To give You some insight this was an offshore marine engine with wet exhaust,I know the guy ran it low on oil and caused lower end failure,and upon removing the heads it appears his exhaust manifolds were bad causing water to enter the combustion chamber,I just tore it down and was happy with my purchase as the bore is .030 over SRP forged pistons and the Gm crank is std/std,balanced assembly but just saw this and was hoping it has been seen before,the divot is about 2" from the bottom,thanks.
Long time period with water in the cylinder and the piston at or very near BTC. More than likely water trap in the ring pack, not on top the piston. I would imagine the rings in that particular piston are trashed more so than the others.
Funny thing is the piston and rings look great,the divot has smooth edges,it is not sharp,it appears to have happened over time
Rings passing over it a few thousand times will sometimes tend to "smooth" things out. Rust does usually eat metal away like a mill and leave nice well defined edges.
If you like, I could tell you its from iron eating termites.
Lets use your head here for a second mouth.
You post up this:
Originally Posted by Flyin-Bryan
To give You some insight this was an offshore marine engine with wet exhaust,I know the guy ran it low on oil and caused lower end failure,and upon removing the heads it appears his exhaust manifolds were bad causing water to enter the combustion chamber
I told what I thought caused that and you didn't buy it.
If you don't like the answer I gave you, I fine with that. Not exactly sure why you think that the exhaust manifolds are BAD, or why you think that water in the combustion chambers is different than water in the cylinders, why you believe water in the combustion chamber would stay there and not go to the bottom of the cylinder and set there. But then, you are the expert. I am still dumb founded why you felt you needed any body elses opinion.
You have the motor right in front of you. Whats your expert opinion of what happened. You ruled out water, even with the above quote, so I imagine you have a theory. Right?