Mclaren-Elva Cam-Am Car 1966
An example of the latest -thinking in all-out sports/racing cars
IN TESTING THIS McLaren Elva Chevrolet, we were for
tunate in several ways. First, it was a rare privilege to be allowed to test a firstrate representative of the latest thinking in all-out sports jracing car design. We were lucky that the owner of the car, Charlie Hayes, was willing to submit his brand new machine to whatever we asked, even though much of our normal performance testing procedure was of no more than academic interest to him. We were also fortunate to obtain the cooperation of Goodyear and be permitted to encroach on their tire testing program at Riverside Raceway to run our own tests.
The car is a Mark 2 McLaren Elva, a production version built by Elva Cars to the specifications of the prototype Bruce McLaren campaigned last fall. Charlie's car is serial number 001, the car that was shown at the London Racing Car Show
in late January. '
The basic price of the Mark 2, without engine, is $11,500. This does not mean that one simply fills the hole in the engine bay and goes racing, however. Hayes is a seasoned campaigner and has learned that although such a car as this, when delivered, may contain the basic elements of racing success, these basic elements must be closely inspected to assure that they are all sound of material and fabrication. In addition, certain components may be replaced by those the owner believes to be better suited to the job at hand.
Hayes and his crew began an inspection and modification program as soon as they received the car. The car was stripped to its bare bones, inspected and re-assembled. One of the major changes in components was to replace the Girling disc brakes with Airheart units. The Airhearts are lighter in weight, neater in installation and save about 5 Ib in unsprung weight at each wheel. Some of the modifications undertaken included reinforcing certain suspension members, changing the pedals to suit Charlie's preferences and fabricating flexible ducting and fittings to cool the brakes. Other changes made during the re-building process included changing all nuts and bolts to Grade 8 Lamson & Sessions, replacing all flexible lines and fittings with aircraft type hoses and hardware made by Aeroquip, and installing Wiggins quick-disconnect units at points where fluid lines require periodic removal for maintenance or replacement. "You do stuff like this to make the car easier to work on," chief mechanic Ed Schafer explains, "as well as to make sure you've got components you can believe in."
The modification and rebuilding program, plus installation of the engine, required a full month of full-time labor for Charlie and his crew. This crew, which is typical of the minimum basic personnel for a one-car race team, consists of Charlie, the owner manager driver, chief mechanic Ed Schafer and helper Bob Morgan. In addition, Charlie's wife Evey is available for odd jobs, parts chasing and secretarial duties.
The engine chosen for use was a 333-cu-in. Chevrolet V-8 prepared by Traco Engineering. This "little" engine (a 327 Chevrolet bored 0.050 in.) was selected because Charlie plans to run a full season on a tight schedule and is not inclined to take a chance on trading reliability for greater output. Equipped with four side-draft 2-barrel 58-mm Weber carburetors, this engine puts out 466 bhp at 6500 rpm and develops 445 lb-ft of torque at 4500. The as-installed engine, including $1300 worth of carburetors and manifolds, comes to $4500. This is practically dirt cheap for a racing engine.
The basic list price of our test car complete with engine and four $70 Goodyear tires is $16,280. Considering the modifications made to Hayes' car, it is likely that about $25,000 would, be required to duplicate it in the "as tested" condition. But even this amount does not mean that you can go racing on this scale for "only" $25,000. There is also the matter of spare parts and of getting from race to race. Basic spares the team will carry this season include a second engine (less carburetors), gearbox, complete sets of gearbox ratios; brakes, hubs, suspension components, wheels, tires and so on. To get the equipment and personnel from race to race, the team has a I Chevrolet sedan, a Chevrolet pickup and an enclosed trailer. A complete one-car team like this probably is worth about $40,000 on the open market. .
Charlie, as an experienced owner with a good reputation both as a driver and a representative of the sport, isn't carrying the entire financial burden by himself. Charlie's prime sponsor is Nickey Chevrolet of Chicago and though Charlie is actually the legal owner of the car, all the emphasis is on the "Nickey" signs carried on the race car and other equipment. Charlie is also under contract to Goodyear and though he does not receive a regular amount per month or per race for using Goodyear tires, he is paid for the use of his car in tire testing programs (which is also valuable to. Charlie because it enables him to sort out the car at somebody else's expense) and can win bonus money for placing well in professional races where Goodyear offers accessory money. Accessory money is also offered by Champion spark plugs and a few other component suppliers in exchange for "billboard" space, a well-known entrant like Charlie can get substantial reductions in price on many items of equipment and this accounts for the display of decals carried on the side of almost all racing cars these days.
Getting to the car itself, the McLaren Elva is small in overall bulk. ]n plan view, it has about the same length, width and wheelbase as an MGB or Lotus Elan but is much lower and has considerably less frontal area (roughly 11.5 vs. 16.5 sq ft). Considering the size and bulk of the engine and gearbox, the McLaren Elva Chevrolet is also light, weighing just over 1500 lb wet but without fuel. Fully laden on the starting grid, including the 175-lb driver and 55 gal of fuel, it weighs slightly more than 2000 lb. With the driver aboard, the weight distribution is 41 /59 percent front /rear.
The basic chassis structure is of small-diameter tubing, but it is modified with structural diaphragms and stressed sheet metal pans for rigidity. ]n this respect it combines some of the characteristics of the semi-monocoque chassis with the multi-tube space frame. This is an admirably practical form of construction for a car that is going to be rigorously campaigned by a private entrant, as it is not only rigid and durable but the almost inevitable collision damage of a minor nature can be repaired using basic hand tools and portable welding kit. It is basically a very simple structure and, once the front and rear body shells are removed, almost everything is accessible for whatever adjustment, repair or replacement is needed.
The suspension is typical of the contemporary road racing car-independent with what is basically an upper and lower arm arrangement-and is simple, light and adjustable. The arms and links are fabricated from mild steel tubing and all
have turnbuckle-type fittings to permit quick, accurate adjustments for chassis tuning. The axle shafts are of Mercedes 300SE origin. The disc brakes are set slightly inboard of the deep wheels for good air circulation and cooling. _
The McLaren Elva has righthand drive, partly as a result of its British heritage but also because road racing circuits traditionally run in a clockwise direction and therefore have a larger number of turns to the right. There is no surplus space in the driving compartment. Charlie, who is over six feet tall, finds the car a very tight fit and is somewhat concerned over being able to tolerate the cramped quarters for long periods of time. He has made some modifications to the seat to give his lower back better support, but there is simply too little space to do very much about it. Though our standard Driver Comfort Rating is not directly applicable to a racing car, the results (under 70, poor for even a driver of average height) do indicate the lack of comfort the driver can anticipate.
From the driver's seat there is excellent forward vision even though the position is semi-recumbent in front of the driver there is a full assortment of instruments, including a 10,000 rpm tachometer with tell-tale needle. In addition to the usual instruments there are gauges for gearbox lubricant temperature and for fuel pressure. There are no warning lights.
The starting procedure has three steps: 1. Switch on fuel pumps, 2. Switch -on ignition, and 3. Jab the starter button. These are all in a group at the right end of the instrument panel and the ignition switch has a spring-loaded cover - to prevent accidental switching off. The engine started readily during our tests and would idle at about 1500 rpm if left to itself. The engine warms up very rapidly when the car is sitting still because there is no engine fan to keep air circulating through the radiator and, like most drivers, Charlie dislikes being kept on a starting grid waiting for the flag to fall.
For a "drive-away" start, Charlie employs a nice balance of clutch and throttle application to get into motion with a minimum of abuse to the clutch. For a racing start, the revs are raised to about 5000, the clutch dropped and the wheels allowed to spin. The "little" Chev engine develops its maximum torque at fairly high revs (4500) and the tach needle must therefore be kept well up in - the working zone if the engine isn't to bog down getting away.
The gearbox is a Hewland LG 500 (the manufacturer's designation for Large Gearbox, 500 bhp rating), a 4-speed manual transmission with straight-cut, non-synchronized gears. The use of a crash box sounds crude in these days of fullsynchro 5-speeds and sophisticated automatics for racing cars but Charlie has found it to be dependable in operation and not so awkward to manipulate as the average driver would imagine. Before using the gearbox in the car, chief mechanic Ed Schafer broke it in by hitching it up to a lathe and running it for 12 hours.
As we tested the car, it was fitted with the gearbox ratios best suited to the 2.6-mile "club" circuit at Riverside. A wide range of ratios is available and in this type of gearbox, the box ratios themselves are changed rather than the final drive. The ratios are ordinarily chosen to suit a particular circuit and are necessarily a compromise between acceleration and top speed. As geared, our test car had a 6.66: 1 first gear overall, which accounts for the comparatively slow acceleration away from' a standstill. At the same time, more than 85 mph is available in this first gear, which makes it a highly practical and usable gear getting away from a typically "slow" 40-50 mph turn under racing conditions. The standing-start quarter-mile of the McLaren Elva Chevrolet (an elapsed time of 12.0 sec and a terminal velocity of 142 mph) exemplifies the difference between a road racing car and a dragster. A dragster with about the same weight-to-power ratio and geared to make use of all its performance in;-a- quarter mile would get through -the quarter as much as two seconds quicker. At the end of the quarter, though, the road racing car would not only be going faster (roughly 142 vs. 130-135) but would have another 20 mph of top speed left while the drag car would be out of revs.
At the end of the drag strip, too, the dragster would pop his chute and come to a gradual halt while Charlie in the McLaren Elva would simply mash hard on the brake pedal. Our decelerometer reads only to -1 G (minus 32.2 ft /sec2) and when Charlie clamped on the brakes from 150 mph or so on the back-stretch, the fluid simply disappeared out the bottom of the tube. The combination of brakes that work plus the adhesion of the wide, sticky tires makes for almost uncanny deceleration, compared to the braking effectiveness of a passenger car or even the well braked production sports car.
The radial acceleration capability of the car is likewise far beyond the experience of the driver of ordinary cars, even ordinary sports cars. A sports /racing car such as the McLaren Elva is probably able to lap most quickly (on most circuits) when set up for light understeer as there is sufficient power to induce oversteer whenever it is needed. In other words, the car is "driven" around most corners but a toss-and-catch technique can be used whenever it is quicker to corner with the tail out. This makes cornering a less spectacular art than it was in the glorious days of side-sliding big-engined specials and indeed the expert driver of today takes pride in making it look easy. From outside the car, a skilh~d driver's trip up through the Riverside esses seems almost one continuous fluid motion, graceful and easy as a waltz. Inside the car, however, the observer can appreciate the dozens, even hundreds, of judgments, movements, corrections and counter-corrections made by the driver even though, with a driver like Charlie, there is absolutely no change of expression to reveal the myriad decisions going through the computer.
At racing speeds, too, the observer becomes aware of the physical stresses imposed on the body. You can almost liter
. ally feel the viscera sloshing about as the car swings up through the esses, and there is a heavy strain on the neck muscles as the head is thrust forward during heavy braking. To the unaccustomed passenger, there is also wonder at the driver's ability to function satisfactorily in the presence of such noise and comparative discomfort. The human body adapts to these conditions quickly, however, and in only a few laps is automatically screening out extraneous data and concentrating exclusively on the relevant impressions being fed to him through hyper-alerted senses. .
All in all, the McLaren Elva Chevrolet is a remarkable machine. It is an all-out road racing car, designed and built for this one purpose, then modified and re-built to suit this one purpose even better. It is a fine machine, too, beautiful in the intelligent simplicity of what is necessarily a complicated mechanism. It also has the fascination that a superb piece of machinery holds for those who appreciate such things, and looking at it for a long time, carefully, makes it possible to understand the genuine affection that a man can experience for such a machine. It seems worthy, somehow, of the hundreds of hours of labor that have been and will continue to be expended on it and the undeniable pride that Charlie, Evey, Ed and Bob have in the car.
The ultimate evaluation of its worth, however, must come on the road racing circuits during the season ahead and it will be interesting to see how well it does compared with the several other cars which, although basically similar, are attempting slightly different solutions to the same problems. Ed. Note Since this was written, Hayes retired from his first two races at Las Vegas and Riverside, leading for 27 laps in the latter, but won handily at Laguna Seca to move into a tie for 3rd in USRRC standings.
Bore x stroke, mm. . . . . . .103 x 83
In. . . . . . . . .. . . . . . . . .4.05 x 3.25 Displacement, cc/cu in.. .5458/333 Compression ratio.. . . . . . . . .10.5:1
Bhp @ rpm.. .. .. ... .466 @ 6500
Equivalent mph. .. .. .:.. .. .178
Torque @ rpm, Ib-ft. .445 @ 4500
Equivalent mph. . . . . . . . . . . .123
Carburetors. . . .4-2V Webers
No. barrels, dia.. . . . . .2-58mm
Type fuel required... . . . . premium ACCOMMODATION
Normal capacity, persons . . .1
Occasional capacity 2
Seat width, L/R .. .. .10.0/13.8
Head room. . . . . . . . . . . . . . . . no top Seat back adjustment, deg. . . . . .0
Step-over height. . . . . . . . . . . . .13.5
Door width. . . . . . . . . . . . . . . . . .20.5 Driver comfort rating:
Driver 69 in. tall. . . .69
Driver 72 in. tall .62
Driver 75 in. tall. . . .. .. .. .. .62
(85-100, good, 70-85, fair;
under 70, poor)
CHASSIS & SUSPENSION
Frame type: multi-tube with struc
tural diaphragms & belly pan
Brake type.Airheart disc, outboard
Swept area, sq in. . . . . . . . . .245
Tire size .9.50-15 f/12.10-15 r
Make. . . . . . . . . Goodyear "I ndy"
Steering type. . . . . . . rack & pinion
Turns, lock-to-Iock. . . . . . . .1.75
Front suspension: lower double Aarm, upper A-arm, coil spring with concentric tube shocks, antiroll bar.
Rear suspension: lower A-arm, upper straight control arm, upper and lower trailing arms, coil springs with concentric tube shocks, anti-roll bar.
Clutch type .Schiefer sdp
Diameter, in. . . . . . . . . . . . . .10.0
Transmission .Hewland LG500
Gear ratios: 4th (0.97) .3.25:1
3rd (1.14) . . . . . . . . . .3.81:1
2nd (1.50) .5.00:1
1st (2.00) .6.66:1
Synchromesh. . . . . . . . . . . . . . . none Differential. . . . . . Dana limited slip
Optional ratios. . . . . . . numerous
Race weight, Ib, no fuel.. . . . . 1505 Test weight (2 up, 30 gal fuel) 2040
Weight distribution (with
driver), front/rear, %.. . .41/59
Wheelbase, in. . . . . . . . . . . . . . .90.2
Track, front/rear .52.0/51.5
Overall length . . .. .. .. .. .. . .147.2
Width. . . . . . . . . . . . . . . . . . . .59.0
Height to top of windscreen.31.6
Height to top of rollbar. . . . .35.0
Height to top of spoiler .34.9
Frontal area, sq ft .11.5
Ground clearance, in .3.3
Overhang, front/rea r.. . .33.7 /23.3 Departure angle, deg. . . . . . . . . .43
Usable trunk space, cu ft O
Fuel tank capacity, U.S. gaL... .55
Instruments: 10,000-rpm tachometer, water temperature, engine oil temperature, gearbox lube temperature, oil pressure, fuel pressure.
Warning lights: none.
Body styles available: 2-seater
sports/racing car (as tested).
Racing, mpg .4-5
Warranty period. . . . . . . . . . . . n.a.
Cruising range, mi . . . .220-275
Lb /h p (test wt).' . . . . . . . . . . . . .4.37 Mph/1000 rpm (4th gear). .. . .25.4
Engine revs/mi (60 mph) .2360
Piston travel, ft/mi. . . . . . . . . .1280 Rpm @ 2500 ft/min.. . . . . . . .4610
Equivalent mph .117
Cu ft/ton mi. . . . . . . . . . . . . . . . .218
R&T wear index .30.2
EXTRA COST OPTIONS
Crankcase capacity, qt. . . . . . . . . .6
Change interval, mi. . . . . . . . n.a.
Oil filter type .full flow
Change interval, mi. . . . . . . . n.a.
Chassis lube interval, mi .n.a.
ROAD TEST RESULTS
Time to speed, sec:
0-30 mph 2.6
0-40 mph .3.2
0-50 mph 37
0-60 mph.: ..4.1
0-70 mph ..4.4
0-80 mph 4.8
0-100 mph .. .6.2
50-70 mph (Ist gear). . . . . . . .0.6
SPEEDS IN. GEARS
Top gear (6500), mph . . . . . . .178
3rd (6500) .147
2nd (6500). . . . . . . . . . . . . . . .110
- 1st (6500) 88
Passing exposure time, sec:
Car ahead going 50 mph. . . . .0.5