Mag rot in the crank case?

[RocketRoss57]

Is this bad or repairable? Nothing as far as I can tell is all the way through. Just looks terrible. Can I fill this with JB or epoxy?

Husqy 61 if that makes any difference...

 

[cus_deluxe]

seen worse...maybe @Glock37 could shed some light.

 

[Glock37]

Blast and powder

The rot by edge could be a proplem after blast may have to have shawn fix edge

When done it will be like new


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[RocketRoss57]

So should I blast it first and then see how deep of a hole i am dealing with? Will epoxy work?

 

[Glock37]

Split old bearing and insert in bearing bores
rubber stopper in seal areas bolt case halves together
blast what u can together then separate and do places u missed
36 grit black beauty is what we use
Wash with hot water
Heat case halves to dry



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[Nutball]

How does that happen? Salt water sitting in there? Methanol?

 

[Glock37]

Water and mag dont mix


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[Al Smith]

I have no idea what might have caused it because I know nothing about where it had sat nor how long .However mag and aluminum are classified as a "sacrificing metal" .Under conditions such as sitting in contact with concrete it can cause the metal to in essence "leech out ".One portion of the mixture to make Portland cement is blue clay slurry which contains an element called alumina which is one or two electrons away from alumina and thus sets up electrolysis ,galvanic action between the saw and the concrete .Then too you have steel or nodular cast iron components within the saw engine , plus a steel bar more reaction .

Now if it were me I'd just wire brush the areas damaged using a die grinder and rotary brush and put it back together .You'll never know the difference and it might run forever .

 

[Basher]

Condensation most of the time, unless the saw is immersed in water and then left to sit long periods. In climates where hot and cold alternate constantly condensation is a big factor in corrosion from the inside outward.
When the corrosion from sitting on concrete occurs its mostly from the outside inward. I just completed cleaning up a very nice 024 that had sit on a concrete floor in a damp shed, very interesting how many parts were affected by this.

 

[Al Smith]

The saw in this avatar is circa 1968 and a classic old Douglas fir cutter from Oregon .It had a hole eaten in the front cover of the oil tank .I just ground out the rot and J-B welded it with no problem

 

[RocketRoss57]

So do you guys think that just blasting this out and if it isn't too bad or all the way through that I could just run it as is. This will be no show piece and see little use. I am concerned that if I were to fill it with something that there is a possibility of it coming loose and damaging the engine. I am installing a new top end and new bearings and seals and would hate to ruin anything right off the bat. I suppose replacing all together may be the best bet. That said if any of you fellers have case halves for a 61 that is for the two piece ignition I would be interested to make you an offer.

 

[Glock37]

So do you guys think that just blasting this out and if it isn't too bad or all the way through that I could just run it as is. This will be no show piece and see little use. I am concerned that if I were to fill it with something that there is a possibility of it coming loose and damaging the engine. I am installing a new top end and new bearings and seals and would hate to ruin anything right off the bat. I suppose replacing all together may be the best bet. That said if any of you fellers have case halves for a 61 that is for the two piece ignition I would be interested to make you an offer.

Im under the belief that powder helps seal the motor
Mag is porous it absorbs oil so it can leak air
I pressure tested alot of powdered saw they hold 8 lbs for well over a hr
Worn painted ones not as long
Start with a good foundation !


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[RocketRoss57]

Im under the belief that powder helps seal the motor
Mag is porous it absorbs oil so it can leak air
I pressure tested alot of powdered saw they hold 8 lbs for well over a hr
Worn painted ones not as long
Start with a good foundation !


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Ok I'll start with blasting. My buddy has a powder setup that I'll use. Thank you for the advise.

 

[timg]

Glyptal paint would be my suggestion. It is what is used internally in powertrain and engine component castings. It is a great impervious sealer that also has dielectric properties. Like Glock37 said it's got to be clean. You wouldn't have to worry about running clearance issues as you would with JB weld. McMaster-Carr or Eastwood stocks it. Hope this helps you out. TG

 

[Glock37]

Glyptal paint would be my suggestion. It is what is used internally in powertrain and engine component castings. It is a great impervious sealer that also has dielectric properties. Like Glock37 said it's got to be clean. You wouldn't have to worry about running clearance issues as you would with JB weld. McMaster-Carr or Eastwood stocks it. Hope this helps you out. TG

Heat cases in cleaner in uc then blast then clean and bake to get more out the mask and powder


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[Glock37]

390 case !!


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[BuckthornBonnie]

Im under the belief that powder helps seal the motor
Mag is porous it absorbs oil so it can leak air
I pressure tested alot of powdered saw they hold 8 lbs for well over a hr
Worn painted ones not as long
Start with a good foundation !


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I’m interested in your take on this, man. Are you saying mag cases that are corroded with no powder coat could be a potential air leak? I’d think any leak of a gas (air) would be nominal and easily tuned out. Mag is porous, but any idea on the porosity size (ie, liquid oil vs. molecules of gas)?

I agree about the blasting and pc being the best option unless money was tight. The gasket surface should be trued, cleaned, and possibly supplemented with 518 or similar... but the rest could be left alone after cleanup.

 

[Glock37]

Abs plastic will not hold air but will hold water pressure

Clutch side cases have a insert cast into them when heated oil gas and what not bubbles out of area between
So if gas and oil in there air can escape
Coat with powder seals that area

Yes after powder i chase all threads and flat sand gasket surface with 320 paper untill flat
When installing fasket i coat both sides with 518 no leaks so far on the ones ive done
Also heat cases to drop bearings in instead of sliding steel on steel or mag flywheel side just my thoughts


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[Al Smith]

I doubt seriously if that case is pure mag but suggest it's an alloy of mag and aluminum .The only way it would be porous is if the casting had porosity .In other words a chitty job of casting .
"glyptal" is the trade name of an electrically insulating paint made by GE ,used years ago in the manufacture of electric motors and it will take a lot of heat .I'm not entirely certain if the insides of old cast iron transmissions and differentials were painted with glyp or red lead .
Stihl used e-coat which holds up real good .On other hand I've disassembled many an old McCulloch and they had no paint and 50-60 years later they still run great .

 

[RocketRoss57]

I dig this conversation! On the other hand, I am a cheap bastard and the cheapest way I can make it work is usually the way I will go. But I am interested in hearing more about the best way to go too. It makes me day dream about a day that I won't be concerned of what it costs and just do the best and coolest *s-word possible. Just to reiterate I only work on my own junk.