Help identifying stihl 460 or 440 ?

[cuinrearview]

That's just carbon.

Indeed, and it looks like a chunk that came off all at once.

 

[cuinrearview]

NWP

What's the thought behind it?

 

[PA Dan]

And smeared down the piston. Most of the scoring is right there.

Yes sir that would be my guess! Scotch bright ball and meteor piston! If it's a keeper I would split the case and start fresh! That's just how I roll!

 

[thinktwicez71]

Well I dunno if this cylinder is salvageable or not . I cleaned up inside with some empty cloth on a drill and there are quite alot of scratches in the plating. I cant feel them with a finger but I can with a finger nail. What are your thoughts on this ? Would a hone take some of those out ? Or junk it ?

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[cuinrearview]

Pics would help. Usually if a nail catches it's done but I've seen a lot of jugs people thought were scored that just needed more sanding.

 

[thinktwicez71]

Here ya go

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[cuinrearview]

Keep sanding. I'm 88% sure that's gonna clean up enough to re-use.

 

[cuinrearview]

I do see some chipping in the plating just above the exhaust port, so be careful there.

 

[cuinrearview]

If you decide not to use that cylinder let me know, I'd grind on it some where that chipping is. But I think it's salvagable.

 

[jltrent]

A few more pics and a person might could tell.........lol

I would throw a piston in that and see what kind of compression it makes. I have seen them like that do 150 and after a few tanks increase, also I have seen them do less than 130 and get no better. Those marks look light and not cut in.

 

[thinktwicez71]

Haha I wanted to give you all a good look [emoji23]

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[thinktwicez71]

The chipping wouldnt affect the saw at all? Or a ring wouldnt catch on it and make it worse ? There is also what appears to be a chip next to the exhaust port also going vertical up and down

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[cuinrearview]

Youd want to smooth the edges to lessen the chance of a ring catching.

 

[cuinrearview]

A few more pics and a person might could tell.........lol

I would throw a piston in that and see what kind of compression it makes. I have seen them like that do 150 and after a few tanks increase, also I have seen them do less than 130 and get no better. Those marks look light and not cut in.

No way I'd throw a new piston in there without finishing the job. Unless I wanted to pull it back apart, finish sanding off the transfer, and buy another piston later.

 

[cuinrearview]

Here's a 562 jug I'm re-doing today because someone stopped before all the transfer was gone and threw a meteor in. They went so hard below the port they got through the plating, but left scratches and aluminum everywhere else. Go until your surface looks like this.

 

[thinktwicez71]

Will these scratches come out ?

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[blsnelling]

Most of the pics are showing where the skirt rides in the bottom of the cylinder. What's critical is the top of the cylinder. There are a LOT of scratches in that cylinder, nearly all the way around the bore. You're not going to sand those all out. That is not transfer.

 

[blsnelling]

Will these scratches come out ?

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Above the exhaust port is what's critical.

 

[blsnelling]

...finish sanding off the transfer...

That is not transfer.

 

[cuinrearview]

That is not transfer.

So do you think it's shot?