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Taking my chances with this unknown cpl engine. Was trying to figure out what happened with this piston. Looks like something beat it up or it started to melt down but why the sharp contrast to the smooth semi circle area. Input appreciated. Fred
 

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As the man says, probably a faulty injector. Is this possibly a marine engine? Those pistons have a marine style bowl but can't tell if they are true marine units or just the ones with that shape bowl. You say unknown CPL. If the injection pump is original that part number may give you a clue.
 

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No one noticed that the intake valve was smacking the piston ? Looks like very high rpm & high egt's. Nozzle wasn't spraying outside bowl, so timing was fine.
 

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Mark, was the intake valve actually hitting the original piston surface or just the area that was being raised by excess heat. That area on the piston appears to be smooth and normal. There is a smooth area where the exhaust valve is also. Normally, it's the exhaust valve that your worry about floating in high RPM situations. No question that the heat in that cylinder was beginning to cause damage. Wonder if the EGT gauge was showing excess heat if it even had one.
 

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did you lose someting in the intake like part of the turbo.. looks almost like a welding spatter.. I'd think hot aluminum or such.. I think tha tis why the clear spots where the valves open.. they are cold spots.. welding don't stick as good there,, just my ignorant old guess
 
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