Triumph Dolomite Supercharged Straight 8

Send This Page To A Friend
Fade To White

Triumph Dolomite Straight 8

United Kingdom
Supercharged Straight 8
1990 c.c.
140 bhp @ 4,400 rpm
4 spd. man
Top Speed:
102.47 mph
Number Built:
5 star
Triumph Dolomite Straight 8
Reviewed by Unique Cars and Parts
Our Rating: 5


ONE OF the most intriguing sports cars produced in the 1930s was the supercharged 2-litre, twin-ohc, straight-eight Triumph Dolomite - not to be confused with the four and six-cylinder (1,767 and 1,991 c.c.) Dolomites that succeeded it in 1936.

This supercharged straight-eight showed tremendous promise, both in its specification and its forceful, purposeful looks - but it fizzled out after only three cars and six engines had been built. Two cars were sold, each with a guaranteed top speed of 100 mph in full touring trim; the third was written off when a train hit it in the Monte Carlo Rally.

The appearance of a British 2-litre straight- eight sports car at the end of 1934 caused plenty excitement and enthusiasm in motoring circles. But it would be relegated to the history books almost as quickly as it appeared. Understandably, given the very low build number, not much is known about the car. As always, we will be attempting to make this article as accurate as possible, but finding information has been difficult.

Finance, or a lack of it, seems to most likely cause of the cars quick downfall. This would have been aggravated by the war clouds and near-slump conditions. But there was another kind of embarrassment that adversely affected the Dolomite Straight-Eight - Donald Healey, who was then the experimental engineer at Triumph's, wanted to produce a car which could compete on equal terrns with this Monza Alfa Romeo and with the 2.3-litre Bugatti.

Mussolini's Triumph, And The British Alfa

In order to study this problem, the 2.3 Alfa which had been raced with considerable success by the Hon. Brian Lewis (later Lord Essendon) was bought from him by T. H. Wisdom and passed, without profit, to the Triumph company where it was taken carefully and inquisitively to pieces. There were stories in existence, possibly even in print, that tell of a reciprocal agreement between the firms of Alfa Romeo and Triumph whereby Triumph motor cycles were to be produced in Italy (partly, so the story goes, in order that they might be used by Mussolini's army in Abyssinia) and a British Alfa Romeo was to appear on their home market.

The reason this rumour gained legs was that a shipload of Triumph motor cycles did actually go to Italy, but the significance is spoilt by the fact that at that time Triumph motorcycles and cars were not under the same management. When the 1934 Motor Show opened at Olympia, it was obvious to everyone, including the representatives of Alfa Romeo in the UK, that the new Triumph bore a remarkable resemblance to its Italian competitor. There is another theory that a law suit was to be set in motion by Alfa against Triumph Cars, but Unique Cars and Parts have been unable to find evidence of this. Friendly remonstrance from Alfa there was, but it seems that no actual patents were infringed.

The Triumph Supercharged Straight 8's Specifications

The Show model had a chromium-plated chassis and was hurriedly prepared for its appearance on the Triumph stand. It was not, in fact, in 100 per cent working order when shown to the public. However, it was an inspiring piece of machinery. The twin overhead camshaft engine of 1990 c.c. (bore and stroke 60 x 88 mm) showed a basic likeness to its Alfa counterpart in having two blocks of four cylinders, with the camshafts driven by spur pinions running in train from the centre of the crankshaft. The cylinder heads were of R. R. Hiduminium, as were the cylinder blocks, which had shrunk into them nitrogen-hardened cast iron dry liners.

The crankcase and sump were made of Elektron and the crankshaft ran in 10 main bearings, having a vibration damper fitted at its front end. Two down-draught Zenith carburettors, using a communal float chamber, were on the off-side, fitted to a Triumph- designed Roots-type supercharger, the fuel coming from a 20 gallon tank. The inlet manifold was in two branches of four pipes, while on the near-side of the car eight separate exhaust pipes ran straight into a large silencer. A three gallon oil tank, ribbed and with air passages through its centre, was housed between the front dumb-irons and fed the dry sump lubrication system. Ignition was by magneto or coil, the former, if specified, being driven from the front end of the crankshaft.

Twin 12-volt batteries were located at the rear of the chassis and received their charge from a voltage-controlled dynamo. A Wilson preselective gearbox, made by Armstrong Siddeley, provided ratios of 3.1, 1.85, 1.23 and 1 to 1, while the rear axle ratio could be 4.5 to 1 or 4 to 1. The gearbox was rigidly mounted to the chassis, with a cushion coupling between gearbox and engine. Transmission was by open propeller shaft. The chassis frame was made of deep channel-section nickel steel graded for flexibility, stiff at the front end and swept up over the rear axle. Wheelbase and track were 8ft 8in. and 4ft 6in. respectively. Suspension was by means of short half-elliptic springs on outriggers having a heavier section master leaf with rebound springs above it.

The front axle was located by radius rods although its springs were shackled at both ends, Lockheed hydraulic brakes were used, having 16in. diameter Elektron drums and light alloy shoes, the front drums being larger than the rear ones, and all of them ventilated. Fort Dunlops (19 x 5.25in.) were fitted to the Rudge Whitworth racing wire wheels. Despite its hard ride the driver had a comfortable seat and was faced with a steering wheel adjustable fore-and-aft, and for rake, and having the preselector lever on its column. The Burman-Douglas worm-and-nut steering called for 1¾ turns of the wheel from lock to lock. The dashboard provided plenty of information having gauges for oil and water temperature, oil pressure, supercharger pressure, as well as an ammeter, a rev-counter and a clock.

The cars were made at the Triumph works and were the result of the labours of Donald Healey's team of designers, one of whom was Swettenham who had been Henry Royce's personal assistant. Another name on the list was that of Middleton. Peter Cowley and Albert Ludgate, the latter being the chief engineer of Lea Francis, had had a hand in the production of the chassis. Three cars were completed and there were sufficient parts for six engines. The legend that one engine blew up on the test bed was scotched some years later by Geoffrey Healey who stated categorically that this was pure fiction.

The supercharger drive was quiet but, according to the very few words written by those lucky enough to have driven one, a pleasant whine emanated from the twin-choke carburettor. The car's docility extended to running with out a snatch at 30 mph in top gear. The overall ratios were first 12.4 to 1; second 7.4 to 1; third 4.92 to 1; and top 4 to 1, while the rev-counter showed 1,000 rpm at 20 mph in top gear. A quotation of Twist's own words reads "When I had been sitting in the passenger's seat, even though we had several times reached about 85 mph, I had rarely been bumped off the cushion." In testing the car's acceleration it was found that the brake bands in the Wilson preselective gear box were inclined to slip but the trouble was marked down for attention and cure.

The taking of a full set of performance figures was impossible as the car at that time was only fitted with a rev-counter and that instrument was a chronometric one which registered at three-quarters of a second intervals. However, apart from the 102.47 mph already mentioned, a complete lap from a flying start was covered at 98.23 mph, and from a standing start a quarter-mile was achieved in 17.8sec, the half-mile taking 28.6sec. The large drum brakes pulled the Dolomite up from 30 mph in 24 feet. The front and rear wings were separate and had no sweep of running board between them as there was on the Show model.

The Danish Rail Crossing Ends Donald Healey's 1934 Monte Carlo Rally Attempt

In the Monte Carlo rally, Donald Healey was starting from Umea in Sweden and was thought to have good prospects of a win, especially as he had already won the Rally in 1931 in an Invicta. From the start all went well but the Dolomite was destined to get no further than Denmark. In this country the cars from Stavanger and Umea were just leaving a ferry in thick fog and at night when the shrill whistle of a train was heard. Unknown to the competitors a railway line crossed the road at an acute angle and there were no gates. J. W. Whalley driving a Ford from Stavanger saw the oncoming locomotive's headlight and made a successful "last across" rush. Poor Healey hadn't a chance. The engine must have caught the Triumph's bonnet behind the offside wheel and swung the car through some 200 degrees, leaving it completely smashed as far as the windscreen, which did not appear, in the press photograph, to be broken, but with its near side headlamp still blazing.

It would seem that the Phorograph was taken a good while after the acci~ent as although it shows interested spectator at all Nineteen years onP. B. Merritt Triumph Dolomite, operating under the pseudonym HSM, the carriage windows, the fog hadcleared. Healey and his passenger were not seriously hurt which was extremely fortunate and as if to compensate for the disaster, a Triumph Gloria driven by J. C. Ridley secured second place in the Rally. The Dolomite was completely written off and was scrapped, leaving two cars and presumably still six engines in assembled or unassembled state. The apocryphal story that the Danish State Railways claimed damages for the repair of their locomotive has no foundation. It would have had the comic value of absurdity had it been true as doubtless some wag thought at the time.

Unforeseen expenses added to the fact that the Triumph Company, like so many other car manufacturers at that time, were struggling financially during the depression years. The decision to drop the Dolomite Straight-8 project must have made sense to the bean counters, but no doubt enthusiasts of the time would have been deeply disappointed. The last sports car the company made was the Triumph Southern Cross, and quite a good one at that, but at this stage attention was concentrated on bread-and-butter motor cars under the new management of Newnhams, the Triumph distributors, who had taken over the Triumph concern.

The Two Survivors Are Sold To High Speed Motors

The Dolomite name was carried on by a completely different type of car. On 7 July 1936 an article in The Motor announced the new Triumph Dolomite Saloon. This was obtainable with a four-cylinder 1,767 c.c, (75 x 100 mm) engine or with a six-cylinder 1,991 c.c. (65 x 100 mm) one, many of the component parts being interchangeable. The two Dolomite Straight-Eights together with the six engines were sold by Triumph to High Speed Motors, a firm managed by the late Robert Arbuthnot and G. Harnponi. By agreement with the makers, the cars were relabelled "HSM-Dolomite" which allowed for any modifications or body alterations that their new owners might choose to make, At the end of 1936, A. P. R. Rolt, then an Eton schoolboy but one, nevertheless, with some racing experience, bought one of these HSM-Dolomites.

By the time he made the purchase the engine had been bored out to 2.4 litres and a larger blower had been fitted to give a pressure of 10 p.s.i, instead of the 5.6lb on the original cars. Rolt acquired the car for competition purposes and his first essay was at a Speed Trial in Cheshire at the Summers Steel Works Estate where a suitable stretch of private concrete road was available. This was early in 1937. The trials were held by the Liverpool University Car Club and Rolt made fastest time of the day with a speed of 101.75 mph over a flying mile. A Ford V8 managed 81.05 mph for second fastest and an MG came second to the Dolomite for the standing half- mile. Rolt then took the car across to Ireland for the Leinster Trophy Race and in this event broke the lap record at 75.53 mph on his fourteenth time round. Next was the J.C.C. 200 Mile Race at Donington but gained no award on that occasion.

At the end of 1937 Rolt sold the HSM-Dolomite in a part exchange deal with Speed Models of Notting Hill, a firm which was run by Murton Neale and some others who were sports car specialists. The ultimate fate of the cars or even how many of the six spare engines were used and in what chassis, if they were, are questions we cannot answer, as the trail goes cold after the 1937 sale. We would love to know if any survive to this day - but the answer is likely to be none - which is a shame.
Triumph Dolomite Supercharged Straight 8

Visitor Rating:

Click stars to vote

Also see:

Lost Marques: Triumph
Triumph Car Brochures
Triumph Car Commercials
Reader Reviews page 0 of 0
Click here to add your review
There are currently 0 reviews to display.

Reader Rides
Sorry, we don't have any reader rides for the Triumph Dolomite Supercharged Straight 8.
Be The First To Upload Pictures Of Your Triumph Dolomite Supercharged Straight 8
Triumph's For Sale
4 cyl.


Classic Cars

$49,950 AUD
4 cyl.


Classic Cars

$15,950 AUD
4 cyl.

Classic Cars

$4,000 AUD