Are there any aftermarket alternator belt tensioners?

[Henrius]

I know it's a weird question. Keeping the twin belts taut that run the alternator and A/C compressor has always been a hassle on my 1972 Newport. Loosen the bolt, try to move the alternator with a crowbar, retighten bolts, then watch the thing slip back.

I was at a show with some hot-rods and a guy had a jackscrew-like attachment to his alternator. The car was a Chevrolet. The jackscrew tensioner must have been aftermarket as it was chromed. Sure made an easy and reliable way of tightening the engine belts!

Is there anything like this made for Chrysler big blocks? Sure would be able to do the same thing. Those alternator-A/C belts sure take a beating in the summer if they are not kept tight. Matched pairs are getting hard to find at the auto parts stores, too!

 

[Ross Wooldridge]

The slotted area on your tensioning rod where the bolt holds it can get spread out a little bit along the length of the slot. When that happens the area being contacted by the bolt shoulder is much less. Try making the slot is as narrow as it needs to be. Also try one of those internal multi-tooth lock washers that bite into the surface - that should hold it.

 

[Carmine]

Actually the factory dealt with this problem eventually, maybe '75+? I tried to Google a pic, but no luck. They added an non-tensioned idler between the AC clutch and Alternator.

 

[Carmine]

Actually the factory dealt with this problem eventually, maybe '75+? I tried to Google a pic, but no luck. They added an non-tensioned idler between the AC clutch and Alternator.

Found one.

 

[CBODY67]

In prior times, the "matched belts" came in pairs, not singles. At certain rpms, they would vibrate and "flap" together. That's just the way they were, back then. Didn't hurt anything. Tension the belts for the normal deflection in the middle of the distance to the alternator and go on. They'll run a looong time like that, by observation.

Trying to tighten the two belts tight enough to decrease flapping puts additional strain on the alternator front bearing AND do the spreading action mentioned on the slotted bracket. Ford used a jackscrew adjustment on their Tecumseh a/c compressors, as I recall.

Just like the flex mount on the power steering pumps, trying to make the belts run smooth with varying loads on the a/c compressor and such is a lost cause. A-blocks had the additional tensioner pulley in the middle 1960s, as I recall.

Notice that on the model years which used the a/c belt tensioner pulley, the alternator was in the "low, close mount" location, rather than in the earlier "high mount" location on the B/RB engines. Belt lengths were usually a little shorter on the low-mount alternator cars, I suspect. As close as the pulley is to the compressor, might not make much difference on the high-mount alternator cars.

On those who have replaced the RV-2 compressor with a two-groove pulley Sanden, do the belts display the flapping action, none, or decreased amounts? Just curious.

CBODY67

 

[Yatzee]

I know it's a weird question. Keeping the twin belts taut that run the alternator and A/C compressor has always been a hassle on my 1972 Newport. Loosen the bolt, try to move the alternator with a crowbar, retighten bolts, then watch the thing slip back.

I was at a show with some hot-rods and a guy had a jackscrew-like attachment to his alternator. The car was a Chevrolet. The jackscrew tensioner must have been aftermarket as it was chromed. Sure made an easy and reliable way of tightening the engine belts!

Is there anything like this made for Chrysler big blocks? Sure would be able to do the same thing. Those alternator-A/C belts sure take a beating in the summer if they are not kept tight. Matched pairs are getting hard to find at the auto parts stores, too!

This is what you need. You can buy specific lengths or make one yourself. I use these on my alternator and power steering pumps, both with twin belts.
Alternator Adjuster

 

[Big_John]

On those who have replaced the RV-2 compressor with a two-groove pulley Sanden, do the belts display the flapping action, none, or decreased amounts? Just curious.

The RV-2 compressor was MIA when I bought my car, so I can only go by previous experience with other cars. I think it flaps less with the Sanden. There's still some, but I'm going to say that is due to the length of the belt.

My problem is getting two belts that match well. I had hoped that my NAPA belts would stretch over time and even out, but that hasn't happened.

 

[Carmine]

It's really just too long of a span without an idler. The factory fix solves the issue. If it bothered me, that's what I'd do. Without the compressor load they generally do not flap.

 

[MrMoparCHP]

I like to run my belts loose to the point of slipping, less wear of parts.
I hold the alternator in place with one hand and lock it, likewise with the power steering pump.

Alan

 

[Henrius]

I like to run my belts loose to the point of slipping, less wear of parts.
I hold the alternator in place with one hand and lock it, likewise with the power steering pump.

Alan

When I did it this way on the alternator/AC belt, I would hear a squeal every time the A/C compressor cycled on! It was less pronounced when I ditched the V-2 and converted to Sangen

 

[CBODY67]

The "matched" belts came two in a package, not singles you bought two of. There are production codes and date codes on the belts. Some melted in, others in ink near the part number. Even so, the flapping happened and seemed to be worse with increasing compressor loadings. Rpm had an affect, too.

CBODY67