CAT Engines Course ( Part 1)
The 3500 Series Engine is a diesel engine with a
4-stroke cycle. It has a 60 degree “Vee” angle between the cylinders of the block. The cylinder bore is 170 mm (6.7 inch) and the piston stroke is 190 mm (7.5 inch). Each cylinder has approximately 4310 cu. cm. (263 cu. in.).
Standard engine rotation is counterclockwise. See
the Service Manual for Firing under specs (V8
Looking at the right side of the engine, we see the:
1. cylinder heads, block and oil pan
2. valve covers
3. rear lifting eye
4. turbocharger (one of two)
5. oil cooler and oil pump
6. fuel priming pump, two secondary fuel filters,
and fuel transfer pump
7. crankcase filler opening and dipstick
8. air starting motor
9. water pump; and
NOTE: This is the first Caterpillar engine designed to
metric dimensions. All engines in the series have the
same bore and stroke and have the push rod valve
design. All engines are turbo charged and
aftercooled. All 3500 Series Engines have direct
injection combustion systems with a unit injector
On the front of the engine, we see:
1. the Caterpillar 3161 governor
2. the water pump and the line to the aftercooler
3. the thermostat housing and the bypass line
4. the vibration damper, and crankshaft pulley
The fan pulley and idler pulley is driven from the
crankshaft pulley belts. The fan pulley and idler
pulley each have an adjustment to adjust the
tension of the fan (drive) belts.
The plates shown on the right can be removed to install
other accessories on the auxiliary drives. The
governor and crankcase breather can be installed
on either the left side or right side.
On the left side we see:
1. the oil supply line (arrow)
2. the oil filter base/housing and four oil filters
3. the oil supply and oil drain for the turbocharger
4. the fume disposal group
Also on the rear we see three auxiliary drives above the
flywheel housing. Two turbochargers are
installed on this engine. This is the location of
the turbochargers on the vehicle arrangements.
Turbochargers can also be installed above the
rear of the engine for industrial generator set and
marine engines (shown later)
This is the flywheel housing and the flywheel. The
standard vehicular flywheel housing is SAE No.
“O”. The flywheel housing for the Marine,
Industrial, and Generator Set is SAE “OO”. The
SAE No. “O” is available for Marine, Industrial,
and Generator Set engines.
The starting motor is normally installed on the right
side of the engine. An air starting motor is
shown. There are two optional locations for the
. . . on the left side. The two plates cover the openings
for the optional locations for the starting motors.
Air or electric starting motors are also available.
SERIAL NUMBER PLATE
The serial number plate is on the left side of the
camshaft compartment near the rear of the
Also you can see the location of the camshaft
compartment covers and the crankcase
The serial number plate has the model number, serial
number, arrangement number, and modification
number. All numbers must be included on
Service Reports with warranty claims and when
This information plate is on the right side of the engine.
On later engines, the plate is on the left-hand side in
front of the cylinder head. This plate has the
high idle rpm, full load rpm, power setting and
other important engine information.
Other plates and transfers (not shown) give you
information about valve adjustment.