BRITISH LEYLAND CAR LIMITED

THE TRIUMPH ROVER DEVISION

Special development nr.1 and the 'new' inline 2300 - 2600 engine

In this article we have some special attention for the developments and the completion of a new source of power within a distressed company in which the SD1 project can't be escaped from.
Britisch Leyland, formed in 1968, had from the beginning about eight different six cylinder engines. Used in several brands within the British Leyland company for instance in the: Austin / Wolseley / Healey / Jaguar / MG / Rover / Triumph / Princess.

Early sixties where exciting for the Standard Triumph, as the Triumph was called those days. The Vanguard Six was dated and ready to be replaced. Ford and Vauxhall where the leading companies those days. In the top range of car manufacturing starting with the Humber Hawk and for instance the Jaguar-Daimler had Triumph no influence at all. But within the philosophies of Leyland's, Standard Triumph new owner was a gap within the two categories. And that gap was filled in on the Earls Court Motor Show of 1963 with the new Triumph 2000 with a six cylinder engine with overhead camshaft after which the struggle with basically the Rover 2000 started: the P6 original model with a 4 cylinder engine with overhead camshaft.

The spacious six cylinder saloons where common used cars in the '70's, sales and the struggle ended at the same time in 1977. Until than it was the Rover 3500 (P6) with the V8 engine who struggled against the Triumph 2500 TC with the 6 cylinder overhead camshaft. The slightly more expensive and technically more complex Rover was a better buy on the market but against all expectations the Triumph won the struggle, although it was not easy.

The Rover technicians where busy back in 1969 with a new project, the P8. The prototype of this car's front has lot of similarity with the P6 with the same double headlights and a side view, which might have looked a bit like a SD1, but someone without car knowledge would have said that there was a new Jaguar born. And so that is what they thought at Jaguar as well!

Rover and Jaguar where within the same British Leyland company revivals but the Jaguar people had a lot of influence. Because of this internal politics the P8 project was changed into the P10. This model would be slightly smaller. The idea was to supply the P8 with a V8 of 3.5 and 4.4 litre engine.

Also the design of this car the P10 project was failed in 1971 due to a bad function of the British Leyland Company where Triumph was called in to help. The now called "Rover - Triumph Division" went on with a combined project under supervision of British Leyland.
The project was called RT1 and placed on to the market as both Rover and Triumph cars. Triumph and Rover engineers where put together in as one division the "Special Development'. The engineers of these older of old strong competitive companies may now join each other in a project what in April 1971 was called SD1; this was to stimulate the cooperation.
The name was almost as if it needed to be this way but was never used in any advertisement, the company commercials or the final project.

The engine bays where created so big that apart from the on the drawing board designs of the six cylinder engine also the already alloy V8 could be used. This first called "Six-inline" was used in the Rover 2300 and the 2600. The final design was completely new and had several different interesting characteristics. The only difference between the 2300 and the 2600 was a shorter stroke and smaller bore and a little difference in the carburettor where for instance an other type of needle was used.

So there was a new type of engine available but it was within an inch or we where driving around in a SD1 with a rebuilt Triumph engine from 1952. And this final achievement wasn't without a blow.

The 'new' 2300-2600 in-line engine

Happily the new 'Rover' engine was not to be developed by the former BMC (British Motor Corporation) division that was located in Longbridge. And now there might be a change that it would be a modern design. However, British Leyland decides that the existing Triumph OHV (overhead valve) engine could be the base.
Introduced in 1968, was a small 6-cylinder version of the Standard 8 (1952), an overhead valve engine with long stroke and small bore. This power source was used in the TR2000 / 2500TC, the GT6 and the Vitesse.

So it was clear that the Triumph engineers and not the Rover ones where responsible for the development of the new engine.
The engine was developed with overhead camshaft, but around 1972 these new components where so isolated that they desided not to use the exhisting components any longer. The basics of the engine would now be based on the knowledge with the developments over the years with the OHC (overhead cam) engine from the Triumph Dolomite Sprint.
The only thing that they needed to be sure of was that the engine should fit into the engine bay of the Triumph 2000 and 2500TC. And must also be manufactured within the Triumph assembling line; the precautions of the size of the engine where done probably to keep the costs low and safe time.

It won't surprise you, but in the end the decision was made that is was not necessary to develop the engine at the exhisting production line so the final model could be made some bigger after all. The only thing was that is still needed to fit in the engine bay of the Triumph.
At the end of 1972 an other decision was made: shorten the height of the engine block just a little so the connection rods of the TR Dolomite sprint could be used. This was probably not done because of love of ease but due to financial problems of the company.

Left: one of the latest of the Triumph Dolomite Sprint, which was built until 1977. The concept P8 (photo 3) shows a lot of influence on the front of this car.

Many of the experiments and developments of the "valve management" were in this stadium already done.
Early 1973 there was decided that the new Rover SD1 model, once ready for production, would be the new replacement for the TR 2000 / 2500 and the Rover P6.

This meant again that the new engine should not fit into the engine bay of the Triumph and therefore could be set up even bigger for the new Rover that was originally designed with a V8 in mind.
The engineers had the time and space to solve the final problems with the engine. This includes lubrication of the bearings, crankshaft and the pistons. The pistons where not able to cope with the high temperatures and the solution was found to inject the oil directly into the pistons by a small hole in every connection rod. This meant that also the Dolomite connection rods where un useful and you could speak of an "unique" concept of engine where now other part was used in any other BL engine. A laborious battle was ended.

Now it was 1974, the World was hit by an oil crisis, and thrift with energy had the highest priority. After some adjustments on the camshaft and the "valve timing" the fuel consumption of the six cylinders was improved. With a proper adjusted engine and similar driving you could get a fuel consumption of 1/12 litres on the high ways. But you can also imagine that this "detuning" has nothing to do with the oil crisis but more with the fact that the new 6 cylinder could easily produce the same amount of power as the dated 3500 V8. If this happened the top model would be sold less. If they could switch to "this time" than it would be a reasonable decision to get ride of the V8 and built a 2600 injection system with approx. 180 BHP beside the normal 2600.

The 2600 were reliable and produced around 150 BHP (133 Pk). And this was still very near the power of a 3500 V8 with 155 BHP.

The power engine with visible camshaft, which controlled on the inlet valve's (not visible) and the rockers. These rockers controlled the outlet valves.

The new engines where ready for production and where built into the same body of the Rover 3500 (SD1) which was built a year before. The smaller six cylinders the Rover 2300 was brought onto the market, half a year after the 2600. The name "Triumph" was removed from the scene with this car even as the Rover P6. It was the intention to built over 1600 engines a week at the "Canley" factory. But this was because the thought the engine would also find it's way into other British Leyland cars as well. However in no other car of the BL Company the engine was ever built. The production went on until May 1986 when the SD1 ended.

The Result

In 1977 the SD1 was chosen to be the car of the year and many distinction where won: so the SD1 won a golden medal for the stylish and aerodynamic design. By using all kinds of safety aspects who where a head of it's time the car won the "Don Safety Award". The first model the 3500 was chosen as "Tow Car of the Year" with a CI distinction, which stand for "Caravans International"; this because of its power and the self-levelling shock absorbers. The 2600S has also these same self-levelling shock absorbers.

Before the SD1 production finally ended where there a lot of different type of car's of the SD1 around the world. Basic-kids where supplied from the UK and where equipped with other power units and power lines. The South African SD and SDX models used the over developed 2.6 litre engine which was originally belong to the British Leyland Princess 2200. In India it was the standard 2000 that used a modification of the gearbox of the old Standard Vanguard. These models where called completely knocked down (CKD). None of these models is ever supplied in the UK.

PRODUCTION

Built Rovers SD1 1977-1987

Four cylinder 2000 20.554
2400SD Turbo Diesel 10.081
Six cylinder 2300/2600S 42.996
2600/2600S-family 108.572
Eight cylinder 3500/3500SE/3500VDP 107.916
V8-S 1.040
Vitesse 3.897
VDP EFi 1.113
Total: 296.169

Together with the overseas car's; "CKD" the total of SD1's built is 305.129 cars in 10 years!

Note: A complete story of the concept car the P8/P10 and documentation can be read in the "Rover SD1' 'The complete story" of Karen Pender.
The photographs of Dutch cars (license plate) used in this article are used with permission of the owners.
To write this article several sources are used for both English as Dutch magazines with one common goal to create a story that covers the cooperation between two major car brands and the design of the Rover SD1 2600 engine.

Written by

Kasper Karssen