'The Cooper-Zerex is frontline road racing’s greatest ‘transformer' — Doug Nye

The Cooper-Zerex sports car’s homecoming, see page 12, marks its survival as perhaps frontline road racing’s greatest-ever ‘transformer’, having in essence run in no fewer than seven distinct configurations.

The first was its 1961 form as a brand-new Formula 1 Cooper-Climax T53P, with 1½-litre four-cylinder FPF engine. Painted Briggs Cunningham white and blue it was crashed by Walt Hansgen in that year’s United States GP.

Its rebuilt form saw it converted for 1962’s major professional West Coast sports-car races. Buyer Roger Penske had it configured with a 2.7-litre four-cylinder ‘Indy’ Climax FPF engine, distinctive wheel-enveloping bodywork with centre-seated cockpit, and a tiny legalising ‘passenger seat’ within its left-side pontoon. This red-liveried ‘Zerex Special’, entered by Penske’s Updraft Enterprises Inc, promptly won at Riverside, Laguna Seca and Caguas.

Configuration 3 then met new 1963 rules, the ‘Zerex Special’ re-emerging with the same engine in a much-modified and rebodied right-hand drive chassis retaining only the F1 Cooper end frames. John Mecom Racing Team-liveried in metallic mid-blue and white, it was driven by Penske to several wins, including the UK’s Brands Hatch Guards Trophy. Fourth transformation – early-1964 after sale to Bruce McLaren; still 2.7 Climax FPF-engined but now UK-legal Cooper-Zerex-Climax repainted green with silver stripe. Entered by the Bruce McLaren Motor Racing Team, driven by Bruce to score two significant wins, at Aintree and Silverstone April/May ’64.

“We had just one day to turn it into a British-regulation sports car”

Form 5 – rebuilt by June 1964; 3.5-litre Cooper-Zerex-Oldsmobile V8 (all-new McLaren straight-tube chassis centre-section re-using original F1 Cooper end frames). Green with silver stripe, BMcLMRT entry driven by Bruce to win the major Player’s ‘200’, Mosport Park.

Iteration 6 – August/September 1964, 3.9-litre Oldsmobile V8, top-ducted radiator, green with white stripe – BMcLMRT entry driven by Bruce to win the Guards Trophy, Brands Hatch, then star in Goodwood’s TT.

Final form – 1965-66, bought by Texan amateur Dave Morgan, fitted with distinctive ‘anteater’ nose body – repainted red – otherwise retaining the straight-tube centre-section chassis with its F1 Cooper extremities. It was raced in SCCA South-Western Region events and in the Bahamas Speed Weeks. In 1967 Morgan sold it to South America, whence it has only now re-emerged.

In 2019 this magazine featured the 1962-style ‘Zerex Special’ which ran at that year’s Goodwood Revival, claimed to have been rebuilt around the Cooper-Zerex’s centre frame cut out by McLaren in ’64. But photos showing “what McLaren cut out” (apparently acquired decades later at a Beaulieu autojumble) do not match Penske’s centre-seat frame. In any case the only tubes from Roger Penske’s 1962 centre-seat ‘Zerex’ that his own ’63 conversion had retained had been the ex-Cooper suspension-mounting extremities which McLaren re-used.

Now ponder just how young the McLaren team really were. In 1964 Bruce was 26, his PA Eoin Young 25, and mechanics Tyler Alexander 24, Wally Willmott and Howden Ganley 23. To them, nothing seemed impossible.

Bruce on the Cooper-Zerex: “Our first event was at Oulton Park on April 4, but… it was late on the Wednesday before the car arrived in London… just one day to fit a luggage trunk, lights, a windscreen wiper… to turn it into a British-regulation sports car – a week’s work in 24 hours. As a result an oil pipe came loose… The car lasted seven laps before the oil pressure disappeared… However, the boys had a clear week before Aintree. In practice I scored best sports car time. I managed to hold a comfortable half-minute lead for most of the race (but) if I hope to keep pace with the Lotus 30 and Tommy Atkins’s fantastic 450bhp Cooper-Maserati, (we) will have to start tweaking the Cooper-Zerex.”

At May Silverstone, Bruce then won by 10.2sec from Roy Salvadori’s Atkins Cooper-Maserati V8 “while the Lotus 30 had another attack of teething troubles”. The Monaco GP followed, after which he “…headed back to England to help rebuild our sports car and fit an Oldsmobile V8 engine”. Autosport later reported “The rebuilt chassis is smaller, lower and stronger with a stressed steel undertray welded on to increase torsional rigidity.” Meanwhile, Tyler and Wally had tired of continually removing the forward body to check brake and clutch fluid levels. So they cut a small front-hinged hatch above the master cylinders, held shut by a Dzus fastener.

The car was flown out to Canada’s Player’s ‘200’ race at Mosport, Bruce winning both heats and overall despite being blasted with stones by A.J. Foyt’s Scarab. In later testing at Goodwood, the little nose flap popped open and Bruce noticed it lifting in the airstream. The trio realised there must be a low-pressure area there. So why not exploit it to suck radiator air upwards through the nose top, instead of deflecting it sideways?

Tyler snipped a U-shape in the body behind the radiator, then folded the flap down as a deflector. Bruce ran with his now top-ducted radiator and bingo – cooling was improved and high-speed understeer reduced. Bruce then won the Guards Trophy race at Brands Hatch before starting from pole position at the Goodwood TT. If ever a race car earned long retirement in exotic parts, this one surely qualifies.

Doug Nye is the UK’s leading motor racing historian and has been writing authoritatively about the sport since the 1960s