[RickRacer]

Hey Guys, I'm looking for a deep groove alternator pulley for my 289. I'd like one that doesn't slow down the amp charge if possible.....any one know of one?

 

[bmcd66250]

If you're just worried about throwing a belt you can install larger diameter sheet metal discs before and after the pulley.

 

[PSIG]

Or just use a good outside-mass belt and proper alignment to prevent flipping. A standard V-sheave should be fine to the rpms you can spin an alternator.

David

 

[RickRacer]

I flipped a belt off way back when in my 70 Stang which in turn took off the other two belts and almost got me into a bad accident. You see I was street racing a Cuda and lost my PS so we almost hit each other because I couldn't steer fast enough.....thank goodness I slowed down just a bit and no accident.
I don't want that to happen again!

What is a outside-mass belt?

 

[fastback.brian]

maybe find a thinner belt the same length..

 

[PSIG]

What is a outside-mass belt?

V-belts used for racing have a grater amount of their weight to the outside. Ones that don't want to flip-over to get the heaviest part outward. The greater the RPMs, the greater the tendency to flip. Pulley misalignment just makes the situation worse, as the belt tends to crawl up one side of the the sheave, giving clearance for the belt to try flipping. Of course, improper tension is the most common issue, as too tight fries your bearings, and too loose allows belts to slip and flip at speed. Worn pulleys are another contributor to flipping.

While racing V-belts are always outside-mass, may generic belts are also. Scalloped belts are usually outside-mass for example. Some companies advertise their belts are outside-mass in their literature.

Serpentine belts do not have a flipping issue, as they are multiple Vs, each stabilizing each other across the width. Serpentine belts can still fly-off, but that is due to the spring tensioners used, and that they can give at high RPM, giving the belt slack to jump. Unusual though, as sprung tensioners are generally placed closely between two other pulleys - to keep the mass effect minimal to the tensioner.

While no single guide covers everything, THIS is an excellent guide to V-belts if you want to become the local go-to guy for them.

David

Generic scalloped or cogged V-belts improve power handling by conforming around smaller pulleys better, and also moves the mass of the belt to the outside circumference: