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And one published in the Jaguar Driver for April 1995

Startling Discovery

JUST BEFORE GOING to press for this April edition, SS Jaguar Historian Reg D.
Bates sent me details of a sensational pro-ject that SS cars were working on in 1938,
and which he has just unearthed after years of patient probing. I'm sure you will
agree with me when I say that, if only the factory had had more time and money at
their disposal, this car could have turned out to be the greatest Grand Tourer of the
1930s, and might have altered the whole of Jaguar's post-war engineering direc-
tion. Reg apologises for the quality of the photo, but it almost turned back into dust
as he handled it, and even with modern reproduction equipment that was the best
he could manage. I will let Reg tell the whole story...

The SS Jaguar Straight Eight Coupe by Reg D. Bates
MUCH HAS BEEN written about the SS Jaguar 100 coupe that caused such a sen-
sation at the 1938 Motor Show, but few are aware that this was only a last minute
substitution for the real SS Jaguar Coupe. The real coupe was based on the SS saloon
chassis and was fitted with a straight eight 3.5 litre engine. So far as I know very little
evidence remains of this extravagant folly but with the recent discovery of a section-
al drawing of the engine and what is believed to be the only surviving photo
taken outside the Holbrook Lane works, now seems a good time to revisit it.
It is well known that the 3.5 litre engine was developed from both boring and
stroking the 2.5 but few people know that this engine was built as an emergency
measure because of the development problems with the straight eight. Retain-
ing the same cylinder dimensions as the 1.5 And 2.5 litre engines the straight eight
was created by further lengthening the castings. Pistons, con rods, bearings and
much of the valve gear was taken directly from the parts bins of the smaller engines.
The result was an engine of 3552 cc which was claimed to produce a power output of
140 bhp at 4500 rpm and have a maximum torque of 180 ft. Ibs at 2200 rpm.
The target vehicle for the eight was the SS Jaguar Coupe. The Coupe shared the
same overall dimensions as the 2.5 litre saloon but was built on a modified chas-
sis in which the gearbox crossmember was 8 inches further back. Unfortunately
this relatively small change when compounded with the increased loading
resulting from the heavier engine block proved to be the downfall of the design.

The front chassis members tended to act like a giant tuning fork which was set
into oscillation by road shocks transmitted through the front springs. By the time
of the Motor Show the car was in no fit state for display to a press and public
keen to try out a dramatic newcomer.
It is said that on the eve of the show 1938 Motor Show it was well known
within the company that all was not well and that William Lyons himself demand-
ed that the car be diverted from Earl's Court to Brooklands where he carried out
the first true test drive on it. The occasion was marked by extreme secrecy but after
a high speed lap of the notoriously bumpy track, Lyons apparently was
incredulous at the behaviour of the car. Those who were present had expected the
somewhat shaken Lyons to vent his anger upon them but in the event nothing fur-
ther was said except that the car would not be appearing at the show.
Thereafter further development work was continued with some small improve-
ment being effected by a doubling in the size of the weights at the ends of the harmonic'
stabilising front bumper, but afterfailing to eliminate the oscillations using two front bumpers
the project was abandoned. Early in April 1939 the only prototype was buried close to the
works in a land fill site along with other debris in what eye witnesses described as an event
marked by a sense of unreality.

Some say that the double bumpers of the Mark V were fitted purely as a reminder of the
incredible problems encountered in the Coupe and that this unfortunate memory has prevented
any further attempts with long straight eight engines. Others blame it on the unlucky out of
sequence chassis number: 010495.

Coupe

8 cylinder engine

Heynes