Dual Alt pulley or Lawn Mower belt?
11-22-04, 11:59 PM
#1
Dual Alt pulley or Lawn Mower belt?
k im kinda confused as to what would be better or if it would matter... Heres an example of the dual pulley alternator i would need to run another belt. http://www.rx-7parts.com/product_inf...roducts_id/196
Or i was wondering if i should use the lawnmower belt recommended in the rats nest removal tutorial that was mentioned by Rx7Carl. This is probley a dumb question but im wondering why would you buy a dual alternator pulley if you could just run another belt without it? Thanks
Or i was wondering if i should use the lawnmower belt recommended in the rats nest removal tutorial that was mentioned by Rx7Carl. This is probley a dumb question but im wondering why would you buy a dual alternator pulley if you could just run another belt without it? Thanks
11-23-04, 12:21 AM
#3
The following is a copy and paste of a post I made on a different forum regarding the lawnmower or 'yoohoo' belt. I've updated it a little here and there in hopes of better answering your questions.
Get a 3L220 belt. It is only 22" long by 3/8" wide. It's so short that it only just barely can be installed onto the main drive and waterpump pullies. Once it's on, it should be snug but not too tight. When running, as RPMs rise, it will grip tighter through centripidal force. It offers slightly over 50% contact area on the main drive pulley and just under 50% on the waterpump pulley. Compare that to single or dual alt belts, which can only give a glancing blow on the waterpump pulley, and it seems like a better solution.
I've got two engines, each with a so-called 'yoohoo' belt, and belt slippage is a thing of the past. One has a clutch fan and the other has extremely limited room to raise the alternator to tension the belt (piston to rotary project). Even though it's got an electric fan, thus waterpump slippage is not an issue, I can't raise the alt high enough to fully tension the belt without contacting the hood. Infact, the other day when I was testing some big jets in the carb, the battery was a little low from sitting for a long time and it put a drag on the alternator; almost every time the engine would cough from an over-rich condition, the alt pulley would slip a little creating a short chirp sound.
I'm going to need to set up a motor and an alternator or something that has a genuine Mazda pulley to pre-run/stretch belts before installing them. It would eliminate the current problem of my superlow alternator's belt slipping as I could purchase a belt one size too small and 'break it in' on the contraption. As it is, I must remove both bolts from the alt and tip the nose down to get the belt to slip over the edge of the pulley,and in no time at all, it becomes to long. As it wears, it's only going to get sloppier. I could also pre-run the slightly too-large yoohoo belts I get at Napa.
Speaking of Napa belts, they aren't quite the right size to be used on our engines. They are 25/64" x 22-1/8". Slightly too wide and too long. You'd think these features would work together, but they don't. These belts are honestly too wide the fit comfortably and can possibly cause premature front stationary bearing or waterpump bearing wear until it's broken in. Because of this, I can no longer recommend the Napa belts to others. This is unfortunate because they're nearly pefect, and if they've already been run on an engine, they can be removed and installed on a different engine without too much trouble (as in my low alternator project; installing a used yoohoo belt was a piece of cake compared to a new one).
I need to set up a motor with a pulley already attatched and at least one Mazda pulley on an adjustable slide... tension, run it for a while, retension, run again, check for stretch etc.
Get a 3L220 belt. It is only 22" long by 3/8" wide. It's so short that it only just barely can be installed onto the main drive and waterpump pullies. Once it's on, it should be snug but not too tight. When running, as RPMs rise, it will grip tighter through centripidal force. It offers slightly over 50% contact area on the main drive pulley and just under 50% on the waterpump pulley. Compare that to single or dual alt belts, which can only give a glancing blow on the waterpump pulley, and it seems like a better solution.
I've got two engines, each with a so-called 'yoohoo' belt, and belt slippage is a thing of the past. One has a clutch fan and the other has extremely limited room to raise the alternator to tension the belt (piston to rotary project). Even though it's got an electric fan, thus waterpump slippage is not an issue, I can't raise the alt high enough to fully tension the belt without contacting the hood. Infact, the other day when I was testing some big jets in the carb, the battery was a little low from sitting for a long time and it put a drag on the alternator; almost every time the engine would cough from an over-rich condition, the alt pulley would slip a little creating a short chirp sound.
I'm going to need to set up a motor and an alternator or something that has a genuine Mazda pulley to pre-run/stretch belts before installing them. It would eliminate the current problem of my superlow alternator's belt slipping as I could purchase a belt one size too small and 'break it in' on the contraption. As it is, I must remove both bolts from the alt and tip the nose down to get the belt to slip over the edge of the pulley,and in no time at all, it becomes to long. As it wears, it's only going to get sloppier. I could also pre-run the slightly too-large yoohoo belts I get at Napa.
Speaking of Napa belts, they aren't quite the right size to be used on our engines. They are 25/64" x 22-1/8". Slightly too wide and too long. You'd think these features would work together, but they don't. These belts are honestly too wide the fit comfortably and can possibly cause premature front stationary bearing or waterpump bearing wear until it's broken in. Because of this, I can no longer recommend the Napa belts to others. This is unfortunate because they're nearly pefect, and if they've already been run on an engine, they can be removed and installed on a different engine without too much trouble (as in my low alternator project; installing a used yoohoo belt was a piece of cake compared to a new one).
I need to set up a motor with a pulley already attatched and at least one Mazda pulley on an adjustable slide... tension, run it for a while, retension, run again, check for stretch etc.
