History of the MGA & Magnette
MGA Chassis (VIN), Engine & Body Numbers
Since the third reprint, 500+ new members have joined NAMGAR, making this a worthy reprint. Bill’s statistical data was used in the book Original MGA by Andres Clausager. It was also used by Safety Fast in a June 1991 article. It has also been reprinted in Dutch and appeared in an article there. This article may help to educate and inform many who have questions of the correlation between VIN Numbers, Engine Numbers and Body Numbers.
As Registrar, I get about two questions a week regarding serial numbers:
• Is my engine original?
• How can I tell if my ID plate belongs to my MGA?
I have only a partial Chassis number, how can I determine the proper number? All of this relates in one way or another to the relationship between the three primary serial numbers found on an MGA: the Chassis Number, Engine Number, and Body Number. (For simplicity, I shall refer to the Chassis Number as the Vehicle Identification Number, or VIN.) Apparently, Abingdon did not bother to help us out by keeping track of any number other than the VIN. So how do we determine the association between the three?
It occurred to me some time ago that with over 4,200 MGAs and Variants now registered with NAMGAR, we should be able to get printouts from the NAMGAR database that would lead to some useful conclusions or at least some generalizations.
When I finally set myself to this task, it turned out to be rather more difficult than I had imagined. It took quite a number of programs to extract the data in a meaningful way, and to do the necessary calculations. Then there was a lot of pencil work to collate, plot, and categorize the information so that a few rules might be established.
Following is the results of that effort. It is not necessarily intended as interesting reading, but rather as a future reference source to answer questions such as those raised above.
First a few ground rules. The best way to deal with the serial number relationships is to use the VIN as the base number, and think of the engine and body numbers as running so much higher or lower than the VIN number. For instance, if we say the engine numbers are running at -9000, we mean that for the range of numbers being investigated, the engine number will average 9000 less than the VIN. If the VIN is 55000, the engine number would be approximately 46000. To go the other direction, just reverse the sign. And speaking of ‘approximately,’ I’ll be using that word a lot.
I will abbreviate it in the tables with the symbol ‘-’, meaning that the number shown was a guesstimate.
Engine Number
A few general observations about engine numbers:
- Coupe engine numbers seem to run in the same range as Roadsters. In 1600s and Mk IIs, the average Coupe engine number runs about 150 below that for the average Roadster, but this could be due to a sampling error because of the limited number of Coupes registered. In any event, I won’t complicate things even more by trying to separate Coupes from Roadsters.
- Mk II Deluxes do not show a significant variation in engine number sequences from the standard Mk II.
Now for the meat of the data. First of all, it is quite obvious that there is not a strict one for one relationship between the VIN and the engine number. That is, the engines were not placed into the waiting chassis in numerical order according to the engine number. One might imagine a room full of engines awaiting installation, and whichever one was closest to the door got installed first. But within this chaos a general pattern exists, and the engines are, if one squints rather hard, in some kind of overall numerical order. That order is sufficient to make some generalizations based on the following analysis:
After eliminating engine numbers from apparent replacement engines, it is fairly simple to determine the average differential between the VINs and the engine numbers. (As in the example above, the average differential might be -9000.) The big question is how much deviation is there from this average difference, and how can we quantify it.
If one examines and plots these deviations from the average, a “bell curve” is established. At the apex of the curve is the averageVIN/engine number differential, and the slope on either side depicts the percentage of engine numbers that are either higher or lower than the standard average. Most engine numbers fall within a range of about 400 numbers, or +/- 200 from the average differential.
If you add or subtract (as indicated) the average differential from/to the VIN, the probability of hitting the actual engine number can be represented as:
• 38% probability of being within +/- 50
• 64% probability of being within +/- 100
• 85% probability of being within +/- 200
Before listing the computed average differentials, one additional item that came to light should be discussed. In 1500s with GB engines, the differential starts at about 9900, and ends up (at VIN 61503) at about -9700. This means that over this range of 51,402 MGAs, approximately 200 engines (or at least engine numbers) did not find their way into an MGA.
To allow for this, I’ve divided 1500s with GB engines into three sub groups to get a more accurate average differential. As an example for using the table, if you have an MGA with a VIN of 94355, we can see that your engine if it is to be original be a type GA (16GA), and must be in the range of 101 to 31660. More specifically, it will most likely be approximately 25655 (94355 minus 68700).
In actual fact, this is my 1600, and the actual engine number (which I think to be original) is 25389, a difference of 266. That makes it in the 15% that falls outside the 200 range indicated above. Applying this test to my Mk II, the computed engine number is only 71 off the actual, making it in the 64% probability range.
Model VIN Range Engine # Range Average Difference
Registrar’s Note: Bill Gallihugh was NAMGAR’s Registrar from 1989-1994. Last month part one of Bill’s article was reprinted explaining the correlation between Vehicle Identification Numbers (VIN) and Engine Numbers. The second and final part of Bill’s article talks about the relationship be tween body numbers and VIN numbers. Bill’s data was used in the book Original MGA by Andres Clausager. It was used by Safety Fast in an article and also been reprinted in Dutch, appearing in an article there. I hope this two part article will help educate and inform those who have questions about the numbering used at the Abingdon factories many years ago.
Model VIN Range Body # Range
Body Numbers
Establishing the relationship of body serial numbers to the VIN is far more complicated because of the following factors:
First, we have much less information on body numbers since we only recently began asking for that information on registration forms.
Second, the method used by Abingdon to number Coupe bodies made a mess of the system. Basically, what they did (apparently) was to periodically reserve blocks of 1000 numbers from the main sequence. For our purposes, this causes two problems.
As the sequence of body numbers for Roadsters increases along with ascending VIN numbers, there are sudden jumps of 1000 in the body numbers. Also, the Coupes are given VINs in sequence with, and integrated with, the Roadsters. Therefore, since the VIN is still incremented by 1 for each MGA (be it Roadster or Coupe) rolling off the assembly line, the body number is incremented by 1 only for the Roadsters since the Coupe bodies are numbered separately from the reserved block of 1000 in use at that point.
As a result of all this it is quite impossible to give pat formulas like we did for engine numbers. (However, the system does work great for 1500s up to about VIN 22300. This, of course, is the pre-Coupe era.
For this range a differential of +9900 may be applied.) The table gives the Body Number and VIN ranges.
General Notes:
- Twin Cam Roadsters and Coupes are both numbered from the same 1000 number blocks that are used by 1500 and 1600 Coupes.
- Deluxes tend to have a body number about 2000 higher than standard Mk IIs for the same VIN range.
- Mk II Coupes use the 37000 to 37999 range for body numbers. This range is also used for Roadsters. Consequently, the average differential for all Mk IIs is consistent throughout the range, and a differential of -68300 may be used. 1600 Coupes above VIN 90000 appear also to use body numbers from the Roadster sequence.
- The Body Number range column in the table represents the block of numbers allocated for the indicated VIN range, not necessarily the lowest and highest number actually observed.
I hope that this helps NAMGAR members establish more certainty on their MGA serial numbers, and on engine or body originality. The above analysis was conducted without regard for any existing factory documentation of the process, or the remembrances of former Abingdon workers.
Author’s postscript:
Almost 20 years have past since I researched and penned this article. In that time, I have talked with people who were familiar with the way the MGAs were assembled in Abingdon – and they have more or less confirmed my mental picture of a “room full of engines,” and the next-to-be-installed was whichever one was “closest to the door.” Even with the large sample base now available, we are left with the unavoidable conclusion: Given one or even two of the MGA serial numbers will not lead you definitively to the third. Sorry…
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Reader Comments (10)
on June 1, 2011 4:19pm
on August 6, 2011 1:52pm
VIN (Serial) 26535 (HMK4326535)
Engine 16666 (BP15GB16666)
Body 32104
Based on the tables in this article, seems right. The difference between engine and VIN is 9869 which falls in the proper 9900 range
VIN/Body fall into the proper range as well. Hmmmmmmmm.
A 1957 1500 coupe in red enamel for North American export. I would be curious as to the approximate build date, etc. I believe I have all of the ownership info as I am the third owner.
on August 13, 2011 12:30pm
I have seen the shortened version (54586) as well as engine numbers used as Vin. Those who don't know any of their car numbers worry me. It appears that officialdom doesn't know or care what identifies an antique car as long as it is consistent when the title transfers.
on August 31, 2011 2:17pm
on March 20, 2012 2:43pm
on March 20, 2012 3:35pm
Glad to help sort that out. Suggest you tell me where the car is listed, the assumed VIN (and what is on the title), and why the owner/seller doesn't have the correct information. Sometimes during a restoration the original tag is lost or misread. My car has a new tag and the VIN was off by one digit.
on March 20, 2012 4:55pm
The car was sold at January's Barrett-Jackson and was listed afterwards on eBay (#250991828566) but I was in process of purchasing it directly from the Seattle dealer. As you can see in one of the pics, the VIN number is on a new plate and reads HDR43/57801. From reading the Original MGA book, this would mean that the VIN on the car is for a convertible 1500, not what is clearly a 1600 Coupe. From research I have done, evidently the factory did not keep track of engine and frame numbers, so all I have is an incorrect VIN and an unknown proper VIN. The car was also sold in 2001 by Barrett-Jackson with the same incorrect VIN. My assumption is that during restoration, maybe they didn't have a VIN for the car and used one from another car that was beyond restoration.
I hope to find out what engine is in the car this afternoon, but that won't help me in importing the car into Canada with an incorrect VIN. The car is titled as a 1959 MGA 2 Door, but our auto registry/insurance check the VIN to make sure that it is correct. I have a coupe, not a convertible. Even though the car is almost blemish free, with only 2300 miles since restoration, I may have to walk away, assuming the company refunds what I have already paid.
on March 20, 2012 5:27pm
I am unclear what you have or what you want and Canada complicates that. I don't think the sales history makes a difference.
Dave Pyle • .(JavaScript must be enabled to view this email address)
on March 20, 2012 7:42pm
The original VIN/chassis number is also stamped into the chassis on the metal strap between the tunnel and the chassis rail, in front of the passenger's seat. However, it is very difficult to see, and rusts out in old cars. Check out the exact location by going to http://www.mgaguru.com.
We live in South Surrey and have a 56 roadster and a 58 coupe, so will email you directly our phone number in case we can help you in any way. You could also speak to ICBC and/or CBSA explaining your dilema, and maybe they can advise you what you need to do. BMHIT can only give you info if they have the correct chassis number.
Good luck, Peter and Anne.
on April 8, 2012 6:31pm
Having already tried without success with Speed, I am wondering if there is anyone out there that recorded the sale of a deep red 1959 MGA 1600 Coupe at the 2012 Barrett-Jackson Scottsdale auction in January? I didn't know it at the time, but that is the car that I ended up buying (at a reduced price). If you know of anyone who did record this, or knows how I could obtain this video clip, I would be very interested in obtaining a copy for memory's sake, and also to see if there was any mention of VIN codes and matching numbers.
Many thanks, Sarah.