Sounds easy, right?? Not so much.

I've been chasing a squealing belt ever since I got rid of the air pump.

I have a double pulley to supposedly compensate. I've tried 6 different Gates belt combos, nothing helps. Set at various tension, some even way too tight for me to be comfortable with.

I took off the water pump pulley and really scuffed it up with a rasp file, no change. Did all pulleys as well.

New water pump, different alternator, no change

With no fan, zero squealing. I've tried three different fan clutches that are known to be good, I'll get to that in a minute.

I ran it without the A/C belt and fan, squealing returns.

Today, I reinstalled the air pump, A/C belt and fan and zero squealing.

The squealing is nonstop above 3500, I would think eventually the fan/water pump would catch up, but it doesn't.

A friend let me swap around various parts on his 83 and all the parts in various combos, no squealing. His 7 has a some sort of porting, but can't imagine that makes a difference.

I hate to run the air pump, but I have no idea what to do next. Maybe sand blast the water pump pulley?? Maybe fab up a tensioner in place of the air pump??

I'm not up for dumping a bunch of money on e-fans, there's got to be a way to make the basic 2 belt system work.

Thanks

 

I had a similar experience on my 1975 REPU. When I purchased it, someone had rigged up a tensioner where the air pump is. I remove it and added a double pulley and twin belts. The double pulley never worked. And like a fool, threw away the tensioner. Wish I had just stayed with it.

 

I think I'm gonna fab something up, there's lots of tensioner options out on the interweb.

It should make it a little easier since the air pump is back in. I can see how a tensioner might work best.

 

A friend of mine got the same problem..... He ordered the belts straight from Mazda....problem solved......

 

Buy quality belts - Gates, preferred.

Also, belts stretch. If you over-tighten them, they stretch worse. Especially cheap belts. Once stretched, they'll never return to shape, and are possibly ruined, as they form into their operation diameter within about 50mi of driving after installed CORRECTLY. That said, old belts tend to dry out and the petroleum used to make them leaches out over time. New belts on a dual-sheeve setup should be purchased at the same time and from the same batch for best fit and function.

I run dual-sheeve Alt-WP-eccentric with nothing else and have never had issues with belt squeal. For a quick test, spray WD-40 on each pulley in sequence until the squealing stops. There's your culprit, if it's the pulley. That's about the only thing WD-40 is good for, aside from cleaning oil stains from your driveway!

 

I have 6 new Gates belts, all vary a little bit and I tried every combination. It's definitely the water pump pulley.

I'm gonna sandblast the pulley tomorrow as a last ditch effort, but I think for the engine health, having a third pulley will take some stress off the engine bearing.

 

Well, just throwing out there that it could also be your water pump bearing about to go out, too. Usually, these start to weep coolant down the front of the engine when they're about to let go, as there's a hole cast into the WP housing designed to let out pressure from the bearing grease expanding. When the bearing goes, that gland is destroyed and the coolant leaks slowly.

I don't run an Air Pump nor it's belt and have never had any issue in many 10s of thousands of miles regarding main bearing stress. The dual-sheeve setup is ideal for simplicity and ensuring the WP pulley has enough traction without overtightening the belts.

 

I just swapped out the water pump for the third time, that was my initial concern given that it was at the limit of shaft play.