Vehicle Id Number
The serial number (VIN) is found in 2 places: a small sticker on the very narrow top of the dash, on the driver's side, near where the lower windshield frame meets it. The main information sticker (including month and year of production) is on the driver's side of the box on which the bottom seat cushion is screwed. You must crouch down to see it.
Since 1954, American automobile manufacturers have used a Vehicle Identification Number, commonly referred to as a «VIN», for the purpose of vehicle description and identification. The early VINs came in a wide array of configurations and variations, depending on the individual manufacturer.
VIN patterns prior to 1981 vary from one manufacturer to the other. Ford used 11 digits, GM and Chrysler used 13, Volkswagen and Shay used 10. Distribution of letters and numbers was not standardized, nor was the meaning attributed to each one. The only thing that could be said with some degree of certainty is that the last 4 to 7 numbers corresponded to the «production number».
Beginning with model year 1981, the National Highway Traffic Safety Administration, U.S. Department of Transportation, required that all over the road vehicles sold must contain a 17-character VIN. This standard established a fixed VIN format.
In the early 2000s, we did an extensive survey of some 800 Shay Roadsters and T-Birds (800 out of 5,000 = 16%) regarding their VIN, date of production and instrument clusters, in order to see if we could determine some trends.
The clearest finding was that you could not equate «production numbers» (the last four in a 10-digit VIN / the last six in a 17-digit VIN) to a strict chronological order of production. Batches of VINs seemed to have been allocated to work teams for them to stick unto cars without coordination with other teams. The second clearest finding was that production numbers could not corroborate the actual number of cars produced in reality.
The first cars that rolled off the assembly line in August 1979 had a 10-digit VIN such as «MOM1EX0001». We found 10-digit VINs on Shays as late as November 1980. We found the first 17-digit VIN as early as January 1980. This means that the 10-digit VINs and the 17-digit VINs cohabitated for nearly the entire 1980 calendar year.
It is likely that 10-digit VINs started with «MOM1EX0001» as the lowest production number we did encounter was «0011». The highest was «5529». Knowing that 3,400 Roadsters had been produced by mid-september 1980 and that the use of 10-digit VINs was nearing termination, it seems highly unlikely that «5529» reflects the actual quantity of cars produced by that time. It is safe to assume that a good number of 10-digit VIN stickers were simply not used. Remember that production numbers did not logically equate to date of completion. For example, VIN «MOM1EX5529» was rolled out in May 1980, whereas the following inferior VIN was found on a car finished later in November 1980 : «MOM1EX4581».
As for the 17-digit VIN, the lowest production number we encountered in our sampling was «000543» and the highest was «006855». Again, production numbers did not equate to date of completion and the difference between the highest and the lowest did not amount to the quantity of cars produced in reality.
Our third finding concerns instrumentation packages. The 1-gauge instrument cluster was the first one installed in cars from the start of production in 1979 and was eventually replaced by the 2-gauge instrument cluster. VINs were not as reliable a source of predictability as was the date of production. August 1980 generally seems to be the time where the factory transitioned between the two types, athough we have seen a spattering of 2-gauge clusters before that moment as well as leftover 1-gauge clusters installed later.
All in all, inconsistency was almost the norm on the factory floor...
DECODING THE 17-DIGIT VIN
Much of the following information comes from the National Highway Traffic Safety Administration's Web Site. VIN coding has so many variables that it comprises a complete book in itself to list all the makes, models, body types, engines, origins of manufacturers, etc. Provided below is a quick guide to the VIN structure. If you should need further information, you could try to contact the National Insurance Crime Bureau (NICB) by website at http://www.nicb.org or by telephone at (708) 430-2430. The NICB publishes various identification manuals.
The following information refers only to the new 17-digit VINs used on Shays. If you have any information on the shorter VINs used previously, please tell us what you know. We'll be glad to expand this text. Let's use VIN number 1HWA31AA5AE006006 found on the sticher above in order to illustrate how things work. The letters I, Q, 0, U & Z are not used in a VIN.
VIN number : 1 H W A 3 1 A A 5 A E 006006
Digit : 1 2 3 4 5 6 7 8 9 10 11 12 to 17
Digit 1 - Nation of origin
1 = U.S.
2 = Canada
3 = Mexico
Digit 2 - Manufacturer
G = General Motors
C = Chrysler
F = Ford
H = Presumably a Shay
Digit 3 - Model
W = Passenger car
X = Pick-Up
Digits 4 to 8 - Vehicle Description Series : These digits represent items such as the car or truck line, series, body type, restraint system, and engine. Since they are assigned at the manufacturer's discretion, they are not always in the same order. For example, General Motors uses positions (4) and (5) for car-line series, position (6) for body style, position (7) for the restraint system (type of seatbelts, etc.), and position (8) for engine type. On the other hand, Ford uses position (4) for the restraint system, (5) for the designation, (6) and (7) for the body type, and position (8) for the engine. Let's presume that Shay used the same order as Ford did :
Digit 4 - Restraint system
A = Lap belts only
B = Passive Restraint System Seat Belts
L = Dual Airbags
P = Active Belts
T = Lap & shoulder belt
Digit 5 - Designation
2 = Super Deluxe Model A (twin sidemounted spares), including Special Edition Super Deluxe (such as the Polar Bear, Golden Oldie and College Classic)
3 = Deluxe Model A (one spare left side mounted)
4 = Standard Model A (one spare rear mounted)
C = Thunderbird
Digits 6 & 7 - Car Line, Series and Body Type
1A = Model A
21 = Thunderbird
Digit 8 - Engine
A = 2.3 liter 4 cylinder
3 = 3.8 V6
F = 5.0 V8
Digit 9 - Check Digit : This digit is mathematically derived from values assigned to the other 16 digits. The check digit will determine whether a VIN is a valid number, or not. See the check digit formula information below.
Digit 10 - Year of Manufacture : There is a common table that all manufacturers use.
A = 1980
B = 1981
C = 1982
D = 1983
E = 1984
F = 1985
G = 1986
H = 1987
J = 1988
Digit 11 - Assembly Plant : In the case of some other manufacturers, these digits are shared by two different plants. For example a passenger car assembled in the General Motors Lordstown plant carries a (7) as does a GM plant in Fujisawa Japan.
E = Probably corresponds to the Elm Street plant in Battle Creek, Michigan.
Digits 12 to 17 - Production Number : This is the sequential number that is assigned to the vehicle as it leaves the plant. It tells you what number on the assembly line your car was. Car lines can start anywhere between 000000 and 999999. Furthermore, please note that there has been instances where the sequential production number of a car exceeded the published total car output for that model year! How can that be? There could be a production number gap, for whatever reason. Or maybe some prototypes were included in there. Or perhaps the total production number is wrong... who knows?
THE VIN CHECK DIGIT FORMULA
The check digit of a VIN appears in the 9th position and provides a way to verify the validity of all of the other characters in positions 1 to 8 and 10 to 17. The check digit is calculated by carrying out the following rather complicated mathematical computation:
1) Assign to each number in the VIN its actual mathematical value & assign to each letter the following value :
A = 1 / B = 2 / C = 3 / D = 4 / E = 5 / F = 6 / G = 7 / H = 8 / J = 1 / K = 2 / L = 3 / M = 4 /
N = 5 / P = 7 / R = 9 / S = 2 / T = 3 / U = 4 / V = 5 / W = 6 / X = 7 / Y = 8 / Z = 9
2) Depending of its Position in the VIN, multiply the assigned value for each character in the VIN by the Weight Factor specified in the following list :
1rst Position = Weight Factor of 8 / 2nd = 7 / 3rd = 6 / 4th = 5 / 5th = 4 / 6th = 3 / 7th = 2 / 8th = 10 /
9th = check digit to be calculated / 10th = 9 / 11th = 8 / 12th = 7 / 13th = 6 / 14th = 5 / 15th = 4 / 16th = 3 / 17th = 2
3) Add all of the resulting products and divide this total by 11.
4) The numerical remainder is the Check Digit. If the remainder is «10» the letter «X» shall then be used instread of a number to designate the Check Digit. The correct numeric remainder, zero through nine (0-9) or the letter «X» shall appear in the VIN Digit Position number nine.
5) Here is an example of a complete check digit calculation :
Divide the Total of the added Products by 11 : 226 ÷ 11 = 20 and 5/11 .
The numeral remainder is 5, therefore the Check Digit designation is «5».
«5» is indeed the number we find in Digit Position number 9.