125psi compression but look at this damage how is it possible

[Beno]

Just looking at an engine for a friend the compression checks pretty good down the line at 125 but just in number two looks bad from the exhaust port side so we wanted to try to replace it..

Pulled the head and saw this, damage on ALL cylinders

What causes this kind of scratches? carbon? bad rings? No oil??

Interesting thing of note that the very bottom center of some of the cylinders has the worst damage

It’s very consistent between each cylinder so whatever this was was something that was DONE to it?

my guess is that this engine set for a long time got Rusty on the very bottom center (maybe water)  and then someone decided to run it hard with no oil

 

[fleetwin]

Compression tests on two strokes can fool you indeed!  The extra oil helps seal the rough surfaces.   I’m guessing lack of oil, or overheating did this

[Beno]

Hey fleetwin! Long time

The scary part is that engine was running..

I Talked to the owner and there’s no point in continuing to try to run something so damaged.. it’s just going to leave him stranded somewhere at some point.

At least at this point the Pistons may have some value .. connecting rods have value.. the crankshaft is great still, reeds good, head good. and he can sell the block to someone who wants to bore it out.

The secret here is to park these motors up before they self destruct, As the internal components will be almost worthless once they’re damaged more.

so I disassembled the whole engine. Going to part it out.

 

[Author]

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