225 knock

Hey guys, looking for some suggestions. Started the Jeep, went inside while it warmed up. When I returned a few minutes later it had died.

Very hard to restart. Now there is a fairly loud knock and it won't hardly run at all.

Any suggestions? Things to check without tearing it apart?

Thanks for the help.

 

Timing chain?

 

Where is the knock sound coming from? Have you pulled plug wires one at a time, restarting to see if the sound goes away? I spun a rod bearing, and it was a rather load knock that would not go away. Mine always started fine with the knock though. I would pull the pan, see if there is metal flakes, and feel the rod ends and see if one moves more than another, and/or you could check the compression. My bad cylinder was down almost 25 to 30lbs. I knew, or had a feeling which side was bad on mine, and a pressure check gave me the cylinder. I changed the timing chain, and lifters before rebuilding the motor, and having the craknk re-done as well.

 

Unfortunately have not had time to do much checking yet. I'll get to it after Christmas. Thanks for the suggestions.

 

I got back to the Jeep today. It wasn't too hard to start but was initially hard to keep running. Had to feather the throttle to keep it going. Knock not as loud.

I started pulling wires one at a time. No significant changes in the knock. It just gradually went away as I went through the cylinders. The idle smoothed out and it runs now like it did before.

Took it out for a 20 minute ride, up and down hills hard throttle as well as compression braking. No issues, no knock, ran as good as it always has.

So, what do you think?

Piston slapping on a stuck valve that unstuck itself?
Lifter problem?

Thanks for the help. Greg

 

May have been a piece of carbon that had broken loose in one of the cylinders and was banging around. Have not seen it happen in many years now, but back in the '60's and '70's it would happen a lot to motors that were not run hard for a long time. I think unleaded gas and electronic ignitions with higher voltages has eliminated the problem to some degree. The noise it would make would sound as if the motor was about to blow.

 

Sounds like Lamar may have it pegged. When a motor sits and gets condensation in the cylinders sometimes the condensation will help loosen up the carbon on top of the pistons and in the combustion chamber. Start it up, a chunk comes loose, and can wedge in places we don't like or bounce around causing a knocking sound. Hopefully it's taken care of itself as it sometimes will.....

 

I didn't think of carbon. I normally drive it at least once a week, lots of hills here so it gets a pretty decent load put on the motor.

Hopefully that is all it was.

Thanks again for the replies.