Single Scored Liner - MBN Cat

All I know is those wrist pin bushings have taken a beating.

 

could you explain?

 

Scored and discolored.

 

That just sux, my 2 cents I only use ome piston cooling nozzles because I've had bad luck with non genuine ones. But your issue looks like over fuelling / over heating in that bore. Hope you get it fixed.

 

You for sure have an over heating problem on that cylinder. I would have that injector checked to see if it was in fact over fueling. If it is I would raise cain with the supplier to warranty not only the injector but also the parts that it made fail.

To me the 2 piston cooling nozzles are not the same. To check, I would find something flat, not diamond plate, C-clamp them both down side by side and use a carpenters square or something similar to compare the angles. The top picture in your set shows some blueing close to the oil drain back hole under the oil scraper ring. The second pic shows some sign of blueing but not as bad. The second sprayer on the cooling nozzle is designed to spray oil in the egg shaped hole on the bottom of the piston in pic #2. It doesn't look like it was getting oil in that hole from the discoloration.

Also who put the engine together? Did they check the ring end gap clearance or the side gap clearance before installing the pistons in the liners? You might have had to tight rings, that will also cause cylinder scoring with low miles like you had.

 

Feeler gauge for ring end gap and ring to groove clearance.