Quote:
Originally Posted by TreeGuy
224MV, I have an honest question for ya as obviously you know of what you speak.
Given the fact that Slough Shark posted that all the plastic housing surrounding the clutch was melted, do you really think a failing clutch bearing could generate that much heat prior to failure? I’m honestly sceptical.
I’ve burnt out a few clutches over the years. None of which were catastrophic. Just wear and tear. Obviously, the clutch bearing is lost. That’s a no brainer.
I’ll stand by my hypothesis of friction induced heat causing the failure because over many years I’ve almost burnt down a few saws and a couple of chippers. Metallic material and super stringy stuff like caragana tend to get wound up in moving parts and become a colossal PITA. The risk of ignition with the oil soaked crud built up within the entire chamber around the crank most certainly exists.
An external and conductive heat source interacting with the clutch mechanism would explain the melted casing (plastics engineered for high heat applications) and a failed clutch bearing.
If it was the the bearing itself, I’d be extremely concerned that that heat energy transferred down the crank and damaged the internals. It’s not a short trip.
Interesting discussion.
Tree
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Tree, I’m not disagreeing with your hypothesis as it is very possible. I’m only providing more possibilities.
I don’t think a failing bearing would cause that much heat to melt the plastic crankcase. But it sounds like there was nothing left of the bearing which I think would cause a lot of heat if you kept running the saw, especially if slough shark was thinking it was just cutting slow due to green wood.
I had a bearing come apart on me on an 044 while cutting some large spruce. The cage was still there but most of the needles were MIA. The oil and sawdust build up on the crankcase was smoking. Probably a good thing it was a magnesium case instead of plastic. I thought my chain oiler had plugged off the way it acted and heated up. I grabbed another saw and finished the job. Didn’t take long to figure out the problem when I got home.
It is quite possible there is damage to the crank bearing and oil seal from the heat if it’s melted that much. The dealership should be able to do a vacuum test to see if the oil seal is still good. If the crank bearing are shot or starting to go you’ll probably hear it when the saw is running(if they are totally shot you probably won’t be able to pull it over)
Definitely an interesting discussion. I would be interested in seeing the pictures of the saw