Pulley Combinations On A Rootes Blower

Common sense would dictate that a bigger pulley on the blower would be stronger because there are more teeth engaged on the blower pulley, it would have a better chance of not jumping teeth. But I already know you knew that! BUT, some would say that the more teeth making contact, the more friction???? I`m going with the bigger pully, thats my story and i`m sticking to it

 

Pulley Combinations

48/32 vs 36/24 both are 50 over but your belt speed is 33% higher with with a 48/32. Belts stretch with speed. On the other hand a 24 tooth creates a tighter radius than a 32 and 14mm aren't as flexible as an 8mm. I would measure your center to center and use a combination that allows to change ratios without changing belts.

 

We have tried it all 13.9 14 and now 8mm. diff pulley combos etc... we've never seemed to get more than 4 runs on a belt, always breaks on the 5th but in my opinion the 8mm is better. the 14 stuff would sometimes break at 2 or 3 runs and the 8mm belts always make 4 runs (dont understand why the belt speed is insane) even if we get it a little hot under the collar!

 

put the big one on the bottom....yes theres one in every crowd....

 

I dont know if this has any bearing or corelation but my father and I used to race radio controlled cars in the off season. In terms of the gearing we chose to run we always tried to used the largest spur gear (the gear on the axle) that we could because it allowed the car to get off the corner better. Now I am not sure that this would have any bearing on this application because in this case the larger pulley or gear is doing the driving. Now wouldnt using the smallest combination of pulleys creat a tighter pulley wrap? Wouldnt a tighter pulley wrap cause more stress on the belt? Just a question.

 

RADIO CONTROL
I use to mess with those Nick i switched to the 48 pitch tiny gear teeth and they lasted for ever, and used less power to turn...LOL

 

Mark,
You should try 11mm belts. Two years ago we ran 13.9 and 8mm, and broke the belt nearly every run. Last year we switched to 11mm, and never broke one. They're expensive, and I'm not too sure we didn't have to have custom pulleys made, but considering the car made a full run, the extra cost was offset by not having to change it, so it was well worth it. We know a couple of tractor pull guys who were changing belts every other run with 8mm, are now getting up to 30 runs out of 11mm.

bryan brown

 

You know how to adj. them the right way then,

 

Mike I'm curios, just how much belt adjustment do you have?With those combinations of pulleys the belt length has to vary quite a bit.Much of the time you can only use certain pulley combinations with certain belt lengths, and those lengths vary with tooth size.