knows just how fast they'll go, these Can-Am cars, but they're
the fastest racing cars in the world, fastest in the sense
of getting around a road course as quickly as possible. They've
proved it several times, with faster lap times at tracks like
Mosport where Formula 1 Grand Prix cars also run.
At the tracks in the U.S. and Canada
they've geared down for maximum acceleration instead of
top speed. Even so, at Riverside they'll appraoch 200 on
the back straight. Considering that the Le Mans Mark IV
Fords could do 200 mph with 100 less horsepower and a higher
roof line, a top Can-Am car might be able to go 250 with
the right gearing!
One thing is certain: In spite of
the fact that this is a championship for drivers, it's equipment
that gets the job done in these events. Even some of the
best drivers admit that there are some places on some tracks,
like the downhill right-hander at Bridgehampton, where the
cars are just too fast.
With no limits on engine size, type
or power (except for a limit on turbines which make them
ineligible), there are certain to be some teams who have
more power, and more durable power, than the others. As
Dan Gurney found out last year, you can try to beat them
with lightness and smartness, but it's very nearly impossible.
Even though there's no limit on engine
size and type, most of the Can-Am cars are powered by modified
stock American V8 engines. There have been exceptions. Ferrari
had cars two years ago for Ludovico Scarfiotti, Chris Amon
and Johnathan Williams, last year for Pedro Rodriguez and
Amon, the latter a very fast special V12 racer with four
overhead cams that will be back in refined form this year.
The Ferraris have to be taken seriously
because they've stopped trying to prove that a small engine
can beat a big one by revving faster, and have built a big
one instead. Meanwhile the big ones are even bigger this
In 1968 most of the aluminum block
ZL-1 Chevrolets and "wedge" Fords were even-steven
at 7 liters, or 427 cubic inches. They were able to produce
between 580 and 620 horsepower, revving safely to 7000.
This year will see more of them at
8 liters, nearer 488 cubic inches, larger than the biggest
production car engine in the world, the 472-cube Cadillac
Because the additional liter in '69
is intended mainly to boost torque through the middle speed
ranges, it won't increase the horsepower in direct proportion.
Even so some of the big engines this year, the stroked Chevys
and the "marine" 490-cube version of Ford's semi-hemi
V8, will reach and exceed the 660hp level.
These very large engines could never
have been used if Chevy and Ford hadn't moved, as they did,
to cast cylinder blocks in aluminum instead of iron. This
saves just enough weight to allow the big V8s, also with
aluminum heads, to be usable in the back of a light car.
The aluminum block actually causes the engine to lose power,
compared to an iron block, but they make up for that by
slicing off weight the power has to push. In 1967 McLaren
annihilated the opposition in Can-Am racing (for the first
time) with fuel injection. His were British Lucas injection
systems, which gave his engines a little bit more poser
and a lot better, sharper responce to the throttle.
McLaren also used the vaporization
of fuel in the manifold to cool the gasoline in the system,
reducing the cause of vapor lock. This slick little trick
had been borrowed from Grand Prox engines and was copied
in 1968 by Traco and Bartz, the most important builders
of Can-Am engines in the U.S. They also used Lucas injection,
while Jim Hall uses a special Rochester injection on his
Chaparral engines, prepared this year by Gary Knutson, McLaren's
Ford's Can-Am power units have had
modified Hilborn injectors much like those used on the Indy
Another important trend has been
to what racers call "dry sump" engine oil systems.
Now, the sump (oil pan) isn't dry, but neigher is it asked
to hold all the engine oil, as it probably does in your
car, unless you have a 300SL Mercedes or a Porsche Carrera.
Instead there's an extra big oil pump whose only job is
to suck the oil out of a shallow pan as it falls from the
engine, and pump it to a seperate oil tank. From there the
oil pressure pump sends it to the bearings.
The seperate oil tank can hold much
more oil than a conventional sump, allowing an engine to
finish a race even if it's using a lot. A larger oil volume
also stays cooler, helped by the seperate oil radiators
that are always used, and a properly designed tank can extract
unwanted air from the oil.
Further, removel of the oil from
the bottom of the engine means that the block can be placed
closer to the ground, lowering the car's center of gravity
and overall height vital advantages these days. That's
why the trend in sumps is towards the extra-dry.
Most Can-Am cars also carry a seperate
cooler for the oil in the transaxle, which can get pretty
warm carrying high torques at high speeds. This is catered
to by Mike Hewland, whose LG500 (four-speed) and LG600 (five-speed)
transmissions are used in most of the top cars.
The fastest don't always have more
speeds; Team McLaren used only four with the big Chevy in
his M8A because it had so much torque it didn't need five
And in the last few years Jim Hall's
famous automatic box has become progressively less so, after
starting out with only a hydraulic torque converter, like
an old Buick Dynaflow. Then a second speed was added and
finally a third one in the manually-shifted box back of
To put all the power on the road,
Can-Am car designers move as much weight as they can to
the rear (driving) wheels. That's one reason Hall put his
radiators in the rear, for example, to bring about two-thirds
of the car's laden weight on those tires to give them the
best possible bite.
Some weight has to be left on the
front wheels, of course, so you can steer the car! But another
approach is being taken this year with new drive systems,
to all four wheels. At least three builders are looking
at four-wheel drive.
Bruce McLaren's designing his own
four-wheel-drive system to use on his Grand Prix cars and
his Can-Am cars. Here's his reason why: "Putting all
the drive through the rear wheels means that you're only
working the front tires for braking, you might as well use
them for traction too. Once we get four-wheel drive working,
we expect the speed through the last half of the corner
and the exit speed from the corners to be up quite a bit."
For similar reasons Lola has built
a new Can-Am racer with Mike Hewland's 4WD system, like
the one on the Indy Lolas of the Penske team, and Armco
Steel has sponsored Bob McKee's latest car, with four-wheel
drive by Britian's Ferguson Research, a pioneer in the field.
Some of the most dramatic tire development
has taken place in Can-Am racing, again because there are
no limits to the expansion of tire width. On an open-wheel
car the tire offers a lot of the aerodynamic drag; a wider
one can sometimes slow the car down! Not so in the envelope-bodoed
Can-Am car, which can have tires as wide as the car is,
and sometimes probably will. They won't go quite that far
this year, but Goodyear and Firestone are still giving fits
to the wheel designers at Lola and McLaren as they come
up with wider and wider tires.
To use the latest rubber, Can-Am
teams often get help from Ted Halibrand, whose cast magnesium
wheels are world-famous, or from Fred Phun, whose new spun
aluminum wheels can be adjusted in width, thanks to their
Around 1960 Lola and Lotus were setting
the style for the kind of independent supension, with tubular
links and concentric coil-shock units, that future racing
cars would use. Today's Can-Am cars are pretty much the
same. There have been some attempts to be different, such
as the King Cobra of late 1967 and the solit-axle Caldwell
D7 and D7B of 1967-68, but they haven't been consistently
successful. The solit-axle approach may well bear fruit
in the future, though, with wider and wider tires which
like to be kept flat on the road.
What holds all this machinery together
in most of the Can-Am cars? A great big fuel tank with a
hole in it for the driver to sit in, that's what. The tubular
space frame, once considered the end of the line for a racing
car chassis, is now completly obsolete.
New Can-Am cars today have frames
riveted and glued together of steel, aluminum and magnesium
sheets to form what looks like, and is often called a "tub."
Fiberglass can also be used and was for the first successful
Can-Am "tub," that of the Chaparral 2. The size
of the center hole in the "tub" is governed by
the pertinent rules in Appendix A of the SCCA's General
Competition Rules, which rather loosely require that there
be room for a passenger.
Inside the "tub" there
are rubber bladders, built to be resistant to tearing in
a crash, retaining the more than 60 gallons of fuel these
thirsty cars need to finish a race of 150 to 200 miles without
a pit stop.
For the M8A, McLaren made a radical
departure from his competitors by using the engine, with
some tubular braces, as the rear part of the frame. The
front of the engine was attached to the "tub"
and the rear part, where the transaxle and attached, carried
the rear suspension. This helped Bruce keep the weight of
his championship-winning car down to only 1450 pounds, a
lettle less than a Healey Sprite, an MB Midget or a fiat
How does it go with more than 600
horsepower? Pretty well, like zero to 100 in little more
than 5 seconds and certainly less than 6.
Both Chaparral and McLaren have led
the way in designing bodies for these cars that help hold
the tires against the highway, replacing older styles that
looked nice but tended to take off and fly.
Certain features are evedent: a wide,
scoop-like nose that's as close to the ground as possible;
an upward flow of air out of the back of th radiator; vents
in the front fenders that keep aire pressure from building
up there, and a high, wide rear spoiler that deflects the
air upward as it's departing. If the complete shape is a
little like a wedge, or a doorstep, it's deliberate, made
to shove its way under the air, producing forces that hold
the car and its tires lightly against the road.
Last year Hall and Surtees were the
only Can-Ammers to use rear wings. McLaren tried them in
the development phase but didn't use them in racing.
This year, following a season in
which wings proved themselves in Grand Prix racing, we'll
see a lot more. And probably have the same trouble the G.
P. car makers have in keeping them attached to the car.
What are the wings for? To keep the tires pressed against
the ground, in the same manner as the latest bodies but
hopefully in a more powerful way, with less resulting drag
to slow down the car.
Those who really make the most of
wings on a Can-Am car will have designed new body shapes
to complement them correctly. Jim Hall, of course, did that