STIHL MS 400

[rogue60]

Interesting reading kind of lol
From what I read on the internets the ms400 comes with this included in the price? something about it helps controlling it's heavy weight?





A bit like this I'm guessing?

 

[drf256]

I believe Mag is alot like Alcohol in terms of it's ability to burn. The old "proofing" of alcohol mixed with gun powder.

Cases are Mag alloy, not pure Magnesium. The alloy varied from manufacturer to manufacturer, hence why some cases are easier to weld than others.

I know pure Mag burns very well, but alloys will vary.

In so far as grindings burning, most finely ground metals will burn. Steel wool will burn as well, it depends on the base metals affinity to combine with oxygen. But an entire chunk of the same metal wont burn.

A flammable piston in a combustion chamber filled with fire would be a giant faux pas that I can't believe any manufacturer would make.

 

[StephK87]

This is very interesting

https://www.highpowermedia.com/Archive/magnesium-as-a-piston-material

especially this lines

With the combination of high-temperature strength, sufficient stiffness and very low density, shouldn’t magnesium be a popular piston material? The most important reason why we don’t use it is its low thermal conductivity – it has around 60% lower thermal conductivity than 2618, which means that without considerable effort put into cooling, the magnesium piston will tend to run much hotter than its aluminium counterpart. This degrades performance, as some of the heat in the piston will be rejected to the incoming fresh charge, raising its temperature and lowering volumetric efficiency in the process,

So the MS400 also has to have a very good cooling solution to keep the perfomance under heat and durability on the same level as the 362 i think. Maybe they increased the airstream from the flywheel in combination with better finn design?!

 

[rogue60]

Just in breaking news they got him! they got the guy who designed the ms400!


Lol just joking about.

 

[MustangMike]

Maybe extra cooling explains the extra weight, because in my mind if the piston is lighter than a 362, the crank+rod can be lighter, so the saw should be lighter (the other components do not weight as much).

 

[lehman live edge slab]

The one statement Stihl put out said because of the light piston it can turn 14,000 rpm and accelerate well for a 67cc saw. Plenty of guys turning an aluminum piston saw at 14,000+ and do fine also the coating I would think is too keep the heat out of the piston since it transfers 60 % less than aluminum. My thought is if this lighter piston that doesn’t transfer heat well is required to let the saw turn 14,000 then the bottom end is built to light. Time will tell but I kinda hope they make an aluminum piston optional for rebuilds. I know we need to try new things but in my mind don’t really see any benefits unless it’s from a company standpoint and they can make them cheaper and have bigger profits.

 

[RI Chevy]

I think Stihl did some thinking. Straight gassing a saw usually ruins both slug and jug.
With the magnesium being a bit softer, if there is an issue with piston, the jug can be saved. Only piston needs replacement.

 

[andyshine77]

Again guys the piston isn't going to be solid magnesium, so it's properties will be different than straight magnesium. And who's to say this isn't also a part of marketing.

 

[RI Chevy]

I was speaking in general terms. Sorry if I am confusing anyone...
I think that is what Stihl was getting at...lighter weight, and a bit softer material...

 

[BonScott46]

Maybe extra cooling explains the extra weight, because in my mind if the piston is lighter than a 362, the crank+rod can be lighter, so the saw should be lighter (the other components do not weight as much).

I assumed it has the same crank as the 462 since it has the same stroke.

 

[andyshine77]

I was speaking in general terms. Sorry if I am confusing anyone...
I think that is what Stihl was getting at...lighter weight, and a bit softer material...

A lighter piston is pretty much always better, and Strato pistons tend to be quite a bit heavier than non Strato pistons, so this should help that. Although I never had any complaints with the first generation 362 I owned. Well the air filter was pretty horrendously design.

 

[RI Chevy]

PS. Just looking out for you.
Don't ask for air filter pics!!!

 

[andyshine77]

PS. Just looking out for you.
Don't ask for air filter pics!!!

Yeah what's that all about?

 

[RI Chevy]

[emoji2357] Oh no...

 

[andyshine77]

[emoji2357] Oh no...

Figure something like that.[emoji44]

 

[Evansaw]

Really weird nobody already got one in US...

 

[RI Chevy]

Figure something like that.[emoji44]

YES!!![emoji16]

 

[RI Chevy]

She could fall back on her keester and bounce right back up...

 

[andyshine77]

Not what you were expecting is it.[emoji1]

 

[RI Chevy]

They are so nice and clean...