Crank wouldn't turn after removing timing belt and sitting for 6 days

[Noodledude]

Just wanted to post my experience in case anyone else runs into the same thing. I was replacing the water pump on my 99 Legacy GT. 2.5 DOHC. No problem, I've done the belts before, quick job. I figured I would replace a leaky cam seal while I was in there and broke the plastic cam pulley trying to get it off. Sucks for me, got a replacement from someone on this forum. No big deal, but the car sat for about a week before I got the part and got it back together.

 

I put the timing belt on and went to rotate everything by hand to make sure it was all free. Crank comes to a hard stop with the #1 and 2 cylinders at the top. I assumed a valve got stuck down somehow when I was messing with the cam, but the pistons were all at the service position the whole time, so there is no way I hit a valve and bent it, never pryed or forced anything. I pulled the valve covers and checked all the valves and found nothing. Nothing wrong whatsoever. I pulled the belt and left all the cams released, no pressure anywhere, but the crank still wouldn't turn, even independently.

 

No spark plugs, no compression, and smooth rotation all the way, until it stops. All the clearances to the shims were spot on. The crank was still stopping in the same spot, but sometime it would roll past the spot, without too much force, and then stop hard in the same spot again. At this point I was getting really worried. What could I have screwed up enough to stop the crank by replacing the water pump? We did a leakdown test and all the valves were sealed except for the #4 cylinder, which was leaking past the intake valves, but not horribly. But the pistons were still stopping at the top of 1 and 2, so it couldn't be anything to do with the #4 valves.

 

At this point I pulled the engine out and removed the oil pan to check the internals. Pristine. No slop in the crank, no bearings or wrist pins loose at all. I really didn't want to pop the heads loose (fresh head gaskets as of 20k ago), so I spent some time playing with it at this point. After 2 days of fiddling, head scratching, and angry pacing, for some reason we dumped a bit of new oil in the spark plug holes. When we tried to rotate it again, it bumped past the spot, and proceeded to get easier to rotate with each revolution. Finally you could barely feel anything as it rotated all the way. Hooked the timing belt back up, and it turns perfect. The only thing I can think of was that the rings dried out enough while it sat that the friction of all 4 pistons changing direction to the end of the stoke caused it to bind? It turns perfect now, and there are no scratches on the cylinder walls.

 

Has anyone ever heard of something like this before? I just wanted to share this experience so if anyone else runs into a similar situation they won't have to come as close as I did to shooting this engine.

[matt167]

Had it happen on a '51 Chevy 235 L6 that sat without oil/ filter for a couple days while I waited for the right filter to come in. in my case the starter bumped it free but you couldn't do that... For sure rings can stick like that

[Fairtax4me]

May have had a bit of rust on the cylinder wall keeping the rings from sliding easily as you turned the crankshaft. That happens occasionally. Not anything to worry about. Usually if I suspect something like that I pull the plugs and put a few blasts of WD-40 or some other oil spray in the cylinder.

[turbosubarubrat]

I pulled apart a ea82 that wouldn't turn over after a certain point. Turned out it had so much carbon build up that 2 pistons were hitting the heads.

[traildogck]

So...I am having a very similar issue. She hasn't run in a while and was running very rich when shut down. I wonder if it is one of the above issues. I need to investigate some. I am going to try the oil 1st. As long as you are careful and don't really push on a bind...I can feel my way.

 

How do I do I set it all back up in the end...after rotating crank and cams. It is just ...line up all the timing marks again? Or is it more in depth. I usually just swap belts out...I have never broken one or had any issue like this.