High Quality Chainsaw Bars Husqvarna Toys

Red Armor* Poll

How long? Bare bore, bare piston

  • Not start

    Votes: 1 2.1%
  • Almost tuned

    Votes: 6 12.5%
  • 1st cut

    Votes: 13 27.1%
  • Half tank

    Votes: 17 35.4%
  • Something else failed

    Votes: 11 22.9%

  • Total voters
    48

Cut4fun

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Dad has been running a bare bore 54cc since 1989. Last time I had it down for av's and boot the p+c still looked great. Piston is chromed with bare bore in poulans like that.
 

Cut4fun

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Not a clue on the rings. Never noticed. Just ordered what ever the bare bore had listed. I will take a look at the ipl's.

But the bare bores are real dark looking.
 

wcorey

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I think it would run long enough for the intended purpose, though the probable difference in comp may skew the results.

Seems like chrome rings may be better than iron, smooth and sort of pre-broken in.
Seems like galling will be the big issue and anodizing the piston would be easier than the bore.
Just watch the pin clearance.
 

Cut4fun

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Going to go to order rings and see what set they put in cart for bare bore to see if above is true. What I seen when running #'s.
 

RIDE-RED 350r

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Maybe I'm wrong, but I would think the hard rings on the soft bare aluminum bore is the real issue here rather than the aluminum piston and bare aluminum bore. Its the ring/s that put the most pressure on the cylinder walls and what I would think will do the most damage to the bare aluminum cylinder bore. Yes, pistons do expand some as they come up to temp, but they should never get to zero clearance...that's when heat builds to the point the aluminum piston starts to soften and melt, transferring material to the bore and seizing up..
 

Manofstihl661

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Maybe I'm wrong, but I would think the hard rings on the soft bare aluminum bore is the real issue here rather than the aluminum piston and bare aluminum bore. Its the ring/s that put the most pressure on the cylinder walls and what I would think will do the most damage to the bare aluminum cylinder bore. Yes, pistons do expand some as they come up to temp, but they should never get to zero clearance...that's when heat builds to the point the aluminum piston starts to soften and melt, transferring material to the bore and seizing up..

I pretty much agree. I think the heat expansion with the hard on soft metal would be the major wear points
 

Red97

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My thoughts are the piston material is likely harder than the bare jug.

Keep the jug slick (mirror) finish. And hope the oil does it's job. Keep a film/barrier between the wear surfaces.

Now the ring will wear the bore, but I can't see it "cutting" chips on every stroke.

A chrome ring would likely help. But a clean smooth ring shod do the trick.


May be way off. I plan to find out though.
 

RIDE-RED 350r

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My thoughts are the piston material is likely harder than the bare jug.

Keep the jug slick (mirror) finish. And hope the oil does it's job. Keep a film/barrier between the wear surfaces.

Now the ring will wear the bore, but I can't see it "cutting" chips on every stroke.

A chrome ring would likely help. But a clean smooth ring shod do the trick.


May be way off. I plan to find out though.

I don't have any first hand experience in this, but in my mind I don't see the ring so much chipping the bore, but grinding it..,making fine aluminum dust similar to what you get when you port a cylinder with your carbide burr. This is just my hypothesis, curious to see how it pans out when you test it.
 

Red97

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I will venture to guess the old Briggs cool bore, and poulan bare bore jugs were a hypereutectic alloy. Over 12% silicon, special casting process brings the silicon to the bore surface. A special honing process removes just the aluminum exposing the silicon grains as the wear surface.

The alum block Vega is one example of this process. Probably explains the dark color bore mentioned above.

Have to do some more reserch on the subject When I try casting my own jug..

Either way still gonna see what happens with the bare bore. It it doesn't work it needs to be bored larger for the iron sleeve anyway.
 
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