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914Driver MegaDork
7/18/23 9:02 a.m.

I bought a really nice car knowing it was locked up and didn't have brakes.  (made it tough finding a shipper).  The seller and family were up front and honest, revealing the car's history and everything they knew so please don't squint at them.  It's been soaking in Marvel for months which ran past the rings and overfilled the crank case.  I drained it out and added oil.  I've been shooting Aero Kroil, PBBlaster and CRC Nut Buster in the plug holes for weeks.  A few days ago with the help of a friend, I towed it backward, dumping the clutch a few times only to lock up the rear wheels.  Push it forward in 1st, same result.

I added brake fluid and bled the brake lines, I have brakes.  There were about 4 drops of gasoline in the tank, so I suspect when it was put away, it was put away dry; hence no lubricity at the rings.

I've studied Youtube et al on freeing up an engine, scared the hell outta me!  "Hit the piston with this here 9 lb. to shock it a bit"; to some guy with a torch heating the pistons.   One guy removed the heads and using the head bolt holes. slipped a round wooden plug into the cylinder and a steel plate above it, screwed the plate down forcing the plug to push the piston down.  That one I am considering.   

Not that it makes much difference, but this is a flat head. don't squish the valves.  BTW, peeking in with a camera scope, everything looks clean, barely any surface rust, no carbon.

Seriously considering any suggestions before pulling the heads off.  Whatcha got?


Thanks, Dan


eastpark HalfDork
7/18/23 9:15 a.m.

The Cold War Motors guys are doing another summer challenge where they're trying to get two old clunkers running and driving. Both cars have stuck engines and they're trying creative ways to get them unstuck. The link is above - forward to the 44:00 mark and you can see some of the techniques. 

outasite HalfDork
7/18/23 9:53 a.m.

A bit complicated, however it worked. Old timer suggested connecting the cooling system hoses of running engine to stuck engine to raise the block temperature.

1988RedT2 MegaDork
7/18/23 10:08 a.m.

When I got the KZ-400, it was locked up, had been sitting for maybe 20 years in a shed.  I would just patiently put some ATF in each cylinder, get on the bike, and rock it back and forth. Gentle roll, clutch dump, repeat. Nothing for a week or two, and then I felt something give a little.  I kept at it, and a few days later, it was free.  I've never been in the engine, and it still runs.

ATF.  And patience/persistence.

Good luck!

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 10:10 a.m.

your efforts have been focused on unsticking pistons.

maybe they're not the problem.

is there something specific to the flattie that could have other components stuck?

1988RedT2 MegaDork
7/18/23 10:26 a.m.

Ran when parked?

Trent PowerDork
7/18/23 10:27 a.m.

I'm sorry to come in with a bad attitude but I have never witnessed a "stuck" motor actually be drivable after freeing it up. Yeah, they will "run" but there is always one or more cylinders with 20psi compression and they have so much blowby they look and smell like the crop duster from north by northwest.

After having hammered stuck pistons out of blocks and witnessing the damage to the bores, pulling those pistons out and having to chisel the rings out of the grooves I just don't have any hope.

I struggle to understand why anyone would do this, other than to generate YouTube content or sell a POS to an unsuspecting buyer.


But as far as what you asked, My dad once filled the block (like to the top of the crankcase) of an old pickup that had been seized for a decade with diesel and let it sit for a few months and got it turning. 

7/18/23 10:48 a.m.

Per Uncle Tony, once you get it to move in one direction (say clockwise), only go as far as it seems comfortable to do so- then rotate it in the opposite direction after until the same. Your goal is to clear it out through that back-forth, if you just force it you risk scraping bores.

Toyman! GRM+ Memberand MegaDork
7/18/23 11:05 a.m.

With old iron farm engines, building a fire under them would do wonders. I have seen people build fires in the cylinders as well. Granted most of these engines had iron pistons as well as iron blocks. 

Have you pulled the heads? There may be so much rust it's beyond getting apart without destroying it. 

Don't get impatient. It may take months to get it to pop free without damaging anything excessively. 

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) GRM+ Memberand UltimaDork
7/18/23 12:22 p.m.

It's possible that it's not just the pistons. Stampie and I pulled the pistons and rods from an engine and I still couldn't get the crank to rotate freely. 

nlevine GRM+ Memberand Reader
7/18/23 12:27 p.m.

Do you know how and when it seized, or did it "run when parked" and was only discovered later to be locked-up?

I bought a 924 with a seized engine that had been sitting outside for a good bit. Ended up pulling the engine disassembling it. Two pistons came out clean, two pistons were permanently stuck in their bores (I used to pound on the piston tops with a sledge hammer to relive stress - nothing ever budged). My theory is that a blown head gasket allowed excessive moisture in those two cylinders, and mother nature did the rest. 

914Driver MegaDork
7/18/23 12:42 p.m.

Ran when parked, but as I said, I believe drained of all fluids.


Without disconnecting the rods, how would you know?

Trent:  Diesel has rust removal properties etc.?

triumph7 HalfDork
7/18/23 12:54 p.m.

Can you put a socket on the crank bolt and use a looooong breaker bar?

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 12:54 p.m.

At this point I'd be disassembling to see what I was working with. 

Also, if you're already doing the towing thing, you can try the highest gear. 1st gives engine best torque against the wheels, but highest gear will give the wheels best torque against the engine. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 12:57 p.m.

also also, put the car in highest gear and rock both forward and back. Doing a forward gear and forward and reverse gear and backward will both only turn the engine one way. You probably want to rock it both ways. 

porschenut HalfDork
7/18/23 1:00 p.m.

Even if you break it loose the motor will need a rebuild, right?  So pull the head and have a look.  Pull the crank and then you can just whack the pistons out.  But if you really feel the need to break it loose try hydraulic pressure.  Put a cylinder at TDC and pump in a fluid under pressure.  It may leak past the valves but that is a safe force to put on the piston.

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 1:30 p.m.

In reply to porschenut :

good call, but he cant 'put' the cylinder wherever he wants. I would try to find one that was at about 1/3rd to 1/2 down from TDC that way it has the greatest torque on the crank to get things moving. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 1:40 p.m.
outasite said:

A bit complicated, however it worked. Old timer suggested connecting the cooling system hoses of running engine to stuck engine to raise the block temperature.

There's also probably a way to pressurize the oil circuit with oil externally. 

Cadman5 Reader
7/18/23 1:40 p.m.

If you are able to get a prybar on the flywheel teeth and against the bell housing, that will give you way more leverage and torque than anything else. Slow movement each direction. Don't use the crank bolt. You'll just either loosen it or bust it. 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
7/18/23 1:44 p.m.
914Driver said:

Angry:  Without disconnecting the rods, how would you know?

i wouldn't.  i think maybe you're at the point of some disassembly required.

porschenut HalfDork
7/18/23 2:13 p.m.

In reply to Robbie (Forum Supporter) :

Good point, but again just pull the head and/or motor and have a look.  If you break it loose starting it would be a very bad idea.

californiamilleghia UberDork
7/18/23 2:19 p.m.

Just an idea ,

Can you put Marvel etc in the cylinder and then add low air pressure thru a spark plug adapter ? Hopefully that pushes the Marvel past the rings, 

you may have to pull the rocker arms to close any open valves.

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) GRM+ Memberand UltimaDork
7/18/23 2:24 p.m.

I bought one of these to turn the ring gear on the flex plate and it did rotate after a few weeks with some Marvel Mystery oil in the cylinders. I still had to have add a 15 inch long box wrench on the end of the handle for extra leverage. 

It didn't change the outcome, but it kept me from breaking anything

QuasiMofo (John Brown)
QuasiMofo (John Brown) GRM+ Memberand MegaDork
7/18/23 2:30 p.m.

So we use a 50/50 mix of non synthetic Type F and acetone to remove rust in cylinders. It's not a guarantee but with the last tractor that we did it on it worked rather well. 

We made over 3 gallons of solution. Emptied the engine of all engine oil. Filled the crank case WAY over the full point, like 1 and 3/4 gallons on a 5 qt system full. Pulled plugs and filled every chamber full. Filled the valve cover until it was nearly full. Then we let it sit for a week. Starting at the drain plug we emptied all the A/A mix. Once empty we slowly moved the crank with the flywheel and a big bar. It broke free with about 100ft lbs of force on a 4 ft bar (yes, that's a lot of force) once free it scraped around about 5 rotations then felt pretty loose. We filled the oil and replaced the filter then cranked it with no plugs for about 60 seconds. Replaced the oil and filter, repeated about 3 more times. Added fresh plugs and fuel and rolled it out of the garage. The neighborhood looked like the Midwest after Canada wanted to fog for mosquitos last month. It DID run. It ran well enough to chuck a rod bearing pretty quickly but compared to not being able to rotate the engine for removal I call it a win.

Cousin_Eddie (Forum Supporter)
Cousin_Eddie (Forum Supporter) Dork
7/18/23 2:35 p.m.
californiamilleghia said:

you may have to pull the rocker arms to close any open valves.

Rocker arms ?

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