V 12
THE LATEST ROD BODS DOWNUNDER
PROJECT
THIS IS A
ONE OFF - UNIQUE
The Only 32 Three Window Coupe
powered by this extremely rare motor
The Rod Bods Downunder
Fibreglass 1932 Three Window Coupe Body is powered by
a GMC V12 Twin Six Motor (702 Cubic Inch) with a Turbo 400 Gearbox.
The body
has been mounted on a 32 Chassis
The interior has been fitted with black leather
bucket seats and has been fully trimmed with black leather and carpet.
A set of six Dolphin Gauges have been mounted
into the 32 Dash Panel, a 21 circuit wiring harness and pulse generator have
been installed.
All external hinges and dress-up chromed
This vehicle has been sold
The king of GMC's
gasoline engine family, the power-laden 702 Twin-Six. It makes
words like durability, performance and operating
economy take on a whole new meaning. It's
true truck horsepower and tremendous torque at low r.p.m.
take on the biggest jobs with an
easy-stroking effort. It digs into grades and requires far less gear shifting
to keep in step.
With relatively slow operating speed, of
only 2400 maximum r.p.m., the Twin-Six combines
ideal fuel / air mixture, economical 2-barrel carburetion, low internal
friction, short
stroke, and good exhaust scavenging to add years to engine life and squeeze
every Mile
from every gallon of gasoline.
The Twin-Six's 60
degree "V" type design compacts it's massive
strength. But ruggedness
does not stop there. For example, it's valve train is
the most outstanding of any production
vehicle. In trucks, engine life is largely determined by valve life. So in the
702, push rods,
lifters, rocker arms, shafts and the valves themselves are made from the best
quality,
commercially practical material available; larger, more
sturdy than valve trains in other
engine of comparable output. It's short stroke reduces
internal friction . . .
gives full power with less piston travel.
Result is less engine wear . . . longer engine life.
Peak torque is reached at low r.p.m. and maintained
over a wide range of engine
speed for longer sustained power. The toughest jobs are handled in stride.
Oil and fuel consumption is low . . . maintenance and service cost are low . .
.
save you money four ways.
It has the highest cooling and lubricating ability of any comparable size
engine.
This means greater engine efficiency . . . longer trouble-free service.
56 major parts are interchangeable between the Twin-Six and all other GMC V-6
engines to provide greater parts availability and standardization.
High mounted camshaft . . . short push rods . . . big, tough, long-lived valves
combine to make an exceptionally rigid, durable valve train. Again . . .
lower cast, longer life, more economy.
Strength where strength counts ! Exceptionally,
rigid crankshaft . . . massive connecting rods . . .
big, rugged, heavy-duty pistons. Many thousands of
miles of dependable service.
THE HIGH OUTPUT OIL PUMP
capable of pumping 17 gallons of oil per minute, provides extra circulation at
all
engine speeds . . . extra protection and well oiled
surfaces on all vital moving parts.
Engine is lubricated as soon as it's started. Cam lobes dip into a built-in
reservoir
of oil as the camshaft rotates, preventing cam and valve scuffing -
a major reason why this engine gives long, dependable service.
118 GALLONS OF WATER
(at 2400 r.p.m.) Are pumped through this engine every minute.
With thermostat open, only
half the water goes to the radiator, the other half returns to the pump through
a by-pass.
This results in excellent cooling ability. There is less than four degrees
variation in
water temperature throughout the engine. This checks the possibility of hot
spots. Here's
cooling efficiency that is not matched by any other comparable size engine.
Life of pistons,
valves, valve guides and spark plugs in much greater, and the possibility of
head-cracking
is held safely in check . . . further proof of the
durability and long
life that is built into this engine.
POSITIVE CRANKCASE VENTILATION
is provided by using manifold vacuum to draw fresh air through the engine. Air
enters through a
replaceable paper-element breather, travels up through the crankcase to the
cylinder head
covers, then through air flow regulating valves directly into an intake port of
each head,
carrying with it, into the combustion chamber, harmful sludge-forming fumes and
moisture laden
air. Bearings and other precision parts last longer . . .
maintenance is less . . . engine life is extended.
Here's The Inside Story GMC's Twin-Six Engine
EXCEPTIONALLY RIGID, FORGED CRANKSHAFT
has 7 extra large main bearing journals . . . 6 extra large crankpins - one for each pair of
connecting rods, and all "Tocco" hardened. It's heavy construction makes it exceptionally
rigid. M400 main and connecting rod bearings, the best available, provide up to
7 times the
life of commonly used bearings. Crankshaft and bearings are freed from
torsional impulses
by a rubber type damper in crankshaft pulley.
CAST ALUMINUM PISTONS
cam ground; and with cast-in steel expansion control
band, eliminate piston slap. Pistons are
balanced to within 1.8 grams to ensure vibration-free performance. Long skirts
are precision-
ground and tin-plated to prevent scuffing during initial run-in. 4 rings, 3 compression, 1 oil
control - provide positive compression sealing . . . improved oil economy. Top
compression ring
and oil control rings are has chrome plating for longest wear. Top ring rides
in a cast-in steel
groove for even more durability.
HIGH STRENGTH, ALLOY IRON CAMSHAFT
Cam lobes and bearing journals are induction-hardened for great wear
resistance. Short, stiff push
rods provide for a rigid valve train and positive valve action. 7 large,
closely spaced bearings
keep camshaft precision-straight. Valves last longer . . . fewer adjustments
are needed . . .
service expense is lower.
FULLY-MATCHED COMBUSTION CHAMBERS
Smooth, precision-machined combustion chamber - rarely found in other engines -
minimizes carbon deposits,
hot spots and pre-ignition. And there is uniform combustion in all cylinders
for smoothest engine
operation. 6 equally-spaced head bolts (not 4 as found in other engines)
surround each cylinder to
reduce bore distortion . . . guarantee gasket sealing for long engine service.
Spark plugs, located
inside the "V", away from hot exhaust manifolds, run cooler, have
much shorter wires,
and are easy to service.
EXTRA HEAVY BLOCK AND CRANKCASE
is solidly cast of high strength, long-wearing iron alloy. A deep, 3-inch
ribbed skirt below the
centerline of the crankshaft provides rigid reinforcement to the crankcase.
Cylinders are widely
spaced and staggered, providing even greater block rigidity and much greater
cooling area around
the cylinder walls for long engine life. Heavy bearing caps and the use of 4
large cap screws on
the rear main bearing assure perfect crankshaft alinement,
minimize crankshaft deflection
and assure maximum bearing life.
ALUMINUM ROCKER ARM BRACKETS
Each of the 4 hardened steel rocker arm shafts is held
firmly in place by 5 aluminum brackets.
As valves warm up and expand, brackets expand too, assuring proper valve
clearance under all
operating temperatures. The engine runs quieter . . . fewer valve adjustments
are needed . . .
valve life is extended. Brackets at both ends of the shaft,
and one bracket between each set
of rockers arms holds shaft deflection in check. This plus the high-up
camshaft mounting and
use of short, stiff push rods provides an exceptionally rigid valve train. Just another way
you save on maintenance and get longer engine life.
TWIN INTAKE MANIFOLDS
with individual ports for each cylinder are a special feature of this engine.
Individual ports
permit faster intake and more uniform distribution of fuel-air mixture to each
cylinder.
Because manifolds are short and have a minimum of bends and curves, too rich or
too lean fuel
mixtures, usually found in longer in-line or V-8 engines are completely
eliminated. This results
in much better fuel economy, cleaner, more complete combustion and greater
engine efficiency.
TOP QUALITY HEAVY RIBBED EXHAUST MANIFOLDS
Interchangeable exhaust manifolds of special alloy iron and highly resistant to
cracking and
warping by extreme temperature changes. Large individual ports for each
cylinder and short,
large diameter passages permit more complete scavenging of exhaust gases.
Result is better
fuel economy . . . longer life . . . better performance.
FUEL FILTER,
is standard. It protects the carburetor from dirt and other foreign materials
that can cause
annoying engine failure and costly down time. The fuel filter is the
replaceable element type.
LARGEST VALVES
This engine has the largest diameter intake and exhaust valves of any
comparable size engine.
This means it is unsurpassed in volumetric, or breathing, efficiency.
Combustion is more complete,
scavenging of exhaust gases more thorough. The engine gets more work out of a
gallon of gasoline . . .
and stays cleaner longer, too. In addition, valves have short, large diameter
stems to reduce
possible distortion and dissipate heat quickly. Positive rotation of both
intake and exhaust
valves is an extra-quality feature. Short, rigid puck rods hold valve train
deflection to a minimum
and help keep engine in top running condition. Valve clearance is controlled by
self-locking adjusting
screws . . . tune-ups are easy . . . upkeep low.
HYDRAULIC GOVERNOR
Extra long life for heavy duty engines is assured by
the hydraulic governor. Operated by oil
pump pressure, this accurate, positive, and reliable governor keeps engine from
exceeding
it's proper operating
speeds.
The above Information came from GMC Truck
brochures put out in 1960. Further information can be located www.6066gmcguy.org
Engine Model |
Gross
Horsepower |
Net Horsepower |
Gross
Torque lbs. ft. |
Net
Torque lbs. ft. |
Bore -
Stroke |
Displacement |
Compression |
Twin-Six |
275 @ 2400
rpm |
250 @
2400 rpm |
630 @
1600-1900 |
585 @
1600-1900 |
4.56 -
3.58 |
702.4
cu. in. |
7.50 to
1 |
The 702 Twin-Six V12 was used in the B-, BW-,
L-, & LW-7000 series trucks.
Maximum Recommended Speeds in rpms:
702 V12 -- 2400
Valve Lash (Hot, Running)
V12 -- Zero
Cylinder Head Bolt Torque -- 65-72 ft-lbs
Idling Speed, Manual Trans, 400 - 450 rpm, Auto trans, 450 rpm
Engine Model |
Quarts |
w/ filter |
702 |
14 Qts |
16 Qts |
Twin-Six V12 Firing Order: 1-4-9-8-5-2-11-10-3-6-7-12
Copyright 2010