[silver69judge]

I bought a 70 gto with a rebuilt 455 that has been sitting 12 years. I couldn't get it to rotate with a braker bar. What is the safest way to loosen it without damaging.

[steve25]

let me ask this , if it's in the car and you do get it freed up and running, what would you do because the chances are darn high that it will run like crap and then you will need to yank it out.

In short if it's in the car then yank it out now to get it freed up, or at least so you can get the pan off it and look at things.

[grandam1979]

Acetones and trans fluid mix in every cylinder with plugs out will help. Still be careful after sitting a few hours or days soaking give it a try. If it’s a valuable engine be very careful don’t want to hurt the block. I would turn by hand not starter. If you have access to a scope it might be worth looking down plug holes to make sure nothing is too bad. My 2¢

[poncho-mike]

I have taken apart quite a few stuck motors.

I start with Marvel Mystery OIl (which is somewhat similar to tranny oil). Fill the cylinder as full as you can, and let it sit for a few days. I've also heard of people using PB blaster. Once you're ready to try turning it over, rotate in both directions to see if it will go. If it is really stuck hard due to water in the cylinder, you may have to take more exteme measures.

If it refuses to budge, remove the head and a 1/8" drill bit or something a little larger. Drill a bunch of holes very close together and about 1/4" from the cylinder wall. Then get a long punch, and position it on the back of the piston and whack it a few times. That will usually break the head away from the piston pin, and it will slide right out. Be careful where you locate the holes in the piston. I gave the same advice to a friend, and his definition of 1/4" was different from mine. He hit the top ring and the drill bit bit into the cylinder wall, requiring a sleeve. The intent is to weaken the piston so it doesn't take much effort to break the head off.

Good luck.

[Sirrotica]

If it's a stick shift car, many times you can put it in 4th gear, and rock the car back, and forth to release the rust ring in the cylinders. Easier than trying to free it up with a breaker bar.

I would use the aforementioned transmission fluid, and acetone previous to trying to break it loose. If you can leave the engine set a week after filling the cylinders with the mixture before trying to break it loose. Time is on your side, the longer it soaks, the better.

You also might want to look into the cylinders with a bore scope to see how much corrosion you're dealing with before you decide on freeing it up, or removing the engine, and disassembling it.

After you get it so you can turn it over you need to back it up to make sure it will turn over a full turn with a bar before attempting to start it.

After you are able to ge it started, let it idle for a half hour, or so to free up anything that is sticking. As it idles things will start to free up.

I've done this many times, and this is the pattern I follow when starting a stuck engine. No guaruntees that everything will start functioning again, but in my experience it's the best procedure to follow.

[turbo69bird]

I’ve used marvel mystery oil with good results had a 70 Porsche that was stuck got it loose car still runs without a rebuild today. I had a shop teacher that did desotos he swore by white vinegar . He said it would eat the rust and the. It would spin free he’d also submerged some tractor engines and used super washing soda and a battery charger to free them. He got all his engines running and never took them apart. Guy was well known for doing it oddly enough they usually ran pretty well . I’ve never tried either of those methods.

Good luck.

[Dragncar]

Originally Posted by turbo69bird

I’ve used marvel mystery oil with good results had a 70 Porsche that was stuck got it loose car still runs without a rebuild today. I had a shop teacher that did desotos he swore by white vinegar . He said it would eat the rust and the. It would spin free he’d also submerged some tractor engines and used super washing soda and a battery charger to free them. He got all his engines running and never took them apart. Guy was well known for doing it oddly enough they usually ran pretty well . I’ve never tried either of those methods.

Good luck.

I got rust off a RAIII block with washing soda and a battery charger.
It worked OK.

[many birds]

12 years of sitting shouldn’t seize a previously running engine. There might be more going on. A borescope would help.

[Half-Inch Stud]

Yinz know the Top & 2nd rings are micro-rusted to the CYL Wall.

Yet there could be a swath of surface rust too on some CYLs from condensation cycles.

Sooo, all thee above need be considered, tried to free the top&2nd rings, work the rings up and down in small motions, then scrub the condensation rust away.

[Schurkey]

Battery chargers and washing soda = electrolysis.

Electrolysis will destroy aluminum...such as pistons and timing covers.

Electrolysis works on exterior rust, that can be located close to a sacrificial iron/steel bar. Doesn't do squat for internal rust.

[Mr Anonymous]

Regarding bore scopes, I recently got this one off the jungle site and it works well, plus its very inexpensive. I have an android phone, and I can tell you it works great. I got great pictures of bad things in my engine.

You could probably do your own colonoscopy, it has plenty of cord and has a wireless connection to the phone app.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[kpbrown31]

Originally Posted by many birds

12 years of sitting shouldn’t seize a previously running engine. There might be more going on. A borescope would help.

I agree with this in terms of it only being 12 years. If there isn't catastrophe inside and it was properly sealed up and didn't have the carb or intake off you'd think it wouldn't be too bad inside in terms of corrosion or rust. I've sure fired engines up after sitting much longer than 12 years.

If they are locked up, I do as others mention. Usually spray a bunch of PB blaster inside. I like the aerosal can because I can spray on the uphill side of the piston if that makes sense. Then if possible, I like to use a flywheel tool to grab the teeth so that I can rock it back and forth instead of trying to only turn one way when using the crankshaft bolt.