Alternator belt tightening

[sigepkat]

I've got a 3g alternator on my truck and, since the initial installation, the belt has gotten looser. Does anyone have any tips on getting it tight enough to quit the squealing and actually output like it ought to?

Thanks,
CM

 

[Eoth]

Squealing is pretty common for 3G with a V-Belt. Obviously serpentine would be ideal.... if you can find the right pulleys then a double v belt would work. Otherwise you need to find a better belt. Top of the line:
Gates Predator Power Band Belts

 

[Steve83]

The tighter the belt, the faster it wears, AND all the bearings of the accessories it drives. You can reduce the tension necessary to keep the accessories spinning by 1) increasing the width of the belt (double or serpentine), &/or 2) increasing the wrap around the pulley (add an idler).

 

[savage]

I've had good luck with Goodyear gator back v-belts.

 

[KyleQ]

Somehow I didn't have an issue with the 3G or a PSC P Pump - I shot blasted my pulleys and used gator belts. When the belt slips it tends to polish the pulley, making it easier to slip. Belts also do stretch -

 

[spap]

I get squealing with my 3 g not that much but I don't have v belts I have the wider seep belts but it routes like a v belt crown Vic 5.0

The police crown Vic's had clutches on their 220 w alternators but don't think they will adap to the 3 g If you change it over to the mustang 5.0 style or explorer style it will all go away. Because of the idler pulley that takes up the slack

 

[blubuckaroo]

This may sound counter-productive for those wanting a big alternator, but I wonder if there is a way to control the field on the 3G to limit the output on V-Belt applications. Or at least delay the full load charging current until the battery gets recharged after startup.

 

[spap]

Very interesting thought on controlling the field , but mine squeals a bit with the trans downshifts too so I'm not sure if can control that.
I looked into the clutches for the alternators on cop cars but those alternators 220 amp are built by Mitsubishi so I don't think the clutches are compatible with the 3 g s don't know for sure though

 

[blubuckaroo]

Very interesting thought on controlling the field , but mine squeals a bit with the trans downshifts too so I'm not sure if can control that.
I looked into the clutches for the alternators on cop cars but those alternators 220 amp are built by Mitsubishi so I don't think the clutches are compatible with the 3 g s don't know for sure though

Maybe your squeal isn't the alternator belt.
Normally the alternator only goes to full tilt for a little while to recharge after start-up. After that the only load on it would be your lights, ignition, and radio.

 

[DirtDonk]

As already said, yours could easily have stretched since new, so tightening up a bit is a good idea. But you definitely don't want to keep it too tight for too long either for the reasons stated.
You should at least try to get it snug before it glazes up the pulley too much though.

Standard alternator cases have the adjustable, threaded hole surrounded by a square boss. You can either use a wrench of some kind to grip this and push/pull while tightening the bolt. Or you can even use one of those j-hook looking scimitar thingies to grip it and then put your 1/2" drive ratchet in to leverage things.

Whichever is more convenient in your particular installation.
Or better yet if you can fit it, is one of the turnbuckle style setups that put outward pressure on the alt. Again though, just don't try to mash it out or you'll be regretting it later.

If your setup allows, a dual-groove pulley is a good answer. If you can find one that's a tiny bit larger diameter and has deep grooves, so much the better.

But 3G's are why many of us go with serpentine in the first place.
Good luck.

Paul

 

[Steve83]

...a way to control the field on the 3G to limit the output...

That's how all alternators work all the time. It's what the Voltage Regulator does.

Or at least delay the full load charging current until the battery gets recharged after startup.

Not without some complicated (expensive) electronic sensing, logic, & control circuitry. It would be MUCH easier to just fix the belt so it could spin the alternator.

The police crown Vic's had clutches on their 220 w alternators...

What year are you talking about? The early 00s up to the end of the Panther platform had a 1-way clutch, but that was to prevent belt squeal during WOT shifts, when the engine RPM dropped suddenly. The heavy alternator windings could cause it to continue spinning fast (regardless of load).