Big GB bar question

[Big Woody]

I picked up a couple of big (44" to 72") of the old style GB titanium bars with the internal roller nose (non-replaceable) which may have been called "speednose" bars. Not the oregon style with the external replaceable roller.

For those who have used these bars what sort of chain tightness have you found to work best. Treat it like a hardnose with a little droop? Or tighten it up so no sag like a sprocketnose?

I made up a loop of skiptooth for the 44" and adjusted the tightness like for a sprocketnose using my 2094 saw. I noticed even with good oiling some sparks flying off the nose and the nose would get noticibly warm just from running the saw for a minute or so without cutting anything. Seems like quite a bit of friction going around the nose. Maybe this disappears as the nose wears a little?

 

[GPH85]

Usually the bigger the bar the tighter the chain will need to be to stay on the bar while in a cut, especially if the saw is being used on it's side any at all.

The way I personally look at this, is that you have a sprocket nose and shouldn't have any problems with running it tight. I usually go by the pull up chain till the drivers just clear the bar method.

Some things of interrest in fixing the heat problem might be to use a different bar oil "I personally like gear oil on the really long bars (36 and up)" and possibly switching to a different greese for lubing the sprocket. The gear oil always seems to travel the length of the bar where as the regular bar oil seems to dissapate right around half the bar length "noticed this even on my 30 inch bar not to mention my 36 or 44 inchers". Don't really know why, other than the fact that most bar lubes are only 30w motor oil with slightly different additives such as the thickener and so on.

Then there's the possibility that since these bars are old, that they might possible have some rust and what not in the bearings of the sprocket, that's possibly causing drag and thus creating heat.

Just some thoughts.
Greg