Extra chainsaw cooling

[glennschumann]

I haven't seen much on this, so I thought I'd ask...


Are there any options to increase cooling on your saw? I run an 066 for milling only, and cooling is always on my mind. While I prefer to run the saw when it is 40 degrees, that isn't always an option. Do some saws (maybe made for the equatorial region) have options for high capacity cooling in the form of extra fins on the flywheel or the like? I've seen Stihl saws set up as ice saws for musky fishing here in Wisconsin (covers over part of the recoil cover), but never anything for extra cooling. I was wondering if anybody did anything else besides rich mixes, carb adjustments, and muffler mods to keep things cool.

Thoughts?

 

[MrGiggles]

I don't really think that you would need any extra cooling. I'm sure Stihl designed them from the factory sufficiently.

 

[computeruser]

Guess it would be interesting to first know what your temps are at 40* versus 80*, and direct your improvements accordingly.

 

[glennschumann]

MrGiggles: for the most part, I'm in agreement, but the way I (and others) mill, I often can run through a half tank of gas or more without stopping to let the saw cool. From what I understand, most saws aren't really designed for that. Sure, I can stop once in a while, but if there are better cooling options, I'm interested.
computeruser: Yes, I wish I had one of those laser-temperature thingies to do some scientific research ala Timberwolf's careful experiments, but I was on Santa's naughty list last year. Maybe some of the "Multiple Super-Nova Stihl expert" senior members have some thoughts about the magnitude of the problem, and potential solutions already.

 

[Philbert]

Good question. Most saws have summer/winter shutters to keep the carb from icing. And keeping the engine clean and the fins clear of chips would be important, especially with milling.

I suppose that you could open up some additional vents in the cover, as long as they did not interfere with the airflow to the air filter and carb?

Electronics use fans and aluminum heat sinks. Perhaps a freon loop?

Philbert

 

[glennschumann]

Philbert: Yes, keeping things clean is a good place to start. After a day or two of milling, I do take things apart, and clean out any built up oil residue, and chips / dust. I keep the cylinder really clean, and the air passage around the coil cleaned up too. I worry about opening up the cooling air intake any more, in that larger chips can be drawn in, potentially getting caught in the fins etc. Most of the dust that makes it into the flywheel area seems to make it back out again. A freon loop sounds nice... if it had no weight, fit in a back pack, and blew cool air over ME. Sheesh it has been warm here lately...

 

[ShoerFast]

Fuel entering the engine is the number one method of cooling, run it as fat as you can.

Heat is the worst enemy of low octane and low quality fuel, run the best highest octane fuel you can.

Speed drives the cooling fan, take it easy, keep it vents clean and run the sharpest chain you can.

 

[7sleeper]

I usualy take off the hood after sawing to facilate cooling. I don't know if that is a good idea either.

7

 

[Haywire Haywood]

Make a shroud for the flywheel cover and attach a largish hose to it. Run that to a bucket full of dry ice. That way you're pulling cold air into the saw.

let me know how it turns out,
Ian

 

[Nitroman]

If you are genuinely worried about it, pop the cylinder off and have it mil-spec anodized black to radiate more heat.

The Aussies on here have much more of a concern than anyone on this continent. So far no-one from Down Under has posted on this.

 

[BobL]

Glen, I wouldn't worry about cooling where you guys are. I don't normally mill when it gets too hot but I have milled some very hard wood when it has been over 100F. The green 45" wide 10 ft long logs were harder than dry hickory. On the widest cuts it was taking me 2+ tanks of fuel to cut each slab with the 076 which it did without batting an eyelid. Because the 076 won't fully fuel up while it is on it's side I was taking it out of the kerf to do this, and while it was out I was also quickly touching up the chain.

This is nothing extra ordinary for what happens in OZ and there are guys out here punishing their saws much harder than this.

The best way I found to keep a saw cool is to have it well tuned for the conditions and the keep the chain as sharp as possible. I do have one of those Infra red temperature thingo's and have used it to measure temperatures the biggest factor seems to be a sharp chain.

 

[BobL]

Make a shroud for the flywheel cover and attach a largish hose to it. Run that to a bucket full of dry ice. That way you're pulling cold air into the saw.

let me know how it turns out,
Ian

Given its low temperature dry ice has a surprising miserable heat capacity or ability to cool. Even the cold nitrogen gas boiling off liquid nitrogen will do relatively little cooling wise. The cooling ability of air is closely tied up with it's water content as well as it's temperature. Low temperature air has relatively little water content so it has less cooling ability than you might think. Higher temperature air can hold more water so even though it is warm it can still cool objects hotter than itself quite effectively.

Air cooled motors can run in very hot conditions. In 1976 I rode across the Nullabor desert on a motor bike (BMW) with a mate who had a Suzuki two stroke, during a week where the daytime max temperatures were over 125F. It was so hot the tarmac was melting and slowing us down. At one point we were overtaken by a big Merc but 5 miles down the road there it was stopped by the side of the road with the radiator boiling. I couldn't put my bike on its stand at one gas station carpark because the stands just pushed their way thru the molten tarmac. At a small down called Eucla it was 126F in the shade and much hotter in the sun and no water cooled vehicle was moving - the only vehicles operating were air cooled motor bikes and VWs! In these temperature you have to ride with full leathers or you dehydrate very quickly. We were able to keep riding by stopping at every gas station (~100 miles apart) and drinking 2 pints of water and just before we would take off we completely saturating ourselves and leathers with water.