Summer Camp Engine Update

[smudvapor]

I pulled the engine apart today and the pics below show what I found. Something must have gotten in their. I don't know what but it did a number on the piston and cylinder. Everything else looks good. I thought maybe the spring clip for the wrist pin was the problem but it was where it was supposed to be so that wasn't it. I don't know what caused the damage. I have another cylinder and piston on the way so you will all see her running in the Fall. Thanks to everyone who helped try to get her running a Pine Lake, especially Don and Mike. We had quite the pack of "experts" around the machine that day. When I get her back together I will give all of you another update.
Scott

[Andyman]

Your working with the best, keep us posted.

[smudvapor]

The new cylinder will be here tomorrow or Thursday. I will have her back together by the end of the week.

[philipatmaxfour]

summer camp engine update

Can anybody advance an educated guess as to what got into the cylinder to cause the damage?

[smudvapor]

Can anybody advance an educated guess as to what got into the cylinder to cause the damage?

I searched everywhere and I can't find anything, no remnants, nothing. I thought maybe a needle bearing but they are all there. You can't see it in the picture but the cylinder cracked and broke just under one of the ports. The only thing that I can think of is that maybe a piece of the cylinder broke off and did the damage.

[philipatmaxfour]

I searched everywhere and I can't find anything, no remnants, nothing. I thought maybe a needle bearing but they are all there. You can't see it in the picture but the cylinder cracked and broke just under one of the ports. The only thing that I can think of is that maybe a piece of the cylinder broke off and did the damage.

Thanks Smud- At least that's a plausible theory. Your pic. shows the ring gaps and there's nothing missing there. Funny that the damage seems at the top of the piston or way down lower on the skirt but not near the center area? Great project for your students.

[ARGOJIM]

A possibility, burnt off or broken electrode.

[miller_time]

Did you happen to look in the exhaust pipe for the piece?

[smudvapor]

Did you happen to look in the exhaust pipe for the piece?

Nothing in there either. Must have come out after the damage was done.

[smudvapor]

A possibility, burnt off or broken electrode.

Plugs were good.

[ARGOJIM]

Plugs were good.

Did the engine run when you acquired the machine?

[Nubs]

Looks to me like something got sucked into one of ports, piece of the baffle from the exhaust? what side was the damage on

[Nubs]

the fact that the grooves are not parallel to the piston travel tells me that something with some size to it was floppin' around in a port and hitting the skirt. a piece looks to have dropped into the the bottom end and back up the side by the wrist pin.

[smudvapor]

Did the engine run when you acquired the machine?

Yes, I rebuilt it three years ago and ran it all summer. It was then removed and put on the shelf in the basement until now.

[hipowerone]

The second image is very perplexing! How did whatever was in there "walk" one way or the other and not drop to the bottom! And still not be found! Image one seems to show that whatever it was went from top down through the rings...but how it jumped 90 degrees to other position and not score the rings? Was engine running when you got it? Or was it DOA from the start? Maybe previous owner did something dumb?