BergenCountyRC

Just changed clutch shoes on my old inferno. Started the engine to let the fuel in the tank burn off before storing the car away. After about 15 minutes of idling the car shut off and now it seems the engine is hydro-locked and possibly seized. I cannot pull the starter cord and I cannot turn the flywheel either. What could have caused this? Is it possible that the engine was running rich and built up excess fuel in the cylinder. Would a rich running engine hydro-lock while idling? This is very strange to me. Any help is appreciated.

earlwb

Although it is possible, ABC types of engines do not normally sieze up, it is in their design. But I have seen that happen twice to myself in the past. With a ABC engine if the engine happens to stop with the piston up neat the top of the cylinder and there is a lack of oil at that moment, it could get stuck. With ABC engines the cylinder has a taper to it that causes a pinch effect at the top of the cylinder. The piston has to be squeezed through this pinch when the engine is cold (which is why you aren't supposed to flip the engine a lot when cold). But when the engine heats up the cylinder expands and the piston fit is just about perfect. But if you stop the engine and there is a lack of oil at that moment and the piston is in the pinch zone when the engine stopped, then when the engine cools of the taper comes back and the piston gets squeezed and it is stuck.

I suggest heating up the engine good, like it is running, in the oven and that should get the cylinder to expand enough to let you turn the engine over. Say set the oven to 250 degrees F or therabouts. Using some penetrating oil in through the glow plug hole is a good idea too. Don't try to force it too hard as you could bend the connecting rod. Remove any plastic parts if there are on the engine, such as the carburetor when you go to heat it up.

BergenCountyRC

Thanks for your input but the engine was running when it quit so its not going to get any hotter than that.

1QwkSport2.5r

If the engine was just idling then it was not hot. it was luke warm at best. Chances are the piston is stuck at TDC like earlwb suggests. Easy way to check this is heat the engine up with a hair dryer until its good and hot. With the glow plug removed, try rotating the flywheel to free the piston. If it doesnt free up, find a small wood dowel and stick it through the glow plug hole and try again to rotate the flywheel. It should come loose one way or another.

Unless your fuel had no oil in it, I doubt the engine is seized. Just stuck most likely.

downunder

I'd guess a car engine probably idles at around 5000 revs and to do that for 15 minutes with no airflow...it's possible it seized. If it was a hydraulic lock then remove the plug and it should turn normally. If the piston is all the way to the top then it might be jammed in the pinch but I think that's unlikely if you tried to turn the engine over shortly after it stopped and was still hot. Personally, I'd take the engine out, remove the plug and the backplate with the pull start because I believe the one way bearing can cause problems. If the rod is all the way to the top then the piston is in the pinch area so try heating in an oven (about 250F) but if the rod/piston is well away from the top then it's most likely seized.