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Technical Report: McLaren Olds Series II

If you want to buy the fastest sports / racing car being built today, you'd better see Bruce McLaren!

Reprinted from the Sports Car Graphic Magazine January 1966

Text & Photos: Pete Biro - Reprinted from the Sports Car Graphic Magazine January 1966

Just about a year ago, Bruce McLaren arrived to do battle on the North American continent with a brand new sports/racer, designated the McLaren I. With it Bruce proceeded to take the circuit record at Mosport, just missing the record at Riverside, winning the qualification race and barely missed taking the whole show because of a minor non-design-caused burst water hose.

Following these very successful performances, Bruce contracted Elva Cars to produce his design in quantity, for sale to aspiring Chaparral hunters. In all there were eighteen Series McLaren I produced, with thirteen of them running in North America. Three chassis were built by McLaren's own crew; the one he raced last season (which is now used for tire testing), one car which he calls "half production" built for Dan Gurney, and now a new car for himself, the Series II, with evolutionary, rather than revolutionary changes.

From all outward appearances the new Series-II McLaren looks like a completely new car. The original bodywork has been scrapped and a new body-designed by English artist Michael Turner has been fitted. Turner did not have a completely free hand to draw just what he wanted from a purely aesthetic view­point; Bruce set down a very rigid set of cross section and aerodynamic requirements, and after the final drawings were made, a model was built for wind tunnel testing. Much attention was paid to the drag and lift characteristics, with a net result of about 20 percent less drag than with the Series I. Radiator ducting studies were conducted to achieve the optimum flow characteristics.

Following contemporary practices, a spoiler has been fitted to the tail of Bruce's car, but a very original bit of thinking went into its construction. It is fabricated from craft quality Plexiglass, and is clear, enabling the driver to see behind him. Many spoilers hinder rearward vision. After a couple of appearances it was noted that three or four other cars switched to clear Plexiglass spoilers.

At Mosport this year in the new car, McLaren led 96 of 100 laps, only be overtaken by Jim Hall's Chapparal in the closing moments. At Kent Phil Hill took over the controls, putting up the only threat to the Chapparals, finally taking the lap record at 1:20 flat, Phil led until he was forced into the pits to repair a sticking throttle. Bruce skipped Laguna Seca and made his next appearance at Riverside, where he smashed the lap record with a 1:26.6, and easily won the qualifying race. In the main event, Bruce found himself in the wrong gear at the start, then in the pits to replace a flat tire, finishing a strong third, much closer, to the winner than the time consumed in his pit stop.

Like the Series I, Bruce's Series II is constructed of round and square tubing with only subtle changes made for strengthening. Four main rails are used, with truss-type outriggers above the side mounted, pontoon-like fuel tanks, adding to the rigidity. The floor pan, as well as the wheel-well sheet metal, is stressed. The firewall behind the driver is aluminum-alloy sandwiching a wood core, with a removable center door in the firewall to get at the front accessory drive units on the engine. A pair of semi-reclining alloy bucket seats are fitted.
 

Anti-dive front suspension layouts are used with very wide-based pickup points. The upper A-arm has a side link, with a leading arm attached to the cockpit scuttle-hoop. The lower A-arm is comprised of a side link with a trailing arm attaching to a forward frame member, placing the fore and aft suspension arms in tension instead of compression. Inclination of the upper arm reduces the tendency to nosedive under braking loads. An anti-sway bar crosses the frame above the driver's feet, angling forward to join the lower A-arm via a ball-jointed vertical link. The bar is carried in a Teflon bearing surface, is removable and is attached with screws. Telescopic shocks, wrapped with adjustable-tension coil springs are fitted front and rear. Girling BR callipers squeeze 12-inch Meehanite discs. Steel braided, Teflon, Aeroquip brake lines are fitted. which eliminate any spongy feel in the pedal. Cool air is fed to the discs via flexible hose, with the air inlets in the nose.

Photo yet to be retrieved from archive 

Above: Jim Travers of TRACO looks on Bruce's 5-litre Olds with tender, loving care as McLaren's use of their engines opened the European market for them. Below, the revamped Series II car has a stubby body that makes it appear smaller, even though wheelbase and track dimensions are the same. Its chassis and suspension have been strengthened and redesigned.

 Photo yet to be retrieved from archive 

Above: Relatively blunt nose has good side-flow to help stabilize the car, cut drag in that area.
 
The rear suspension follows conventional practice, with a single upper sidelink, a reversed lower wishbone and trailing links for fore and aft location. Bruce is still experimenting with the upper-link length and pick-up point, trying to get the least camber change with a link about two inches longer at Kent than on the production versions, but at Riverside the car was fitted with the shorter link. The same size Girling calipers are fitted at the rear, as are fitted up front.

The rear anti-sway bar runs across the chassis below the trans-axle, along the rear frame bulkhead, mounted in Teflon, attaching to the upper end of the hub carrier via vertical ball jointed links. A choice of gearboxes is offered with the five-speed ZF being fitted to Bruce's, Oldsmobile version. Weighing but 127 pounds, the ZF is not considered heavy enough for use with bigger torquers, like Fords or Chevies, and for these applications Bruce recommends the 135­pound Hewland LG-4. The wheels are driven through Mercedes Benz internally splined drive shafts.

Above: Long upper arms for the rear suspension were used at Kent, but replaced for Riverside race

Steering arms are sheet steel, doubled and boxed to support spherical joint top and bottom

Front bay of the space frame car is typical of the efficient simplicity designed into it

Above: The “office” is businesslike. Fresh air duct that may find its way in the cockpit at speed

Above: Pannier fuel tanks are low mounted on both sides, outside of frame tubes, hold 62 gallons
 
McLaren cast magnesium wheels are fitted, carrying Firestone "Indy" tires, with two-inches wider track than before. His wheel design appears to provide very good ventilation for the brakes, without sacrificing strength.

The bodywork fitted to this car is aluminum, and future copies, once finalized, will be made from fiberglass. One thing that has allowed Bruce to build a much slimmer, slipperier car is the revised F1A rules, particularly in the case of not having to carry a spare tire. Looking at the Series I, it appeared that the biggest design limitation was having to carry the spare above the driver's legs. Quite stubby looking, the new car is 14 inches shorter than the Series I.

The handling of the new car appears to be equal to anything going, Phil Hill stating: "It's the most honest car, with the best manners, I've ever driven." Phil liked the engineering, adding: "The controls are very consistent, and the brake equalizer really works."

Through the very difficult Turn Six at Riverside, we were able to get corner times from Shelby driving instructor John Timanus, who has special points of reference he uses in his classes. Timanus said: "The fastest cars through six were McLarens, with Graham Hill at 10 seconds flat in the Series I, while Bruce went through at 10.3-seconds. Graham's car had a bit more oversteer allowing him a slightly quicker exit." The oversteer probably hurt Hill in the quicker turns, Bruce having the faster lap times.

Part of the reason for Bruce's fast times can be attributed to what's under the rear hood. For some time now Bruce has been working very closely with Jim Travers and Frank Coons, the Whiz Kids from Venice, California known as TRACO. Their emblem shows a big arm with a dumbbell bending to its grip, bearing a tattoo with the words "STRONG MOTHER" in the appropriate spot. They aren't kidding.

Taking a little aluminum Olds block, TRACOizing includes an increase of displacement to 300 inches (five liters), adding an Engle roller-camshaft, with stock rocker arms, but a specially fabricated steel rocker stand. JE pistons are running' Warren-machine 'H-beam' rods that just don't give up, which in turn are motivated by a Moldex 3.400 crank. Pins are special, as are oversized valves, with rings by Perfect Circle. Four two-throat 45mm Weber carburetors ride on a special TRACO manifold. Horsepower has been increased over last year's 350 to a very healthy, long-living, 392.

Bruce chose the Olds over the bigger, more powerful Chevy because it is 200 pounds lighter than the Chevy, and with the Olds, lighter running gear can be used. There is less of a problem with weight transfer too. Dry weight estimates run right around 1285 pounds, with a ready-to-charge weight, including driver and fuel, right near 1550.

One of the key men in the McLaren operation is Tyler Alexander, who does much of the car building, and of course team manager, Teddy Mayer, who handles the business end, as well as the strategy. Assisting with preparation (you'll have to go a long way to find a better prepared car) is Bruce's namesake, "Little Bruce" and "Beany". Tyler says: "The only thing you can get, right now in racing that you can just turn on and have it absolutely right, ready to go, is a TRACO engine." It looks like the new McLaren can be added to that list.

Carl Haas, the U. S. importer, told us he plans to be able to start delivering copies in January, at about eleven­thou, less engine, but with gearbox and tires.

Oh yes: Bruce is testing a new three-liter Formula One car with his name on it. If it goes like his sports/racing car...look out Wee Jimmie!

 

 

Zerex Special

Photo by Don Markle

This was Bruce's first race car for the American series. The chassis was rebuilt in the UK and was based on rebuilding from just behind the front suspension to just ahead of the rear suspension with a new McLaren-designed tube frame that was welded in. This chassis was far stiffer that the willowy Zerex original and it had the sophistication of having the water and oil flowing through the chassis tubes. There was no time to fabricate the new exhaust system and the car was flown to Mosport with eight stub exhausts poking up through the tail. First time out it won at Mosport that year and at Brands hatch at the end of August 1963.

The car had three names, one "The Jolly Green Giant" (because due to a lack of time to finish the car, a handyman's store was visited and a can of garden gate green was obtained), the second name was the "Zerex Special" (re-framed and reengineered, which the car was more commonly known as) and for various reasons Bruce decreed that the car should be known as the "Cooper Oldsmobile". Officially the car was a Cooper Oldsmobile when Bruce won with it at Mosport in June 1964. The car won another race in the Guards Trophy at Brands Hatch at the end of August that year.

M1A

M1A - 1964-65

The original McLaren-built Group 7 sports racing car was a simple spaceframe design with a light and compact Oldsmobile V8 engine; Cooper wheels, uprights and steering arms, and a Hewland Gearbox. Fitted with the engine effort the Zerex, the McLaren M1 lowered the Zerex's records at Goodwood by a clear three seconds.

The car was painted black with a silver stripe (New Zealand's colours) and it was the fastest car on the track at Mosport in September, but with a broken throttle linkage and a long pit stop, Bruce came back to finish third. Later on that season at Nassau the car was painted an orange red colour and the car finished second to Roger Penske's Chaparral.

In England, Frank Nichols of Elva Cars called on Bruce and a long association was formed with Peter Agg of Trojan (Elva's parent company) to build McLaren replicas. They were to be called McLaren-Elvas. The M1A was put into production as the McLaren-Elva Mark 1 and versions appeared with 4.7 litre Ford V8 power in addition to the standard 4.5 litre Olds. A total of 24 were built and met with success, although it became apparent that the Olds engine was just too small for the class.

Chassis: Large diameter round and square tubular frame with light alloy sheet riveted and bonded to it, forming a stressed undertray and bulkheads.

Suspension: Independent by unequal length wide-based wishbones, anti-roll bar and adjustable coil spring/shock units in the front. Trailing radius arms with single top links, reversed lower wishbones, anti-roll bar and adjustable coil spring/shock units at the rear.

Brakes: Dual circuit Girling discs all around.

Body: Four-section polyester resin with integral brake and radiator ducting and side sections housing twin fuel tanks.

Engine: Traco Oldsmobile 4.5 Litre V8 standard with Hewland LG 4-speed gearbox.

Dimensions: Wheelbase 91 inches, front track 51 inches, rear track 51 inches.

M1B

M1B - 1965-66

This Group 7 sports racing car was the 1965 development of the original M1A design. The design of the M1B was evolved the by artist Michael Turner, working with Tyler Alexander and Robin Herd. It had a blunter noise and sharper cut off at the tail. Design work by Robin Herd saw the M1B gaining a 20% stiffer chassis than the M1A, and the M1B was no heavier. The first race was at St Jovite and resulted in an ignominious retirement in practice when the Oldsmobile blew up wrecking the transmission as well. Before Mosport, a new 4.5 litre had arrived from Traco and with this installed Bruce finished second to Jim Hall’s Chaparral.

For the first Can-Am series in 1966 it became obvious to team McLaren early in the season that their 5-litre Traco-Oldsmobile were going to be no match for the 6-litre Chevrolet. After the opening races in Canada, Bruce switched from the aluminium engine to the cast iron 5.4-litre Chevrolet which weighed 200lbs more, but gave an extra 100 horsepower.

The works car driven by McLaren and Amon competed in the 1966 Can-Am series powered by the 6-litre Chevrolet V-8 with Hilborn injection. Both Bruce and Chris were pace setters, but they were not winners, with Bruce finishing second in the series to Jim Surtees.

Trojan manufactured twenty-eight cars that were sold in the US as McLaren Elva Mark 2's.

Chassis: Large diameter round and square tubular frame with light alloy sheet riveted and bonded to it, forming undertray and bulkheads.

Suspension: Independent by unequal length wide-based wishbones, with anti-dive characteristics, anti-roll bar and adjustable coil spring/shock units in the front. Trailing arms with lower wishbones, single top links, anti-roll bar and adjustable coil spring/shock units at the rear. McLaren-Elva cast magnesium wheels, 15 x 8˝ front, 15 x 11˝ rear (5.50 and 6.50 - 15 tyres)

Brakes: Dual circuit Girling discs all around. 12˝ inch diameter front and 11˝ inch diameter rear.
Body: Four-section polyester resin with integral brake and radiator ducting and side sections housing twin 25-gallon rubber fuel cells

Engine: Traco Oldsmobile 4.5 litre V8 standard with single plate Scheifer clutch and 4-speed Hewland LG gearbox. Hypoid ring and pinion with limited slip differential standard in transmission. Chevrolet and Ford engines and ZF transmission optional equipment

Dimensions: Wheelbase 91 inches, front track 51 inches, rear track 51 inches, overall length 146 inches, width 64 inches, height to top of windscreen 31 inches, weight less fuel 1300 pounds distributed 40 percent front / 60 percent rear.

M1C

M1C - 1966-67

The M1C was built by Trojan as customer cars, using the spaceframe design from the original design. These M1C variants, sold as Mark 3s, were generally powered by Chevrolet engines, although Ford or Oldsmobile options were listed. The model was a further improved and developed M1B with a separate spoiler wing at the tail. Twenty-five were built and were sold in the USA as McLaren Elva Mark 3s.

Chassis: Large diameter round and square tubular frame with light alloy sheet riveted and bonded to it, forming undertray and bulkheads

Suspension: Independent by unequal length wide based wishbones, with anti-dive characteristics, anti-roll bar and adjustable coil spring/shock units in the front. Trailing arms with lower wishbones, single top links, anti-roll bar and adjustable coil spring/shock units at the rear. McLaren-Elva cast magnesium wheels, 15 x 8˝ front, 15 x 11˝ rear (5.50 and 6.50 - 15 tyres)

Brakes: Dual circuit Girling discs all around. 12˝ inch diameter front and 11˝ inch diameter rear.
Body: Four-section polyester resin with integral brake and radiator ducting and side sections housing twin 25-gallon rubber fuel cells

Engine: Traco Oldsmobile 4.5-litre V8 standard with single plate Scheifer clutch and 4-speed Hewland LG gearbox. Hypoid ring and pinion with limited slip differential standard in transmission. Chevrolet and Ford engines and ZF transmission optional equipment

Dimensions: Wheelbase 90.5 inches, front track 52 inches, rear track 52 inches, overall length 146 inches, width 66 inches, height to top of windscreen 31 inches, weight less fuel 1300 pounds distributed 40 percent front / 60 percent rear.

M12 - 1969

This was an out of sequence designation applied to the 1969 production Group 7 sports/racer. It used an M8-type body-shell on an M6 series similar monocoque tub. Standard mountings were provided for Chevrolet engines and a total of 15 were produced, including one with a narrower M6-type body shell for hill-climber driver Phil Scragg. Chaparral campaigned one while its own 2G model was being developed. Several GT versions were built by Trojan.

Chassis: Monocoque with aluminum alloy paneling bonded and riveted to fabricated steel bulkhead, with three fuel cells in the sills and under the driver’s knees holding 52 gallons.

Suspension: Unequal length wide based wishbones, anti-roll bar and coil spring/shock units in the front. Single top links and reversed lower wishbones with twin radius arms and coil/springs shock units at the rear. McLaren cast magnesium wheels, 15x10 front and 15x15 rear (10.55 and 12-50-15 tyres)

Brakes: Girling ventilated discs, 12 inch diameter front and rear, with 16-3-LA calipers and dual hydraulic circuits.

Body: Formed by monocoque sides with detachable fiberglass top panels.

Engine: Standard mountings for Chevrolet V8 and Hewland LG 5-speed transaxle.

Dimensions: Wheelbase 93.5 inches, front track 57 inches, rear track 55 inches, overall length 155 inches, width 75 inches, height to top of windscreen 30 inches, weight less fuel 1300 pounds distributed 40 percent front/60 percent rear.
M12GT

Specifications as for the M12, however it had a shortened M6GT coachwork fitted to it. Read the story about this car.

Photos by Don Markle

M12


M17

The M17 designation was allocated to a 3-Litre prototype sports car but the project was abandoned.

 

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