barecycles

2002 V6 Manual

Not sure what went wrong but I was on my last cylinder of a valve seal replacement and tried to rotate engine by hand to get that last piston up top and it just would not budge past a certain point. In fact, it felt as though the crank bolt actually tightened slightly.

It's in neutral, all rockers, push rods and spark plugs are removed. There is 1 keeper unaccounted for but I'm having a hard time believing it could have fallen down and caused this.

Thanks!

barecycles

I went fishing in the cylinders with a magnet at pistons in the up position and came up empty. I even gave each a shot of compressed air while the magnet was in there.

I did however rotate the engine counterclockwise and the same hard stop occurs almost 360 degrees the other way, maybe 20 degrees short of it.

NFortin1966

I am not familiar with the v6, so my idea is purely a guess. I am assuming that the engine is an over head cam engine, and since you are missing one keeper, perhaps it dropped down on the timing chain and stuck, and when the keeper gets to the cam or crank sprockets, it locks it up. As I said, this is purely a guess...

kd4gij

The 4.2 is a push rod engine.

barecycles

Yes, it's a push rod engine.

I did get access to a borescope and the initial look into each cylinder did not reveal much. I'm having surgery tomorrow so I may have to put this on hold until I recover at which time I'll have more time to look inside each cylinder more thouroughly.

Thanks!

barecycles

I thought of something else. In tapping on the tops of the valve spring retainers to loosen the keepers before compressing the spring, would it be possible to break off a piece of the valve head? I guess I could introduce compressed air again into the last cylinders i worked on and see if much air escapes. It shouldn't since all the valves should be closed now.

Thanks!

mbb

I doubt you could break a valve by tapping on it.
You could dislodge a chunk of carbon from a chamber that had some problems.

Are you sure there's nothing interfering in the valve train or somewhere else that would cause the engine to appear to bind?

barecycles

Finally, recovery is over and Doc finally released me so I'm back working on this issue. Here's what I did.

I'm going to do a valve job at this point so I first removed the driver's side head. Tried to bar the engine over and still stuck. I removed the passenger side head and now I can bar the engine with no problem. I see nothing obvious that would have caused it to be stuck so I'm confused. Maybe I just play dumb and say it's fixed but it will bother me not knowing the reason.

Jbrew

Did you time everything correctly ? Have to time the synchronizer on those as well.

kd4gij

You may of had a valve to tight and it was hitting the piston.