Just pulled a friend's engine apart because he said it locked up. Was able to turn it by hand with the heads still on after pulling plugs so that didn't add up. Pulled engine anyway, looks like one the pistons had a rough day. Any idea what happened? And any idea why the DOD cylinders have this much crap and buildup in the pistons and valves?

P.s. please disregard any wet oil in the chambers. That mostly happened after the heads came off.

 

That is one coked up mill. Sucking oil from somewhere and grannied to death. Prolly never saw the high side of 2500 RPM...

 

Does not surprise me lol.

As far as the oil goes. This one had several DOD related failures in which it would misfire like crazy and the dealer would just change the fouled spark plugs. Can't speak to what exactly it was because i never got my hands on it. And then later atleast one DOD lifter failure.