Parts Question
I just aquired a used 445 chainsaw and bought an 18"...escalated
Parts Question posted September 12, 2012 by Bill Sizemore
442 Views, 3 Comments
Question:
I just aquired a used 445 chainsaw and bought an 18" bar and chain for it. The bar number is 508926172 and the chain number is 531300439. When I put them on and run the saw, the chain and bar become very hot (smoking). Is this the correct replacement bar and chain for this model?
I have oil in the chainsaw and can see a little on the bar and chain....is the smoking/heat normal?
I have oil in the chainsaw and can see a little on the bar and chain....is the smoking/heat normal?
Answer
Bill, Stop using the saw if its smoking, there is definitely something wrong.
The bar under normal loads may reach a temperature of about 130-140 degrees but definitely not enough to smoke the bar or oil, the bar normally could get hot enough that you would not want to hold your finger on the bar for a minute, immediately after cutting wood, but should not discolor, or remove paint, or cause smoke.
The Bar and Chain per your operating manual is the recommended bar and chain, which ia an H30-78, and matches the bar number 508926172 and the chain number 531300439, so that is correct.
It is difficult to say what is causing the bar to overheat. Do you have the correct tension on the chain? Overtensioning the chain would definitely overheat the bar, also Not getting sufficient cutting oil will also heat up the bar and chain. Has the bar or chain actually changed color from the overheating? If it has there is a good possibility you will need a new bar and chain.
Anyhow, I would recommend that you take the bar and chain to an Authorized Husqvarna repair center for their assessment or you could just purchase a new bar and chain. A great site for helping you select a bar and chain is Oregonchain.com, they also have a "800" number and one of there techs may be able to give you some additional suggestions, also there automatic bar and chain selector guide is easy to use, I use it all the time.
I hope the above information helps.
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Bill, Just some additional information.
Today, I was cleaning a couple of Husqvarna chainsaws so I decided to do a quick experiment by taking some Infra-red thermography temperature readings, and I was kind of surprized but it does make sense.
First the 130-140 degrees fahrenheit that I quoted yesterday on the bar temperature is an average, and depends on where you take the temperature at on the bar, closer to the engine it gets much hotter. I compared a T435 with a 12" bar to a 455 Rancher with a 20" bar, just to see the range of temperatures and was quite surprized. The small 12" saw after about a minute or two with WOT (Wide Open Throttle) and No real load, not cutting wood the Bar near the engine reached 180-190 degrees fahrenheit, and the 20" bar on the 455 with the same conditions and about the same location for temperature only reached 110 degrees.
Anyhow, It still should Not cause the bar to smoke, and the other question which I forgot to ask yesterday. Are you using regular bar chain oil ? or some other type of oil, I would definitely recommend that you use a good bar chain oil.
Oh the bar temperatures kind of make sense because I believe the larger bar dissapates the heat better so it should be cooler than my small bar, there are also a number of other variables that come into play like the speed of the chain, how close to the muffler exhaust, etc. Oh, also the chain gets hotter than the bar by another plus 10-20 degrees fahrenheit, so Just alot of interrresting stuff.
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Thanks Karl. I am using husqvarna bar oil, so it should be good stuff. I loosened the chain a little and ran it again yesterday.....still got very hot (no way to tell temp) as I ran it much like you did WOT and no load. I held the nose close to a piece of cardboard I placed on the ground and could see a mist of oil "tracking" on the cardboard, so I think the oiler is working fine. Have seen no discoloration of the bar, so I believe it will be OK, just heating up a bit like you found with your test.
Thanks for all of your feedback and knowledge. I am new to the chainsaw world, but look forward to using it!
Bill
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