HELP! MS440 crankshaft heat color

[JD22]

Maybe someone can help me with some information, I’m wanting to rebuild this chainsaw. And want to know if this color of crankshaft is okay. Before putting in a new oem piston/ seals

also piston seems to be getting black in some spots, where is this excess heat coming from, normal?

Wanting this to be a very reliable saw.

 

[drf256]

Looks totally normal. The rod is darker at the small end because the mix isn’t cleaning off the coking. That’s a normal looking piston. There is always a bit of ring blowby that accounts for the coming between and above the rings.

I‘d probably add a new Caber top ring only and run that piston with existing bottom ring, as along at there isn’t more than .002 skirt to cylinder side clearance on the intake side. That’s a good looking piston.

 

[Al Smith]

Often times people get concerned of a bluish color of the rod and crankshaft .It's called in the biz as "running the colors " caused by using electric induction heaters in the manufacturing process .I spent 29 years in an auto engine plant and have seen that countless times .

 

[Stump Shot]

Often times people get concerned of a bluish color of the rod and crankshaft .It's called in the biz as "running the colors " caused by using electric induction heaters in the manufacturing process .I spent 29 years in an auto engine plant and have seen that countless times .

If you would have worked at the Stihl plant instead you wouldn't have seen that at all.

 

[Al Smith]

Did you work in a Stihl plant?

 

[Stump Shot]

Did you work in a Stihl plant?

Nope. However...
I know a fella that's worked with Stihl for thirty plus years and he says no heat discoloration when new at all.

 

[Al Smith]

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[Mastermind]

Nope. However...
I know a fella that's worked with Stihl for thirty plus years and he says no heat discoloration when new at all.

Then why have I seen it on new saws hundreds of times?

 

[Stump Shot]

Then why have I seen it on new saws hundreds of times?

I dunno, getting conflicting reports now.

 

[Stump Shot]

Then why have I seen it on new saws hundreds of times?

Might be older vs newer production would explain it possibly.

 

[Mastermind]

Might be older vs newer production would explain it possibly.

Seen it on hundreds of older saws too.

Consider this Steve....if the connecting rod became so hot that it glowed cherry red (which is what it would take to change it's color), would the thin sheetmetal cage that is part of the rod bearing not melt?

The answer is yes. It would melt, and ooze out from between the crank and the rod. I've seen that too BTW.

 

[Lone Wolf]

Then why have I seen it on new saws hundreds of times?

I see it all the time on used saws.

 

[Al Smith]

FWIW you can run the colors too in general blacksmithing using a forge or even a torch .Off the subject but when I turned the worm gear wheel for repairing a hundred year old drill press in making the hob I used a piece of A2 steel .That needed heated to orange,about 1400 degrees then tempered back to straw which is blue .I know a little bit of metalurgy but I'm not an expert. I do have the rotating assemblies from two saws .A Stihl 200T and a Partner p-100 I could take pictures of .Fact some place I have same from a later model of the Lombard AL 42 engine which also used a pressed together assembly and it's nearly 45 years old .I have no idea which box of parts it's in .

 

[Stump Shot]

Seen it on hundreds of older saws too.

Consider this Steve....if the connecting rod became so hot that it glowed cherry red (which is what it would take to change it's color), would the thin sheetmetal cage that is part of the rod bearing not melt?

The answer is yes. It would melt, and ooze out from between the crank and the rod. I've seen that too BTW.

Well upon reflection I don't think that when I say old you're quite digging what I'm laying down, I'm talking 1960's era when this(now old fart) fella was in Germany working for Stihl. This came about years ago when I was building a saw for myself see and had an 044 and a 440 the crank to choose from, the 044 crank was normal metal looking and the 440 was purple on the rod end. Got talking to the gentleman and he thought the purple one was junk. So I put that one in my saw, lol, figuring if it was to go sour on me, not to worry. Well it never did that I could make it anyways and that's the story, reckon now that I'm another year older today, maybe I got a little smarter as well, all in the same day, who'd have thunked it.

PS. That must take some dedication/determination to melt a rod bearing, haven't seen that as of yet, still have time though and ya never know, maybe one day.

 

[Mastermind]

Well upon reflection I don't think that when I say old you're quite digging what I'm laying down, I'm talking 1960's era when this(now old fart) fella was in Germany working for Stihl. This came about years ago when I was building a saw for myself see and had an 044 and a 440 the crank to choose from, the 044 crank was normal metal looking and the 440 was purple on the rod end. Got talking to the gentleman and he thought the purple one was junk. So I put that one in my saw, lol, figuring if it was to go sour on me, not to worry. Well it never did that I could make it anyways and that's the story, reckon now that I'm another year older today, maybe I got a little smarter as well, all in the same day, who'd have thunked it.

PS. That must take some dedication/determination to melt a rod bearing, haven't seen that as of yet, still have time though and ya never know, maybe one day.

The melted rod bearing was in a ported 088 that was being used to mill with at 80:1. LOL

 

[Stump Shot]

The melted rod bearing was in a ported 088 that was being used to mill with at 80:1. LOL

Well it had 80 in the name, that might should have gone back on the manufacturer. Lol

 

[Al Smith]

The melted rod bearing was in a ported 088 that was being used to mill with at 80:1. LOL

What on earth were they thinking----

 

[farminkarman]

The melted rod bearing was in a ported 088 that was being used to mill with at 80:1. LOL

That was an expensive brain fart.

 

[Mastermind]

What on earth were they thinking----

They followed the hype behind Amsoil Saber at 100:1 They were like....WTF? I used it at 80:1 !!!!

That was an expensive brain fart.

Indeed. It trashed the crank, bearings, jug, and slug.

 

[Al Smith]

The hoopla and hype about what kind of oil and ratio has probabley wrecked more saws than you can shake a stick at .I'm going to remain old school forever .I spend a lot of time rebuilding and restoring them and I'l be damned if I'll cook one just because some know it all says I'm wrong