Deere 6068h broken piston and sleeve

[mattyt1984]

I have a loader with a Deere 6068h engine. It didn't run right and leaked coolant into oil. I replaced the broken liner which was cracked and the piston was broken in half. Rod and crank looked fine but I also installed a new connecting rod and replaced the 2 bent push rods. Any ideas on what caused this? I rebuilt that cylinder runs good but after a couple minutes it makes a faint knocking sound.

 

[skata]

Sounds like the cylinder filled up with coolant, and since coolant doesn't compress, something had to give..... The piston and rod.
Did you check the bearing clearance on the new rod? Is the knock coming down low or on cylinder head?

 

[mg2361]

What machine is it in? Machine serial number? Hours on machine/engine? Post pictures of the old piston and liner (inside and outside). Might get more answers as to the cause that way.

 

[mattyt1984]

Attatched is pic I ran for a bit today and no blowby or knock until you run it for a about a minute After that sounds like a knock coming from crack but hard to tell for sure. Would a knock only start after engine is warm? Also there is no smoke out breater but soon as the knock starts the smoke out breather starts too. At cold start up no smoke or knock.

 

[skata]

I don't see any attachments.
The only thing that would heat up in a minute would be the valves or piston I think. The crank would take a while to get heated up.
An undersized or worn piston could make a knocking noise, but it would do it the opposite. Knock when cold, and then go away real quick when the piston warms up.
Did you put a new piston and rings? Was the size checked?

 

[mattyt1984]

Yes new piston sleeve bearing and rings in that cylinder. Attached now should be pic m

 

[skata]

Pic shows. It's hard to determine over the internet where the noise is coming from though....

 

[partsandservice]

I would venture to say the cooling nozzle is plugged / damaged on that cylinder, the noise you hear is probably the failure repeating. Checking the injector on that cylinder would be wise as well.

 

[skata]

Did the knock start right away or after using machine for a while?