7T vs. 8T sprocket

[don]

What is the longest bar (depends on the wood) you would run a 8T sprocket on? Don't have much time to experiment right now (forest closed) and wondering up to what length I can go up to on a 8T sprocket on an 066. Do I need to be concerned with lubrication? I guess this would apply to any saw with similar power. Run full skip full chisel Stihl chain.

 

[rahtreelimbs]

I run a 42" bar on my 066. I had concerns about lubrication. I contacted the local Stihl rep. and he told me a 42" bar was OK. Mine slings all kind of oil too. As far as a 7 or 8 tooth. I've run both with the 42" bar and the saw runs real good with either sporocket. BTW I use full-skip full-chisel chain. 7 tooth: more torque, less speed. 8 tooth: less torque, more speed. there's roughly 12% difference between the two.

 

[don]

Thank you rich

Used the 8T with a 42 inch bar last night and it pulled it just fine.
Still concerned about the amount of lubrication the blade is getting. Turned it up all the way. After one tank of fuel the oil resevoir is about 3/4 empty, 1/4 full. Wonder why there is so much variance between each saw when it comes to chain lubrication. If every 066 has the oil screw wide open the oil usage should be pretty close, right? I guess I need to find a local 066 user and see what they are doing.
Thank you for your help.

 

[rahtreelimbs]

Don

No need to worry. My 066 has the same amount of oil left in the tank as yours. As long as the oil is slinging off the tip of the bar you're alright.

 

[rick_reno]

7t vs. 8t

I run a 8T on my 056 with a 32 inch bar, full chisel chain. It's seems to work fine when I use it.

 

[tundraotto]

the reason a saw runs out of fuel before oil is to make sure you dont run the bar/oil pump dry. it kinda forces you to top both tanks off while you refuel.

 

[Newfie]

"After one tank of fuel the oil resevoir is about 3/4 empty, 1/4 full"

Sounds like that isn't a problem. I'd be worried if you discovered you were 3/4 empty, 1/2 full.

 

[don]

tundraotto makes sense to me

I guess they would want the fuel to run out before the oil.
Just concerned how much more oil for a 42 inch bar and 8T sprocket. More chain, more speed more friction etc.

 

[timberwolf]

Question, wouldn't using a 7T cause one to put more load on the chain/bar? in doing this drive up the bar heat and reduce the efectivness of whatever oil it was getting?

I was wondering about this with regard to milling with the 066, and considered going to a 7T for milling with my 32 inch bar.

I think I will stick to the 8T keep the chain speed up and try not to load the saw by pushing too much. But I'm not positive this is the right approch.

Any thoughts?

Timberwolf

 

[tundraotto]

i think you may load your saw up a bit too much in milling using a 8T, would stick to the 7T. Not a milling expert though, but I think that milling is hard enough on a saw as it is - your not going to gain that much speed on a ripping chain anyway are you?

its not so much the load you put on the bar - its the friction of the chain against the wood & bar - fresh wood helps cool the bar and chain a little (= why dull chain overheats and ruins bars..)

 

[Tony Snyder]

This is in a little smaller size range, but I fired up one of those new 952 Efco; I thought it had enought torque to go up to 8 tooth, I tried ist and switched back; I bogged too easily.

I has a more successful experience with the 651 Solo; It actually did have enought extra muscle to pull the 8 tooth well.

I put 8 tooths on the Efco 956s, 18" bar, Carlton .325 chisel, They scream.

When I go to cut firewood with the boys, I like to take my 956 demo, and my KD2159. I'm gonna take the 651 out and get some breakin on it.

 

[don]

7T slow 8T fast

7 tooth: more torque, less speed.
8 tooth: less torque, more speed.
there's roughly 12% difference between the two.

I think this is correct timberwolf.