Wesbank Modified BMW 535i
Race Car Build
The third generation E34 5-Series BMW was launched in Europe in December 1988, and arrived in South Africa in April 1989, being produced at the Rosslyn plant outside Pretoria. The introduction models were the 2.5 litre 525i in and the top of the range 3.5 litre 535i, both models available with manual or automatic transmissions. The following year the range was expanded with the 'poverty' 520i, the haloed M5, and the V8 540i.
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Two bodies were delivered to Owen Ashley, which went through some extensive modification. The roll cages built into the cars were not just a safety device, but were built to add torsional rigidity and strength to the bodies. The rear doors were welded in place and were covered internally. The front suspension strut mountings were cut out and new structures were built in to accommodate the horizontal cantilever suspension units designed by Owen Ashley. The gearbox tunnels were enlarged for the new gearboxes and the bodies were changed to left hand drive to allow the required space for the exhaust manifolds and exhaust system.
The external fiberglass body panels, bumpers, bonnet, boot lids, splitters and rear wings were formed and made by Keith Bright of Bright’s Fiberglass.
The detail engine modifications are unknown, but based on the research and deductions made by Nick Sheward during the restoration of the two cars. Engine blocks were M30B35 units, but for the European 745i Turbo, which sprayed oil into the bottom of the pistons through oil jets. Crankshafts were standard, but conrods were M5 units, and the engine was enlarged to 3.6 liters with a 94mm bore and 86mm stroke
Cylinder heads were standard units, but would have had polished ports and appropriate racing camshafts would have been made. The lubrication system was changed to a dry sump system, which resulted in a bespoke smaller sump fitted to the engines. The engine was mounted on solid engine mountings.
Inline with Class B regulations, the fuel injection system was replaced with 48mm twin choke side draft carburettors, Webers on the Viana car and Dellorotos on the Joubert car.
The belt drive oil pumps were locally made and supplied by Dorino Treccani at Trepal Automotive Engineering. The position of the oil pumps required the alternators to be mounted inside the cars at the rear of the propshaft tunnel and were driven off the propshaft.
The gearboxes used were Xtrac dog boxes with straight cut gears, with a dog leg first gear. The propshafts needed to be shortened and the flex disc mountings were replaced with machined aluminium units.
The rear suspension control arms were bespoke adjustable units with rose joints that supported special made rear wheel hubs. The front suspension control arms were also custom-made adjustable units with rose joints and bespoke wheel hubs. Both the front and rear suspensions were horizontal cantilever units designed by Owen Ashley. All the engineering and turning work was done by the well-known and respected engineer, Eddie pinto.
Rear diffs were standard 535i units, but diffs were changed with different ratios depending on which track was raced. Viana’s car was the only car fitted with a diff cooler and oil pump
Brakes were beefed up with AP calipers all round, with the front discs being 28mm thick and the rear discs taken from an M5. The wheels were split-rim BBS or Compomotive rims, with centres turned Eddie Pinto.