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MG MGB Technical - BGT Engine number origin?

I've checked archives and would appreciate help with the meaning/origin of my engine number.
The car is '73 BGT so as I understand it, it has to be UK built; I don't know when it came to Australia. Before I come to the engine number, other engine bay plates are as follows:
Nearside front wing inner : GBD 065197 P
(I think this is Body Number?)

Offside Front wing inner: Austin Morris Group
British Leyland UK Ltd
GHD5 321152 G
(I think this is the Car Number).

Commission No. G23D 066101 Z
(The numbers 066101 are stamped in this plate).

Engine Number: embossed in the plate on the flat plinth on the block: DBL 230 71036 E
(The "E" on this plate is stamped, the rest embossed).

From what I can see in the archives, a '73 BGT would have started with an 18GG engine; mine appears to be an English rebuilt engine, probably using the original block; I haven't been able to look for head identification this weekend as have only just emerged from shoulder surgery.
In the meantime, I would appreciate any advice as to the possible identity or meaning of the Engine number appearing on this plate.

With thanks - John.
J P Hall

Going by Clausager you are correct in your statements about Body, Chassis/car number and Commission number.

However a 73 would have had an 18V engine prefix (since Aug 71) and if to UK spec would have been 18V-581-F-H (no OD), 582 (OD) or 583 (auto) with HS4 carbs. Export other than North America (i.e. could be RHD) would have a Y in place of the H for HIF carbs, and possibly an L in place of the H for Low compression.

This,721390 also has someone with a DBL230 (also a 73 GT!) but no one there had heard of it. B- series engines were used in a many BMC/BL models including the Sherpa van, but DBL isn't listed here or

Does the block carry a date code as described here?
Paul Hunt

Paul, without being able to crawl under cars at present, I'm limited to seeing the casting on the block: 12H3503. There appear to be numbers above that, but will have to wait until I can get at it. Beneath the filter housing, I can't see a stamping such as the "clock" pattern indicating date of casting. What I do notice is that although the block was at some time painted black, traces of the original colour look like a slightly metallic blue or blue/green. I'll provide more info when I can. I would really like to identify the "DBL 230" engine build details - it's interesting that there is at least 1 other '73 B in the UK with the same engine prefix. Regards, John.
J P Hall

12H3503. Well it looks like an 18V. As for paint..........well!!!! It's obviously a re-build, could be Silver seal, i.e., a factory supplied short motor or just A N Other and whatever paint they had lying about!!
Allan Reeling

"at least 1 other '73 B in the UK with the same engine prefix" Ohio USA, it seems, although what difference that would make I don't know. Clausager mentions some funny engine prefixes that have cropped up very occasionally, but not that one.

My date code is visible from above, as in the first two pictures here

Where is the 12H3503? That's harder to see on mine that the date code, but does indicate an 18V as said.
Paul Hunt

Paul, I'll check for date code when my shoulder is a bit more mobile; in the meantime, received an email today from a guy in England suggesting that my block "is same as diesel (same bore/stroke" and that the DBL letters come from "D - diesel; B - B Series, and L - low compression". Also that they were used in something called a Leyland Sherpa, apparently a small van.

Well bugger me, and I thought I was driving a nice peppy MGBGT! I'd be interested in what you and anyone else think of the suggested meaning of DBL. I'd rather the letters came from something more relevant, like Dealer - British - Leyland!

Regards, John.
J P Hall

And a PS - I found a third "DBL 230 *****" engine number, a '72 BGT owned by John Fraioli in Denver, Colorado. So one in Australia (my '73), one in Denver and a third in Cincinatti Ohio. So there must be some history behind the DBL 230 numbers being assigned - but by whom, and from what authority ... the engine builder/installer is not just making these numbers up!

All sleuthing help gratefully received. John.
J P Hall

I forgot to mention the Sherpa, which has been used as a source for MGB petrol engines in the past, as well as Marina, Austin/Morris and Wolseley which have different prefixes. Loads of stuff on Sherpa Diesels by Googling, apparently a huge number of the same engine in marine applications, unfortunately no mention of that prefix. Originally based on the petrol version as it had such a good bottom-end, presumably not much more than a head would be needed to convert it to petrol, subject to compression ratio.

72 was the peak year for MGB engine production, maybe they had to pinch and modify a few Diesel engines to keep up! One wonders if the BMIHT records would show that, but then I'd have expected Clausager to have uncovered them ... unless some got through with the original engine tag.
Paul Hunt

IIRC the 1500 diesel had extra cylinder head studs. I don't know about the 1800.

I've seen a number of 1500 diesel Marinas in Malta. I believe they were locally assembled.
Dave O'Neill 2


The BMC 1800 B series diesel engine is featured in the December 2015 edition of 'Practical Classics' mag. I purchased that on Sunday here in Canberra so might have recently arrived at a newsagent in your local. Might be worth a look.

As Dave mentions, it has three extra head studs over the petrol version. Also the head is flat faced on the diesel but the head must have been changed on your petrol running engine if we are in fact looking at a diesel block number.

I suppose an exchange engine could have been fitted based on the diesel block at any time. I seem to recall that the diesel version was used in tractors as well as applications mentioned above. Perhaps the source here in Oz?

R Taylor


Just had a memory flash, I think the diesel was also used in a marine version. Another possible source.

R Taylor

Hmmm - interesting, innit!

Roger, I'll be chasing Practical Classics, to which I subscribe. It shouldn't be too hard to check the number of head studs or any other clues to see whether I do have an ex-diesel block with presumably a non-original (petrol) head fitted at some time in the past.

I still don't understand where the engine builder got the DBL 230 ***** number from - there must be an origin, for the same letters and numbers to crop up in at least 2 other cars.

But at the end of the day, what I do have is a well performing, ULP compliant engine with which I can find no fault other than the irritation of not having a "correct" engine number.

Thanks to everyone for their input. I'll let this exchange sit in the archives in the hope that one day more light is shed on the DBL 230 series of non-original engine numbers. Regards, John.
J P Hall

Presumably you would have to remove the head, to see the tapped holes for the extra studs, as a petrol head wouldn't have the holes for them.

Many marine applications as mentioned earlier, particularly in UK canal boats. The British Waterways Board used them extensively in their Sherpas as well as water-based vehicles, perhaps an enquiry to canal groups would elicit more info.
Paul Hunt

Here's a 'snip' from my BMC 'Tempest' 1.5 diesel WSM showing the extra studs.

Dave O'Neill 2

A very interesting thread. RAY
rjm RAY

John Hall,
Yes, I have an 1800 B series engine with the ID number of DBL230 E 52802 K Like yours with the E stamped my has the K stamped the others are raised what you called embossed. I did read the tread you started on Jan. 10th Let me correct you a little bit.... Yes, I do own a 1972 MGB-GT but the engine we are speaking about is from my 1979 Inca Yellow mgb roadster. I have a question for you.....What color is the engine in your car painted? Mine still has the original color paint and that color is Blue.....No one has heard of an MGB engine painted Blue....supposedly they only came in Red or Black.

I had to take the engine out of my 1979 MGB (several years ago) because it lost compression with some bad rings. Before sending the block to the machine shop for inspection I took the Engine ID tag off the block. Here is a picture of my ID tag.

Also before I began disassembling the engine I watched a video by a Dr. James Doolin of Canada who has a video detailing how to disassemble an MGB engine. I noticed in the video that the 1800 B series engine that he was working with was also the color Blue. As a coincidence I believe that my 1979 MGB was originally imported into Canada from England when new....I say this because the later model MGBs imported to Canada from England had only one electric radiator cooling fan instead of the two electric fans on the cars imported to the US.

I found Dr Doolin's e-mail address today and I sent him this e-mail below asking for any imput he might have. Like you I have never had any luck finding the origin of this unique engine ID.
Here is a copy of the e-mail I sent Dr. Doolin. I will let you know if I gain any further information.

Dear Dr. Doolin,
I have watched your video and noticed that the engine you use in the video is painted Blue....As far as I know MGB engines only came in the colors of Red or Black. I live in the USA and I purchased a 1979 MGB Roadster in 1993....It has a Blue engine in it which puzzled me.....Also it has a very unorthodox engine ID number....I am quite certain that the engine is not the original one fitted to the car.....but I have no prior history on the car.....I do suspect that the car was originally imported to Canada from England as it only has one electric cooling fan rather than the two that normally come on later model MGBs imported to the US. Do you have any idea what vehicle these Blue 1800cc B series engines were fitted in. Finally the engine ID number that is fitted to the block is DBL230E 52802 K
Any light you can shed on this mysterious engine would be greatly appreciated.
Thank you,
John C. Fraioli
John Fraioli

OK, here is the picture of my engine ID tag that did not upload a few minutes ago.
John Fraioli

John Fraioli

Hi John - great to receive your update and clarification. I just can't believe that the DBL 230 ... engine numbers were allocated randomly - they must have originated somewhere, and as the keepers of 2 of them it behoves us to get to the bottom of it! I reckon this BBS is as good a place as any to put out the call for help with this ... so HEEEEELLLLLLP! Anyone.

As to my engine, the block is now painted black (PO or earlier), but there's clear evidence of what looks to be the original paint : definitely blue, possibly slightly hammered finish and/or slightly metallic. I'll take a photo with my ipad and try to send it as a follow-up.

It will be interesting to see what more we can dig up to better understand the origin of the blocks that our cars appear to have in common.

Regards, John.
J P Hall

For these three engines it would be interesting to see the date code clock - if they have one, not all did, and it seems pretty random over the production of the MGB as to whether they did or not, perhaps different foundries. The attached shows the location of the clocks. If no clock the other numbers by the starter may help.

Paul Hunt

OK, Here is a picture of the date code clock from my block. I don't readily have a picture of the block before it was tanked at the machine shop. The machine shop found a small crack in the block so I did not have it bored. I just brought it home and stored it in the garage and it now has a coat of rust on it. So you can't see how it looked with the original blue paint that it had. According to the date clock I believe it has an "E" on the lower left which I would take it to represent the month of May (fifth letter in the alphabet to correspond to the fifth month) The top number should be the day of the month (13) and the number 5 at the lower right would indicate 1975 I believe. So cast on May 5th 1975. Do I have that right?

John Fraioli

And here are the other numbers on the block. The ones that would be beside the starter.

John Fraioli

OK, I was reading the date code clock wrong.
I guess it is a Pattern "E" Week 13, 1975
And here is a picture of the top of the block to see the number of holes.

John Fraioli

Interesting numbers,

On my 69 roadster the 'clock' reads 8 at top, 68 lower right and 11 lower left which I understand to mean 8th November 1968 ie read counter clockwise.

The numbers at the rear of my block RHS are:

12H1442 AF3

On the LHS of my block are:

1800 MOWOG

Some weeks ago, out of interest in the topic, I searched the net for a reference for the mystery number DBL 230 relating to engine numbers. Like others I found nothing concrete, except AC DELCO (Aus I think) site showed this combination in the Google search results but revealed only a PDF file of engine numbers for their rebuilt replacement engines.

This was, from memory, a 2006 document and contained nothing of engines for the 1800 series era. There must have been something deeper within that site though to cause the shown response to this number. I wonder, could there once have been an AC DELCO replacement engine with this designation - Delco British Leyland (DBL) perhaps? Could also explain the appearance of DBL 230 on two continents.

I've been distracted with other things so did not follow up. Might it be worth someone doing so?

R Taylor

Yes 75 for John and 68 for Roger.

I've not seen enough to determine how high the numbers and letters go, but I lean towards the pattern or mould and week number for the others rather than day and month. It is very common for British manufacturers to mark things with week or fortnight numbers, and as I'm sure many moulds were being used they would want to know which one was the culprit if they started finding bad blocks during machining. But that's insignificant beside the year number.

I've not seen CAM 1628 before, often there are one or 12H numbers. AF numbers are common, but they are not sequential as I've seen AF5 on a 1970 and AF1 on a 75.
Paul Hunt

John, I've found this thread quite fascinating and have been doing a bit of searching on the web and have found some info on this website.

"BMC recons for marine use were metallic blue. They were done at Morris Engines no2 works, Durbar avenue in Coventry. I know this because I had a recon 1622cc for a J4 van once."

"They weren't marinised at the works...they were sent to Leyland recognised firms like Calcutt and Thorneycroft for marinisation - in the case of narrowboats - and others for rivers and sea.

I had a tour of the assembly lines and rest of the works when I picked it up. There were hundreds of them...short engines in Silver and long engines in gold and metallic blue.

Another interesting thing was that they were also sent all over the world"

I've also found the following on this website

There was also a diesel version of this capacity, used in the Leyland Sherpa van, and built under license in Turkey for many years. It is still widely used on narrowboats on the canals of the UK.

•1962–80 MGB
Early numbering system

Numbers were of the style "BP15GB" followed by a serial number, where:
•B = B series engine
•P = Pushrod
•15 = capacity
•G = MG (for full list see Later numbering system below)
•The final letter is the version of the engine.

1957–70 numbering system

Numbers were of the style "15GB-U-H" plus a serial number, where:
•15 = capacity
•G = MG (other letters were: A = Austin, B = Industrial, H = Miscellaneous, J = Commercial, M = Morris, R = Riley, V = Vanden Plas and W = Wolseley )
•B = B series engine
•U = Central gear change (other letters were: A = Automatic, M = Manumatic clutch, N = Column change, O = Overdrive and P = Police)
•H = High compression (alternatively L = Low compression)

So maybe DBL means DIESEL B SERIES L = Industrial use or Low compression?

Andy Robinson

Here is one more photo showing the spot where the engine ID tag would be placed....Now I am pretty certain that this engine DBL 230.... Is a reconditioned engine because you can see two extra holes where the second tag was secured. Also when I brought the block to the machine shop for inspection they told me that the cylinders had previously been bored 30 thousands over.

John Fraioli

Andy - terrific research, thank you. I'd say my block was metallic blue; there appears to be no set of "clock" numbers, just the 12H3503 in the usual place.
So looks like a marine recon block, possibly made in Turkey, back to UK for installation and then the car ended up in Australia. But see my earlier comments - I'm perfectly pleased with the car's performance, notwithstanding the slightly irregular upbringing/pedigree. Regards, John.
J P Hall

I don't know about B-series engines, but 'CAM' part numbers were quite common in A+ engines, as fitted to Metros, Maestros and later Minis.

A couple of examples are CAM4545 - cylinder head nut - and CAM6648 - MG Metro camshaft.

It is possible that late 'B' engines had some similar numbers.

My 1980 car doesn't have its original engine block, so there's probably no point in me checking.
Dave O'Neill 2

Roger Taylor - sorry mate, I read your suggestion about the AC Delco site and, being away from home, forgot to acknowledge it. I don't think my computer skills are quite up to your level, but I'll have a go at following it up! Regards, John.
J P Hall


All good. I think my search term was something like 'DBL 230 AND engine numbers' but perhaps just try direct with 'ACDELCO AND DBL 230'. Happy hunting.

R Taylor

Also, for anyone who is interested, there was a similar question raised by Bryan Matthews of Cincinatti, posted on the MG Experience forum on 28/1/2008 under the heading "What Engine Number is this?". It didn't elicit any definitive responses. Regards, John.
J P Hall

This thread was discussed between 10/01/2016 and 19/02/2016

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