Any benefit to polishing inside the crank case?

[Andrew Wellman]

I am doing a complete restore of a MS440. It was a gift for saw work on my neighbors 046 and he got it from a logger who used it up. P/C ex cond, but lower flywheel bearing fell out in pieces, clutch side still good. No damage to saw. I split the case and stripped the paint, what was left and then polished the inside of the crank case. This means that I removed the paint but wonder if the paint was "Polishing", due to the fact that once removed it showed casting roughness. I did not remove material just polished.
Is the paint important to protect the Magnesium? I bout a book on how to performance tune 2 strokes but I have not received it yet. I hope to learn enough to make some safe smart porting changes to the top end. I am all ears if you have info
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[Jacob J.]

Modern Stihl cases are powder-coated rather than painted. The mixing area inside has that coating to protect the inside of the case from corrosion. However, I've
seen many saws run with that coating stripped and the inside area polished as you've done without any problems. That coating comes off eventually anyway.
Probably one out of every two used saws I tear down has that coating already flaking and peeling and I end up stripping some or all of it.

The main source of corrosion of saw cases comes from people either leaving saws out in the weather or markets where saws are run with particularly low
grades of fuel, like third world countries. So if you take your saw to central Africa, you may run into problems.

 

[Dan_IN_MN]

I am doing a complete restore of a MS440. It was a gift for saw work on my neighbors 046 and he got it from a logger who used it up. P/C ex cond, but lower flywheel bearing fell out in pieces, clutch side still good. No damage to saw. I split the case and stripped the paint, what was left and then polished the inside of the crank case. This means that I removed the paint but wonder if the paint was "Polishing", due to the fact that once removed it showed casting roughness. I did not remove material just polished.
Is the paint important to protect the Magnesium? I bout a book on how to performance tune 2 strokes but I have not received it yet. I hope to learn enough to make some safe smart porting changes to the top end. I am all ears if you have info
View attachment 236881

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[genestar]

Modern Stihl cases are powder-coated rather than painted. The mixing area inside has that coating to protect the inside of the case from corrosion. However, I've
seen many saws run with that coating stripped and the inside area polished as you've done without any problems. That coating comes off eventually anyway.
Probably one out of every two used saws I tear down has that coating already flaking and peeling and I end up stripping some or all of it.

The main source of corrosion of saw cases comes from people either leaving saws out in the weather or markets where saws are run with particularly low
grades of fuel, like third world countries. So if you take your saw to central Africa, you may run into problems.

If your in Africa you will have other problems so the saw won't mat:msp_razz:ter...

 

[Fish]

I wonder if the coating over the rough metal may be more for the fluid dynamics than for corrosion purposes. Likely one would not notice any performance differences, but it may still affect the overall power output.

Just a thought...

 

[Andrew Wellman]

Powder coat smoothing

Then if paint or powder coat smoothes surfaces then polishing would do the same, less a layer of material. Would the powder coat insulate and thus retain heat longer. Would this be a negative? Would a bald crank case be better for heat diffusion? Or in another post I asked, would a aluminum metalic paint for the exterior of the case help cooling of the saw? Have at it guys, let me hear your thoughts.

 

[Fish]

Cooling is not an issue down there.

As far as the physics/air-fuel flow, that is what I was thinking. That is why they wash airplanes and jets....

 

[Rubber duck]

I was thinking of striping the paint on old magnesium crankcase and handle and polishing it and putting some clear coat on it made for magnesium sense I hear it has to be a special kind I think it would just look cool like a harley with the chrome and black paint theme and I know a lot of you are going say it's just a saw for work but man would look cool just wondering has anyone ever done this and would there be any negative effects I know they powder coat for looks but mainly for moisture to protect the magnesium but wouldn't it be protected from special clear coat any feed back would be appreciated . Rubber duck.