[hiyabradHO]

I wanted to replace my belts on my 1971 TA with 80 amp alternator.

I was looking at AMES and their "Correct" belt with date codes, etc., for the alternator says it will not work if the car has an idler pulley which I believe a 80amp car does indeed have that.

Can anyone point me in the right direction?

Thanks,

[hiyabradHO]

Anyone?

[Transamric]

Have you tried Quanta Products LLC?
I'm assuming you also have A/C with the 80A alt.?

[johnta1]

Does your car have the idler pulley?

['ol Pinion head]

Should have the idler pulley, 481040 wp pulley & 481038 crank pulley.

Years ago when I first bought my '72 TransAm project, the idler pulley bearing had prev seized, and prev owner pitched the idler pulley asm and swapped on a big car/'73-76 A body 80 amp front alt bracket, knowing the adj slot would allow tightening the 80 amp alt. While it did allow adjustment, the problem with running the B series '80 amp bracket is when the engine torqued over, the alt rubbed up under on a hood brace... In examining the hood brace and the parts store replacement 80 amp alt, it was easy to figure out what was going on. Thankfully, a PY member came through with the correct date coded 1015 alt. Tom V always notes "Engineers do things for a reason", such is the reasoning for the use of the idler pulley/ fixed alt bracket setup for low hood line '80 amp Pontiac applications.

[hiyabradHO]

Here are pics. Is that an idler pulley? If so, does no one make a repro "correct" belt for it?

[johnta1]

That's the idler pulley setup.



I would think there is probably in the other years?
They used that setup for awhile.
Wouldn't a 72 or 73 work?
(if need a specific date code have them put whatever you want on it?)

[Transamric]

Interesting paperwork there John. But if I'm reading it correctly, the changes only apply to 'A' bodies.

[hiyabradHO]

So I am guessing no one makes a period correct belt for the 80amp alt with idler pulley?

[johnta1]

Yes, that is right.
I think at the time I thought I was in the Judge Forum.



I left it in for the info.

[Red Goat]

Here is a picture of an idler pully setup from a 73 Firebird. This car had a 400 w/AC & 80 amp alternator.

['ol Pinion head]

Originally Posted by hiyabradHO

So I am guessing no one makes a period correct belt for the 80amp alt with idler pulley?

Did you call Quanta and see if they have a 52.50" long embossed belt like the replacement above?

Ames isn't going to know show a listing until such an embossed belt is marketed to them. Without going through a multitude of old GM parts books, am not sure what other GM applications used that same size belt.

[vidguy]

I can look and see what belt I used on my setup with idler. I rebuilt my Idler with a new bearing too.

[hiyabradHO]

Originally Posted by 'ol Pinion head

Did you call Quanta and see if they have a 52.50" long embossed belt like the replacement above?

Ames isn't going to know show a listing until such an embossed belt is marketed to them. Without going through a multitude of old GM parts books, am not sure what other GM applications used that same size belt.

Thank you. I will check it out.

[Held for Ransom]

My '74 Firebird w/80 amp alternator and idler pulley uses the 9433755 GM 440x5150 belt (in this case GM refers to the pick code). Did the '71 use a larger pulley for their idler?

[njsteve]

Does anyone have a photo of the warranty parts decribed in the bulletin above?

[johnta1]

Does anyone have a photo of the warranty parts decribed in the bulletin above?

[hiyabradHO]

Originally Posted by vidguy

I can look and see what belt I used on my setup with idler. I rebuilt my Idler with a new bearing too.

Thank you, please do.

[njsteve]

Originally Posted by johnta1

Which part in the diagram is the 9790677 replacement part that supercedes the idler pully assembly?

['ol Pinion head]

Something else to note, '72 Bird HO Auto with AC would have the smaller diam wp pulley, 485397. Other AC application engines would have had the slightly larger diam 481040 wp pulley. The difference in diam of those two AC application wp pulleys, could effect belt use.

To try and add more light to this, went to my 3/72 dated Pontiac Master Parts book.
While Master Parts Books don't always give the exact original application piece, using a close dated one helps much more than one that is dated years later.

Belts:

Alternator:
71-72 All F /455 HO H.T.-P.S. & A.C....545297...BELT (1/2" x 49 3/4")
71-72 A, B, & G-AC, w 80amp............1378417..BELT (1/2" x 51")

note: H.T. is hydramatic trans, first uses the 55amp alt. The latter listing does not use the idler pulley and fixed alt mtg bracket, instead, the alt adjusts on the "B series" 80 amp alt mtg plate

Confusing enough? The above listing, if one looks really close, and considers the above memo John posted, one can note how quickly master parts books begin combining and superceeding parts usages.

Power Steering Pump
71 A & F - P.S.-A.C......9789230...BELT...(1/2" x 52" double wrap) (w 80 amp alt)
72 F...........................9789230...BELT...(1/2" x 52" double wrap) (w 80 amp alt)
71-72 All P.S. & A.C. exc X....9790635..BELT..(1/2"x 50 1/2")

Air Conditioning Compressor
70-72 All V/8 A.C. exc 307...478012...BELT..(1/2" x 59 1/4")
(no issues here)

hope this helps.