Unsticking an unused engine........

-
M

Miranthis

Well-Known Member
Joined
Jun 5, 2024
Messages
59
Reaction score
47
Location
Shawnee, Kansas
273 Commando with 125K on a rebuild was parked in 1987 inside, but in an old laid stone basement, so it had humidity fluctuations. It was below the house in a drive out basement at ground level in Kansas City, but the temp was not well controlled (we fluctuate from -10 to +110 F over the years). No pipe freezing in the house, but still it has surface rust. I had last driven it in 1989, thoroughly brought it up to temp, reparked it, and drained the oil afterwards. I got it out a short while ago and am dealing with a stuck engine. I have pulled the plugs and used Marvel Mystery Oil, PB Blaster, WD40 Penetrant, and a mix of acetone and ATF. have filled the cylinders and it usually drains in few days or less. Tried to fire up starter and it engages but does not budge. I have been working on the crank bolt with a breaker bar and so far the only hint of movement has been tightening of the crank bolt. Don't want to break a ring (or the crank bolt, if that is even possible), so aside from patience and continuing to fill and refill with penetrant, etc.

Is there anything else to do? Heat, oil priming with drill and a shaft, percussion? I just want to do no harm, however. At some point I will throw in the towel and pull the engine to send off for the rebuild it is going to get anyway, but I would like to try to move the car from time to time under its own power.

Jeff-in-KC
 
Miranthis said:
At some point I will throw in the towel and pull the engine to send off for the rebuild
Click to expand...
Take the heads off and you will find out why it's stuck.
The condensation over time will cause the metal to rust. It's what happened to my first 318. It had a good amount of water in it from just sitting, it was bad before I even got the motor. I had to go find another one because it was not economical to fix.
 
Typically you will find that only two of the cylinders are stuck (the one with an open intake valve and the one with an open exhaust valve), prop the engine so you can soak the cylinder with Marvel Mystery Oil. Let it soak for a week and try rotating it with a breaker bar. Go both ways.

It took me a couple days of working it to get 6 cylinders moving, another couple weeks to get the last two. This was on a 440


Alan
 
You've about covered it. I'd try Sea Foam if you have not.
 
We use to unstick old tractors and car engines in the 80's by completley fill the entire engine with kerosene now they fill the engine with diesel fuel pour it right in were you put the oil in on a small block v8 it is around 8 gallons let it sit for a week then drain it turn it over with the spark plugs out then fill it with oil I guarantee it will turn over
 
i agree with filling the motor with diesel. if the cylinders drain whatever you put in them after a few days the diesel should go the other way past the rings, from the crankcase up into the cylinders.
the only other suggestion i have is (again) fill to the oil filler cap but with white vinegar. it dissolves rust very nicely over a few days leaving clean metal. also remove the carb and fill the intake to the top too so it can get 'in' every way possible.
neil.
 
Deisel and acetone is what an old machinist told me .
But what’s the point? The engine will need to come apart .
 
FWIW I often watch those "start this abandoned car" videos similar to DDG and it's always surprising how long it takes them to pull the valve covers. You should do that if you haven't already.

As a specific example, watch this video, or just go ahead and skip to where he finally takes the valve cover off. Days were wasted.
 
Last edited:
74 360 dart sport said:
We use to unstick old tractors and car engines in the 80's by completley fill the entire engine with kerosene now they fill the engine with diesel fuel pour it right in were you put the oil in on a small block v8 it is around 8 gallons let it sit for a week then drain it turn it over with the spark plugs out then fill it with oil I guarantee it will turn over
Click to expand...
I have successfully freed a stuck engine using used diesel engine oil. Filled entire engine, let sit for a couple months. Results may have happened sooner, only couldn't get back to it for that long. Running like a top today.
 
mygasser said:
the only other suggestion i have is (again) fill to the oil filler cap but with white vinegar. it dissolves rust very nicely over a few days leaving clean metal. also remove the carb and fill the intake to the top too so it can get 'in' every way possible.
neil.
Click to expand...
Vinegar will eat aluminum, so there goes the pistons. This is not something do do if you want it running again.
 
mbaird said:
Deisel and acetone is what an old machinist told me .
But what’s the point? The engine will need to come apart .
Click to expand...
The point to me would be to get it apart easily. But you're 100% correct. If the rings are rusted to the cylinders, it 100% needs to come apart and likely needs to be bored.
 
Thanks for the suggestions. I suppose I should add that none of the spark plugs were rusty at all when I pulled them, so i hope that means the rust is just the usual stuck rings and surface rust in the unsealed portions of the engine. I will be rebuilding this one, but will keep trying at this point to unstick it as having it running, even a little, will make loading/unloading etc. so much easier. Will pull a valve cover to get an idea of the inside engine rust.
BullyDodge said:
I have successfully freed a stuck engine using used diesel engine oil. Filled entire engine, let sit for a couple months. Results may have happened sooner, only couldn't get back to it for that long. Running like a top today.
Click to expand...
diesel engine OIL or diesel fuel?

Jeff-in-KC
 
RustyRatRod said:
The point to me would be to get it apart easily. But you're 100% correct. If the rings are rusted to the cylinders, it 100% needs to come apart and likely needs to be bored.
Click to expand...
That will be the rebuild that is coming, but in the mean time just moving it around is rough without a powerplant.
 
It takes about 45 minutes to pull a small block out of an A body. It takes about 4 hours to install one. Just fyi. Instead of messing around with a stuck one (unless it’s a numbers 340 or something) I’d just swap it. Pick up a used long block for cheap and swap it out.
 
TT5.9mag said:
It takes about 45 minutes to pull a small block out of an A body. It takes about 4 hours to install one. Just fyi. Instead of messing around with a stuck one (unless it’s a numbers 340 or something) I’d just swap it. Pick up a used long block for cheap and swap it out.
Click to expand...
It's the original 273 Commando and has significant sentimental value, so not really an option. This one gets rebuilt. I know, I know... I'm a fool.
 
Miranthis said:
It's the original 273 Commando and has significant sentimental value, so not really an option. This one gets rebuilt. I know, I know... I'm a fool.
Click to expand...
I don’t think that’s foolish. That’s as good a reason as any to save one. I hope you’re successful
 
Definitely drive the oil pump with a hand drill to get oil pressure before turning the engine over, even by hand. I didn’t and I spun a rod bearing.

As for fluid to fill cylinders to get it unstuck, my buddy who buys stuck farm tractors uses dot 3 brake fluid ( not synthetic brake fluid) and coke cola mixed 50/50. He does this before winching it out of the field up onto his trailer. The ride home bounces the tractor a good bit and he says 1/2 the battle is won by then. You could simulate the same effect with a few palm sanders duct taped to the block.
 
iffin you're fixing to rebuild it anyway, i'd just pull it rather than fiddle ******* around with soaking it in this or that or the other thing.

yank the **** out, pull the crank and bust the piston & rod assy's back thru the bottom and be done with it.
 
See if it will turn counter clock wise.
Pull the plugs, look inside with snake camera for foreign debris and or rust truffles....check if any rockers are loose 'stuck/seized valve'- hitting piston.
 
This is the 170 Slanty I just picked up a little while ago, would only turn back & forth ~1/4 turn after squirting some WD40 in the plug holes;
20240507_191148.jpg

Pull the covers & rocker shafts, be certain none of the valves are stuck, You No Fuke-arown......
And I prefer rare-earth razorbacks to find rust-truffles.....
 
in ref to question above

diesel fuel.... safest can't even light it by flicking in a match or a cigarette
waxy stuff....

low enough viscosity to get everywhere but doesn't evaporate much so you don't risk an explosive situation, don't use petrol...!

diesel left for long enough grows mould and bacteria in it... just keep that in mind before eating

diesel engine oil is just like petrol engine oil with more detergent to deal with diesel combustion particulate pollution of the oil. its the fuel you want
 
only thing Ive seen in a boat engine is the scale gets so thick on the cylinder the rings may break...-
 
You must log in or register to reply here.
-

Back
Top