Systems Operation Testing and Adjusting _SENR9773_03_.pdf

SENR9773-03

July 2008

Systems Operation Testing and Adjusting C32 Marine and Auxiliary Marine Engines RNC1-Up (Engine) RND1-Up (Engine) RNE1-Up (Engine) RNR1-Up (Engine) T3T1-Up (Engine) RNY1-Up (Engine) RNZ1-Up (Engine)

SAFETY.CAT.COM

i01658146

Important Safety Information Most accidents that involve product operation, maintenance and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills and tools to perform these functions properly.

Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death.

Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.

The hazards are identified by the “Safety Alert Symbol” and followed by a “Signal Word” such as “DANGER”, “WARNING” or “CAUTION”. The Safety Alert “WARNING” label is shown below.

The meaning of this safety alert symbol is as follows:

Attention! Become Alert! Your Safety is Involved.

The message that appears under the warning explains the hazard and can be either written or pictorially presented.

Operations that may cause product damage are identified by “NOTICE” labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.

The warnings in this publication and on the product are, therefore, not all inclusive. If a tool, procedure, work method or operating technique that is not specifically recommended by Caterpillar is used, you must satisfy yourself that it is safe for you and for others. You should also ensure that the product will not be damaged or be made unsafe by the operation, lubrication, maintenance or repair procedures that you choose.

The information, specifications, and illustrations in this publication are on the basis of information that was available at the time that the publication was written. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete and most current information before you start any job. Caterpillar dealers have the most current information available.

When replacement parts are required for this product Caterpillar recommends using Caterpil-lar replacement parts or parts with equivalent specifications including, but not limited to, phys-ical dimensions, type, strength and material.

Failure to heed this warning can lead to prema-ture failures, product damage, personal injury or death.

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Table of Contents

Table of Contents

Systems Operation Section

General Information Electronic Control System Components Fuel System Air Inlet and Exhaust System Closed Crankcase Ventilation (CCV) System Lubrication System Cooling System Basic Engine Electrical System

Testing and Adjusting Section

Fuel System Fuel System - Inspect Air in Fuel - Test Electronic Unit Injector - Adjust Electronic Unit Injector - Test Finding Top Center Position for No. 1 Piston Fuel Quality - Test Fuel System - Prime Fuel System Pressure - Test Rear Gear Group - Time

Air Inlet and Exhaust System Turbocharger - Inspect Inlet Manifold Pressure - Test Exhaust Temperature - Test Aftercooler - Test Engine Crankcase Pressure (Blowby) - Test Compression - Test Engine Valve Lash - Inspect/Adjust

Lubrication System Engine Oil Pressure - Test Engine Oil Pump - Inspect Excessive Bearing Wear - Inspect Excessive Engine Oil Consumption - Inspect Increased Engine Oil Temperature - Inspect

Cooling System Cooling System - Check (Overheating) Cooling System - Inspect Cooling System - Test Water Temperature Regulator - Test

Basic Engine Piston Ring Groove - Inspect Connecting Rod Bearings - Inspect Main Bearings - Inspect Cylinder Block - Inspect Cylinder Liner Projection - Inspect Flywheel - Inspect Flywheel Housing - Inspect Vibration Damper - Check

Electrical System Battery - Test

Charging System - Test Electric Starting System - Test Pinion Clearance - Adjust

Index Section

Index

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Systems Operation Section

Systems Operation Section i02773874

General Information SMCS Code: 1000 g01118350Illustration 1 Right front view

The C32 marine engine is a 65 degree V-12 arrangement. This engine has a bore of 145 mm (5.7 inch). The engine has a stroke of 162 mm (6.4 inch). The bore and the stroke provide a total displacement of 32 L (1953 cu in). These engines are designed for either right or left hand service.

The Mechanical Electronic Unit Injector (MEUI) fuel system eliminates many of the mechanical components that are used in a pump-and-line system. The electronic control and mechanical actuation also provide increased control of the timing and increased control of the fuel injection pressure. The timing advance is achieved by precise control of the unit injector timing. Engine speed is controlled by adjusting the injection duration. A special speed-timing wheel provides information to the Electronic Control Module (ECM) for detection of cylinder position and engine speed.

The engines have water cooled exhaust manifolds, risers and turbochargers. These components will minimize the heat that is radiated into the engine room. Changes to the cooling system of these engines minimize the weight and the size of the engine. These changes also improve the engine’s performance. The cooling system’s heat exchanger, the expansion tank, and the deaerator help to prevent cavitation of the water pump. This helps to maintain the performance of the jacket water pump.

The C32 marine engine uses a low emission system which is integrated into the engine air cleaner. This system eliminates the venting of oil vapors into the engine room. The closed crankcase ventilation system is completely enclosed. This system requires a minimum amount of maintenance.

The engine has built-in diagnostics in order to ensure that all of the components are operating properly. In the event of a system component failure, the operator will be alerted to the condition via the diagnostic lamp that is located on the control panel. Caterpillar Electronic Technician (ET) can be used to read the numerical code of the faulty component or condition.

Intermittent faults are also logged and stored in memory.

The engine’s ECM will automatically provide the correct amount of fuel in order to start the engine.

Do not hold the throttle down while the engine is cranking. If the engine fails to start in twenty seconds, release the starting switch. Allow the starting motor to cool for two minutes before using the starting motor again.

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Electronic Control System Components SMCS Code: 1900 g01385558Illustration 2

Front View

(1) Engine oil pressure sensor

(2) Coolant level sensor

(3) Secondary speed/timing sensor

(4) Primary speed/timing sensor g01118656Illustration 3

View A-A

(5) Fuel pressure sensor

(6) Fuel temperature sensor g01118661Illustration 4

Top View

(7) Inlet air pressure sensor

(8) Inlet air temperature sensor

(9) Coolant temperature sensor

The electronic control system is integrally designed into the engine’s fuel system and the engine’s air inlet and exhaust system in order to electronically control the fuel delivery. The electronic control system provides better timing control and fuel air ratio control in comparison to conventional mechanical engines.

Injection timing is achieved by the precise control of the fuel injectors. Engine speed is controlled by adjusting the injection duration. The Electronic Control Module (ECM) energizes the unit injector solenoids in order to start the injection of fuel. Also, the ECM de-energizes the unit injector solenoids in order to stop the injection of fuel.

Refer to Systems Operation/Testing And Adjusting, “Fuel System” for a complete explanation of the fuel injection process.

The engine uses the following three types of electronic components:

• Input component

• Control component

• Output component

An input component is one that sends an electrical signal to the ECM. The signal that is sent varies in either of the following ways:

• Voltage

• Frequency

• Pulse width

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The variation of the signal is in response to a change in some specific system of the engine. Some specific examples of an input component are the engine speed-timing sensors, and the coolant temperature sensor. The ECM interprets the signal from the input component as information about the condition, environment, or operation of the engine.

An ECM receives the input signals from the input components. Electronic circuits inside the control component evaluate the signals from the input components. These electronic circuits also supply electrical energy to the output components of the system. The electrical energy that is supplied to the output components is based on predetermined combinations of input signal values.

An output component is one that is operated by a control module. The output component receives electrical energy from the control group. The output component uses electrical energy to make an adjustment in one of the engine’s systems. An output component may also provide information to the operator.

As an example, a moving solenoid plunger will perform work. By performing work, the component has functioned in order to regulate the engine.

As an example, a control panel light or an alarm will provide information to the operator of the engine.

These electronic components provide the ability to electronically control the engine operation.

Engines with electronic controls offer the following advantages:

• Improvement in performance

• Improvement in fuel consumption

• Reduction in emissions levels

Various sensors feed data to the ECM. The following sensors are used by the ECM for data:

• Engine coolant temperature

• Engine oil pressure

• Engine speed

• Inlet air pressure

• Injection actuation pressure

• Fuel temperature

• Fuel pressure

• Inlet air temperature

The ECM processes the data. Then, the ECM sends an electronic signal to the fuel injector. The signal will control the amount of fuel that is injected into the cylinder. This will optimize the efficiency and the performance of the engine.

Data Link A data link is used for the following items:

• Communicate engine information.

• Communicate with Caterpillar Electronic Technician

(ET).

• Calibrate the electronic engine control system.

• Troubleshoot the electronic engine control system.

• Program the electronic engine control system.

The data link is used to communicate engine information to other electronic control systems. Also, the data link can interface with Cat ET.

Cat ET can be used to program the customer specified parameters. The tool is plugged into the data link connector. This allows Cat ET to communicate with the ECM. Also, Cat ET can be used to display the real time values of all the information that is available on the data link. This will help diagnose engine problems.

Electronic Control Module (ECM) g01118503Illustration 5 Electronic Control Module (ECM)

The engine uses an ECM. The ECM is a microprocessor based device. The ECM is mounted on the top of the front valve cover on the left side of the engine.

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The inputs and the outputs to the ECM are designed to withstand short circuits without damage to the control module. The electronic engine control system has the following features that are designed into the system.

• Resistance to radio frequency

• Resistance to electromagnetic interference

The system has passed tests for interference by two-way radios and by switching noise.

The ECM power supply provides electrical power to all engine mounted sensors and actuators. The following precautions have been designed into the

ECM.

• Reverse voltage polarity protection

• Swings or surges of the voltage in the power system due to sudden alternator load

The ECM also monitors all sensor inputs and the ECM provides the correct outputs in addition to acting as a power supply. Also, the ECM ensures the desired engine operation.

The ECM is programmed with a selected factory engine rating. The ECM memory contains a personality module identification code. This code is used to avoid unauthorized tampering or switching of personality modules and other pertinent manufacturing information.

The wiring harness provides communications to the following areas:

• ECM

• Various sensors

• Data link connector

• Engine connectors

The ECM is programmed to perform the following functions:

• Diagnostic tests on all inputs

• Diagnostic tests on all outputs

• Identify a faulty circuit.

Once a fault is detected, the fault can be displayed on a diagnostic lamp. The diagnostic code can be read by using Cat ET. A multimeter can be used to check most problems. Also, a multimeter can be used to troubleshoot most problems. The ECM will record most diagnostic codes that are generated during engine operation. These logged codes or intermittent codes can be read by Cat ET.

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Fuel System SMCS Code: 1250 g01565594Illustration 6

(1) Electronic unit injector

(2) Heat exchanger

(3) Cylinder heads

(4) Fuel tank

(5) Primary fuel filter and water separator

(6) Fuel transfer pump

(7) Electronic Control Module (ECM)

(8) Fuel priming pump and secondary fuel filter

Note: The fuel cooler is part of the heat exchanger.

, The fuel cooler is optional on Tier I engines with prefixes (S/N: RNC) and (S/N: T3T). The fuel cooler is standard for Tier II engines that are rated pleasure craft with the prefixes (S/N: RNR) and (S/N: RNZ).

The fuel supply circuit is a conventional design for unit injector diesel engines. The system consists of the following major components that are used to deliver low pressure fuel to the unit injectors:

Fuel tank – The fuel tank is used to store the fuel.

Fuel priming pump – The fuel priming pump is used to evacuate the air from the fuel system. As the air is removed the system fills with fuel.

Fuel filters – The primary fuel filter is used to remove abrasive material and contamination from the fuel system that may be large enough to damage the fuel transfer pump. The secondary fuel filter is used to remove abrasive material and contamination as small as two microns that could damage the injectors.

Supply lines and return lines – Supply lines and return lines are used to deliver the fuel to the different components.

The purpose of the low pressure fuel supply circuit is to supply fuel that has been filtered to the fuel injectors at a rate that is constant and a pressure that is constant. The fuel system is also utilized to cool components such as the fuel injectors and the Electronic Control Module (ECM).

Once the injectors receive the low pressure fuel, the fuel is pressurized again before the fuel is injected into the cylinder. The unit injector uses mechanical energy that is provided by the camshaft to achieve pressures that can be in excess of 200000 kPa (30000 psi).

Control of the fuel delivery is managed by the engine’s ECM. Data from several of the engine systems is collected by the ECM and processed in order to manage these aspects of fuel injection control:

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• Injection timing

• Fuel injection timing advance

• Injection duration

• Engine cold mode status

The mechanical electronic fuel system relies on a large amount of data from the other engine systems.

The data that is collected by the ECM will be used in order to provide optimum performance of the engine.

Low Pressure Fuel Supply Circuit The flow of fuel through the system begins at fuel tank (4). Fuel is drawn through the primary fuel filter and water separator (5) from the fuel tank by fuel transfer pump (6). The fuel transfer pump incorporates a check valve that will allow fuel to flow around the gears of the pump during priming of the fuel system.

The fuel transfer pump also incorporates a pressure relief valve. The pressure relief valve is used in order to protect the fuel system from extreme pressure.

The fuel transfer pump is designed in order to produce an excess fuel flow throughout the fuel system. The excess fuel flow is used by the system to cool the fuel system components. The excess fuel flow also purges any air from the fuel system during operation. Air that can become trapped in the fuel system can cause cavitation that may damage the components of the unit injector.

After leaving the fuel transfer pump, the fuel flows to the ECM in order to cool the ECM. Next, the fuel flows to the secondary fuel filter and fuel priming pump (8).

The fuel priming pump is located on the fuel filter base. The fuel filter base and the secondary fuel filter also incorporate a siphon break that prevents fuel from draining from the fuel system when the engine is not in operation. The priming pump is a hand operated pump that directs the flow of fuel during the priming pump’s operation. The secondary fuel filter is a two micron fuel filter. The fuel is filtered in order to remove small abrasive particles that will cause premature wear to fuel system components.

The filtered fuel then flows out of the fuel filter and returns to the passages in the fuel filter base. Prior to exiting the fuel filter base, the fuel pressure and the fuel temperature are sampled by the fuel pressure sensor and by the fuel temperature sensor. The signals that are generated by the sensors are used by the ECM in order to monitor the condition of the engine’s components. This information is also used to adjust the fuel delivery of the engine in order to optimize efficiency.

After leaving the secondary fuel filter, the fuel flows to the heat exchanger (2) in order to be cooled. Some engines may not be equipped with a heat exchanger that cools the fuel. The fuel is then transfered by the fuel supply lines to the cylinder head (3). Only a portion of the fuel that is supplied to the fuel injectors is used for engine operation. This unused fuel is discharged into the return passages of the fuel gallery. The fuel is returned to the fuel tank by the fuel return lines. A continuous flow of fuel is experienced within the low pressure fuel system.

During engine operation, fuel injectors (1) receive fuel from the low pressure fuel system. The injector pressurizes the fuel to high pressure. The fuel is then injected into the cylinder. The excess fuel is returned to the tank.

A pressure regulating valve is located in the fuel return. The pressure regulating valve allows the low pressure fuel system to maintain a constant pressure.

A flow control orifice is also located in the fuel return.

The flow control orifice maintains a system back pressure that is constant. The orifice allows the flow of fuel through the system to be constant. This prevents excessive heating of the fuel.

Fuel Heaters Fuel heaters prevent the waxing of the fuel, and the plugging of the fuel filters in cold weather. The engine does not dissipate enough heat in order to prevent waxing during cold weather conditions.

There are two types of fuel heaters that can be used: thermostatically controlled and self-adjusting.

Heaters that are not thermostatically controlled can heat the fuel in excess of 65 °C (149 °F). High fuel temperatures can have the following effects:

• Reduced engine efficiency

• Fuel pump damage

• Premature wear

Note: Never use fuel heaters without some type of temperature regulator. Ensure that fuel heaters are turned OFF during warm weather conditions.

Fuel System Electronic Control Circuit The fuel system is equipped with an electronically controlled, mechanically actuated electronic unit injector in each cylinder. A solenoid on each injector controls the amount of fuel that is delivered by the injector. An ECM sends a signal to each injector solenoid in order to provide complete control of the engine.

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There are two major components of the electronic control system that are necessary in order to provide control of the mechanical electronic unit injectors:

• ECM

• Personality module (storage for the ECM flash file)

The ECM is the computer that is used to provide control for all aspects of engine operation. The personality module contains the software that defines the characteristics of the engine control. The personality module contains the operating maps. The operating maps define the following characteristics of the engine:

• Horsepower

• Torque curves

• Engine speed (rpm)

• Other characteristics

The ECM, the personality module, the engine sensors, and the unit injectors work together in order to control the engine. Neither of the four can control the engine alone.

The ECM maintains the desired engine speed by sensing the actual engine speed. The ECM calculates the amount of fuel that needs to be injected in order to achieve the desired engine speed.

Fuel Injection

The ECM controls the amount of fuel that is injected by varying the signals that are sent to the injectors.

The ECM sends a high voltage signal to the solenoid in order to energize the solenoid. The injectors will inject fuel only while the injector solenoid is energized. By controlling the timing and the duration of the high voltage signal, the ECM can control injection timing and the amount of fuel that is injected.

The ECM sets certain limits on the amount of fuel that can be injected. The Fuel Ratio Control (FRC) limit is an adjustment which controls the amount of air and of fuel for the purpose of emission control. This limit is based on the boost pressure. When the ECM senses a higher boost pressure, the ECM increases the FRC limit. The rated fuel position is also a limit that is based on the horsepower rating of the engine.

This is similar to the rack stops and to the torque spring on a mechanically governed engine. The rated fuel position provides horsepower and torque curves for a specific engine family and for a specific engine rating. All of these limits are programmed into the personality module by the factory. These limits are not programmable by the service technician.

Injection timing depends on three factors: the engine speed (rpm), the engine load, and the operational conditions of the engine. The ECM determines the top center position of No. 1 cylinder from the signal that is provided by the engine speed/timing sensor.

The ECM decides when the injection should occur relative to the top center position. The ECM then provides the signal to the electronic unit injector at the desired time.

Electronic Unit Injector Mechanism g01385564Illustration 7 Electronic unit injector mechanism

(9) Electronic unit injector

(10) Adjusting nut

(11) Rocker arm assembly

(12) Camshaft lobe

The electronic unit injector mechanism provides the downward force that is required to pressurize the fuel in the electronic unit injector pump. The electronic unit injector (9) allows fuel to be injected into the combustion chamber with precise timing.

Movement is transmitted from the camshaft lobe (12) for the electronic unit injector through the rocker arm assembly (11) to the top of the electronic unit injector.

The adjusting nut (10) allows the injector lash to be adjusted. For the proper setting of the injector lash, refer to the topic on adjustment of the electronic unit injector in Testing and Adjusting, “Electronic Unit Injector - Adjust”.

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Electronic Unit Injector g01385565Illustration 8 Electronic unit injector

(13) Spring

(14) Solenoid connection to the Electronic Control Module (ECM)

(15) Solenoid valve assembly

(16) Plunger assembly

(17) Barrel

(18) Seal

(19) Seal

(20) Spring

(21) Spacer

(22) Body

(23) Check valve

Fuel at low pressure from the fuel supply manifold enters the electronic unit injector at the fill port through drilled passages in the cylinder head.

As the electronic unit injector mechanism transfers the force to the top of the electronic unit injector, spring (13) is compressed and plunger (16) is driven downward. This action displaces fuel through the valve in solenoid valve assembly (15), and into the return manifold to the fuel tank. As the plunger travels downward, the passage in barrel (17) is closed by the outside diameter of the plunger. The passages within body (22) and along check valve (23) to the injector tip already contain fuel for injection. After the passage in the plunger barrel is closed, the injector is ready for injection at any time. The start of injection relies on the software in the Electronic Control Module (ECM).

When the solenoid valve assembly is energized from a signal across solenoid connection (14), the valve closes and fuel pressure is elevated in the injector tip. Injection begins at 34500 ± 1900 kPa (5000 ± 275 psi) as the force of spring (20) above spacer (21) is overcome. The check valve begins to lift from the valve seat. The pressure continues to rise as the plunger cycles through a full stroke.

After the correct amount of fuel has been discharged into the cylinder, the ECM removes the signal to the solenoid connection. The solenoid valve assembly is de-energized and the valve in the solenoid valve assembly is opened. The high pressure fuel is then dumped through the spill port and into the fuel return manifold. The fuel is then returned to the fuel tank.

The check valve in the injector tip seats as the pressure in the tip decreases.

The duration of injection meters the fuel that is consumed during the fuel injection process. Injection duration is controlled by the governor logic that is programmed into the ECM.

As the camshaft lobe rotates past the point of maximum lobe lift, the force on top of the electronic unit injector is removed and the spring for the injector mechanism is allowed to expand. The plunger returns to the original position. This uncovers the fuel supply passage into the plunger barrel in order to refill the injector pump body. The fuel at low pressure is again allowed to circulate through the fuel injector body.

After circulating through the fuel injector body, the fuel flows out of the spill port. This continues until the solenoid valve assembly is re-energized for another injection cycle.

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Air Inlet and Exhaust System SMCS Code: 1050

The air inlet and the exhaust system includes the following components:

• Turbocharger (3)

• Air cleaner (4)

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• Exhaust manifold (5)

• Exhaust valves (6)

• Inlet valves (7)

• Aftercooler (10)

• Cylinder head (11)

• Valve system components g01122516Illustration 9

Air flow through the engine

(1) Exhaust outlet

(2) Air inlet

(3) Turbocharger

(4) Air cleaner

(5) Exhaust manifold

(6) Exhaust valves

(7) Inlet valves

(8) Sea water inlet to aftercooler

(9) Sea water outlet from aftercooler

(10) Aftercooler

(11) Cylinder head

Clean inlet air from the air cleaner (4) is pulled through the air inlet of the turbocharger (3) by the turning of the compressor wheel. The compressor wheel causes a compression of the air. The turbocharger compresses the inlet air so that a larger volume of air can be drawn into the cylinders. This compressing of the inlet air is referred to as boost. The compression of the inlet air causes the temperature of the air to increase. The air then flows to the aftercooler (10).

The aftercooler utilized cool sea water in order to cool the inlet air. Cooling of the inlet air causes the air to become more dense. This increases the combustion efficiency and the horsepower output of the engine.

The air then flows from the aftercooler to the inlet manifold of the engine. When the inlet valves (7) open, the air flows into the engine cylinders. The air is mixed with the fuel for combustion. When the exhaust valves (6) open, the exhaust gases go out of the engine cylinders and into exhaust manifold (5). From the exhaust manifold, the exhaust gases flow through the blades of the turbine wheel in the turbocharger (3). This causes the turbine wheel to spin. The exhaust gases then flow out of exhaust outlet (1) of the turbocharger.

Turbocharger Two turbochargers are mounted on the rear of the engine. All of the exhaust gases from the left exhaust manifold goes through the left turbocharger, and the right turbocharger uses the exhaust from the right exhaust manifold.

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g01385582Illustration 10

Turbocharger

(12) Air inlet

(13) Compressor housing

(14) Compressor wheel

(15) Bearing

(16) Oil Inlet port

(17) Bearing

(18) Turbine housing

(19) Turbine wheel

(20) Exhaust outlet

(21) Oil outlet port

(22) Exhaust inlet

All of the air that enters the engine passes through the turbocharger. All of the exhaust gases from the engine pass through the turbocharger.

The exhaust gases enter turbine housing (18) through exhaust inlet (22). The exhaust gas pushes on the blades of the turbine wheel (19). The turbine wheel is connected by a shaft to the compressor wheel (14).

Air that passes through the air filters enters the compressor housing air inlet (12) by the rotation of compressor wheel (14). The compressor wheel causes the inlet air to be pushed into the inlet side of the engine. Boost pressure is caused when the compressor wheel pushes more air into the inlet side of the engine. This results in an inlet manifold pressure that exceeds atmospheric pressure. This allows the engine to burn more fuel. When the engine burns more fuel the engine produces more power.

When the throttle is opened, more fuel is injected into the cylinders. The combustion of this additional fuel produces greater exhaust temperature. The additional exhaust temperature causes the turbine and the compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, more air is forced into the cylinders. The increased flow of air gives the engine more power by allowing the engine to burn the additional fuel with greater efficiency.

Bearings (15) and (17) for the turbocharger use engine oil under pressure for lubrication and cooling.

The oil comes in through oil inlet port (16). The oil then goes through passages in the center section in order to lubricate the bearings. This oil also cools the bearings. Oil from the turbocharger goes out through oil outlet port (21) in the bottom of the center section.

The oil then goes back to the engine oil pan.

Aftercooler The C32 has a sea water aftercooler. The aftercooler is installed above the inlet manifold.

g01385585Illustration 11 Air inlet system (typical example)

(23) Turbocharger

(24) Aftercooler

(25) Elbow on the front bonnet of the oil cooler

The inlet air from the compressor side of the turbocharger flows into the aftercooler. The air passes through the core assembly which lowers the temperature as much as 38°C to 93°C (100°F to 200°F). The cooler air flows out of the bottom of the aftercooler and into the air chamber.

The cooler air then flows through the inlet ports (passages) in the cylinder heads. Cooling the inlet air causes the air to become more dense. Dense air will help the engine burn the fuel more efficiently. This gives the engine more power.

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Valve System Components g01385586Illustration 12

Valve system components

(26) Rocker arm

(27) Locknut

(28) Rocker arm shaft

(29) Camshaft

(30) Valve bridge

The valve train controls the flow of inlet air and exhaust gases into the cylinders and out of the cylinders during engine operation. The camshaft

(29) controls the timing of the valves during engine operation.

The crankshaft gear drives the camshaft gear through an idler gear. The camshaft must be timed to the crankshaft in order to get the correct relation between the piston position and the valve position.

The camshaft has three camshaft lobes for each cylinder. One camshaft lobe operates the inlet valves.

One camshaft lobe operates the exhaust valves.

One camshaft lobe operates the unit injector. The camshaft lobes cause the follower on the rocker arm in order to actuate the valves and the unit injector.

Each cylinder has two inlet valves and two exhaust valves. Valve springs hold the valves closed and the valve springs resist the opening of the valves. This ensures that the valves will close at high rpm and under high boost pressures. Valve rotators cause the valves to rotate while the engine is running.

The rotation of the valves prevents the valves from burning by constantly changing the contact area of the valve face and the valve seat. This rotation gives the valves longer service life.

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Closed Crankcase Ventilation (CCV) System SMCS Code: 1317-FI g01385596Illustration 13

(1) Fumes disposal filter

(2) Air cleaner element

This engine is equipped with a Closed Crankcase Ventilation System (CCV) that is used for capturing fumes. Fumes from the crankcase exit the engine through the crankcase breather. The fumes from the crankcase are collected in the filter base. The engine oil is separated from the fumes from the crankcase in the filter base. The engine oil collects in the filter base and drains back to the crankcase through a drain line in the bottom of the filter base. The fumes from the crankcase are directed back into the air cleaner assembly in order to be consumed by the engine.

Higher crankcase pressures will tend to create oil leaks. The CCV filter base has a service indicator that will indicate when the filter needs to be replaced. If the filter becomes plugged the engine will not be able to relieve the crankcase pressure. This will cause the engine to develop external oil leaks. For more information, refer to the OMM, “Closed Crankcase Ventilation (CCV) System Fumes Disposal Filter - Replace”.

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Lubrication System SMCS Code: 1300

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g01087263Illustration 14

Lubrication system schematic

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(1) Upper rear idler bearing

(2) Oil passage for the rear housing

(3) Middle rear idler bearing

(4) Rear oil line

(5) Lower rear idler

(6) Oil passage to rocker arms and camshaft bearings

(7) Oil passage to the heads

(8) Oil gallery in the head

(9) Camshaft bearings

(10) Shaft bearing for the live idler

(11) Connecting rod with drilled oil passage

(12) External oil line to rear gear train

(13) Piston cooling jets

(14) Lower front idler gear bearing

(15) Main bearings

(16) Right side turbocharger oil supply line

(17) Left side turbocharger oil supply line

(18) Auxiliary oil filter (if equipped)

(19) Main oil gallery

(20) Extension for the oil gallery

(21) Oil filter bypass valve

(22) Oil cooler bypass valve

(23) Oil cooler

(24) Oil pump

(25) Oil pump bypass valve

(26) Oil pan

(27) Oil filter

The oil pump (24) is mounted to the bottom of the cylinder block within the oil pan (26). The oil pump

(24) pulls oil from the oil pan (26). The oil then flows through a passage to the oil cooler (23). Oil then flows through the oil filters (27). The oil can flow into the main oil gallery (19) from the right side or the left side of the block. The location of the incoming oil supply is dependent on the location of the oil filters which can be located on either side of the block. The oil then flows through a set of cross-drilled holes to the opposite side oil gallery.

The main oil gallery (19) distributes oil to the following components: the crankshaft main bearings (15), the piston cooling jets (13), the extension of the oil gallery (20), the turbocharger oil supply line (16), the turbocharger oil supply line (17), and the live front idler gear bearings (10). The main oil gallery (19) also distributes oil to the rear accessory drives through an external oil line (12).

Oil enters the crankshaft through holes in the bearing surfaces (journals) for the main bearing (15). Passages connect the bearing surface (journal) for the main bearing (15) with the bearing surface (journal) for the connecting rod (11). The oil flows upward through a drilled passage in the connecting rod to the piston pin bearing.

The extension for the oil gallery (20) is located in the front right corner of the engine block. The extension for the oil gallery (20) supplies oil to the lower front idler gear bearing (14).

The oil flows to the live front idler gear bearing (10) and around bearing (10) to the oil passage for the cylinder head (7). The oil then flows to the oil gallery in the cylinder head (8) and the oil flows to the oil passage (6) for the camshaft bearings (9) and the rocker arms.

The oil for the lower rear idler bearing (5) is feed from a passage that is connected to the last rear main crankshaft bearing (15). Oil is also feed from the rear main bearing to the rear oil line (4) and to the oil passage in the rear housing (2) for the middle rear idler gear bearing (3) and the upper rear idler gear bearing (1).

This oil circuit typically operates at a pressure of 214 kPa (31 psi) at low idle and at 400 kPa (58 psi) at rated speed.

The oil pump bypass valve (25) limits the pressure of the oil that comes from the oil pump (24). The oil pump (24) can put more oil into the system than oil that is needed. As the oil pressure increases, the oil pump bypass valve (25) will open. This allows the oil that is not needed to go back to the suction side of the oil pump (24).

Cold oil with high viscosity causes a restriction to the oil flow through the oil cooler (23) and the oil filter (27). The oil cooler bypass valve (22) and the oil filter bypass valve (21) will open if the engine is cold. This will give immediate lubrication to all components. The oil pump (24) sends the cold oil through the bypass valves, around the oil cooler (23), and the oil filter (27), and to the main oil gallery (19) in the cylinder block.

When the oil gets warm, the pressure difference in the bypass valves decreases. This closes the bypass valves. This creates a normal flow of oil through the oil cooler and through the oil filter.

The bypass valves will also open when there is a restriction in the oil cooler (23) or a restriction in the oil filter (27). This action lubricates the engine if the oil cooler (23) or the oil filter (27) are restricted.

The bypass valve opening pressures vary with applications.

An oil cooling chamber is formed by the forged lip at the top of the skirt of the piston and the cavity behind the ring grooves in the piston crown. Oil flow from piston cooling jet (13) enters the cooling chamber through a drilled passage in the skirt and returns to the oil pan (26) through the clearance gap between the crown and the skirt. The four holes that have been drilled from the piston oil ring groove to the interior of the piston drain excess oil from the oil ring.

The oil breather allows blowby gases from the cylinders during engine operation to escape from the crankcase. The blowby gases discharge through the flywheel housing to a preformed tube that is routed to the atmosphere. This prevents pressure from building up that could cause seals or gaskets to leak.

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Note: Engines that are equipped with an auxiliary oil filter (18) will pick up oil at a port. The filtered oil will be returned to the oil pan (26).

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Cooling System SMCS Code: 1350 g01122741Illustration 15 Schematic of coolant flow

(1) Turbocharger

(2) Engine block and cylinder heads

(3) Exhaust manifold

(4) Engine oil cooler

(5) Aftercooler

(6) Water pump

(7) Auxiliary water pump

(8) Heat exchanger

This engine has a pressure type cooling system that is equipped with an expansion tank (10) and a recovery bottle (9).

g01122952Illustration 16

(9) Recovery Bottle with a vented cap

(10) Expansion Tank with a pressure relief cap

A pressure type cooling system offers two advantages:

• The cooling system can operate safely at a temperature that is higher than the normal boiling point of water.

• The cooling system prevents cavitation in the water pump.

Cavitation is the sudden formation of low pressure bubbles by mechanical forces in liquids. The formation of air or steam pockets is more difficult within a pressure type cooling system.

The shunt line prevents cavitation by the water pump.

The shunt line provides additional flow of coolant to the water pump inlet.

The recovery bottle (9) provides space for expansion of the coolant volume while the engine is running.

Also, the recovery bottle provides space for expansion during the warm up cycle. The recovery bottle also provides a means for checking the coolant level.

Raw Water Circuit In many instances, a separate cooling source is used to supply coolant to the aftercooler. The coolant supply can be fresh water, or the coolant supply can be sea water. Because of the possible unknown composition of the cooling water, a special pump is needed to move the coolant through the system.

Two types of pumps are available for use in the raw water circuit.

• A bronze pump is used when sea water enters the system. This type of pump will resist the corrosive action of the coolant that passes through the pump.

• A cast iron pump is used when the coolant is pure and noncorrosive.

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Raw water is drawn in through the inlet of the auxiliary water pump (7). The raw water is forced out of the pump and into the aftercooler (5). The raw water flows through the aftercooler in order to cool the inlet air. The raw water then exits the aftercooler and travels through the heat exchanger (8). The raw water is then discharged.

Coolant Flow Circuit Water pump (6) is located on the side of the cylinder block (2). The water pump is gear-driven from the crankshaft.

Coolant from heat exchanger (8) is pulled into the inlet of the water pump by impeller rotation. After the water exits the water pump, the water is dispersed to the following components: oil cooler (4), left exhaust manifold (3), and right exhaust manifold (3).

The coolant that was directed to the exhaust manifolds continues to flow to the turbocharger (1) on each side of the engine. The coolant that was directed to the turbocharger on the right side of the engine combines with the coolant flow from the oil cooler. The coolant then enters the right side of the cylinder block. The coolant from the turbocharger on the left side of the engine enters the left side of the cylinder block. The combined coolant then flows through the cylinder block and cylinder heads. The coolant then exits the front of the engine and flows to the water temperature regulator. Next, the coolant flows through a deaerator in order to purge excess air to the expansion tank. The coolant is then returned to the heat exchanger in order to be cooled.

Note: The water temperature regulator controls the direction of flow. When the coolant temperature is below the normal operating temperature, the water temperature regulator is closed. The coolant is directed from the cylinder head to the inlet of the water pump. When the coolant temperature reaches the normal operating temperature, the water temperature regulator opens. Coolant then travels to the heat exchanger for cooling.

Note: The water temperature regulator is an important part of the cooling system. The water temperature regulator divides coolant flow between the heat exchanger and the bypass in order to maintain the normal operating temperature. If the water temperature regulator is not installed in the system, there is no mechanical control, and most of the coolant will travel the path of least resistance through the bypass. This will cause the engine to overheat in hot weather and the engine will not reach normal operating temperature in cold weather.

The coolant recovery bottle adds volume for expansion of the coolant in the engine cooling system. The coolant recovery bottle also provides a convenient way to check the coolant level. Coolant is forced into the bottle during the warm up cycle.

Coolant returns to the heat exchanger from the recovery bottle during the cool down cycle.

Air vents are provided on the water outlet of the turbocharger. The air vents aid in removing air from the system during the initial filling of the cooling system. The air vents also aid in removing air from the system after a flushing process.

Coolers for the System There are two types of systems for heat dissipation that are recommended for use with Caterpillar marine engines. These systems for heat dissipation involve the use of either inboard mounted heat exchangers or outboard mounted keel coolers. This engine utilizes an inboard mounted heat exchanger. These heat exchangers are typically designed as a shell that surrounds many thin tubes. Systems that are cooled with a heat exchanger require a sea water pump in order to circulate sea water through the thin tubes in the heat exchanger. Cooling system water is then circulated in the opposite direction through the shell that surrounds the tubes. Heat is transferred from the hot coolant to the cool sea water that is flowing through the thin tubes.

i02290289

Basic Engine SMCS Code: 1200

Cylinder Block Assembly The cylinders in the left side of the block form a 65 degree angle with the cylinders in the right side. The main bearing caps are fastened to the block with four bolts, two bolts through each bearing cap and two bolts through the side of the block.

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The cylinder liners can be removed for replacement.

The top surface of the block is the seat for the cylinder liner flange. Engine coolant flows around the liners in order to keep the liners cool. Three O-ring seals around the bottom of the liner make a seal between the liner and the cylinder block. A filler band goes under the liner flange. This makes a seal between the top of the liner and the cylinder block. A steel spacer plate is used between the cylinder head and the block. The spacer plate provides improved reusability and durability. A thin gasket is used between the plate and the block. This thin gasket seals water and oil. A thick gasket of metal and graphite is used between the plate and the head. This thick gasket seals the combustion gases, water and oil.

Cylinder Head Assembly The cylinder heads are a one-piece cast iron head.

The cylinder head supports the camshaft. Steel reinforced camshaft bearings are pressed into each bore for the camshaft. The bearings are lubricated under pressure. The cylinder head contains two inlet valves and two exhaust valves for each cylinder, which are controlled by a rotating camshaft for each cylinder. Bridge dowels have been eliminated as the valve train uses floating valve bridges.

The unit injector is mounted in a stainless steel adapter. This adapter has been pressed into the cylinder head injector bore.

Pistons, Rings And Connecting Rods The piston is a one-piece design that consists of a forged steel crown and a skirt. The piston is retained by the piston pin to the small end of the connecting rod. The pistons have three rings that are located in grooves in the steel crown. These rings seal the combustion gas. The rings provide control of the oil.

The top ring has a barrel face. This ring is a Keystone ring with a plasma face coating. The second ring has a tapered face and the ring has a coating of chrome finish for the face. The third ring is the oil ring. The third ring has a coil spring expander. There are four holes that are drilled from the piston oil ring groove to the interior of the piston. These holes return excess oil from the oil ring groove to the crankcase.

The connecting rod is a conventional design. The cap of the connecting rod is attached to the shank by four bolts that are threaded into the shank. Each side of the small end of the connecting rod is machined at an angle of 12 degrees in order to fit within the piston cavity.

Crankshaft The crankshaft converts the combustion force in the cylinder into rotating torque. A vibration damper is used at the front of the crankshaft in order to reduce the torsional vibrations.

The crankshaft drives a group of gears on the front and the rear of the engine. These gear trains provide power for the following components: camshaft, water pump, oil pump, fuel transfer pump, and accessory items that are specific to the application.

The cylinder block has seven main bearings that support the crankshaft. The cylinder block uses four bolts to hold each of the bearing caps into the block.

Pressurized oil is supplied to all bearing surfaces through drilled holes in the webs of the cylinder block. The oil then flows through drilled holes in the crankshaft in order to provide oil to the connecting rod bearings.

Seals and wear sleeves are used at both ends of the crankshaft. The seals and wear sleeves are used for easy replacement and reduction of maintenance cost.

Camshaft The camshaft has three lobes at each cylinder.

These lobes allow the camshaft to operate the unit injector, the exhaust valves, and the inlet valves. The camshaft is supported in the cylinder head by seven journals which are fit with bearings. The camshaft gear contains integral roller dampers that counteract the torsional vibrations that are generated by the high fuel pressure during fuel injector operation. The design reduces gear train noise. The camshaft is driven by an adjustable idler gear which is turned by a fixed idler gear which is turned by a cluster idler gear in the gear train. Each bearing journal is lubricated from the oil manifold in the cylinder head.

A thrust plate that is located at the front controls the end play of the camshaft. Timing of the camshaft is accomplished by aligning marks on the crankshaft gear and idler gear, and camshaft gear with a mark on the front timing plate.

Vibration Damper The twisting of the camshaft is called torsional vibration. The torsional vibration is caused by the regular power impacts along the length of the crankshaft. The vibration damper is installed on the front end of the crankshaft. This vibration damper is used to reduce the torsional vibrations. This eliminates any damage that could occur to the crankshaft.

The rubber damper is made of an outer hub connected to an inner hub by a rubber ring. The rubber makes a flexible coupling between the outer hub and the inner hub.

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The viscous damper consists of a casing that is welded to the inner hub. The casing contains a steel weight that is suspended in a viscous silicone…