Can-Am – Rounds 4 and 5
The highlight of the fourth round of the Canadian-American Challenge Cup series, the Klondike 200, at the Speedway Park circuit in Edmonton, Alberta, was the first appearance of Jim Hall’s long-awaited Chaparral 2H. The car was originally entered in the first 1968 Can-Am race last September but it is an entirely new design (not simply a development of the 2G) and its numerous novel features have required considerably more development time than had been expected. The programme was further delayed by Hall’s serious accident in the final Cam-Am race last November. Hall’s main design objectives with the 2H were to combine a low-drag body with a suspension that makes optimum use of the very wide tyres now available.
The chassis and front body section of the 2H are one fully-integrated structure made up from a fibreglass-reinforced plastic material. The chassis ends at a bulkhead behind the seats and the 7-litre all-aluminium Chevrolet engine, combined with Hall’s three-speed automatic transmission, serve as the mounting points for the rear body and suspension. The body is extremely smooth and certainly appears to have low drag. The nose is sharply pointed and all cooling inlets are flush N.A.C.A.-type ducts, the largest being for the rear-mounted radiator. Although Hall, more than anyone else, was responsible for the development of wings in road racing, they can be a source of considerable drag and Hall hoped that the body shape and suspension of the 2H would make a wing superfluous. In practice a wing has been found necessary but instead of being mounted on struts attached to the suspension it is very smoothly integrated into the extreme rear of the body. It is closer to an adjustable spoiler than a true wing.
The most intriguing features of the 2H is the rear suspension, which, in very much over-simplified terms, could be called a de Dion. Hall refers to it as a semi-axle suspension that is independent in all respects except camber. The suspension uprights are attached to the outer ends of a box-section fabricated "bridge" that passes over the forward part of the transmission. A pivot joint in the centre of this bridge permits slight fore and aft compliance but prevents independent movement of the two sides in a vertical plane. The bridge is located by a somewhat complex series of links attached to the transmission housing, while the coil spring/damper units and the sway bar run from the outer ends of the bridge to attachment points on the engine. The front suspension is relatively conventional by comparison, with upper and lower wishbones acting on coil spring/damper units and a sway bar, but it is designed in such a way that only the sway bar is subject to bending loads—everything else is in simple tension of compression.
After the great interest generated by this new Chaparral, the race itself was an anti-climax. The works McLaren M8Bs of Hulme and McLaren were again the fastest qualifiers, this time with identical laps of 1 min. 22.9 sec. (an average of 109.737 m.p.h. around the 2.527 mile circuit) that were 3.1 seconds below their qualifying times last year. Amon in the Ferrari 612 was third fastest, at 1 min. 27.8 sec., followed by the McLaren M12 of the Canadian, Eaton, at 1 min. 27.8 sec., and then the Chaparral, driven by Surtees because Hall is still not fully recovered from his injuries, at 1 min. 28.1 sec.
A terribly think field of 17 cars started the 80-lap 202-mile race and four of those retired within the first 11 laps. It was clear from the practice times that the works McLarens were still beyond the reach of anyone else but for the first half of the race Hulme, McLaren and Amon put on a show for the spectators as they played "musical chairs" with the first three places. On the 36th lap, however, the top suddenly broke off a piston in McLaren’s car—the first mechanical failure on either of the works McLarens in four races. Hulme quickly ended the "musical chairs". He retrieved the lead from Amon on the 39th lap, opened up a margin of 10 seconds and held it for the remaining 41 laps to the chequered flag despite a spirited final assault by Amon’s Ferrari. Having lost all but fourth gear after the halfway mark, Eaton drove well to finish third, three laps down. Surtees in the Chaparral was one lap further back after making two pit stops to replace a broken throttle spring.—D. G.
Several teams that skipped the long haul to Edmonton returned to the Can-Am series for the fifth round, the Buckeye Cup at the Mid-Ohio Sports Car Course. They were joined by two significant newcomers. Among those returning were Revson, who has taken over the T163 Lola-Chevrolet driven by Bucknum at Watins Glen, and Dean in his ex-works Porsche 908, that was also last seen at the Glen. One of the newcomers was also a Porsche—a 4.5-litre 917PA owned and entered by Porsche Audi of the United States with Ginther as team manager and Siffert as driver. The chassis is identical to all other Porsche 917s (except for a few modifications to permit the use of wide wheels) but the body is an open spyder not unlike that on the most recent 908 Spyders. Dispensing with the coupé top helps to save about 50kg, but the 917 coupés were designed to the Group 4 minimum of 800kg and it is difficult to subtract weight once it is built in. There are no flaps or stabilizers on the open car and with the flat-12 engine producing 580 h.p. Siffert said there was a noticeable improvement in controllability compared with the coupé. The other new car making its first appearance was Penske’s 7-litre T163 Lola-Chevrolet for Mark Donohue. Although Donohue has been the leading American in the Can-Am series for the past two years, the team’s 1969 Can-Am programme has only been third on its scale of priorities behind the Trans-Am and Indianapolis programmes. This perhaps explains why the Lola suffered three driveshaft failures in a week—one in testing, one in practice, and one after only nine laps in the race, when Donohue was lying fourth.
Qualifying was continually interrupted by rain but this didn’t stop Hulme in the works McLaren M8B from recording the first 100 m.p.h. lap ever made at Mid-Ohio and winning the pole position with a time of 1 min. 25.9 sec. (100.58 m.p.h.), 4.9 seconds below the previous qualifying mark. McLaren also broke the 100 m.p.h. barrier with a best lap of 1 min 26.2 sec. Donohue maintained his reputation by qualifying third fastest, at 1 min. 29.5 sec. with Parsons’ similar Lola half a second behind. Hall had added additional damping struts to the rear suspension of the Chaparral to cure a roll oscillation but Surtees could only manage fifth starting position, with a lap of 1 min. 30.2 sec. Next to him on the grid was Eaton’s McLaren M12, at 1 min. 30.8 sec., and they were followed by Siffert in the Porsche 917 at 1 min. 30.9 sec. and Revson’s Lola at 1 min. 31.1 sec. One of the Ferrari’s pistons shattered before Amon had done any fast laps and he had to start from 12th place—a severe handicap on a circuit that manages to cram fifteen turns into 2.4 miles and is so narrow that virtually the only place to pass is on one straight.
There was a fierce early scrap as Amon and Siffert tried to carve their way past Eaton, Surtees, Donohue and Parsons, and when Amon made it to third place in only nine laps he found that McLaren was already 14.8 seconds ahead in second place and Hulme a further 10 seconds away in the lead. Despite giving away 1.7 litres to the Ferrari and 2.3 litres to everyone else in front of him, Siffert was giving a superb display in the Porsche 917 and was up to fourth place by lap 14.
By the halfway mark in the 80-lap, 192-mile race Hulme had lapped the entire 21-car field except for McLaren and Amon, and by the three-quarter mark he had lapped Amon as well. Having shown he could do it, Hulme backed right off and allowed Amon to unlap himself. Hulme eased off so much, in fact, that McLaren caught and passed him on the 72nd lap. The next time around, however, McLaren’s oil pump seized and he dived into the pits. There was nothing the crew could do, so they sent him back out with no oil pressure at all, just to see what would happen. Somewhat amazingly, the engine held together for the final six laps (a performance the Gulf Oil people pointed to with pride) and McLaren nursed the car to the finish 51 seconds behind Hulme. Amon and Siffert were one lap down, in third and fourth. Surtees was two laps down in fifth despite two stops for goggles and a face shield, and Eaton drove for 180 miles on seven cylinders to take sixth place, three laps behind the victorious McLarens of Hulme and McLaren.—D. G.