Author Topic: Date of mfg. based on VIN  (Read 6584 times)

nuch_ss396

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Date of mfg. based on VIN
« on: January 25, 2007, 05:17:49 AM »
I have a question for those of you knowledgeable with 69 Camaro VIN's.  If a particular Camaro has a VIN, but no cowl tag, how can you tell the actual date
of manufacture?  I know Jerry MacNeish published the VIN's and the corresponding months in his 69 Fact Book, but I was wondering how closely you can
zero in on the build date ( or week ) based solely on the VIN.  I'm not sure why the cowl tag is missing on this particular Camaro. 

Thanks,
Steve
69 SS 396, Hugger Orange, D/80, D/90
Chambered Exhaust, N/66, THM400, 3:73 posi

Steve A.
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rich69rs

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Re: Date of mfg. based on VIN
« Reply #1 on: January 25, 2007, 11:17:39 PM »
Steve:

This is the rationale that I have used in trying to estimate the build date of my ride.  Also, the same VIN by month info is on the CRG site at:  http://www.camaros.org/geninfo.shtml#When

For example, let's look at Jan 1969 Norwood numbers.

First unit produced in Jan '69 VIN:  569987;  Last unit produced in Jan '69 VIN:  589720; Total units produced in Norwood in Jan '69:  19733

From the following link:  http://www.camaros.org/forum/index.php?topic=983.msg5279#msg5279 JohnZ tells us that Norwood produced 912 units / day.  In January, there are 22 "working days" (assume Monday - Friday and excluding New Years day = 22 days).  19733 units / 912 units per day = 21.64 days or rounded up = 22 days; so far so good.

My car was built in Jan '69 (O1C on the Cowl Tag) and has VIN #581767, or the 11,780 unit built at Norwood in Jan '69.  11780/912 = 12.92 days (during the 13th production day of the month).  Starting with Jan 2 as day 1, and excluding weekends, the 12th day of production was 17 Jan (Friday) and the 13th day of production would have been Monday, 20 January.  Consequently, I would conclude that most probably my car went through final assembly at Norwood on Monday, 20 January 1969, the 13th day of production in January 1969.

As an aside, my cowl tag is 01C amd my PowerGlide is date coded:  C9A16N (Cleveland, 1969, Jan 16, night shift)  All of this fits nicely.

Richard
« Last Edit: July 03, 2007, 10:12:19 PM by rich69rs »
Richard Thomas
1969 RS

nuch_ss396

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Re: Date of mfg. based on VIN
« Reply #2 on: January 26, 2007, 01:17:28 AM »
Richard,

Thanks for the links and thorough explanation.  Based on your example, I looked at 912 cars per day in October 1968 and arrived at 10/25/68 as the possible
build date for my SS ( N528412 ).  That jives with the 10D build date on my cowl tag.  Only question I have now is what was/is the allowable deviation in this
formula?  In other words, is the build date +/- one day, +/- one week, within that particular build week? 

Stated another way, if the cowl tag has 10D, could the car possibly have been built late 10C or early 10E?  Sorry if I'm reading more into this that there should be.....

BTW, 10/25/68 was only three days earlier than my 11th birthday.  How cool would it have been to have a car born the same day as you? ::)

Steve
69 SS 396, Hugger Orange, D/80, D/90
Chambered Exhaust, N/66, THM400, 3:73 posi

Steve A.
  CRG

Rich

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Re: Date of mfg. based on VIN
« Reply #3 on: January 26, 2007, 05:22:50 AM »
As the various links explain (and you should read JohnZs assembly process report also), you can use this data and the math with approximations to get kinda/sorta about when a car was built.  But it isn't guaranteed to be exact, as we disclaim all over the place.  The only way to know for sure exactly when a car actually came of the assembly line is to have a piece of GM paper that says that, and those are rare.

LOS cars have a Fisher production date code that gets you an idea of the working day of the month when it got tagged on the Fisher side.  GMAC papers have the shipping date that is usually within a day or two, no more than a week, later than production.  BBCs have the order rec'd at factory date that also tends to get you close.  The Manufacturer's Statement of Origin has the transfer date from GM to the dealer that is no later than the shipping date.

I was fortunate to find the MSO during my extensive title search for my car, a 9Jan68 MSO date for my 01B car that is LOS with a J day of month in the scheduling code, which is interesting - our other data show that the January scheduling period started during the 12E week and accounts for a couple of days - and taking other things into account, the J day from our other data has to pretty near be either the 8th or at most the 9th for my car, meaning that it would have been built and shipped very fast, which isn't always the case. And that also means they did something wacky with that first A week of the year, which they do seem to have done (perhaps like spending more of that first short week building Impalas rather than Camaros). That these dates don't fit a conventional calendar is one of our points, and unless you have several pieces of converging data, getting closer than a week is pretty uncertain.

However, our Canadian friends are fortunate in this regard as the GM Canada data has both the build and ship dates included.
68 L30/M20 RS

rich69rs

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Re: Date of mfg. based on VIN
« Reply #4 on: January 26, 2007, 06:00:21 PM »
I mentioned my transmission build date as one other piece of information that helps to bracket the earliest possible final assembly date. 

My transmission was assembled in Cleveland on 16 Jan during the night shift.  After that, it had to be shipped 250 miles or so to Norwood.  Since the tranny still had to be shipped from Cleveland to Norwood, in my case it would have been impossible for my car to have been assembled any earlier than the day shift on the 17th, and that would be assuming that the tranny got shipped from Cleveland immediately after completion so it could arrive at Norwood for a day shift assembly - possible, but probably not the case.  It is more reasonable to assume that the tranny arrived at Norwood some time during or after the day shift on the 17th.  If that logic holds, late during night shift on the  17th or day shift on the 18th would be reasonable assumptions for final car assembly - assuming no other scheduling issues.

Definitely not an exact science.  It is those other production items, strikes, etc, that most of us are not aware of that really mess up a linear extrapolation of data.
« Last Edit: January 26, 2007, 06:04:57 PM by rich69rs »
Richard Thomas
1969 RS

 

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