Blydenstein’s Viva SL
With only 38 b.h.p. at the back wheels, a Vauxhall Viva SL is certainly not going to win very many traffic light grands prix. But this fairly large and good-handling chassis can obviously use very much more power, as Vauxhall themselves fit the larger 1,600 and 2,000 c.c. engines. Obviously the Viva SL will benefit more than most from some extra b.h.p. and the Blydenstein-tuned example we tried recently had certainly benefited from an improvement of 18 b.h.p.
This is obtained by a combination of two different items of tuning equipment from the Bill Blydenstein/Coburn Improvements consortium, which has established itself as the leading Vauxhall tunist of late. The first item is one of Bill’s popular Stage 2 reworked cylinder heads, which have been on the market some considerable time now. Item two is new to the market and is an ingenious design of aluminium rocker cover incorporating an inlet manifold. A similar idea on the Borgward Isabella that Blydenstein used to race six or seven years before, decided Bill to design and patent a rocker cover along somewhat similar lines for the Viva about a year ago. Not only does the manifold have a cleaner flow than the standard one, but due to more uniform heating improves petrol consumption if anything. The cover also includes a snap-up oil filler cap and is obviously more attractive than the normal piece of metal stamped out by Vauxhall. The manifold is fed not by a standard Viva carburetter but by a Weber 28/36 DCD as used on the old Mk. 1 Cortina GTs but with different jets and chokes. An uprated oil pump has also been fitted, although this is not strictly necessary.
The car we tried was Blydenstein’s own personal machine with 38,000 hard miles and even a race at Lydden on the clock. In its time the engine has been used as a testbed for various conversions and is now starting to burn oil. Throughout, the very tough bottom end has remained standard and can be revved without problem to 7,000 r.p.m.
The engine retains the standard exhaust and camshaft, although an SL 90 cam and a fabricated exhaust would up the horsepower some more.
Other improvements made to the car include an oil cooler kit which is only really necessary if you are going to cruise along the Motorway flat out and an additional instrument cowl. The suspension has also received treatment and shortened top wishbones give the front wheels negative camber and, together with Spax adjustable shock-absorbers and Michelin XAS tyres on the optional 4J wheels, the handling is definitely improved. The shock-absorbers were screwed to their hardest so the ride did tend to be rather hard and jerky. The rear axle had a 4.1:1 differential fitted instead of the usual 3.9 and has also been fitted with an experimental Borg Warner limited slip device.
All this, however, does not make the Viva into a tyre-screeching racer on the road, for with the standard exhaust it is still quiet and very few motorists would give the car another look. It also remains completely tractable so this is no problem either. The conversion improves the top end acceleration and top speed considerably, but the car is still not exactly fast up to 40 m.p.h. Once 70 m.p.h. is reached the improvement is much more formidable. Thus this is a car that needs a heavy right foot if decent results are to be obtained. On the Motorway in particular the conversion pays its way, as we found that the fuel consumption worked out at 29 m.p.g.., the same as on a standard Viva SL. The performance panel shows the degree by which performance is improved, to much better advantage than simple words.
Viva brakes are good so there are no worries in that direction, and they remain unmodified on the test car. The coat of the conversion is broken down below and at first-hand the cost of the engine conversion may seem a little steep at £66. However, an off-the-shelf Brabham Viva with similar performance will cost you considerably more.
There must be quite a lot of readers with Vauxhall Vivas who are at present frustrated by the lack of performance of their cars. Why not write to one of the two firms, whose joint venture this is, for more details? Bill Blydenstein is at Station Works, Shepreth, near Royston, Herts. (telephone: Melbourn 1251), and Coburn Improvements Ltd. are at Netherhall Gardens, London, N.W.3 (telephone: Hampstead 6743).—A. R. M.