The Stovebolt Site Forums The Shop Area Engine Shop seized motor tricks

I have a seized motor from sitting up over time. Does anyone know of any shortcuts to getting a motor turning again. I know a few but Was hoping for other ideas. I have heard of pouring Marvel mystery oil or PB Blaster in each cylinder and letting it sit for a while. Any cool ideas would be great?

Myself I would use Kroil. Have heard of all sorts of stuff used though from engine oil to diesel or gasoline.

Let sit for while LEAVE SPARK PLUGS OUT or put em back in LOOSE then remove before turning.

Then get wrench and attempt to turn GENTLY first one way then the other. I say gently since you do not REALLY know what the problem is. If just stuck rings you might be OK to get it to rotate. Think I would be tempted to take the head off and have a look see.

Should also make double sure transmission is not jammed.
Look for obstructions to ensure flywheel is not jammed.
Dan Bentler

Acetone and Atf mixed up. Good stuff.

I have heard transmission fluid before. Acetone mixed I have not that seems like a great idea.

I heard this was the best, 50/50 mix. And Kroil the next best.

ATF/ACETONE mixture is hard to beat!

The acetone will thin the oil and it also eats on the carbon that has built up behind the rings. Once free be sure to drain the crankcase as all of the stuff you pour into the cyinders will end up there. Remove the valve cover and check for stuck valves as they can lead to bent push rods and other problems.

also once it turns over make sue all pushrods are oilling after start up

Not to hijack this thread but I have never ever seen any of this stuff (Kroil, PB blaster, WD 40, Knock-R-loose, MMO) actually work. Am I alone on this? ATF/Acetone just might do the trick as well as other home brews but the commercial stuff I think is snake oil.

Weeds

I say this because I had a case of atf and a few gallons of acetone. I had a badly plugged up Rochester model B. I submerged it in a 50 50 mix for about two weeks. When I pulled it out, butterfly's were turning and the passages were clear. I also use it on siezed marine engines with great success. The trick is to periodically shake the mixture to keep it mixed up.

Weeds, I've used the Kroil on badly frozen 46 engine but I was in no hurry. All in all it took me 6 weeks but it freed up..... but, I had one that after weeks of Kroil, marvel mystery, half this and half that I ended up pulling the heads and taking a piece of firewood and hitting the tops of the pistons to finally break it loose....... depending on how bad one is stuck, and the product used is what everyone things is the best!!

I have used PB blaster many times on motorcycles and other small engines that have set up a long time. But larger bore engines are different I would assume.

I have used a piece of firewood myself to free up a motor. That was pretty tough but def the quickest way.

Hook it up to another truck, put it in gear, depress clutch, have other truck slowly take off and periodically pop the clutch.

It works but I would put a little oil in each cylinder before I tried this.

......OUCH

Well, after two weeks with marvel mystery oil and PB blaster in each cylinder the motor rotated freely with one hit of the starter this morning. Now to solve the spark issue because there is no spark.

That's a good way to break an axle, trash the transmission, or bend a bunch of connecting rods. If it won't free up with penetrating oil and a long pry bar on the flywheel teeth, take it apart!
Jerry

Ditto...I had to finally take mine apart with a log. A little strange hitting a cylinder head with a log and sledge hammer, but curiously fun too.

Here is a test I did a few years back.

https://www.stovebolt.com/ubbthread...l&topic=0&Search=true#Post215167