Engine damage... with less than 50 miles

So i decided to part out my LT1 car due to owning a house and the fact that i haven't really driven it since i got it back. I never had the heads or intake off of the car but the intake and heads came off to verify that everything was in good condition. this is what was found.






Never had a bad spark plug come out (the damage looks too long to be an electrode anyway) and it's only been down the track twice on spray (only a 100 shot) and once on the dyno (225 shot that the builder installed). Any idea on what the damage could be from?

[sweetbmxrider]

I'd say intake casting but aluminum doesn't just up and vanish.

[WildBillyT]

Any damage to the valves? Like debris got in there via the intake manifold, bounced around in there, and went out the exhaust?

Originally Posted by WildBillyT

Any damage to the valves? Like debris got in there via the intake manifold, bounced around in there, and went out the exhaust?

no, idk how anything could've gotten in. i never ran it without a filter or anything. The damage is about the size of the tip of a flat head screw driver.

[Blackbirdws6]

Piece of the intake maybe from machining or w/e likely got in the cylinder and jumped around. Prob got mashed around quite a bit before either getting destroyed or exiting the exhaust valve. Prob only took a moment for that to happen.

[LTb1ow]

Piston top ring was melted a little and the ring couldn't move, which caused that one scour I would guess. Hot spot from off jetting or bad spark plug choice maybe.

Off jetting for one cyl? it had a plate kit on it...

[LTb1ow]

Originally Posted by JerzLT1

Off jetting for one cyl? it had a plate kit on it...

yea, IDK, just odd, for so low miles

[WildBillyT]

Originally Posted by Blackbirdws6

Piece of the intake maybe from machining or w/e likely got in the cylinder and jumped around. Prob got mashed around quite a bit before either getting destroyed or exiting the exhaust valve. Prob only took a moment for that to happen.

Yeah, I'm no pro builder but this really looks like a piece of debris, maybe something stuck in the intake somewhere. I dunno if detonation of any kind will make identically shaped lines like that.

Originally Posted by WildBillyT

Yeah, I'm no pro builder but this really looks like a piece of debris, maybe something stuck in the intake somewhere. I dunno if detonation of any kind will make identically shaped lines like that.

yeah, i was thinking the same but idk how it could've happened since i never even had the filter off since i got it back until i started taking apart the car

[Blackbirdws6]

Originally Posted by JerzLT1

yeah, i was thinking the same but idk how it could've happened since i never even had the filter off since i got it back until i started taking apart the car

Could have been just a piece from machine work that was waiting to come loose? You could speculate that maybe the builder ran it without the filter to make sure everything fired properly before slapping on the intake. It would still be odd for something like that to get sucked in so I'm still thinking it was a piece from the intake.

Yeah idk. Builder never responded when I sent pictures. With the lack of detail on some of the work (in my opinion) I wouldnt rule out something falling in the intake upon installation. But there's no way to know when it happened since it ran fine immediately before being disassembled.

[sweetbmxrider]

Originally Posted by JerzLT1

yeah, i was thinking the same but idk how it could've happened since i never even had the filter off since i got it back until i started taking apart the car

A parts delivery driver swapped intakes on his flathead from a single carb to a triple carb setup. They started it up and immediately shut it down after hearing a metallic sound like a marble was bouncing in the cylinder. Low and behold, a piece of casting fell into the head and beat the snot out of the piston but the bore and head were unscathed. The motor was run for mere seconds and it had very much the same damage as your piston. They fished out the piece and replaced the piston.

[KirkEvil]

The damage seems too concentrated on the piston and chamber for a piece of intake falling in and bouncing around.

[NHRABill]

had one look like that once, broken timing nylon gear 73' corvette had those darn plastic nylon like timing gear. The valves smacked the pistons. trying to recal it happened back in the mid 90's and that is mostly a blurr for me