The Bentley Burma was an interesting six-cylinder saloon borne from BMC’s short-lived Joint Venture with the Rolls-Royce Group.
It was to have been the company’s first monocoque production car, but fell at the final hurdle before being pulled off the shelf by BMC. Site contributor Nate M tells the story.
Bentley Burma: the missing link
This article sets out to expand more on the background of the intriguing Bentley Burma. The main question it answers is where did the Burma-based ADO58 project stand in relation to Rolls-Royce’s prototypes for what became the Silver Shadow and Bentley T-Series, as well as the collaboration between BMC and Rolls-Royce in general?
The original intention of Rolls-Royce was to develop a range of vehicles around an all-new monocoque. They would all feature very different exterior styling to separate the models. The first was the Rolls-Royce Tibet and, from it, a Bentley version known as the Borneo with revised frontal treatment, was developed.
It was based on a 126-inch wheelbase, and a longer 130-inch version was also being projected. Power was to come from the upcoming V8 that would end up being used in the Shadow and T-Series. The project would be cancelled in 1962 after many prototypes were built (each with progressively improved exterior styling), and not before countless development miles had been covered.
From the Tibet came the Burma
But back to the new-world model plan, and a second member of Rolls-Royce’s planned new range was the Bentley Burma. It was was based on the Tibet and had 6.5 inches removed from a wheelbase for a sportier look. The Burma was initially planned to be equipped with the 3909cc FB60 six-cylinder as used in the Vanden Plas 4-Litre R – but the plan was soon abandoned in favour of the 6230cc V8 that was currently in development.
There was good reason for this – it was an imposing car, and while the former was rated at 175bhp and 218lb ft, it was considered weak compared with the unstressed V8’s net outputs of 183bhp and 258lb ft of torque.
As the Burma’s development progressed, a Rolls-Royce version of the shorter wheel-based car was also investigated and given the name Tonga. However, it did not progress beyond the drawing broad and was cancelled.
The Bentley Korea Coupe
The third member of the planned range was the shortened V8 powered two-door continental sports saloon called the Bentley Korea (above). It was based on a wheelbase of 113.5 inches, and was conceived as a replacement for the beautiful Continental models.
It originally looked quite traditional, almost Alvis-like, but that look was soon evolved into something much more radical. Progressive developments to Korea Mk2 onwards (below) included significantly more modern styling than the earlier Korea Mk1 (above).
It was penned by a Norwegian, Vilhelm Koren, while working at Park Ward for an interesting and quite daring overall style. The Mk2 was joined by a short-tailed scale model for Korea Mk3, which featured another 3.0-inch reduction in wheelbase.
A single prototype was built, which was clocked reaching a top speed of 133mph while covering a standing quarter mile time of 17.1 seconds. Impressive compared with what it was competing against – and it seems a shame that the project was axed due to being seen as too modern, not traditional enough and too expensive to manufacture.
Clearly, the Korea Mk3 (below) was too much, too soon.
Rationalistion into one project
Eventually, these projects were all cancelled and development was streamlined into one all-encompassing programme known as the SY. This car would eventually emerge as the Rolls-Royce Silver Shadow (below) and Bentley T-Series, and combined the best features of the Tibet Mk2 – its looks being much improved over the first Tibet.
Developing the three Burma prototypes into production would have incurred huge costs, and rationalisation was the name of the game here. This was a time when when finances were tightening, and it soon became clear the once proudly different Bentley would end up being little more than a badged-engineered Rolls-Royce.
However, in essence, the SY was based on the Bentley Burma, and its Rolls-Royce Tonga spin-off, which carried over the wheelbase and some body panels of Burma. It also used the V8 engine from Tibet, and underwent significant styling changes to ease the commonality between the Bentley and Rolls-Royce versions.
BMC converts Burma into ADO58
In 1962, and after all the Burma-based projects were cancelled, one prototype weighing 1803kg was later dismantled and sent to BMC to be converted into an ADO58 prototype. BMC’s version was basically a toned-down Burma with revised front and rear styling.
It was planned that the ADO58 was to be produced exclusively by BMC under one of its upmarket brands such as Riley, Wolseley or Vanden Plas (probably the latter). The possible intention was that it would replace the aging D-Series Vanden Plas Princess limousine.
Unlike the Burma, it would retain the FB60 engine and would perform adequately through a weight reduction programme to take 115kg out of the package. BMC was possibly warned beforehand that the FB60 engine was underpowered in the Burma (the similarly-powered Vanden Plas Princess 4-Litre R, below, weighed 1575kg). It ran as the ADO58 in 1962, although only survived for four weeks before the plug was pulled.
A sporting postscript?
After its takeover of Jaguar, BMC lost interest in collaborating with Rolls-Royce, although not before the latter came up with a twin-cam version of the FB60 engine, known as the G60.
Designed for the ADO30 – later ADO24 or Austin-Healey 4000 Mk4 (TNX 65G) – and sharing little in common with the FB60, the G60 was offered to BMC in 200, 225 and 240bhp states of tune. It was also capable of around 268bhp on triple SUs, matching the Jaguar E-type with further potential for an easy 300bhp.
In contrast, the FB60 was quoted as having an output of 175bhp though Geoff Healey reckoned the automatic transmission sapped about 15bhp when fitted to the Austin-Healey 4000 Mk4. which was created as a vehicle to put surplus FB60 engines into after BMC had committed to buying significant quantities for the commercially unsuccessful Vanden Plas Princess 4-Litre R (above).
All ties cut
However, the 4000 project was cancelled when Rolls-Royce suspected BMC would not be taking its full allocation of engines. It also had little faith in the ADO30 amounting to anything, and got rid of a lot of tooling as a consequence.
The net result of that was certain critical castings would no longer be available, and Rolls-Royce would no longer be in a position to start immediate production of the engine for the 4000.
BMC was running out of money by this point anyway, and decided not to bother contracting Rolls-Royce for an additional 2500 engines. The situation wasn’t helped by Rolls-Royce informing BMC that, if it wanted additional engines, there would be additional expenditure to replace that tooling.
In short, the promising Joint Venture ended not with a bang, but a rather disinterested sigh…
- Written with reference to Malcom Bobbitt’s ‘Rolls-Royce Silver Shadow/Bentley T-Series, Camargue & Corniche‘ and Ian W. Rimmer’s ‘Rolls-Royce and Bentley Experimental Cars‘.
- In addition, further information has been taken from Jon Pressnell’s ‘Austin-Healey: The Bulldog Breed’ and Karl Ludvigsen’s ‘Bentley Great Eight’.
- Concepts and prototypes : Bentley Burma (1958-1962) - 25 August 2023