John deere LUC motor issues

[Mountain_anderson]

Hi all
I have a Deere 11a with the LUC motor, I've noticed some strange issues with. When I bought it, it was seized and I got it as unseized as I could but it was still hard to spin. I noticed when it spun, the exhaust valve wouldnt return to the down position and found it was slightly bent so I replaced it. I also noticed a small but serious dent on the edge of the piston. I pulled it out and it crunched down on the rings and cracked it, so I bought a replacement. After removing the whole piston, the motor freed up a ton. I also removed the other as I plan to change the rings anyway. I spun the motor a few times with the pistons removed and as I did that, I noticed every now and then, I noticed a ratcheting sound and a rough stop when I spun it. Not sure if it has anything to do with the camshaft or what. Looking at it from the holes to the bottom end from the valve area, it spins fine. But I also noticed the same side intake valve was stuck as well. The cracked piston and both stuck valves are all on the same side. What all could this be? Overheating motor in the past? Is this all repairable? The exhaust valve seemed not to need a new guide even though I bought a replacement, there was no play when I inserted it. It is hard to see the bottom as I have no engine stand and its just placed on a homemade wooden stand I made.

 

[Roger in Iowa]

Ratcheting sound may be impulse in magneto as it winds down.

 

[Mountain_anderson]

Ratcheting sound may be impulse in magneto as it winds down.

It like brings the crank shaft to a halt, is that normal?

 

[Roger in Iowa]

Don't know. When impulse engages it gets harder to turn crank but stalling?
When it stops continue to turn crank and you should hear when magneto snaps. Does crank get easier to turn? If so may be normal operation of magneto.

 

[M-MAN]

Piston took an extremely hard hit. Good chance the rod is bent. Compare the two closely.

 

[Mountain_anderson]

so I found the sound was the camshaft bearing down against the bent intake valve, removed all valves and spins freely now. However does anyone know what couldve caused that much damage to that side of the motor?

 

[Mountain_anderson]

Piston took an extremely hard hit. Good chance the rod is bent. Compare the two closely.

What couldve caused that?

 

[JOCCO]

Not sure, but if i was you go to bare block and start over. Measure all components, bearings etc. You are already in a house of pain. Good news is last I knew some parts were not to expensive.

 

[Duner Wi]

My guess is you had a solid object/objects inside the combustion chamber to damage piston. Heat can soften a piston but I have never seen rings misshaped like that from heat . Maybe I need to see more stuff.