Here's a new one !!!!

[Boatdoc58]

During the winter months I rebuild/repair powerheads. A guy throws a motor off and says I can have it because he is tired of it. He tells me #1 has no compression and it made noise when it ran. Heh, FREE with a lower unit and all, might be a money maker.
Imagine my surprise when I pulled the head off and saw this.
You can actually see where the wrist pin cut into the cylinder wall in FOUR places as it slammed up and down.
I cannot under stand why it did not break the rod and have it exit out the block.
There are no "tool marks" on any of the case bolts. All the factory paint is there and the original "Test run by" sticker is still on the block.
Where did the piston go?
What are your thoughts?

 

[HighTrim]

Boy Ill bet that made noise, lol. You got me. Maybe a joke?

 

[gm280]

Maybe the piston pulverized? :noidea:

 

[flyingscott]

The piston broke apart I will bet you find more broken in the motor when you tear it down.

 

[oldboat1]

Seriously though, I think your new motor might be dropping a cylinder. I would look into that before rebuilding the carburetor. Could be wrong. The noise -- where does it seem to be coming from?

[and never buy a Chevy or an Evinrude assembled on a Friday before a holiday....]

 

[oldboat1]

Quick historical note:

Older listers will remember that in late '75, pistons were optional as a cost saving measure. Usually, you bought the motor with one piston missing, with the idea you would get one later. Most people didn't get the additional one because the cost of gas was rising, and motors ran more cheaply if they were missing a piston. A lot of younger folks probably don't know this.

 

[Boatdoc58]

No Title

The strange part is that the motor turns over smooth as can be with no grinding or tight spots.
The "BBs" in the cylinder head wipe right out with you finger and the head shows no signs of melted aluminum stuck to it !!
I have removed the exhaust plate and there is no sign molten metal, aka piston, went through it.
The depth of the grooves cut by the wrist pin show that this thing HAD to run a bit making one hell of a noise !!

 

[Fun Times]

Oh wow!! Is there anyway for you to track down the guy that dropped it off to you for more user/service history info?

What engine model and year is that one?

 

[oldboat1]

really incredible. PO give you any more to the story?

 

[Faztbullet]

Uhhh....whats holding the wrist pin in place??????

 

[gm280]

With the additional picture of the BB's, it really looks like the aluminum piston literally melted and exited the cylinder. A lot of heat had to be generates for that to happen. With fuel being delivered to that cylinder to help the melting issue, I could see that happening, although extremely unbelievable. JMHO!