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See Homepage. This page: Rubber-bumper US-specification MGB reg. RBW 486T used for development by British Leyland in the 1970s.
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MGB development car No.6 (RBW 486T).


A number of MGBs were put to one side by MG/British Leyland for use by test and development engineers during the 1970s for various reasons. Some were used to trial alternative engine installations beneath the B's bonnet, a handful were fitted with the "O" Series engine for example. Others were used to trial fuel injection systems. Both options were considered in a bid to improve the B's "smog" emissions for the all-important US market, at a time when regulations relating to vehicle emissions were ramping up quickly. The MGB's engine could trace its root back to the 1950s, and it was becoming increasingly difficult to encourage the ageing all-iron 1.8 litre engine to comply with anti-smog requirements of the 1970s. As far as I can tell, this car has always been fitted with the original B-Series unit, built to LHD Federal (US) specifications as it was initially destined to head Stateside, before being diverted to Gaydon for testing.
This car, known as development car No.6 by MG/British Leyland engineers, appeared for sale a while ago and I was able to buy it, its history and accompanying documentation from its early activities behind the scenes at B.L. making it of particular interest. This page is being posted here in the hope that more information regarding the tests that it was put to, might emerge over time.
The MGB Roadster as found
The MGB "as found", dusty, non-running, but complete. The cardboard boxes on the left contained a new hood, and the original smog-spec single Stromberg carburation setup fitted to the car. At some point this had been removed, to be replaced by UK-spec twin SUs. The remainder though is US-specification MGB, including the triple windscreen wiper arrangement, extra marker lights on the wings, the comedic ride height, and slightly different interior - of which more anon.
Since December 1977 it's covered just over 18,000 miles, the first 14k of which were during its time as a development vehicle, as confirmed by the factory documents that (happily) remain with the car to this day. No doubt a fair percentage of this 14k was on rolling roads. Not all the work done by this Brooklands Green Roadster, or Tourer as it's referred to on the build plate and card, was emissions related, as will be described further down this page. After its time with B.L., it passed to a retiring finance director, who used it infrequently over a number of years during the 1980s, the road fund licence (tax) expiring in October of 1989.
Collection day for the non-running 1977 Roadster
The 1977 hood covering has seen better days, hence the new one that was included in the sale. The remainder though is pretty good. This view shows the slightly different rear lamp lenses that were fitted to American-spec MGBs. The numberplates are later replacements - fortunately the original metal plates were retained, and will be re-fitted to the car.
Having seen little use, and dry storage for all of its life, the bodywork is mostly like-new, although the paint has picked up numerous blemishes. Someone has also daubed spots of primer here and there, perhaps in a bid to halt mild corrosion spots from getting any worse. A little paint rectification will be required at some point, although I hope that the majority of the paint can be preserved, with the new areas blended in successfully to match the original. For the timebeing I hope to get it into running and driveable condition again, and continue the research into its past.

Accompanying documentation from the 1970s.

MG documentation

Build card.

Vehicles with an interesting past really appeal to me. RBW 486T has a small but fascinating collection of paperwork with it, which shed light on the roles that it was put to. I wonder how many B's still have the original build card with them? As far as I know they didn't usually make it beyond the factory gates. I believe that the information from these cards was put onto microfiche by the factory (maybe forming the basis of information that's now available on Heritage Certificates?). The chassis number has been partially obscured in these scans. Notes in a journal confirm that the B was removed from the Abingdon production line, as paint rectification work was required to the offside B-post area. This may well explain how the car came to be retained for test work. What does "Orlean" refer to on the build card - the shipping destination in the US (New Orleans) perhaps? The remainder of the information is self-explanatory.
MGB Roadster build card


The MG was built in December 1977, and was used throughout 1978 (and later) for various testing duties. It's documented as being a "1979 Model Year Reference Car". Curiously, it was only actually road-registered in November of 1978, presumably prior to that date it was driven around on a trade plate. The old V5 confirms that Mr Hoare, the former finance director who took over ownership of the car once its duties had come to an end, was the third registered owner (1986 onwards). Prior to him, the previous keeper is recorded as BL Cars Ltd, Central Administration 017607, Company Vehicles, Sales Block, Longbridge, Birmingham, B31 2TB. It passed to BL Cars Ltd on 15th December 1980, presumably once MG had finished with it. I'd be interested to find out who the first registered keeper was documented as with DVLA - MG itself? I'm hoping that a V888 enquiry with DVLA will provide the answer.

Leyland Cars Service.

The Leyland Cars Passport to Service survives, although was only filled out for the 1,000 mile service. This was signed-off by R. Lyne, on 7th April 1978. Does anyone know who R. Lyne was/is? A number of names appear within this car's history file, if anyone can provide more information on these people, I'd very much like to hear.

Test journal.

Journal of testing role with MG Cars
The most interesting item of paperwork by a long chalk though is a journal that records the life of the car while on development duties at Gaydon, between December 1977 and December 1980.
For example, it confirms that at the time of the aforementioned 1,000 mile service (7th April 1978, Castrol GTX used), a special exhaust system was fitted for noise trials purposes (again signed off by R. Lyne). Three days later it was taken to Enstone (?) for the noise tests to be undertaken. On the 14th April the car returned to base (with its mileage now at 1,108), at which point the standard exhaust system was re-fitted. Mr D. Swanborough signed off this job. A few days later the MGB was driven to MIRA (the Motor Industry Research Association, near Nuneaton) for dynamometer tests, during which time 220 miles were added to the odometer.
Sample page view from 1978
There are pages and pages of notes like this. They'll be typed up and added to this section of the site shortly. Again I'd very much like to hear from anyone who may remember working on this car, or has experience of performing these tests at this time.

Federal specification MGB.

As the build card shows, the B was built to Federal specification. Visual giveaways are the wiper arrangements, the LHD steering, a (to my eyes anyway) much improved dashboard layout, altered seat coverings (compared to UK cars), and the side marker lights fitted to all four wings. The very high ride height - higher even than UK rubber-bumper cars I believe - is another clue that this car was originally destined to spend its life in America. Under the bonnet, smog equipment accompanied the fitment of a single Stromberg carburettor.

Non-standard features.

The plan it to preserve the car as-is, with rectification work undertaken only where necessary. Quirks will be left in place. The accelerator pedal for instance, has been modified at some point, with an extra piece welded onto it. The bonnet release catch has also been cobbled together slightly. Inside the glovebox lid, there is a scrap of masking tape stuck inside, on which a few notes regarding catalyst tests have been scrawled. Obviously that'll be retained, as will the remains of an old "Austin Rover" sticker on the windscreen, which may just post-date the car's testing life (ARG was formed in 1981).
Inside the glovebox lid
One, I think, pretty ghastly alteration to the car is the installation of a Rover SD1 steering wheel (someone pointed out that the early Range Rover also had a fairly similar wheel). In what's supposed to be a sporty car, it looks very out of place. Fortunately, despite the improved driver safety that I'm sure it offered, it was never adopted into production Bs. Equally fortunate in my opinion, is that no-one decided to remove it and file it in a bin. A journal entry dated 19th January 1979 reads as follows:
Speedo 2246 [miles]. Special 14" steering wheel with large dia 'soft' rim fitted, [signed by] A. Moon.
Rover SD1 steering wheel in the MGB
Despite its appearance in the otherwise good-looking cabin, the wheel will remain in-situ (as a documented nod to its past, and also a conversation piece!).

Re-commissioning work planned.

As of now, the car is on stands in my garage, with all the wheels removed. A number of fuel pipes have been replaced, and currently the replacement SU HIF 4 carbs are on the bench. I'm awaiting a new set of needle valves as the originals are gummed up, plus the float chambers need a good clean. I've had it running briefly with a squirt of fuel into each carb, so I don't think it'll take long to get it running. The clutch appears to be stuck with having stood for years.
After its time spent at MG and later BL Cars Ltd, it passed to the former Company Secretary of BL as has been mentioned. He, Mr Hoare, used it infrequently until 1989 when it was taken off the road and put away. I wrote to Mr Hoare. He advised that in addition to his roles within British Leyland, he was also the Secretary for the BMIHT, or British Motor Industry Heritage Trust, which is how he became the car's conservator. Interestingly, he mentions that on his taking possession of the car, the footwells and boot areas were "liberally strewn with sand". Was this as a result of a specific test?

Current condition.

In the main, the steel bodywork has survived well. There are a few small bits of corrosion low down on the n/s/r wing which will need attention, but that's all bar stonechips and marks here and there. The top of the passenger door will need re-painting, as will a few odd places here and there. The underside needs a clean and a wipe over with something oily, but no welding that I can see. The engine bay wants some localised touching-up of the paint, where fuel has leaked in the past, but is sound. The footwells, sills, inner wings, castle sections and so on are fine, which is a bonus.


MGBs are plentiful even all these years after production ended, so there's no need for too many photos, just a few to show its current condition. The engine bay still shows some of the emissions equipment that was originally fitted.
Nearside rear view
Engine view
Underside photo 1
Underside photo 2

Research ongoing.

I'd love to hear from anyone who remembers this car, or who worked at Abingdon and/or Gaydon in the late 1970s on test work. The journal starts at page 12 in the notebook, and beneath the label on the cover, and inside, there are covered-over references to another car - No.4 and also No.9 - one of which appears to have been a Citron yellow Roadster, from 1973. Did my green No.6 replace the yellow car, No. 4 or No. 9, which would have been a chrome bumper model? Without peeling off the masking tape from the journal, on which my car's details have been entered, I can't be sure of what is written below. All advice welcome.

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