard the acetone mix mentioned above when left overnight works. The removal of the valve cover and hosing everything down with a full can of penetrating oil sounds like a good idea. too though. Then put it in neutral, and stand on the hand crank.
 
Are you sure it's stuck??? A lot of posts on here turn out out to be starter issues jammed into flywheel...clutch issues....etc. Have you tried just "popping" the clutch in gear? When did this STUCK motor last turn over? I read a guy here said his motor seized in a week! It was the starter. Post more specific stuff about this motor....in my opinion.. if you please.
 
After trying all the penetrants you can devise and if it is still really stuck, I'd take it out of the car and start taking it apart. Once the rods are detached from the crank, remove the crank and with the head off, start in on it with a FBH. Breaking a piston or even all of them won't matter. There is no point being gentle with stuff you will be throwing away anyway.
Once you can see the crank journals, cam shaft etc, you might even decide that there is so little in there worth saving that you pass on it.
 
FWIW, Suggest inspection to determine the cause before applying a solution. I had one which was reported to have “ran when parked” in a garage, 30 years prior. It looked pretty clean to. I wasted time material.... when I finally pulled the head pistons were corroded and the rings rusted like the one above. Another the valve chamber was filled with rodent poop and acorns.....
Lesson learned.
 
Pull plugs fill with vinegar let set rock in.high gear it will come loose

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Disassemble,clean.shim main and rod bearings,lap valves hone and install rings..an old fashioned overhaul..dont fool with a 90 year old engine,especially one worth more than a two buck drag and run..
 
To free mine up I pulled the head. Poured Mouse Milk on top of each piston. Normally all cylinders are not all stuck.Figured out which one was stuck by tapping lightly on the piston with a small hammer (The stuck one will have a different sound that is very noticeable.) Made a "piston pusher" from a flatbar that bolts across the stuck cylinder and a long 3/4" bolt and 2 nuts that put a little pressure on the piston. Used a piece of aluminum so the bolt wouldn't scar the piston top. If the offending cylinder is at BDC, put the pusher on another cylinder. Every now and then tighten the bolt to apply pressure. After a few hours, mine moved. Cleaned and oiled all 4 cylinders and replaced the head with a new gasket. Put in fresh oil and it has been running for over a year. Most recommend pulling the pan and cleaning out the tray.
 
I have read many of the posts related to freeing up a stuck engine and decided to use the 50/50 mixture of Acetone and ATF poured into the spark plug holes of my 1930 Briggs body Model A pickup truck.

Before doing so, I checked everything else, starter and bendix, battery and grounds, starter switch mounting screw length, Starter mounting screw length, etc.

Now that I have used the ATF and Acetone I am concerned about what to do next.

After the engine is freed up, how do you go about removing the ATF and Acetone?

I am worried that those fluids will get into the intake and exhaust manifolds and create problems if I turn the engine over any more than just enough to know that it is now free. Should I remove the intake and exhaust manifolds
before attempting to turn the engine over?

Thanks, Elmopquackenbush
 
The acetone is just a carrier to thin the ATF and get it to creep into the rusty areas. I think it will evaporate pretty quickly and just leave the ATF. ATF won't be harmful to anything. Carry on.
 
Good afternoon...If you don't know anything about the engine...keep in mind that in addition to rings sticking to the cylinder walls, valves can be stuck in the guides, even the distributor gear can stick the engine...pull the head, valve cover and the pan...take a good look, clean everything out, clean out the oil pump...make sure the oil passages to the three mains are not clogged...check the timing gear...check the shims for the mains and rods...gently check the torque on the mains and rods...then put her back together and fire her up...more old engines are damaged by trying to start them too quickly than anything else...patience is important and it saves money in the long run...come to think of it, I even had a girl friend named Patience, once upon a time...Ernie in Arizona
 
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