The Stovebolt Site Forums The Shop Area Engine Shop motor froze

I just bought a complete rolling frame with drive train. It's a '42 GMC with a 1954 GMC 248 motor. I want to see if I can make it run. Motor won't turn by hand. What's my Best approach? I really like the motor and want to make it run. Thanks, john.

I would try turning it using one of the rear wheels.

I agree to pull it to break the engine free. This will also allow for the clutch not being stuck too. If that doesn't turn it then start soaking the cylinders and valves with Kroil or another brand you like. Let that sit for several days and try it again. Do this until it breaks the rings loose. Also pull the valve cover and makes sure the valves are free and working. After several attempts at this if it is still froze then you may as well pull the pan and start taking it apart.

I agree, sorta, with the others. Pull the valve cover and the spark plugs. Drain the oil to see if there is any water/coolant in the pan. Soak the cylinders with the penetrating oil of your choice. Then wait... a few days or so. Then try to gently turn the motor by hand, with the fan, or with a big screw driver on a flywheel tooth. Or by jacking up one rear wheel with the trans in high try to rock it back and forth. If you can get it to turn completely around without binding - then you can probably get it to run. Of course fill with oil. Some suggest priming the oiling system by pulling the distributor and sticking a big screwdriver bit in an electric drill in the oil pump slot and run it to pressurize the system... Then if you can get it to turn by hand, with the spark plugs out and full of oil, turn it over (and over) with the starter... Good luck.
You'll be so proud when you get the old thing running. There's something about reviving a sleeping old motor that is satisfying.

The absolute worst thing you can do is try to make the engine turn by towing the truck! If it's stuck really tight, you can bend connecting rods, trash gears in the transmission, or break a rear axle shaft.

Pull the spark plugs, and squirt some type of penetrating oil into the cylinders. Some people swear by PB Blaster, Diesel fuel, automatic transmission fluid, and even WD-40. Personally, I like Kroil.

www.kanolabs.com

I've used it for 30+ years, and it frees up stuck engines the other stuff can't touch. 2 or 3 ounces of Kroil in each cylinder will creep past rusted-tight piston rings and go into the crankcase in about a week's time, where you can drain it out and pour it through again. Drain as much oil as possible out of the crankcase first, obviously. After a few cycles like that, put a pry bar on the flywheel teeth and nudge the crankshaft a few degrees in each direction. When things tighten up one way, turn it back the other direction. Also remove the valve cover and soak the tops of the valve guides to try to free up any sticky valves. Once you get the engine making full turns in both directions, try spinning it with the starter and do a compression test.

Worst-case scenario will be deeply pitted cylinders that will need to be rebored or sleeved. You just might get by with a good cleanup, and/or maybe a valve job. Just don't get impatient and destroy an otherwise good engine by trying to force things.
Jerry

Thanks everyone for the info. I'm taking the conservative approach. I got the cylinders soaking with WD-40 right now. I need to find some Kroil! The oil is black but atleast it doesn't have any signs of water in it. I'm really intrigued with this motor. I won't use the rear end or the tranny but the motor is awesome. I wanna make it run.

Wow, after soaking the cylinders for several days, I actually got the motor to turn over by hand! Quite nicely I might add. No scraping sounds. I'm gonna give the motor a complete tune up and every thing else it needs and hope to make it run. Gonna be AWESOME!

How exciting!
Be sure to come back here and update us, will ya?
Fingers crossed, good Luck!

Jerry

Another caution; don't use any old, stale gasoline. You probably won't be tempted to do that if you just have a chassis. Use a gas can with new, clean gas and a length of fuel hose ran directly to the fuel pump.
Also you should be sure the transmission is full of oil. That's important even if you never drive it. Hopefully there won't be a mouse bed in the clutch and the trans bearings are good.
Does it have a radiator?
Good luck!

Thanks for the input Frank. I do have a radiator. Forgot about the tranny, gotta check that too!