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

Mastermind

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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.

I remember the Vega blocks well. Lots of them were ruined by rebuilders using the wrong hone in them. Seems they needed to be honed with ceramic stones.
 

Red97

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I remember the Vega blocks well. Lots of them were ruined by rebuilders using the wrong hone in them. Seems they needed to be honed with ceramic stones.
Supposedd to be a fancy flexible stone.
To remove the aluminum and leave the silicon particles.

Supposed to be a 3 step process. First 2 achieve a mirror finish 5-15* crosshatch then use the fancy stone to rough up the finish a bit.

I can see how it would be easy to mess up iffin you are used to iron bores.

Sent from my SM-G950U using Tapatalk
 

jk14

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Thinking the bore finish needs to be smooth as possible. 800-1000 grit.

I remember the Vega blocks well. Lots of them were ruined by rebuilders using the wrong hone in them. Seems they needed to be honed with ceramic stones.

Yup the old Vega's as well as the Porsche 944 also had an aluminum bore 4 cyl. We did a few of them back in the day, can't quite remember the "grits" used but we had a few sets of stones specifically for the aluminum bore motors. I know they were supposed to hone away the aluminum and leave the silica exposed for the piston and rings to ride against.

Here's some info if anyone's interested.

http://www.sunnen.com/NewsDetails.aspx?NewsID=11
 

Mastermind

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Yup the old Vega's as well as the Porsche 944 also had an aluminum bore 4 cyl. We did a few of them back in the day, can't quite remember the "grits" used but we had a few sets of stones specifically for the aluminum bore motors. I know they were supposed to hone away the aluminum and leave the silica exposed for the piston and rings to ride against.

Here's some info if anyone's interested.

http://www.sunnen.com/NewsDetails.aspx?NewsID=11

We're showing our age huh Jeff?
 
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