Ouch!

mkirsch · Mar 10, 2014

The good news:

I dumped the oil on my "new" 240U yesterday. No water in the oil.

I also dropped the oil pan. Nothing obvious down there.

The bad news:

This is what the top of the #1 piston looks like:

Baelee05 · Mar 10, 2014

Uh oh!

Janicholson · Mar 10, 2014

Interesting imprint. It looks like a pin with a clip groove in it got inside. With an updraft carb it would seem difficult to be sucked up, and what did it come from? It could be from being left in the cylinder when "repaired". If the sleeve is not scored from smashed ring land and displaced broken ring, a new piston should be all that is needed. It does not look like it would fit past an intake valve! Jim

the tractor vet · Mar 10, 2014

I have seen worse , now the big question is , WHAT DOES THE HEAD look like ???
If there is no damage to the head and the walls look good don't worry about it .

mkirsch · Mar 10, 2014

Tractor vet, you told me exactly what I wanted to hear.

Sleeve wall looks good.

The head needs help. There's a chunk out of the exhaust valve on #2, and the seats look kinda rough in general.

old · Mar 10, 2014

As Vets says and if the cylinder walls are fine you should be good to go. If I where you I might think about pulling the pistons and checking the ring just to make sure there not chipped or something

John G. Hasler · Mar 10, 2014

> With an updraft carb it would seem difficult to
> be sucked up, and what did it come from?

Broken valve? Someone fixed the other damage but left the dented piston in?

mkirsch · Mar 10, 2014

A chipped ring would show up as a gouge on the sleeve wall, or a loss of compression in that cylinder, right?

#1 and #2 were only making 75PSI compression but I suspect that's head related.

John M · Mar 10, 2014

That piston is cracked.

xfarma · Mar 10, 2014

You're right John, it is cracked.

Janicholson · Mar 10, 2014

The groove is too close to the top for valve keepers
to get a stem that far into the hole, would leave much more damage. Jim

Janicholson · Mar 10, 2014

The crack running down the center of the middle indentation is for sure unacceptable. It will fail!
Jim

Jason the Red · Mar 10, 2014

Looks like you have a valve issue. Possibly valve spring failure (or near failure).

Rick Remmert · Mar 10, 2014

I am not familiar with this size of engine, but it sure looks like it dropped a valve. You only see the keeper end because the valve head would hold the rest of the valve up. It would be interesting to see the rest of the piston and the inside of the combustion chamber. In my years of drag racing I have seen blow engines with some really strange damage.

Janicholson · Mar 10, 2014

I am confused by your statement that [the] valve head would hold the rest of the valve up. Up where? the keeper is on the valve cover side of reality. If the valve stem is in the combustion chamber the total of the valve must be in there as well! Jim

Jon Hagen · Mar 10, 2014

I have found valve parts/ rings/ piston bits from a blown up V8 race engine cylinder in several cylinders, sometimes in the opposite bank of cylinders. . Really amazing how air velocity and vacuum / pressure pulses can move heavy bits of steel around inside an engine intake system.

Pretty common to "drop a valve" in a race V8 at high rpm and find "chicken tracks" on the top of the other 7 intact pistons and chambers.

old · Mar 10, 2014

Broken ring will show up as a gouge but a chipped ring will not leave much if any mark till it is to late

mkirsch · Mar 11, 2014

(quoted from post at 18:53:15 03/10/14) I am confused by your statement that [the] valve head would hold the rest of the valve up. Up where? the keeper is on the valve cover side of reality. If the valve stem is in the combustion chamber the total of the valve must be in there as well! Jim

Up, as in up out of the combustion chamber, from contact with the piston, maybe?

Up, as in upright, because a 6" long valve can't flip end-for-end in a 3" diameter hole?

I checked last night, and there are no marks on the head anywhere around the #1 cylinder.

gene bender · Mar 11, 2014

Chipped ring cant get up there unless top part of piston is gone

fixerupper · Mar 11, 2014

Looks like something went in the spark plug hole while the plug was out at some time in it's life. Jim

Ouch!

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