paulutions

I'm putting a used 95 engine into my 98 XJ. I put it on the stand and flipped it over to replace the oil pan gasket, rear main seal, and filter adapter o-rings. Unfortunately, I guess I just assumed that the oil had been drained out of it, but it hadn't. Oh well. Thought it then drained all out the top. When I got the pan off & turned the crank by hand with the engine upside down to get a look at the cylinders, pistons, etc it would make a loud thud noise that I assumed was compression pushing left over oil past the valves. Then, after doing the fore mentioned work, I flipped the engine back over, right side up & again tried turning the crank over by hand just to make sure it turned over smoothly after putting the rear bearing back in. I got it to go over a couple times but then it got very difficult & no matter how hard I pushed, it wouldn't turn over. So, I took the spark plugs out (which I also should've done in the first place) and, with the release of pressure, it turned over freely by hand as it shot oil out #3 and #5 cylinder spark plug holes. My question is, would it have been possible for me to damage the engine trying to turn it over by hand with the increased pressure of oil having flooded the upper end of the cylinders? I knew a guy who bent pistons in a similar fashion when he fired his engine up, but i just turned mine by hand and am doubting that I'm strong enough to do that. However, I wonder about gaskets, valves, and that thudding sound I heard in the top end, through the exhaust manifold with the engine upside down and the oil pan off. Guess I could do a compression test. Any advice, input, or stories I might want to hear before I fire this thing up?

Cherojakee

It wouldn't crank because you can't compress liquid. It didn't have anywhere to go. There was no more pressure in your engine than there is in a bottle of oil. I'd be more concerned about the oil getting into different passages. Others might have more input on that but I seriously doubt you dmamaged any components.

paulutions

Thanks.

cruiser54

If you cranked it by hand only, you're good to go.

s346k

it's fine. you might consider checking all of the plugs before firing it.