seized?

[rivergypsie]

I bought my neighbors old atomic 4 because he was switching to diesel.
I thought it would be a good rebuild project, he said it was overheating and had bad compression in 2 cylinders.
The water jacket was full of corrosive crud, and when i tried to turn the crank it wouldn't turn.
I'm guessing it overheated and seized, When this happens what part of the crank seizes? is it the pistons , the journals or the rod bearings and what is the best way to free it up.
I'm pretty sure this is going to be a total rebuild.

[Marian Claire]

Welcome to the forum. I am sure others here have done this procedure and I have not. So take my suggestions with that in mind. Drain/check the oil for water. If there is water drain the old oil and refill. Pull the head or at least the plugs and give the valves and pistons a heavy dose of MMO. Give it a day or so and try to turn her over. Do you have a hand crank? The A-4 is known for being very tolerant to over heating. FWIW. Dan S/V Marian Claire

[Baltimore Sailor]

I also remember Don saying that he's broken seized engines loose after a good penetrating oil soak by using a big flat-bladed screwdriver (a BIG one) in the teeth of the flywheel somehow, but I forget what he used to get leverage.

[hanleyclifford]

seized engine

Usually when an engine seizes under these circumstamces it is the piston rings that have actually seized. It is a good shot to fill the cylinders with mystery oil, let a few days pass, and then do the big screwdriver trick on the flywheel using the flywheel housing as a fulcrum. Do this gently trying both directions. Even if you cannot free up the engine, you can still take it apart a free it up "by pieces".

[rivergypsie]

unseised

Thanks everybody,
I ended up taking the engine apart. I had the journals loose and pistons no,2 and 3 out before I discovered it was the rings on no. 1 that had stopped everything.
The piston was real hard to get out but once out , the rings looked like they were melted flush, but the piston looks o.k..
Now I can start working on the valves I know some of them were sticking.

[Marian Claire]

Fast work and congratulations. Do you have the MMI manual? If not it is defiantly worth getting. Dan S/V Marian Claire

[hanleyclifford]

MM manual

Please allow me to second the motion on getting that manual - the very first dollars you spend.

[roadnsky]

...the very first dollars you spend.

... BUT most definitely NOT the la$t!!

[rivergypsie]

manual

Yes I did buy the manual, and you are all correct in saying it is the best way to start.
I think it helps prevent collateral damage while disassembling it.

[David Masury]

If you have a seized engine there is something better than MMO to remedy the situation. I just freed up an 8 hp mower engine that was run dry of oil.

Go buy a few quarts of ATF, automatic transmission fluid, the cheapest you can find. Pour a healthy amount into each cylinder, over the valves, etc.

Go away for a while, I let the mower set for a week, then try using a long breaker bar to turn the crankshaft. It may or may not required jiggling back and forth. It will loosen the most stubborn engine. You may have to mix a large solution of thin old motor oil and atf and fill the crankcase as well, but first just do the cylinders for now.

Once everything is moving then, dump out the ATF and replace with clean motor oil and go about the business of the rest of the restoration. You can save the ATF for the next engine.

David

[rivergypsie]

A.t.f.

Great idea,
I like the idea of the A.T.F. because it's cheap and can use more of it.
I think I heard of people using kerosene also, but I'm not sure if that was for seizing or just to clean out sludge.