can you sand a piston?

[Stump Shot]

seal the ports best i could for now.

That looks pretty good, you might have some hope after all. Try and measure or use a feeler gauge if you can to make sure there isn't excess play in the skirts and go from there.

 

[oaky]

so put the gauge between the bore and piston skirts from the top?
smallest one i got .04mm doesnt fit

 

[oaky]

well technically the bottom

 

[Stump Shot]

so put the gauge between the bore and piston skirts from the top?
smallest one i got .04mm doesnt fit

That's good, now time to go with what your gut tells you.

 

[Dub11]

Normally I say it's just a piston, smoke'em, if you got 'em and I will put a new one in. Knurling is a kind of a last resort fix, or as a hot rodding trick for less friction. I think of it as old school Teflon coating.

View attachment 163357

Lol that's a hell of a collection lol.

 

[Stump Shot]

Lol that's a hell of a collection lol.

2018

 

[oaky]

no *s-word.. thanks stump shot

 

[oaky]

what do you guys think of the cylinder, still has visible marks, feels smooth against my fingernail, but i can still fell little marks with a bent pick, been using 320 grit paper and scotch brite
.

 

[Stump Shot]

what do you guys think of the cylinder, still has visible marks, feels smooth against my fingernail, but i can still fell little marks with a bent pick, been using 320 grit paper and scotch brite
.View attachment 163384 View attachment 163385 View attachment 163386 View attachment 163387 View attachment 163388

Get all the aluminum transfer out of there until it is butter smooth.

 

[oaky]

butta

 

[Al Smith]

And for the record, Model A Ford pistons are not a good candidate for knurling as the were of a hard/brittle type alloy.

I was just using an A model as an example meaning it was done years and years ago .I'm not certain what the alloy was on an A of if they were cast iron not that it makes any difference but I'd about bet they used something like knurling during the great depression .Which BTW I'm not certain how you knurled that piston but it looks good .Doesn't look like it raised the metal too much .It also looks like a person should use some heavy mix ratio on the oil which is not a bad thing .

 

[Al Smith]

Now let me tell you about automotive pistons .Firstly I worked over 40 years in or around the automotive business .I installed one piston line for Honda and three for Ford and did the maintenance on 4 for Ford before I retired . A piston is perfectly round on the ring portion but below the rings has ovality and taper .On a chainsaw engine because it is so small you most likely cannot measure it but it's there .
How much skirt wear determines performance I really can't say .Only to say with kart engines it was kind of loose .In fact Ford 429 NASCAR specials were loose ,I've seen them . Now how long they might run might be another subject .

 

[tickbitintn]

Normally I say it's just a piston, smoke'em, if you got 'em and I will put a new one in. Knurling is a kind of a last resort fix, or as a hot rodding trick for less friction. I think of it as old school Teflon coating.

View attachment 163357

That looks like close to $3 at the scrap yard...
Just took a box full of piston and cyls...

 

[tickbitintn]

seal the ports best i could for now.

Looks like that should survive for a while... what is it??