An elegant limousine with an avant-garde Diesel engine.
A diesel for the Rover SD1. At British Leyland this was suggested for years and as well
the public called for it. Yet caution had to be taken: to simply put any diesel engine in the gorgeous
limousine would ruin the image of the Rover brand as a distinguished, innovative and avant-garde car
For Rover a compromise like a petrol engine with diesel-like fuel consumption and accompanying
performance or a tuned conventional diesel engine with slightly more BHP was out of the question.
Rover had to find themselves a worthy diesel, in fact a super diesel.
Therefore Rover started investigating their options and in the end they chose an engine built by VM,
an Italian company of the Iri-Finmeccanica group. At VM they found a very modern design diesel engine,
built for using a turbo compressor. It was as robust as a traditional diesel but light and powerful
enough to resemble a normal petrol engine.
Under these conditions the cooperation between Rover and VM, between elegance and reliability,
between aerodynamics and avant-garde technology, was simply unavoidable.
The 2400 SD Turbo is the sprout of this rare marriage.
This extraordinary car didn't go unnoticed by the public. Everyone that had anticipated the Rover
diesel was rewarded even better than their expectations. Space, luxury that was the same as on the
2600 S and reliability fully met Rover standards.
This same can be said for the vehicle in general. The decision for a diesel engine was no pretext that
a large elegant limousine can drive cheaper as well. The 2400 SD Turbo is now generally seen as the
most modern diesel of its time, a real alternative for a petrol engine car instead of a sorry excuse
The choice for the VM-engine combined with the aero dynamical and well built car leads to
good performance, not only in the field of fuel consumption. 6 Litres of diesel suffice for driving
65 miles at a constant speed of 60 mph. Moreover the car performed very well on the field of speed
and acceleration. With its top speed of 165 km/h it was the fastest diesel of its time and it could
drive a kilometre from standing still in 37,7 seconds.
A real European cooperation.
The Rover 2400 SD Turbo evolved from a cooperation of two large companies in the field of car manufacturing, one
English and the other Italian.
The cars were built in Cowley, close to Oxford, where the engines came from the VM factory in Cento, Ferrara Italy.
This engineering collaboration between Rover and VM was a real step forward in the striving towards close European
The Italian heart of the Rover diesel.
Its type name is'HR 492 HT'.
It is a turbo diesel engine, which VM built for the five door Rover SD1.
The abbreviation stands for the following:
HR means High Revolution,
a 92 mm bore,
H stands for water cooling
and the T for the turbo.
VM started work on the HR engine series just after the Kippur-crisis with the objection to find a modern answer
to energy problems. Lots of investigations and attempts were carried out in this time, both for petrol engines as
for diesel ones, all with the same goal of reducing fuel consumption.
The HR engine was in fact the first where this modern technology was put to use.
Other achievements have been acquired against nature's natural drawbacks of the heavy sturdy diesel.
In some cases a clever but simple conversion of a petrol engine was realised but much more was attempted to
improve diesel performance by applying turbo compressors.
With the HR engine VM had set very ambitious goals:
a diesel of the newest generation, which was designed for use with a turbo from the initial design.
A very robust design that was built according to industrial stationery engine production tolerances, cutting edge
design solutions which should lower the traditional engine weight close to that of a petrol engine and patented
innovations decreasing engine vibration and silencing the dreadful diesel sound.
The HR series consists of 3, 4, 5 and 6 cylinder engines, each in two capacity versions of either 500 or 600 cc
In total the series consists of 8 engines with indirect injection using a Ricardo Comet V pre-chamber.
The engine used in the Rover is a four cylinder with 600 cc per cylinder, making a total capacity of 2393 cc.
The common denominator or the HR engines is their modular structure. All engines have been designed as multiples
of each other.
A tunnel in the direction of reducing energy consumption.
Two further important characteristics of the HR engine are the tunnel shaped block and the separated cylinder
heads. The block is built entirely from cast iron, in which a tunnel for the crankshaft is left open.
The usual main bearing caps that support the crankshaft are integrated in the engine block.
In the direction of the sump the engine has five barriers in between each cylinder. Through these barriers runs
one single tunnel in which the crankshaft is built in. The crankshaft in its turn is supported by five strong
aluminium main bearings. These bearings are in no way connected to the tunnel. With the engine running the
expansion of the aluminium being three times greater than that of steel presses the bearing tightly to the block.
And that's not all that happens. The thick layer of aluminium between the crankshaft and the iron block is a
perfect 'sandwich panel' to reduce engine vibrations and noise. The barriers mentioned earlier run into the
oil in the sump muffle vibrations effectively and add greatly to the stiffness of the block.
The cylinder heads are made of aluminium and are fully separated. They are absolutely identical and
interchangeable pieces. This makes them harder to produce but is a key factor in making a strong reliable engine.
The greatest problems with this engine were deformation of the cylinder heads and their seals.
To attach the heads to the block the way of greatest freedom was chosen: every single cylinder head can expand in
every direction, without raising pressure on the cylinder block and expand separately from the other cylinder heads.
The result being a diesel engine that will pass any heat/stress test without problems. It should be noted here
that during heating up the difference in expansion between a single cylinder head and the head of the cylinder
block exceeds 1 millimetre!
Designed for a turbo.
When the use of a turbo is already taken in to account in the early stages of the engine design there will be
no limitations in performance. Any limitation will be merely caused by cost issues. If on a lean burn engine
performance is pushed with a turbo this will lead to a mixture getting leaner with about 10-15%.
On a petrol engine this will eventually lead to detonation effects and bad efficiency, yet on a diesel engine
the turbo only brings advantages with it. Fuel consumption, emissions, cylinder head temperature, performance and
even cycle life will benefit. But only, and this must be made very clear, when the use of a turbo was taken
into account in the design of the engine.
In the case of the Rover engine the surplus of air reaches 0,85 bar, i.e. per cylinder 85% more air is sucked in
as on an atmospheric engine. If the heating of the intake air in the turbo is taken into account, the surplus will
be around 60%. Yet the increase in fuel flow is limited by 30%. Fuel therefore burns with a surplus of air,
which in the case of a diesel engine lowers burning temperature, and improves fuel consumption and emissions.
Increase in performance is 45% and is purely powered by exhaust gasses. The applied KKK turbo compressor K24
extracts some 12 BHP from the gasses.
Further advantages of a properly designed lean burn engine are further reduction in engine noise, both at air
intake as at the exhaust manifold, a reduction of heat stresses in the cylinder, which is a critical issue on most
diesel engines, and equal performance at altitude differences.
Tip of the Iceberg
Five months after the show (Turin 1982) at which river announced the
fitting of the Italian built and designed VM turbo diesel to the SD1 may seem a little late for the announcement of
the first "modern"British made car diesel.
The Perkins "Iceberg"is a turbocharged diesel adaptation of the 3.5 litre aluminium alloy Rover V8 petrol engine, a
joint development between Perkins Engines Ltd and Land Rover Ltd, which will start production on the Rover V8 petrol
engine building line at Acocks Green next September, to provide diesel power fot the Land Rover and Range Rover.
First discussed three years ago, the project was originally conceived by Perkins as the diesel for the Rover 3500
The started "speculative work"off their own bat, kept prodding BL but increasingly found that it was Land Rover/Range
Rover who were their most enthusiastic listeneners. The V8 line at Solihull has never been by any means fully occupied,
so Land Rover Ltd. who control the engine plant had spare capicity in plenty to build a diesel alongside the petrol
unit. Design work proper started 18 months ago, and the legal agreement between the two companies was drawn up Spring 1983.
The arrangement leaves Perkins, who provided the design know how and entire development, whith World marketing
rights; they can sell the Iceberg to anybody other than another four wheel drive manufacturer, when the agreement of
Land Rover must be obtained. Perkins have the option to build the engine at their huge Peterborough factory
(claimed to be the worlds's largest diesel plant), but expect (and would prefer) to do without, either buying
"core engines"(unfinished ones) for finishing and fitting themselves, or simply buying the entire unit.
Their reluctance is understandable;
Peterborough is a high volume factory, and this engine isn't a true high volume one.
The Iceberg is the first of three projects (the name is a project code, which unusually for Perkins has stuck -
as a production unit.
It would be called the TV8.215 - Turbo V8 cylinder 215 cu inch ) Perkins, who since 1959 have been a wholly owned
subsidiary of one of their customers, Massey Ferguson of Canada, decided some time ago that they needed to broaden
their market by launching into the small high speed diesel market.
An advanced direct injection engine suitable for cars was planned and prototypes were built, but particularly in
Britain, with its trditional reluctance to go diesel, and a car market in full recession, no one bit.
However, Perkins realised the obvious - that the recession means spare production capacity amongst the major car
makers, which given collaboration like the Iceberg plan would provide the lower cost manufacturing of the car firm to
make the Perkins designed diesel.
The Iceberg is the first of two such benevolently cuckoo like projects form Perkins.
The second was the recent announcement of a joint venture with Chrysler in North America to dieselize a range of
2.2 to 3.7 litre Chrysler car petrol engines, using a mothballed Chrysler factory to produce them.