Posts Tagged ‘AC Cobra Coupe’

(Klemantaski)

Jack Sears, Dunlop Curve, Le Mans in the ill-fated long, low, swoopy AC Cobra Coupe 20-22 June 1964…

Sears was hoping to do better than his marvellous fifth place at Le Mans in 1963 aboard the Maranello Concessionaires Ferrari 330LMB he shared with David Piper.

The talented British sedan and sportscar racer was partnered with Peter Bolton in the one of a kind AC Cobra Coupe, AC Cars Ltd owner Derek Hurlock and his team built to take on the ‘works’, Shelby Daytona Coupes in the famous 1964 24 Hour classic.

It was also a chance for AC to improve upon its 7th place finish at Le Mans in 1963 when the factory Cobra driven by Ninian Sanderson and Peter Bolton finished 7th.

The big Coupe was registered ‘BPH4B’ to allow some testing on public roads, despite this the first Carroll Shelby knew of AC Chief Engineer Alan Turner’s in-house design was at the car’s competition debut during the Le Mans test day in April.

Visibly lower than the Pete Brock designed Daytona coupe (41 inches compared with 48 inches- its height a function of uncertainty over Le Mans windscreen height regs) both designers sat the drivers lower in the car. Turner had also raked the windscreen, created a lower nose section and a longer flowing roof as well as designing the ‘eyebrows’ over the tops of the wheel arches he claimed help clean up airflow.

The cars promise of speed on the Mulsanne Straight was met- Bolton achieved the 27th fastest time in a fast run without ‘going for a time’ in a car which still required development.

Back in the UK brake overheating problems were addressed with ducting, a burned piston replaced and a rear spoiler added for stability and to reduce lift. The car was then tested at the MIRA facility for which it proved too fast, there was not a road section which allowed the car to run to its maximum speed…

AC’s Alan Turner created a marvellous, handsome, cohesive, masculine shape with demonstrable aerodynamic properties- such a shame only the one was built (Autocar)

During Le Mans Sears and Bolton were timed at 180.2mph @ 6300rpm, matching the Daytona Cobras despite giving away 30bhp to the Shelby entries- AC cars chassis #A98 had a 289cid/4.7 litre ‘Windsor’ engine which developed circa 355bhp, the Shelby cars had around 385bhp.

The car qualified conservatively second in class behind the Gurney/Bondurant Shelby entry and ran in that race position, at one point leading the class early in the race averaging 20mph for the first 3.5 hours.

The big coupe began to have fuel feed problems which were found after the race to be caused by newspaper in the fuel tank- sabotage- which blocked the fuel filter. Much time was lost as the filter blockage was diagnosed and remedied.

Circulating at the pre-race determined lap times the next stint was trouble free with the slippery machine able to match the Shelby’s top speed despite less power and a higher diff ratio (2.88:1 rather than 3.09:1- the fastest Daytona speed of the weekend was 186.4mph @7000rpm using the 3.09 ratio).

It was an unusually bitterly cold night for mid-summer with occasional patches of mist. Some reports have it that the teams tyre supplier advised not to change the cars tyres. At around 10.15pm on Saturday evening, with Bolton at the wheel a tyre blew at Maison Blanche- the car spun and was collected by Giancarlo Baghetti’s following works Ferrari 275P. The Ferrari speared off into the barriers and crushed three French, late teenaged spectators standing in a prohibited area.

The AC flew over the guardrails, lopping branches from trees at a height of 20 feet before coming to rest in a crumpled heap. Baghetti was uninjured with Bolton taken to hospital with minor injuries.

The best placed of the Shelby Daytona Coupes was the Dan Gurney/Bob Bondurant driven car which qualified 10th and finished 4th. Sears qualified his machine 13th, the Jean Guichet/Nino Vaccarella works sports-prototype Ferrari 275P 3.3 V12 won the race that year.

The wreck of Coupe A98 was brought back to the AC headquarters in Thames Ditton and never rebuilt and or raced further ‘in period’. The very significant car was restored by Barrie Baird who negotiated its purchase in 1972. The work took over 12 years, many of you will have seen it at Goodwood and the like.

What a superb looking machine the car is, Le Mans paddock 1964. #43 is the Hunt/Wagstaff Lotus Elite 22nd, #42 is the Lawrence/Spice Deep Sanderson 301 BMC DNF. What a magic atmospheric photo (ITMSP)

The high speed excitement about the AC Coupe started in much more amusing fashion, although it wasn’t seen that way at the time, not long before Le Mans.

Given the Motor Industry Research Association (MIRA) roads had not allowed a flat-out run AC decided to test the high speed stability of the car on Britain’s M1 motorway in an incident which has gone down in motoring lore.

‘Gentleman Jack’ Sears recalled the early morning run in articles published in ‘The Car Connoisseur’ and ‘Autocar’ magazines.

‘About a fortnight before Le Mans AC thought they really ought to try and test the car to see what top speed it was likely to attain. We decided to get up at dawn on this early June morning and do a run up and down the M1 motorway. There was nothing special about that in those days when the M1 was used by other manufacturers with nearby factories such as Jaguar, Aston Martin and Rootes Group (Humber, Hillman and Sunbeam-Talbot).’

‘So we all met at Southern Service Station, warmed the car up, and I went up the north carriageway for several miles, and clocked what I thought was terminal speed before returning south without passing any traffic – it being 4.30 am. Back at the service station I told them how many revs I’d done, they knew what the back axle ratio was, they knew what the tyres size was, the wheel size etc etc, and from their slide rules (no calculators in 1964) they discovered that we had done 185mph. Then Peter Bolton, who was to be my co-driver, went off and did the same thing. We were both happy with the car and by 8.30am I was back home in Norfolk eating eggs and bacon.’

‘Around lunchtime I took a call from a journalist on the Sunday Times who had somehow picked up the story in a Fleet Street wine bar from a chap called Tony Martin, Derek Hurlock’s nephew, who was on the administrative side of the paper and had been present earlier in the day. It must have been a ‘quiet news day’ because they blew up the story out of all proportion. It hit the headlines and the press followed the story right up to Le Mans, where sadly the car was destroyed after a rear tyre burst, putting Peter Bolton into hospital.’

‘I am actually the only man in the world who has raced a Shelby Daytona Cobra Coupé, the AC Car Company Cobra Coupé and the Willment Cobra Coupé.’

Sears AC during the early Saturday Le Mans laps, #18 the Aston DP214 driven by Salmon/Sutcliffe NRF , 250LM or 275P back a bit (unattributed)

Not too long after Le Mans Sears stopped racing to return to farming in Norfolk but he was still very much in demand as a test and development driver, but a monumental accident in a sports-racing Lotus 40 Ford at Silverstone came way too close to costing him his life, aged 35. It took him 12 months to recover but he never strayed far from racing, not least because his son David became a racer and team owner.

(B Bird)

In sequels to the M1 incident the publicity was very good for AC Cars, but the compulsory 70 mph speed limit introduced on British roads in 1967 was sheeted home to the exploits of AC and Jack!

He chuckled at the memory, ‘I took a lot of flak for being responsible. Indeed at the time there were those who felt that sort of speed on a public highway was irresponsible behaviour and I had to live with this for some time. I am glad to say that I was eventually exonerated when, towards the end of her life, Lady Castle was interviewed by Tony Martin and asked whether the story concerning his uncle’s car had any effect on her decision to impose the speed limit three years later. She remembered all the publicity but claimed that the speed limit was already under review long before – so I was vindicated!’

Wowee. Thames Ditton, AC Cars Ltd (Just a Car Guy)

Specifications in brief…

Three shots from ‘The Cobra-Ferrari Wars’.

Top-the Coupe body framework being constructed at Thames Ditton. Middle is the engine bay with the Weber 48IDA fed, cast iron, 355bhp pushrod 4.7 litre ‘Big Henry’ V8- what a marvellous race engine this ‘Windsor’ family of small block Fords is! At the bottom is Jack Sears alighting the car after THAT M1 morning run.

Etcetera: owner Barrie Bird adds…

A day after uploading this article ‘A98’s owner and restorer Barrie Bird kindly got in touch and added hugely to this story with some comments which are at the end of the piece in the readers comments area.

He also sent in some wonderful material, which he is sharing with us all- the first photos are ‘…ones of Jack on his farm and you can see the little farm roads which were traversed for half an hour or so at three figure speeds’.

‘Jack was very funny on the farm- he gathered a couple of his farm hands who knew what they were about and briefed everyone in very military and commanding style; “You will be positioned here, you will lookout for traffic there, the photographer will stand there. I shall only make two passes at low speed to be sure you get your shots”. So off he went at high speed, getting faster and faster, declining to stop, wearing a big grin all the while. Magic!’

(B Bird)

(B Bird)

(B Bird)

See the padlocked fuel caps below- ‘All I can tell you about the padlocked fuel caps is that the photo was taken before the race. Was it a case of bolting the stable door, or did the saboteur slip in during the refuelling? Who knows?’

(B Bird)

What a mess! A98 post Le Mans shunt- Peter Bolton was a lucky boy to escape with his life. The top front suspension leaf spring, steering rack, tank and a rocker cover are about all of the components I can pick.

(B Bird)

Barrie’s adds this piece about Jack Sears comments on the comparative merits of each of the different AC Coupes…

(B Bird)

Technical Specifications in Detail…

Barrie Bird advises as follows;

‘The specifications are in theory the same as the FIA homologation for the standard Cobra, except that, in those days, it was permitted to build a different body on the homologated chassis and still run as a production GT. I think this went all the way back to the inter-war years when the manufacturers would supply rolling chassis to be bodied by coachbuilders. In any event by 1964 this provision was being well abused and chassis modifications, ostensibly to support the special bodywork, were used to stiffen things up.’

‘A.C. to their great credit kept to the spirit as well as the letter of the law and A98 is quite usable on the road as a GT with a comfortable cockpit and a normal boot which will swallow a couple of big holdalls. The ground clearance has to be kept in mind and of course the car was designed before the era of speed bumps and potholes. The lowest point under the car is the diff. oil cooler and this does not take kindly to being in contention with tarmac!’

Dimensions et al

Wheel base 90 inches, Length 176 inches

Track Ostensibly standard at 51″ but in fact wider by reason of the largest homologated wheels 7.5″ front and 9.5″ Rear. The largest track is obviously on the rear and with the original Goodyears fitted increases to 66″

Weight at scrutineering 1964 le Mans 2482 Lbs. Weight in 1986, after reassembly, with tools, spare wheel & tyre, jack, oils and water, but without any fuel 2365 Lbs

Capacities- Fuel 30 Imp.Gals, Engine oil,wet Aviaid sump, 6 Imp Qts

Wheels and Tyres

Tyres Goodyear Bluestreak 26.5 x 8 – 15 and 26.5 x 10.5 – 15

Wheels Halibrand Indy 500 pattern WH6S 2528 and 2532 F & R 7.50″ and 9.50″. Often incorrectly described as ‘FIA Pattern’

Transmission

Gearbox Borg Warner T-10 four speed. Nitride alloy gears ‘Pontiac Gearset’ – 1:1 – 1.31:1 – 1.637:1 – 2.196:1. Axle Ratio 2.88:1 Gearing in 4th gear 27.6 mph per 1000 RPM No allowance for tyre growth

Engine

289 V8, cid 4727 c.c. supplied by Ford Dearborn 355 bhp. Four 48 IDA Webers, ported big valve heads, high lift camshaft, standard High Performance crank and rods, HP 5 bolt block, damper and flywheel. Standard HP clutch

Lucas 28 amp competition dynamo, Lucas 100/100 watt le Mans headlamps, Lucas SFT foglamps

‘Apart from the body not much different to the production roadster, but Alan Turner certainly got the aerodynamics right.’ And so say all of us, it is a glorious motorcar.

Credits/References…

Barrie Bird, many thanks for making contact and contributing both comments and material from your archive for this article

‘Cars for The Connoisseur’, Klemantaski Collection, Inside The Motorsport Paddock (ITMSP), Autocar, ‘The Cobra-Ferrari Wars’ Michael Schoen, ‘Cobra: The First 40 Years’ Trevor Legate, Just a Car Guy, MotorSport

Tailpiece: Thames Ditton, AC men admire their handiwork pre Le Mans, simply superb looking machine…

(Just a Car Guy)

 Finito…