What caused this! Piston Pics

[grandpatractor]

Ok check them out. Bonus points if you can tell me what saw it is from.:msp_confused:

 

[RAMROD48]

What condition was your air filter in?

 

[grandpatractor]

What condition was your air filter in?

partially plugged but not terrible.
This is a saw that was traded in.

 

[chainsaw kid]

Big end let go???

 

[Bowtie]

Husky or Jonsered or possibly poulan. Not from air filter, looks like exhaust side is scored.

What condition was the jug in prior to damage? Just a question.

 

[cambl]

Poor fuel, detonation.

 

[chainsaw kid]

266

 

[Jacob J.]

Poor fuel, detonation.

That's what I'm thinking. Stale fuel most likely. I'd have to see a side shot of the piston to ID it.

 

[mweba]

Offset comb chamber leans me toward Dolmar. I'm going with bad bearing as well.

 

[mweba]

OR Pele measured the squish before reassembly:hmm3grin2orange:

 

[grandpatractor]

266

You are really close to the right size!
wrong brand.

 

[chainsaw kid]

670

 

[chainsaw kid]

The only reason I didn't say 670 was because of the impulse hole in the jug. I have a seen them with the hole and without, but the 266 always has it.... Now tell me it's not a 670 :hmm3grin2orange:

 

[Jacob J.]

Offset comb chamber leans me toward Dolmar. I'm going with bad bearing as well.

Two thick rings and high wrist pin lead me to believe it's a Dolmar/Sachs-Dolmar as well, like the 120 Super or 6800.

 

[grandpatractor]

Mitch got the brand right.:hmm3grin2orange:

 

[grandpatractor]

Two thick rings and high wrist pin lead me to believe it's a Dolmar/Sachs-Dolmar as well, like the 120 Super or 6800.

Bingo-6800!

 

[Bowtie]

Two thick rings and high wrist pin lead me to believe it's a Dolmar/Sachs-Dolmar as well, like the 120 Super or 6800.

How the hell did you know that?

 

[grandpatractor]

Bottom end was good. I believe it was poor fuel/ detonation also.
Just hadn't seen one eroded away quite this bad before.
almost a knife edge on the piston.

Went thru carb and put a new piston and cylinder on it and it runs like a champ.

I did check the key in the flywheel too.

 

[chainsaw kid]

damb! :hmm3grin2orange: Never worked a dolmar...yet
Fun thread! Now, was it only detonation or did the big end let go?

 

[chainsaw kid]

Bottom end was good. I believe it was poor fuel/ detonation also.
Just hadn't seen one eroded away quite this bad before.
almost a knife edge on the piston.

Went thru carb and put a new piston and cylinder on it and it runs like a champ.

I did check the key in the flywheel too.

Was the piston hittinh the top of the combustion chamber? It looked from the picture it was. Was the OEM base gasket installed and was the piston slapped out so bad it was rocking?
I wish I was there!