Squeal AC Belt

[jopizz]

The kit you purchased is basically the same one I put on my '59 when I converted to an alternator. The brackets are not strong enough to support the load. Even after I reinforced them my 70 amp 10si alternator would squeal whenever I put the top up and down. There is too much flex on the bracket to keep the belt at the correct tension.

John

[Deanj]

John, I glad I'm not getting paid to diagnose this problem. I sprayed water on the belt (which was done before) and now it stops squealing a few seconds which points to the belt? Or is that just making the alternator turn easier?

If these brackets aren't strong enough, why didn't this squeal constant from the start as it does now? Did the belt weaken? If reinforcing the brackets isn't the answer, such as like bolting a cross bracket between the two brackets, what is the permanent solution?

I'm going to try a new belt for starters.

[jopizz]

I tried putting a third bracket in but it didn't help. If I put a crowbar between the alternator and the block I could move it pretty easy. There's just too much play in the long bolt and it's way too thin. Probably welding it would help but the design is much too flimsy compared to the original generator mounting.

John

[Deanj]

I changed the alternator belt (Gates) and it's definitely the alternator. All that work to be sure.

Larry's will warranty, but only if I send this one back first. They wouldn't listen to reason. I'm doing it myself, but what if I brought it to a shop? It is a 3 o'clock set-up if anyone wants to know.

[simplyconnected]

Why send it back? Doesn't it work ok? With simple fabrication, just about any alternator will mount.

You only need three points; two in the front and one in the rear. If your 10SI doesn't have convenient mounting holes, make a steel 'C' to wrap half way around the alt, then you can place your own holes wherever you want.

Yes, GM and Ford alternators and generators can swap pulleys. I simply got a larger diameter pulley for mine.

When you pour water on rubber IT SLIPS MORE. That's why you didn't hear the squeal.

There's nothing wrong with using a 10SI as long as it's not one of those 1-wire alternators. - Dave

[olevet]

Been there and done that (often)! Still have a couple of pieces of soap in the tool boxes for that quick temporary fix.

Does that make me an "old timer"?

LOL Im 66 Never Had the Guts to do it, Guess that comes from :Looking at a Used car when I was just 16 and the salesman was showing off and Reached for the throttle and was Reving that engine up, The Fan blade came apart and one of the Blades flew up and Cut the **** out of his arm. Had to call the Ambulance and at 16 apply my 1st ever tourniquet. But saw a Lot of Folks do that LOL

[Deanj]

I did buy a 63 amp 10SI Delco from O'Reillys. I was looking up alternators for a 1975 Chevy. That's what you have to do to find a 63 amp 10 S I. It seems you can't bring any part up to the counter anymore and ask them to match something up. Anyhow, only O'Reilly's had one in stock.

Now, it took me an hour and a half to remove the battery, alternator, and buy the replacement. That doesn't count the research time the day before to locate the alternator. I thought this would be real smooth, except the adjustment bolt on the replacement alternator was metric. And I needed a longer bolt for this application. That meant a trip to Lowe's. Second, the mounting hole on the case for the long bolt was too narrow. I had to drill that out on my drillpress. You have to understand that I didn't know if there was another application, or if I should just drill out the hole. I figured I could look all day for a case that had a larger hole.

I had to stop for the day, so the alternator should go in Wednesday.

[scumdog]

I did buy a 63 amp 10SI Delco from O'Reillys. I was looking up alternators for a 1975 Chevy. That's what you have to do to find a 63 amp 10 S I. It seems you can't bring any part up to the counter anymore and ask them to match something up. Anyhow, only O'Reilly's had one in stock.

Now, it took me an hour and a half to remove the battery, alternator, and buy the replacement. That doesn't count the research time the day before to locate the alternator. I thought this would be real smooth, except the adjustment bolt on the replacement alternator was metric. And I needed a longer bolt for this application. That meant a trip to Lowe's. Second, the mounting hole on the case for the long bolt was too narrow. I had to drill that out on my drillpress. You have to understand that I didn't know if there was another application, or if I should just drill out the hole. I figured I could look all day for a case that had a larger hole.

I had to stop for the day, so the alternator should go in Wednesday.

I'm a hot-rodder, stuff like that is one of the 'delights' of the hobby - making stuff fit when it seems like it was never meant to!!

Persevere my man, persevere!

[Deanj]

Alternator installed and there's something to John's logic about a bigger pulley. Squeal went away as long as you don't have the "bright's" on, AC on high, and don't rev the engine. I'm fine if I don't belong to the Alternator and Fan Belt of the Month Club. The bright lights and AC alone won't make it squeal, but it's definitely the same noise. I wonder if I had both belt and bearing noise before.

[Deanj]

Please revisit this situation to install a 2 groove pulley on the alternator (conversion) to eliminate belt squeal. I want an appropriate 2 groove pulley. The Larry's conversion came with a one groove pulley and an offset of about 7/8ths or 22mm to the first and only groove. The 2 groove pulley would need an additional 10mm groove beyond the first one to mate with the forward fan belt pulley.

I called Larry's because the Delco 10si kit comes with the one groove pulley, but the replacement alternator has 2 grooves! They couldn't help with any information. I checked out pulley's for sale online and there doesn't seem to be a match to fit the criteria.

[DKheld]

Found my dual groove pulley for the generator on flea bay. Supposedly they came on the optional 40A Ford generator. Maybe on heavy trucks etc? Took a couple of tries but finally got the right one. Not sure if it would fit the alt.

Might try an alt / generator / starter repair shop if there is still one around in your area.

Do your belts have the "teeth" on the inside? Those are the ones I've always had the best luck with not squealing. (don't have my A/C belt on at the moment)




The PS belt is in front of the two generator pulleys - requires a new pulley for the PS pump to line up perfectly (from a Galaxie) - constructed 95% of unobtanium.



Eric

[simplyconnected]

Please revisit this situation to install a 2 groove pulley on the alternator (conversion) to eliminate belt squeal. I want an appropriate 2 groove pulley.
... I checked out pulley's for sale online and there doesn't seem to be a match to fit the criteria.

A two groove pulley would be ideal IF you can find two, one for the water pump and the other for your alternator.

My suggestion to use a larger alternator pulley solves the problem of belt squeal. It may be regarded as a temporary or permanent fix because it works, is an inexpensive solution, is much easier to find and it is very easy to install.

My suggestion is nothing new because with high rpm racing engines, it is regarded as an 'overdrive' pulley, and very common for many decades.

A larger diameter pulley offers two major advantages with only one drawback:

• Think of the pulley radius as a 'lever'. The longer the lever, the easier it is to turn. (Thank You, Archimedes of Syracuse, over 2200 years ago.)
• A larger diameter offers much more surface area for the V-belt to grab.
• The only drawback is, the alt runs slower so you don't want one too large (or too small).

Let's do the numbers... The circumference of a circle is Pi times Diameter.
If your original pulley is 2.5"-diameter it has a circumference of 7.85". (Assume the belt contacts half the dia., BUT the belt has two contact sides so it's a wash.)
A 3.5"-dia pulley's circumference is 10.99 (or 11"). That's nearly half-again more surface area AND the diameter ratio factor (3.5:2.5) is 1.4:1. That means the alternator drag torque required to turn your new pulley is reduced by nearly 1/3.
So, more belt surface together with reduced drag will stop belt squeal, simply by changing your pulley.

Let's put things in perspective:
Air conditioning draws about 6-Hp on a large-diameter pump pulley, usually driven directly by the crankshaft.
An OEM 30-amp generator draws .5-hp on a 2-1/2" pulley, and only when RPMs are over 1,000.
A 100-amp alt draws 1.6-hp on a modern car's 2"-dia., flat pulley. That's why the pulley needs so much surface area. Here we are, converting that to a V-belt application. - Dave

[Deanj]

Thank you gentlemen. Eric can you tell me what element number Unobtanium is?

In using a 3.5" diameter pulley vs. a 2.5" pulley, half of its circumference would increase 40mm and so I would need a belt of 1147mm, 40mm over the standard belt of 1107mm. Calculating diameters around the pulleys:

3.5 x Pi/2=5.5"
2.5 x Pi/2=3.93 with the difference being 1.57" or 39.9mm.

One thing, there's that offset problem of getting the groove to line up with the fan and water pump pulley.

[Deanj]

I found a 3.35" diameter pulley on Quick Start: "# 242103 2-V Groove Alternator Pulley for Ford 1G and 2G Series, GM and other Alternators Dimensions: 10mm/13mm Belts x 85mm OD x 17mm Bore."

It seems very close in total length, around 40-41mm, it has the standard 17mm bore, and the outer groove is 10mm for my belt. The inner 13 mm groove is along for the ride.

It does represent a 34% increase in circumference.