[Brock1030]

After a related thread sparked my thoughts on how the build sheet codes translate into part numbers, what is the resource that does that code translation for alternators?

The build sheet for my car shows a code in Box 31 that seems indicate “WP” - a bit blurry, with the “P” clear and a “W” as a strong possibility for the preceding letter. I was told the correct alternator is Delco part number 1105360. This for a 1979 SE W72 Y84 WS6 4-speed car with A/C, but w/o rear defrost and built in Van Nuys in late November 1978.

Thanks so much for any help.

[Keith Seymore]

The build sheet codes (aka broadcast codes) for the various part numbers reside in the Engineering Part List (ie, "EPL"). The EPL is maintained in the GM computer mainframe system.

The design/release engineer requests the part numbers and codes from Engineering Specifications, who generate the necessary information and, after all the approvals, release it for production and service. Both the part number and the broadcast code are assigned "randomly", that is, there is no intelligence encoded in the part number and the code is just whatever comes up next. Although - the specs guys can and do have a sense of humor and might designate a fun code if it's in the ballpark, like "PAM" as the code for the biggest radiator released by an engineer of the same name. Naturally, sometimes the last two or three digits of the part number can also be used as a broadcast code, which makes it a bit more straightforward.

The engineer develops and maintains a handwritten or typed spreadsheet with the information to try to keep all this straight. This is what usually finds its way into the hobby world.

Any component that has a lot of proliferation will have that kind of matrix: engine, trans, drive shafts, rear axle, shocks, alternators, radiators, instrument clusters, etc.

I have a few of these but unfortunately do not have a reference for alternators, nor do I know if one exists. We GTO guys can use Eric White's book as a reference; hopefully you bird guys have something similar.

Brake chart is attached as an example and for your reference/entertainment.

K

[Keith Seymore]

Originally Posted by Brock1030

After a related thread sparked my thoughts on how the build sheet codes translate into part numbers, what is the resource that does that code translation for alternators?

Hopefully you weren't asking "what time it is" and I told you how a watch is made, but it seems like the way you phrased your question that maybe you had some interest in the process.

K

[Brock1030]

Yes, thank you, as I knew there must have been some system. Amazing though that given how many cars were produced, no resource seems to be extent to de-code these alphabetical references to the original part numbers used. I suppose, need to check low mileage original cars, though even those could have components changed from those installed at the factory by GM.

[johnta1]

No one seemed interested in them until long after the fact.

There is a guy who broke down all of his items on the buildsheet for a 1979 TA I believe. Took him a long time.

He was on transamcountry I believe and posted some on PY.

[johnta1]

I don't know that alternator #, seems to be for a later year?

I show a 1102844 or a 1102908 as for the AC equipted Bird.

The sheet I talked about shows a 'PB' for the alternator which he had as alternator # 1102849
His was a Feb 1979 build.

[Brock1030]

Are those part numbers successive, in that the lower nos could be used in earlier builds?

['ol Pinion head]

Originally Posted by Brock1030

After a related thread sparked my thoughts on how the build sheet codes translate into part numbers, what is the resource that does that code translation for alternators?

The build sheet for my car shows a code in Box 31 that seems indicate “WP” - a bit blurry, with the “P” clear and a “W” as a strong possibility for the preceding letter. I was told the correct alternator is Delco part number 1105360. This for a 1979 SE W72 Y84 WS6 4-speed car with A/C, but w/o rear defrost and built in Van Nuys in late November 1978.

Thanks so much for any help.

Not sure who mentioned 1105360 is correct. That number makes little sense, the last 4 digits are too big a number, & 1105360 is not listed in any factory literature I have (I'm deep in original Pontiac tech literature). My bet is that number is some sort of much later Delco part number for a replacement 10SI 61 Amp alternator. I would expect an 1102908. Have a heavy loaded 400 4spd T/A built less than a month before your '79. I have yet to drop the original gas tank to retrieve the build sheet, but will put it on the to do list. I picked up a nice core 1102908 for the '79 after examining two other original '79 400 4spd AC cars that were built in the Fall.

On the broadcast sheet codes, have examined many original late 70's F & B series broadcast sheets, & compared the way the cars were built to the abbreviated codes in each box, those codes are fairly easy to understand. Realize, not everything is spelled out correctly in enthusiast published books, & often even in tabular form on enthusiast compiled websites.

A Sun Tuneup sheet is a secondary source that's yet to mislead me on the original part numbers for specific application alts, starters, & distributors. Unfortunately, I do not have one for a 79 Pontiac.

[Brock1030]

Excellent data, ‘oPH - thank you! When in doubt, look for other vehicles produced around the time of your own as sound leads.

As far as date coding, for a 4th week of November 1978 car build, what you expect for the alternator - perhaps August or September 1978? Kindly advise. Thanks so much.

['ol Pinion head]

Brock, cked the cowl tag on my '79 & it is 11C VanNuys, closer to your car's build than I prev thought. After digging through a ton of alt cores on shelves in a few old yards, the 2908 I came up a few years ago is dated in early Oct 79. Would have been happy with one slightly later, but am not going to fret it. 3-5 weeks date span is what I typ see on early 70's Fremont CA (A-body) plant builds w what were at the time much more common "927" & "928" numbered alts. Not exact apples to apples comparison, but both plants are near same distance from Indiana.

[Brock1030]

Correction on my car - it’s actually a 5th week of November 1978 build - serial 131357. Found a late October 1978 build alternator, which places it at about 4 weeks between alternator build date and the car build date. Could have been that way, so without any record, go with what could likely have been grabbed off the parts shelf during assembly in Van Nuys.

Thanks for all your kind help!

['ol Pinion head]

glad could help, as I get further along on the '79, will prob have some questions for you.

[Brock1030]

Glad to assist!

[Held for Ransom]

If you look at the 1979 MVMA sheet for Firebird, you will see 3 alternators for the 301/400/403 engines.
Standard is the 42A, PN 1102389. Pick code was HJ.
A/C and/or heated rear glass used a 63A, PN 1102908. Pick code was WP.
Last was a high output option, also a 63A, PN 1102910. No clue on the pick code though.

[Brock1030]

Excellent HFR! The build sheet code in box 31 is “WP” so this confirms it for my car: the correct alternator is indeed 1102908. Thanks so much!

[Held for Ransom]

Here is the sheet...

[Brock1030]

Where is the reference to “WP?” Kindly advise.

[Held for Ransom]

From studying build sheets. Down in the body of options, the WP will call out the K81 option. No upgrade to alternator won't show any option. I never found the HO option.

[Brock1030]

Great connection! Checked my build sheet list of options and sure enough, the K81 option! Thus, “WP” in Box 31 equals the 63A 1102908 alternator. Thanks so much!

[Keith Seymore]

Originally Posted by Brock1030

Yes, thank you, as I knew there must have been some system. Amazing though that given how many cars were produced, no resource seems to be extent to de-code these alphabetical references to the original part numbers used.

Originally Posted by johnta1

No one seemed interested in them until long after the fact.

I agree - it didn't occur to us to keep any of this stuff.

I threw assembly manuals away by the dumpster load at model change.

Followed my own truck down the line, drove it off the end of the line myself - and it never occurred to me to keep any of the paperwork.

K