79 Fan Belts P/N Discrepancies. Which parts to order and use?

[Ken S.]

I have a 79 L82, 4-spd, A/C, car that I ordered new back in 1978. It is #421639, was built on 2/2/79, and delivered on 2/28/79. It has 23K original miles. I have all paperwork, records, manuals, etc.
On the return trip to CT from Corvettes at Carlisle last year, it spent the last leg of 140 miles on the back of a flatbed. The coil had failed. But, that was a good wake up call, as all of the original parts I've been running will only last so long. I replaced the coil with a big box store version to get the car up and running last fall. This year, I freshened up the ignition system. I replaced the cap, rotor, retainer, spark plugs, ignition wires (that was fun), coil, & ignition module. Except for the coil and module, for all parts I used NOS, GM service replacement, and/or as close to factory original as I could get. I used pertronix for the coil and module.

The next freshening up project I was planning on was to replace all 4 fan belts. I was planning on picking up all 4 at Carlisle this week. But, I'm running into a P/N discrepancy between the all original belts now on my car, the AIM P/N, the 3rd Ed NCRS TIM P/N, and Quanta part numbers.

Here's what I'm trying to resolve: (all belts are 4Q-78)

P/S Belt-
Original - GM 9433622 AY .380 X 36.0 DAYCO 5.5864 4:P:15
AIM - 9433622
TIM - 9433622
Quanta - 9633622
So good, so far.

Alternator -
Original - GM 9433654 CG .380 X 52.0 DAYCO 5-7244 4:P:18
AIM - 9433653
TIM - 9433653
Quanta - 9433653
Looks like car was assembled with the wrong (w/o A/C belt)?

A/C -
Original - GM 9433916 PE .500 X 55.5 DAYCO 42-1081 4:N:12
AIM - 9433915
TIM - 9433915
Quanta - 9433916
Don't know who is right here?

AIR pump -
Original - GM9433616 AS .380 X 33.0 DAYCO 5-7271 4:P:13
AIM - 9433616
TIM - 9433615
Quanta - 9433616
It looks like a yellow page revision 1 to the TIM made a previously correct number now out of step with all other "correct" references.

So, that's where I'm at.
Can someone with knowledge and/or experience in this specific area on a 79 comment on what belt P/Ns I should use to:
1) be factory correct; and
2) be fully functional in a car that is used sparingly.
It's clear that different belts will work across these applications. I'm looking for the best way to go.

Thanks !

[Joe L.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

I have a 79 L82, 4-spd, A/C, car that I ordered new back in 1978. It is #421639, was built on 2/2/79, and delivered on 2/28/79. It has 23K original miles. I have all paperwork, records, manuals, etc.
On the return trip to CT from Corvettes at Carlisle last year, it spent the last leg of 140 miles on the back of a flatbed. The coil had failed. But, that was a good wake up call, as all of the original parts I've been running will only last so long. I replaced the coil with a big box store version to get the car up and running last fall. This year, I freshened up the ignition system. I replaced the cap, rotor, retainer, spark plugs, ignition wires (that was fun), coil, & ignition module. Except for the coil and module, for all parts I used NOS, GM service replacement, and/or as close to factory original as I could get. I used pertronix for the coil and module.

The next freshening up project I was planning on was to replace all 4 fan belts. I was planning on picking up all 4 at Carlisle this week. But, I'm running into a P/N discrepancy between the all original belts now on my car, the AIM P/N, the 3rd Ed NCRS TIM P/N, and Quanta part numbers.

Here's what I'm trying to resolve: (all belts are 4Q-78)

P/S Belt-
Original - GM 9433622 AY .380 X 36.0 DAYCO 5.5864 4:P:15
AIM - 9433622
TIM - 9433622
Quanta - 9633622
So good, so far.

Alternator -
Original - GM 9433654 CG .380 X 52.0 DAYCO 5-7244 4:P:18
AIM - 9433653
TIM - 9433653
Quanta - 9433653
Looks like car was assembled with the wrong (w/o A/C belt)?

A/C -
Original - GM 9433916 PE .500 X 55.5 DAYCO 42-1081 4:N:12
AIM - 9433915
TIM - 9433915
Quanta - 9433916
Don't know who is right here?

AIR pump -
Original - GM9433616 AS .380 X 33.0 DAYCO 5-7271 4:P:13
AIM - 9433616
TIM - 9433615
Quanta - 9433616
It looks like a yellow page revision 1 to the TIM made a previously correct number now out of step with all other "correct" references.

So, that's where I'm at.
Can someone with knowledge and/or experience in this specific area on a 79 comment on what belt P/Ns I should use to:
1) be factory correct; and
2) be fully functional in a car that is used sparingly.
It's clear that different belts will work across these applications. I'm looking for the best way to go.

Thanks !

Ken-----


I have no specific experience with a 1979. However, I can tell you that I have found instances where GM did not originally use the belt specified in the AIM. I expect this "phenomenon" is what explains your discrepancies.

The GM #9433653 belt is 51.5", so it's only 1/2" shorter than the belt you found on the car.

The GM #9433915 belt is 55.0" in length, so it's only 1/2" shorter than the belt you found on the car.

There may have been some cars built with the GM #9433615 AIR pump belt as the TIM shows since this belt is only 1/2" shorter than the 9433616 found on your can and shown in the AIM. I expect that someone observed a 9433615 on a known-original 1979 and "extrapolated" this to mean that this is the only correct belt.

I think you could use either belt for each application and it would cause absolutely no problems, whatsoever. Usually, only captive belts (i.e. belts with no adjustment) require an absolutely exact belt length.

[Steven B.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Ken, Zip has repro belts, Quanta's I think, and for their belts they include the original PN. Hope this helps. Steve

1979 Corvette Fan Belts FB-41579 L48 w/70 Amp Alternator Belt $26.00 FB-41379 L48 w/AC Alternator Belt $26.00 FB-42379 L48 w/o AC A.I.R. (Smog) Pump Belt $26.00 FB-42479 L82 & L48 w/AC A.I.R. (Smog) Pump Belt $26.00 FB-41679 L82 w/70 Amp Alternator Belt $26.00 FB-41479 L82 w/AC Alternator Belt $26.00 FB-41879 Power Steering Belt $26.00 FB-41779 w/o AC Water Pump Belt $26.00 FB-41979E L48 Air Condition Belt - 1st Design $26.00 FB-42079E L82 Air Condition Belt - 1st Design $26.00 FB-42179L L48 Air Condition Belt $26.00 FB-42279L L82 Air Condition Belt $26.00

[Ken S.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Joe - thanks for the good advice.

Steven - thanks for the info. My problem is not where to get the belts, but what belts to get because of the P/N discrepancies between my original belts now on the car vs the PNs in the AIM, the NCRS TIM, and Quantas catalog. Quanta advises they use the AIM as their source of information.

I want to continue to keep the car as factory correct as possible. I've done that for 34 years now, so the hard part is behind me ......

[Terry M.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Joe - thanks for the good advice.

Steven - thanks for the info. My problem is not where to get the belts, but what belts to get because of the P/N discrepancies between my original belts now on the car vs the PNs in the AIM, the NCRS TIM, and Quantas catalog. Quanta advises they use the AIM as their source of information.

I want to continue to keep the car as factory correct as possible. I've done that for 34 years now, so the hard part is behind me ......

Maybe I am missing something here (I often do); but if you know what came on the car originally it seems to me a no brainier to get the best reproduction (including numbers) of that item. All of the reference materials you cite can be wrong for your car for a variety of reasons. Stick with what you know is real and the AIM & TIM be damned. If enough people do that the TIM will get changed.

On the other hand, if all you want is judging points, give in to the TIM -- but check with the NTL (National Team Leader) first to be sure what is in the TIM is not a known mistake.

[Tom R.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Ken

I did some research on the AIR/AC belt because I came across the same discrepancy in the TIM and when sourcing through Quanta. The TIM covers both 1978 and 1979 and you would expect the applications should be consistent across the two production years...but they are not.

Part of this discrepancy was what I found from the broadcast codes called out on buildsheets that conflicted with the TIM. I studied several low-mileage Corvettes (1978) to conclude that the TIM was incomplete. The results were published in The Corvette Restorer and the table below illustrates the recommendation that should be incorporated into the TIM. This would make it consistent with Quanta and fix the conflict for the AIR/AC application but limited to the 1978 production year.

I have a 79 L82, 4-spd, A/C, car that I ordered new back in 1978.

Based on 1979 buildsheets your application would call out the AS code. I would follow Quanta...the TIM lacks consistency with buildsheet broadcast code sources. The other codes for fan belts CG, PD, & AY for L82, C60 four-speed application...all with A.I.R.

AIR Fan Belt.jpg

[Joe L.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Maybe I am missing something here (I often do); but if you know what came on the car originally it seems to me a no brainier to get the best reproduction (including numbers) of that item. All of the reference materials you cite can be wrong for your car for a variety of reasons. Stick with what you know is real and the AIM & TIM be damned. If enough people do that the TIM will get changed.

On the other hand, if all you want is judging points, give in to the TIM -- but check with the NTL (National Team Leader) first to be sure what is in the TIM is not a known mistake.

Terry-----


I have absolutely no doubt that the belts Ken found on his car are original to the car. So, if it were me, I would replace with the same belts regardless of what any other reference might say.

[Ken S.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Terry and Joe - thanks for the great advice.

Tom - when I created this post, I was at my knowledge limit P/N, AIM, & TIM wise. You have taken the analysis to another level by referencing the build sheet and broadcast codes, so now I'm in learning mode. I follow what you are saying. I will review your info/article in the Restorer. I will also check my build sheet - I found that years ago tucked up in the rear end. I recall that parts of it are not readable. I have never studied my build sheet. I will do that next.

[Ken S.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Tom - Oh, You wrote THAT ARTICLE in the Fall 2012 Restorer!!! Now I understand why I'm a novice in learning mode!

Well, I pulled out my build sheet -
Section V-Belt Groove, on the third line of the document:
Box 35-1 = CG
Box 36-2 = PE
Box 37-3 = AS
Box 38-4 = AY.

This "suffix" (broadcast code?) matches all of the known for certain original belts on my car.

I think this means I have a bingo?

[Tom R.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Well, I pulled out my build sheet - Section V-Belt Groove, on the third line of the document:
Box 35-1 = CG
Box 36-2 = PE
Box 37-3 = AS
Box 38-4 = AY.

This "suffix" (broadcast code?) matches all of the known for certain original belts on my car.

I think this means I have a bingo?

You got it! What's interesting is your buildsheet calls out the PD while the other buildsheets in my collection called out the PE belt. Yet, the configurations are identical: L82, M20(21), C60 & A.I.R. I noticed the PE vs what you had listed above for the PE A/C belt. Go figure! This would be a good write-up for The Corvette Restorer!

[Tom R.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Tom - when I created this post, I was at my knowledge limit P/N, AIM, & TIM wise. You have taken the analysis to another level by referencing the build sheet and broadcast codes, so now I'm in learning mode. I follow what you are saying. I will review your info/article in the Restorer. I will also check my build sheet - I found that years ago tucked up in the rear end. I recall that parts of it are not readable. I have never studied my build sheet. I will do that next.

Thanks and the Corvette Buildsheet Book takes knowledge to yet another level! The NCRS carries it and members get a discount.

[Ken S.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

You mention PD? I don't understand that part, as mine is PE, like the rest?
I will scan and email you a copy of my build sheet - Done.

I will be ordering belts to match the ones on my car / build sheet.

I guess I was not expecting such a discrepancy among the reference material.
The Quanta catalog matched 3 of my original belts.
The AIM called out 2; the TIM only 1.

Thanks!

[Tom R.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

You mention PD? I don't understand that part, as mine is PE, like the rest?
I will scan and email you a copy of my build sheet - Done.

Yes...would appreciate viewing a copy. The PD refers to another belt option that was called out on 1979 buildsheets (in my possession) for A/C equipped vehicles. I don't understand that application versus yours. Maybe I can make sense of it when I see your buildsheet. As you have concluded...stick with what is on your vehicle and you know to be accurate.

I guess I was not expecting such a discrepancy among the reference material.
The Quanta catalog matched 3 of my original belts.
The AIM called out 2; the TIM only 1!

I guess the TIM loses out in this analysis but offers some interesting insights!

[Edward A.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

Opening and commenting on this thread as I am encountering a similar situation. I am in the process of replacing all the original belts on my 1979 L82 Automatic w/AC. The discrepancy I am noting is that the original alternator belt is:
GM 9433654 CG .380X52.0 DAYCO 5-7244 4:P:10 13
However both the Quanta store site and the NCRS Technical Manual indicate that the correct Alternator belt for L82 w/A.C. is 9433653 CF, which is 1/2" shorter that the original (GM 9433653 CF GATES .380X51.5) The CF belt is too short to install properly in this vehicle. I can't determine what the anomaly is (is it the belt pulley?), but I had to remove the alternator belt guide since it could not be adjusted any further out and the belt would rub against it, also the alternator is practically up against the valve cover at it's extreme inward adjustment. The build sheet confirms that belt (Box 35-1=CG) is original correct. A note should be added to the NCRS Technical Manual to annotate that the CG belt WAS also used on L82 w/A.C. cars from factory.

I will request and replace the incorrect belt I ordered with a correct GM 9433654 CG Belt. Is there a way to forward this information to the proper NCRS person to address the discrepancy?
Thanks!!

[Ken S.]

Re: 79 Fan Belts P/N Discrepancies. Which parts to order and use?

I replaced my belts with the same ones that match the originals that were on my car. I have had no issues using that approach. In my case the reference materials are wrong.

The TIMs advise to notify the appropriate team leader when discrepancies are found. I sent in all of my supporting documentation to the 78-82 team lead when I ran into this problem in 2013. Your information will provide additional documentation.