McLaren Can-Am Cars

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The mighty 7-litre McLaren M8A of 1968 was the first of the series which dominated Can-Am for five years, driven by McLaren, Hulme and Revson
 
ABOVE Bruce McLaren at the wheel of his M8B, powering it through a left-hand bend at Laguna Seca in 1969; he won the race.

Reprinted from The Car Volume 6 Part 68 - 1985

In 1966, the debut year of the Canadian American Challenge Cup series - the Can-Am for short - Bruce McLaren's M1B sports cars were outclassed by their more powerful Lola and Chaparral opposition. In 1972 the M20s lost out in the power stakes to Roger Penske's brutally fast turbocharged Porsches. In the intervening years, however, the Can-Am was McLaren. The orange cars from Colnbrook notched up 38 victories, while privateer cars accounted for two more. Even in that final year of eclipse the works cars won twice and a private example once, bringing the final marque tally to an incredible 43.

McLaren himself won the Can-Am title in 1967 and 1969, while team-mate Denny Hulme won it in 1968 and salvaged something from the team's distress by taking his second title in 1970, the year in which Bruce was killed testing an M8D. Hulme's 1971 team-mate was colorful American Peter Revson, who took the title in the M8F.
When McLaren began planning a replacement for the amazingly successful M6A at the end of 1967, the Can-Am had already been dubbed 'The Bruce and Denny Show'. In that year's six-race series Hulme had achieved a hat-trick and Bruce a brace of wins, only 1966 champion John Surtees in a Lola getting a look in at the Las Vegas finale when the McLaren steamroller ran into trouble. If the opposition had been trampled into the dust in 1967, it was a case, in American parlance, of 'you ain't seen nothin' yet' for 1968.

Delays with delivery of the BRM V12 engine for McLaren's 1967 M5A GP car had allowed the team to concentrate almost exclusively on the M6A, which was consequently tested exhaustively. McLaren had grown eminent in GP racing in 1968 with the Cosworth-powered M7A, but the M8As weren't quite so race worthy although they had still done 500 miles (805 km) running. Similar in concept to the M6A with bathtub monocoque chassis, the M8A was four inches (10 cm) wider and comprised a full monocoque using aluminum and magnesium panels bonded and riveted to steel bulkheads. Its engine was now a stressed member supported by tubular framework and where the M6A had used 5.8-¬litre Chevrolet V8s with 520bhp, the M8A went the whole way with 7-litre unit, developed by Gary Knutson. These gave 620bhp, transmitted to the road via a Hewland LG600 gearbox to 15-inch (38 cm) wide Goodyear shod rear wheels. The suspension followed M6A practice with upper and lower lateral links and trailing radius arms at the front and a lateral top link, lower wishbone and twin radius arms at the rear, all allied to outboard coil spring damper unit. Solid disc brakes were replaced by ventilated units all round.

Start with two M8Bs on the front row

A typical grid in 1969, with McLaren (4) a Hulme (5) at the front

The number 4 M8B of Bruce McLaren

McLaren in full flight in the Monterey Grand Prix, California, in 1968

In its first race - Elkhart Lake, Wisconsin on 1 September the M8A romped away, Hulme leading McLaren home in a convincing display that set the opposition quaking, especially as Hulme broke a rocker arm part way through and finished on seven cylinders...

At Bridgehampton they led again, and although they were sidelined by engine problems, American Mark Donohue (later to play such a significant role in McLaren's eventual Can-Am eclipse) won for Roger Penske in an M6B. At Edmonton he had to be satisfied with third to the M8, Hulme again leading McLaren home, while a torrential rainstorm at Laguna Seca, and a good wet tyre choice, saw John Cannon win in his aged Oldsmobile-powered MIB with Hulme second and McLaren fifth.

Victories for the M8A

Bruce's turn for glory came at Riverside, where he won the Los Angeles Times GP from Donohue, with a bodywork damaged Hulme fifth. Donohue clinched his title at the Stardust GP finale at Vegas, with Bruce nursing his ravaged car home sixth. Throughout the series, only Donohue had posed a consistent challenge through reliability. Both Peter Revson in a Ford powered M6B and Texan Jim Hall in his Chevrolet-engined Chaparral 2G had been able to match the M8A for speed on occasion, albeit without reliability.

For 1969 the M8 design was developed to B specification into what McLaren's Teddy Mayer would later describe as the team's most successful car. The spoiler on the rear bodywork was deleted and replaced by a strut-mounted overhead aerofoil, the front wheel arches were cut back to help exhaust air from beneath the nose, and a short stroke, big bore version of the 1968 engine, now 7046 cc and 630bhp, was prepared by George Bolthoff. Testing again began early with a modified M8A which was converted to full B specification once that had been settled.

In an ill-disguised attempt to give rivals a better chance of getting on terms with McLaren, the Can-Am organisers had stretched the series from six to 11 rounds, but as it was to transpire, the ‘Bruce and Denny Show’ had only been playing in the provinces in 1967 and '68. For 1969 it made it right to Broadway. In an unmatched achievement, McLaren won every one of those 11 rounds. Bruce triumphed in six, Denny five. In eight the 'orange elephants', as the M8Bs became known were first and second. At Michigan Raceway in the eighth race they were first, second and third, Dan Gurney handling the spare car after Jack Brabham had qualified it. A year later in less happy circumstances he would again play a significant role for the team…

M8D

Hulme in his McLaren M8D, 1970

M8B
Hulme won this race at Las Vegas in November 1968, driving the M8A
 
While the M8C production version built and marketed by Trojan in Britain was still a season away in 1969, there were various customer M6s and M12s, and Gurney tried unsuccessfully to match his M6B 'McLeagle' on 5.6-litre Ford power against the M8Bs when he wasn't guesting for Colnbrook. Lola, whose T70 had won Surtees the first Can-Am title in 1966, had had a poor 1968 with the T160 and didn't fare much better with its development T162/163 models, while Ferrari, having raced sporadically in 1968, ran Chris Amon in a developed version of the 612 six-litre V12 car at he had driven in the last round the previous year. The former McLaren driver finished third on his debut at Watkins Glen and created a sensation by leading Hulme at the next race at Edmonton before finishing only five seconds in arrears. Thereafter, though, the Italian thoroughbred proved breathless with its litre disadvantage and never again posed a real threat. After it broke its engine at Laguna Seca practice McLaren offered his old employee a ride in the spare M8B but with typical Amon luck its differential broke.

The narrow-track Chaparral 2H for Surtees was a total disaster, proving that even Jim Hall could make mistakes, while Jack Oliver's Peter Bryant-designed Autocoast Ti22 (type numbered after the chemical symbol and valency of the titanium from which it was made) showed late series promise. The car that caused the greatest interest, however, and which would ultimately prove the most significant newcomer from McLaren's point of view, was the 4.5- then 5-litre Porsche 917 Spyder driven by Jo Siffert. He had a few reasonable placings but, like Amon, suffered from a capacity deficit, proving the American adage that there Revson's 8F, at Laguna Seca in 71 is no substitute for cubic inches. Later Porsche would add its own rider to the effect that there was no substitute unless you had a turbocharger…

With the train running smoothly on its rails, McLaren spent the winter perfecting the latest M8 derivative, the M8D. A ban on strut-mounted wings saw the rear bodywork sprout attractive fins between which a low wing was slung, and as the existing tubs were retained, albeit with 4¬inch wider suspension, the wider bodywork curved in neatly where it rested atop the chassis. Bolthoff overstretched himself and the engines by trying an 8-litre 700bhp version in tests, and when this monster exhibited self-destructive traits, 7620cc units were substituted. These developed 670bhp at 6800rpm and a massive 600 lb ft of torque. This was thought to be sufficient.

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