64 Hubcap question

[William C.]

Re: 64 Hubcap question

I think you are falling into a trap that many folks do who aren't familiar with GM assembly plant operations fall into, looking for a defined cutoff point on a running change. Unless the engineering document releasing the change had a defined change point date called out, it would be considered a "running change" which essentially means "when you run out of the old stock, use the new version". In reality, if another box or two of the first style was pulled out of storage after the introduction of the second design, the probability of them being used is pretty good, remember they were not installed on the car until delivery at the dealership. The AIM has a note indicating a revision, but a hole for my notebook ring goes right through it. Someone with a better AIM than mine might want to check for a part number change.

[Alan D.]

Re: 64 Hubcap question

Interesting about your AIM. I find the item in Sec10 sheet 1.00 as item 32 36 - it being pn 3843387 called Wheel Trim Cover Asm. with a NPC-231

I find no change symbol (the circle) on my sheet. The revision table at the bottom does reference 3-27-64 as SYM 3 for a Redrawn & Revised as a result of ECR 62064.
As for the Misc Shipping List (Sec14 sheet A3.00) only a quantity of 4 is called for.

[William C.]

Re: 64 Hubcap question

That would indicate a stock disposition of "use" and render into question any hard "cutoff" date especially if there was not a part number change.

[Michael H.]

Re: 64 Hubcap question

Interesting about your AIM. I find the item in Sec10 sheet 1.00 as item 32 36 - it being pn 3843387 called Wheel Trim Cover Asm. with a NPC-231

I find no change symbol (the circle) on my sheet. The revision table at the bottom does reference 3-27-64 as SYM 3 for a Redrawn & Revised as a result of ECR 62064.
As for the Misc Shipping List (Sec14 sheet A3.00) only a quantity of 4 is called for.

Alan,

If the AIM sheet was "redrawn & revised", it's likely that all previous revision history is lost. We may never know the history on the 1st design cover, at least not from the AIM.

The only way we would be able to find the actual date of change on the assembly line is if we had the original NPC (notice of production change) showing the actual date that the change occured.
Dates in the AIM's can be off by weeks or months, depending on the importance of the change.

If a change occurs during production, it may or may not be a change in the part number for the part involved. Some changes do not affect assembly or appearance so no part number change would be required.
Other changes that do affect assembly or appearance, such as our 64 wheel cover, would definitely have a different part number.

The parts book shows two parts/numbers for the 64 cover. A 1st design, 3849557, and a 2nd design, 3862137. These numbers are for the cap "assembly that includes ornament (spinner) and attaching parts.
a part number in the 64 AIM would be for the cover only, minus ornament.

NPC's usually have a section called "disposition of existing stock". In otherwords, what does St Louis do with the current stock of 3849557.

There are several different instructions on NPC sheets including "mix with, (the new part) return to warehouse, use existing stock first, and scrap. (and a few more)

If there isn't a part number change, it's possible/likely that the selection would be "mix with" existing stock. However, since there is a part number change, and a substantial difference in appearance, I'm pretty sure the instructions would be "return to warehouse" for the 1st design cover.

Mixing the 1st and 2nd design covers on the assembly line wouldn't be at all logical and difficult for stock/inventory control.

It's highly unlikely that there was a mix of shinny and frosted caps coming of St Louis. Much more likely that the change occured suddenly and permanently.

I know that when the 1st design frosted covers were replaced with the shinny covers in production for the 63's, the existing stock of frosted covers were sent to scrap.