Viva La Difference
Another article from Vauxhall Mirror, this was taken from September 1964, a nice early article featuring the HA 1057 cc engine.
JOHN HESELTINE (Project Engineer, Chaul End) and Derek Clark (Experimental,Sheet Metal) built a very special Special in 1960 and raced it for three years in the 1172 Championship. At that time it was named the Vanford U2, the U2 referring to the chassis frame bought as a proprietary component. The rest of the car was made up of suitably modified parts from other production vehicles.
The Viva engine in the Special raced by John Heseltine (Product Engineer, Chaul End) is installed sloped over at 15° to improve the carburettor inlet path. In the photograph John, left, and Derek Clark,are making adjustments to the carburettor. A box of jets can be seen in the foreground.
The body was designed and built in aluminium, apart from the nose cowl which was moulded in fibreglass—replicas of which Derek and John have since marketed to meet a steady demand.
They had several successes with the Special, finishing in the first ten of the 1172 Championship (with over one hundred cars competing) in 1961-2-3, but for 1964 they decided to make an engine change.
John told us “We changed to a Viva engine, both because the specification showed it to be capable of much development and because we considered it to be a strong unit and unlikely to explode in a shower of hot metal pieces if over-stressed—this had been the fate of our last engine!”
They worked on the engine throughout last winter and finally installed it in the car, now renaming it the Vivan U2, in readiness for the Woburn Park Speed Hill Climb in April. Although the car was only completed in the early hours of that morning, it came second in the sports racing class.
In all, it has appeared in nine events including race meetings at Silverstone, Mallory Park and Oulton Park and speed hill climbs at Valence (Kent), Woburn Park and Ragley Park.
On the circuits it has not met with any great success, partly due to unsuitable gear ratios and also to “over-experimenting”. In hill climbs, however, the special has been placed in its class on three occasions, often against much more expensive and powerful machinery, such as cars powered by Coventry Climax racing engines.
John agreed that the engine has been considerably modified. He explained “it is installed sloped over at 15° to improve the carburettor inlet path, and has a large Weber twin-choke carburettor mounted horizontally on our own manifold. Derek modified thecylinder head extensively, and fitted it with larger valves and special valve springs. The compression ratio was raised progressively to its present level of 10.2 to 1.”
A closer examination reveals that almost every other part of the engine has been modified in some way; the oil pump for increased flow, the pistons for better lubrication, the sump to prevent oil surge on cornering. The crankshaft, bearings and connecting rods have been used as standard, but only after careful balancing had been carried out. An oil cooling radiator was found to be essential and this called for a change to the oil circulatory system in order to incorporate it successfully.
After trying several different camshafts, they designed and made one to their own specification. The exhaust manifold is also their own design and uses four pipes into the silencer, the cylinder head having been altered to have four instead of the normal three exhaust ports. The Viva gearbox was left standard and has given no trouble despite some rather cruel use!
“The dynamo”, Derek told us, “had to be moved to the opposite side of the engine to clear the steering and over 5 pounds in weight was saved by reducing the case thickness of the dynamo. In addition, a special pulley in alloy was cast for the dynamo to reduce its speed (a source of power wastage when racing) and to improve the cooling effect with better vanes. No fan was fitted, and no overheating problems occurred so long as the car was not kept too long on the starting grid”.
The performance of the car is exciting, as would be expected from an engine producing between 60 and 70 brake horse-power in a vehicle weighing only seven hundredweight. On the faster parts of the downhill straight at Oulton Park, John told us, the engine was turning over in excess ember, 1964 of 7,500 r.p.m. in top gear (a speed of 108 m.p.h.) and in the intermediate gears the engine was often taken to 8,000 r.p.m.
“This does not indicate the possible maximum speed”, said John, “since the car is deliberately low geared to give good acceleration out of corners, which is of great importance on twisty circuits.
“The interest shown in the car, because of its Viva power unit, has been somewhat out of proportion to its successes. We feel that competitors and spectators are getting bored by the domination of other engines in competition cars and they look forward to a challenge. We have certainly not yet realised the full potential of the engine but we have proved that it responds to modifying and is robust enough to take the stresses imposed in racing”.
In order to develop the engine further John and Derek would need the use of an engine test bed on which they could try out rather more ambitious tuning
schemes. Unfortunately, neither have a dynamometer test house in their back garden ! They are proud and pleased to have been the first to appear on a racing circuit with a Viva engine but are quite certain they won’t be the last.