Unfiltered oil is drawn  from the oil pan through

the suction pipe and front  cover passage by the

crankshaft driven oil pump. Pressurized oil is forced

through a front cover passage, into the cylinder block

gallery, and to the engine oil cooler assembly. Oil flow

at the engine oil cooler assembly is controlled by the

oil thermal valve assembly.

The turbocharger is lubricated with filtered oil from a

supply tube assembly that connects the oil system

module assembly to the  center housing of the

turbocharger. Oil drains back to the oil pan through a

drain tube connected to the cylinder block.

The front gear train is lubricated with oil that drains

from the high-pressure reservoir.

The thermal valve assembly allows unfiltered oil to

bypass the oil cooler when the oil temperature is cold,

and flow directly to the oil filter. As the oil temperature

begins to warm, the thermal valve assembly begins

to open. This allows unfiltered oil to flow into the oil

cooler and oil filter.

i04031016

Cooling System

When the oil temperature is hot, the thermal valve

assembly allows unfiltered oil to flow through the oil

cooler before entering the oil filter.

Unfiltered oil moves through plates in the oil cooler

heat exchanger. Engine coolant flows around the

plates to cool the surrounding oil.

Oil that exits or bypasses the oil cooler mixes and

enters the spin-on oil filter. Oil flows from outside the

filter element towards the inside to remove debris.

When the filter is restricted, the oil filter bypass opens

and allows oil to bypass the filter to maintain engine

lubrication. The oil filter bypass is located in the oil

system module assembly. The filter bypass valve

opens when pressure reaches 345 kPa (50 psi).

After passing through the filter, the oil travels past the

oil pressure regulator. The regulator directs excess

oil back to the oil pan to maintain oil pressure at  a

maximum of 379 kPa (55 psi).

Clean regulated oil enters the main oil gallery of the

engine to lubricate the crankshaft, camshaft, and

lifters. The crankshaft has cross-drillings that direct

oil to the connecting rods.

Oil is also provided to the high-pressure reservoir

through a passage in the front cover.

Piston cooling jets continuously direct cooled oil to

the oil gallery of the piston. The piston cooling jets

direct oil to the piston pin for lubrication purposes.

Oil from the main oil gallery exits upwards through

a passage at the rear of  the crankcase. Oil flows

through a passage in the cylinder head and enters the

hollow rocker shaft which lubricates the rocker arms.

The crankcase breather assembly  is driven by

unfiltered oil pressure taken from the right side  of

the crankcase. Oil flows from the crankcase into the

breather assembly. Passages direct the oil through a

pressed brass nozzle that controls oil flow into a drive

wheel. Oil drains into the base and mixes with waste

oil from the breather system. The collected oil drains

into the cylinder block and then into the oil pan.

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KENR8772

Systems Operation  Section

g02729201

Illustration 33

Typical example

(1) Exhaust gas cooler (NRS) (if equipped)

(2) Water temperature regulator

(3) Cylinder head

(4) Cylinder block

(5) Water pump

(6) Engine oil cooler assembly

The engine cooling system includes the following:

•  Radiator

•  Cooling fan

•  Water inlet elbow

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KENR8772

45

Systems Operation  Section

•  Water pump

The exhaust gas cooler receives coolant from the

water pump through a supply tube. Coolant passes

between the exhaust gas  cooler plates, travels

parallel to the exhaust flow, and exits into another

coolant tube. Coolant is supplied to the intake side

exhaust gas cooler from this tube. Coolant passes

between the exhaust gas cooler plates, parallel to

the exhaust flow, and exits into the  coolant return

tube which connects to the  cylinder head water

jacket. The deaeration port on the top of the intake

side exhaust gas cooler directs coolant and trapped

air through the exhaust gas valve and towards the

coolant surge tank.

•  Cylinder block

•  Cylinder liners

•  Cylinder head

•  Engine oil cooler assembly

•  Water temperature regulator

•  Exhaust gas cooler (NRS) (if equipped)

•  Exhaust gas valve (NRS) (if equipped)

•  Surge tank

An optional coolant heater is  available to warm

engine coolant in cold weather. The coolant heater

warms the coolant  surrounding the cylinders.

Warmed engine coolant aids in performance  and

fuel economy during start-up. The coolant heater is

located on the left side of the crankcase, in front of

the Electronic Control Module (ECM).

•  Coolant heater

Coolant is drawn from the radiator through an inlet

elbow and front cover by the water pump. The water

pump pushes coolant into a passage  in the front

cover.

The water temperature regulator has two outlets.

One directs coolant to the radiator when the engine

is at operating temperature. The other directs coolant

to the water pump until the engine reaches operating

temperature. The water temperature regulator begins

to open at 88° C (190° F) and is fully open at 96° C

(205° F).

Coolant flows to the cylinder  block and through

the water jackets from front to  rear. This coolant

flows around the cylinder liners to absorb heat from

combustion.

Swirling coolant flow in the  cylinder liner jackets

directs coolant through passages in the head gasket

and upwards into the cylinder head.

Coolant flows through the cylinder head water jackets

towards the water temperature regulator cavity at

the front of the cylinder head. Depending on coolant

temperature, the water temperature regulator can

direct in two directions to exit the cylinder head.

When the water temperature regulator is  closed,

coolant is directed through the bypass port, cylinder

block, front cover, and into the water pump.

When the water temperature regulator is open, the

bypass port is blocked, and coolant is directed from

the engine into the radiator.

Coolant passes through the radiator and is cooled

by moving air from the cooling fan. The coolant will

return to the engine through the inlet elbow.

g02729545

Illustration 34

The engine oil cooler assembly receives  coolant

from a passage in the cylinder block. Coolant passes

between the oil cooler plates and returns through a

tube leading back to the water pump suction passage

located in the front cover.

Typical example of a water temperature regulator closed

(A) Coolant flow to heater  port

(B) Coolant in from  engine

(C) Bypass to water pump

When engine coolant is below the 88° C (190° F) the

water temperature regulator is closed, blocking flow

to the radiator. Coolant is forced to flow through  a

bypass port back to the water pump.

This document is printed from SPI². Not for RESALE

46

KENR8772

Systems Operation  Section

Cylinder Block

g02729546

Illustration 35

g02394136

Typical example of a water temperature regulator open

Illustration 36

(D) Coolant out to radiator

(E) Coolant flow to heater  port

(F) Coolant in from  engine

Typical example

The cast iron cylinder block for the engine has six

cylinders which are arranged in-line. The cylinder

block is made of cast iron in order to provide support

for the full length of the cylinder bores.

When coolant temperature reaches the  nominal

opening temperature 88° C  (190° F) the water

temperature regulator opens allowing some coolant

to flow to the radiator. When coolant  temperature

exceeds 96° C (205° F), the lower seat blocks the

bypass port directing full coolant flow to the radiator.

The cylinder block has removable cylinder liners.

The cylinder block has seven main bearings which

support the crankshaft. The seven main bearing caps

have two bolts per main cap.

i04031088

Basic Engine

Thrust washers are installed on both sides of number

7 upper main bearing in order to control the end play

of the crankshaft.

Introduction

Passages supply the lubrication for the crankshaft

bearings. These passages are cast into the cylinder

block.

The eight major mechanical components of the basic

engine are the following parts:

The engine has a cooling jet that is installed in the

cylinder block for each cylinder. The piston cooling jet

sprays lubricating oil onto an oil gallery in the piston

in order to cool the piston.

•  Cylinder block

•  Cylinder head

•  Pistons

The cylinder block has bushes that are installed for

the camshaft journals.

•  Connecting rods

•  Crankshaft

A cylinder head  gasket is used between  the

engine block and the cylinder head in order to seal

combustion gases, water, and oil.

•  Vibration damper

•  Timing gear case and gears

•  Camshaft

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KENR8772

47

Systems Operation  Section

Cylinder Head

The connecting rods (4) are machined from forged

steel. The connecting rods have bearing caps (6)

that are fracture split. Two connecting rod bearings

(5) are installed between the connecting rod (4) and

the bearing cap (6). The bearing caps  on fracture

split connecting rods are retained with Torx bolts (7).

Connecting rods with bearing caps that are fracture

split have the following characteristics:

The engine has a cast iron cylinder head. There are

two inlet valves and two exhaust  valves for each

cylinder. Each pair of valves are  connected by a

valve bridge that is controlled by a pushrod  valve

system. The ports for the inlet valves are on the left

side of the cylinder head. The ports for the exhaust

valves are on the right side of the cylinder head.

•  The splitting produces an accurately  matched

surface on each side of the fracture for improved

strength.

The valve stems move in valve guides in the cylinder

head. There is a renewable oil seal that fits over the

top of the valve guide. The valve seats and the valve

guides are replaceable.

•  The correct connecting rod must be installed with

the correct bearing cap. These are matched mated

surfaces and are not interchangeable.

Pistons, Rings, and Connecting

Rods

Crankshaft

g02394381

Illustration 38

Typical example

(1) Crankshaft gear

(2) Crankshaft

(3) Crankshaft thrust washers

g02394336

The forged steel crankshaft has seven main journals.

Thrust washers are installed on both sides of number

7 upper main bearing in order to control the end play

of the crankshaft.

Illustration 37

Typical example

The pistons (9) are one-piece  forged steel. The

pistons (9) use a floating piston pin (8). The piston pin

(8) is retained in the correct position by two circlips

(3).

The crankshaft changes the linear energy  of the

pistons and connecting rods into rotary  torque in

order to power external equipment.

Three rings are installed on each piston to seal the

combustion chamber and to control oil on the cylinder

walls.

A gear at the front of the crankshaft drives the timing

gears. The crankshaft gear turns the lower idler gear

which then turns the following gears:

The pistons have two compression rings (1) and an

oil control ring (2).

•  Upper idler gear

•  Camshaft gear

Piston cooling jets spray oil on  the bottom of the

pistons for cooling and lubrication.

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48

KENR8772

Systems Operation  Section

•  The spline gear for the engine oil pump

•  The gear for the high pressure oil pump

•  Accessory drive gear (if equipped)

Vibration Damper

Lip type seals are  used on both the front of the

crankshaft and the rear of the crankshaft.

A timing ring is installed to the crankshaft. The timing

ring is used by the ECM  in order to measure the

engine speed and the engine position.

Camshaft

g02317733

Illustration 40

Typical example

(1) Setscrews

(2) Setscrews

(3) Vibration damper

(4) Crankshaft pulley

(5) Crankshaft adapter

The force from combustion  in the cylinders will

cause the crankshaft to twist. This is called torsional

vibration. If the vibration is too great, the crankshaft

will be damaged. The  vibration damper has an

inertia ring and a rubber element in order to limit the

torsional vibration.

g02394390

Illustration 39

Typical example

Gears and Timing Gear Case

The engine has a single camshaft. The camshaft is

made of steel alloy. The camshaft lobes are induction

hardened.

The crankshaft oil seal and  engine oil pump are

mounted in the aluminum timing case. The timing

case cover is made from aluminum.

The single roller tappet camsha, ft is turned  by the

upper idler gear. As the camshaft turns, the camshaft

lobes move the valve system components. The valve

system components move the cylinder valves.

The timing gears are made of steel.

The crankshaft gear drives a lower idler gear  and

an upper idler gear. The upper idler gear drives the

camshaft and the high-pressure oil pump.

The camshaft gear must be timed to the upper idler

gear. The relationship between the lobes and  the

camshaft gear causes the valves in each cylinder to

open at the correct time. The relationship between

the lobes and the camshaft gear also  causes the

valves in each cylinder to close at the correct time.

The camshaft rotates at half the engine speed.

This document is printed from SPI². Not for RESALE

KENR8772

49

Systems Operation  Section

i04112653

All of the ground paths must be capable of carrying

any likely current faults. An AWG #0 or larger wire is

recommended for the grounding strap to the cylinder

head.

Electrical System

The engine alternator should be  battery ground

with a wire size that is capable of managing the full

charging current of the alternator.

Grounding Practices

Correct grounding for the application electrical system

and engine electrical systems is necessary for correct

application performance and reliability. Improper

grounding will result in uncontrolled electrical circuit

paths and unreliable electrical circuit paths.

NOTICE

When boost starting an engine, the instructions in Op-

eration and  Maintenance  Manual, “Engine  Starting”

should be followed  in order to correctly  start the en-

gine.

Uncontrolled engine electrical circuit paths can result

in damage to main bearings,  crankshaft bearing

journal surfaces, and aluminum components.

This engine is equipped with a 24 volt starting system.

Only equal voltage for boost starting should be used.

The use of a higher voltage will damage the electrical

system.

To ensure correct functioning of the application and

engine electrical systems, an engine-to-frame ground

strap with a direct path to the negative battery post

must be used. This may be provided  by way of a

starting motor ground, a frame  to starting motor

ground, or a direct frame to engine ground.

All electrical connections must be disconnected on the

Electronic Control  Module (ECM) before  welding on

the application.

The engine has several input components which are

electronic. These components require an operating

voltage.

An engine-to-frame ground strap must be used in

order to connect the grounding stud of the engine

to the frame of the application and to the negative

battery post.

Unlike many electronic systems of  the past, this

engine is tolerant to common external sources of

electrical noise. Buzzers that use electrical energy

can cause disruptions in the power supply. If buzzers

are used anywhere on the  machine, the engine

electronics should be powered directly  from the

battery system through a dedicated relay. The engine

electronics should not be powered through a common

power bus with other keyswitch activated devices.

Engine Electrical System

The electrical system has the following  separate

circuits:

•  Charging

•  Starting (If equipped)

•  Accessories with low amperage

g01407491

The charging circuit is in operation when the engine

is running. An alternator makes electricity  for the

charging circuit. A voltage regulator in  the circuit

controls the electrical output in order to  keep the

battery at full charge.

Illustration 41

(1) Starting motor to engine block

(2) Starting motor to battery negative

The engine must have a wire ground to the battery.

The starting circuit is activated only when the start

switch is activated.

Ground wires or ground straps should be combined

at ground studs that are only for ground use. All of

the grounds should be tight and free of corrosion.

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50

KENR8772

Systems Operation  Section

Charging System Components

NOTICE

Alternator

Never operate the alternator without the battery in the

circuit. Making  or breaking  an alternator connection

with heavy load  on the circuit  can cause damage to

the regulator.

The alternator is driven by a belt from the crankshaft

pulley. This alternator is a three-phase, self-rectifying

charging unit, and  the regulator is part of  the

alternator.

The alternator design has no  need for slip rings

and the only part that has  movement is the rotor

assembly. All conductors that  carry current are

stationary. The following conductors are in the circuit:

•  Field winding

•  Stator windings

•  Six rectifying diodes

•  Regulator circuit components

g00425518

Illustration 42

The rotor assembly has many magnetic poles that

look like fingers with air space between each of the

opposite poles. The poles have residual magnetism.

The residual magnetism produces a small magnetic

field between the poles.  As the rotor assembly

begins to turn between the field  winding and the

stator windings, a small amount of alternating current

(AC) is produced. The AC current is produced in the

stator windings from the small magnetic field. The

AC current is changed to direct current (DC) when

the AC current passes through the  diodes of the

rectifier bridge. The current is used for the following

applications:

Typical alternator components

(1) Regulator

(2) Roller bearing

(3) Stator winding

(4) Ball bearing

(5) Rectifier bridge

(6) Field winding

(7) Rotor assembly

(8) Fan

Starting System Components

Starting Solenoid

•  Charging the battery

•  Supplying the accessory circuit that has the low

amperage

•  Strengthening the magnetic field

The first two applications use most the current. As

the DC current increases through the field windings,

the strength of the magnetic field is increased. As the

magnetic field becomes stronger, more AC current is

produced in the stator windings. The increased speed

of the rotor assembly also increases the current and

voltage output of the alternator.

g00317613

Illustration 43

The voltage regulator is  a solid-state electronic

switch. The voltage regulator senses the voltage in

the system. The voltage regulator switches ON and

OFF many times per second in order to control the

field current for the alternator. The alternator uses

the field current in order to generate  the required

voltage output.

Typical starting solenoid

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KENR8772

51

Systems Operation  Section

When two sets of solenoid windings are used, the

windings are called the  hold-in winding and the

pull-in winding. Both sets of windings have the same

number of turns around the cylinder, but the pull-in

winding uses a wire with a larger diameter. The wire

with a larger diameter produces a greater magnetic

field (1). When the start switch is closed, part of the

current flows from the battery through the  hold-in

windings. The rest of the current flows through the

pull-in windings to the motor terminal. The current

then flows through the motor to ground.  Solenoid

(2)is fully activated when the connection across the

battery and the motor terminal is complete. When

solenoid (2) is fully activated, the  current is shut

off through the pull-in windings. At this point,  only

the smaller hold-in windings are in operation. The

hold-in windings operate for the duration of time that

is required in order to start the engine. Solenoid (2)

will now draw less current from the battery, and the

heat that is generated by solenoid (2) will be kept at

an acceptable level.

g00425521

Illustration 44

Typical starting motor components

(1) Field

(2) Solenoid

(3) Clutch

(4) Pinion

(5) Commutator

(6) Brush assembly

(7) Armature

The starting solenoid (2) is an electromagnetic switch

that performs the following basic operations:

•  The starting solenoid (2) closes the high current

starting motor circuit with a low current start switch

circuit.

•  The starting solenoid (2) engages the pinion of the

starting motor (4) with the ring gear.

Solenoid (2) has windings (one or two sets) around

a hollow cylinder. A plunger that is spring loaded is

inside the cylinder. The plunger can move forward

and backward. When the start switch is closed and

electricity is sent through the windings, a magnetic

field (1) is made. The magnetic field  (1) pulls the

plunger forward in the cylinder. This moves the shift

lever in order to engage the pinion drive gear with the

ring gear. The front end of the plunger then makes

contact across the battery and motor terminals of

solenoid (2). Next, the starting motor begins to turn

the flywheel of the engine.

When the start switch is opened, current no longer

flows through the windings. The spring now pushes

the plunger back to the original position. At the same

time, the spring moves the pinion gear away from

the flywheel.

This document is printed from SPI². Not for RESALE