3306B Industrial Engine Caterpillar

Restriction Of Air Inlet And Exhaust

There will be a reduction in the performance of the engine if there is a restriction in the air inlet system or the exhaust system.

Air flow through the air cleaner must not have a restriction of more than 7.5 kPa (30 in H₂O) of water difference in pressure.

Back pressure from the exhaust (pressure difference measurement between exhaust outlet elbow and atmosphere) must be more than 6.7 kPa (27 in H₂O)on engines with a turbocharger.

Measurement Of Pressure In Inlet Manifold

Table 1

Tools Needed
Part Number	Part Description	Qty
1U-5470	Engine Pressure Group	1
8J-7844	Adapter Fitting	1
3K-0360	O-Ring Seal	1
4M-5317	Terminal Bushing	1

The efficiency of an engine can be checked with a comparison of the pressure in the inlet cover and the information in the Technical Marketing Information (TMI).

This test is used when there is a decrease of horsepower from the engine, yet there is no actual sign of a problem with the engine.

The correct pressure for the inlet manifold is also given in the Technical Marketing Information (TMI), "Fuel Setting and Related Information". These standards are established under the following conditions:

• 99 kPa (29.7 inches) of Hg dry barometric pressure

• 29 °C (84 °F) outside air temperature

• 35 API rated fuel

Any change from these conditions can change the pressure in the inlet manifold. The outside air may have a higher temperature and a lower barometric pressure than the values that are given above. This will cause a lower inlet manifold pressure measurement than the pressure in the TMI. Outside air that has both a lower temperature and a higher barometric pressure will cause a higher inlet manifold pressure measurement.

A difference in fuel density will change horsepower (stall speed) and boost. If the fuel is rated above 35 API, the pressure in the inlet manifold can be less than the pressure that appears in the TMI.

If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than the pressure that appears in the TMI.

Ensure that the air inlet and the exhaust manifold do not have an air restriction when you check the pressure.

Note: The electronic service tool may also be used to check the pressure in the inlet manifold.

Illustration 1	g00295554
1U-5470 Engine Pressure Group

To check the inlet cover's pressure, remove one of plugs on the top of the inlet cover. Connect the following items to this opening:

• Adapter

• Seal

• Reducing bushing

• 1U-5470 Engine Pressure Group

The 1U-5470 Engine Pressure Group has a gauge that indicates pressure inside the inlet cover. Instructions for using this tool group appear in the Special Instructions, SEHS8907.

Checking the Operation of the Aftercooler

Illustration 2	g00509120
4C-6500 Digital Thermometer

Use the 4C-6500 Digital Thermometer to check the operation of the aftercooler. Refer to Special Publication, NEHS0554 for more information on the testing procedure.

Air-to-Air Aftercooled Systems

Table 2

Tools Needed
Part Number	Part Description	Qty
FT-1984	Air-to-Air Aftercooler Leak Test Group	1
FT-1438	Engine Dynamometer Test	1

Visual Inspection

Inspect the following components of the air-to-air aftercooler system:

• Lines

• Hoses

• Gasket joints

Ensure that the constant torque hose clamps are tightened to the correct torque.

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Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.

Note: Whenever any parts for the air-to-air aftercooler system are replaced, perform a leak test. Also perform a test when one of these parts has been repaired.

Check the welded joints for any cracks. Check the brackets for correct positioning. Also, ensure that these brackets are in good condition. Use compressed air to clean any debris or any dust from the aftercooler core assembly. Inspect the aftercooler core assembly's fins for the following conditions:

• Damage

• Debris

Use a stainless steel brush to remove any corrosion. Ensure that you use soap and water.

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Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.

Note: When air-to-air aftercooler parts are repaired and air-to-air aftercooler parts are replaced, a leak test should be completed.

Air System Restriction

Periodically, take pressure measurements at the turbocharger outlet and at the inlet manifold. The air lines and the cooler core must be inspected for internal restriction under both of the following conditions:

• The air flow is at a maximum level.

• The total air pressure's drop of the charged system exceeds 13.5 kPa (4 in Hg).

If a restriction is discovered, inspect the cooler core for cleaning, for repairing, and for replacement needs, as required.

Turbocharger Failure

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Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.

If a turbocharger failure occurs, follow this procedure:

1. Remove the air-to-air aftercooler core.

2. Flush the air-to-air aftercooler core with a solvent for removing oil and other foreign substances.

3. Shake the aftercooler core. This may allow any trapped debris to escape.

4. Wash the aftercooler core with water that is hot and soapy. Then, thoroughly rinse the aftercooler core with clean water.

5. Blow dry the assembly with compressed air. Blow dry the assembly in a reverse direction of the normal air flow.

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NOTICE
Do not use caustic cleaners to clean the air-to-air aftercooler core. Caustic cleaners will attack the internal metals of the core and cause leakage.

6. Take extra care to ensure that the system is clean.

Inlet Manifold Pressure

Normal inlet manifold pressure with high exhaust temperature can be caused by blockage in the aftercooler core assembly's fins. Clean the aftercooler core assembly's fins. Refer to "Visual Inspection" for the correct cleaning procedure.

Low inlet manifold pressure and high exhaust manifold temperature can be caused by any of the following conditions:

Plugged air cleaner - Clean the air cleaner, as required. Replace the air cleaner, as required.

Blockage in the air lines - Blockage in the air lines between the air cleaner and the turbocharger must be removed.

Aftercooler core leakage - An aftercooler core leakage should be pressure tested. See "Aftercooler Core Leakage" for the correct procedure to clean parts. Use the same manual for information on repairing parts and on replacing parts.

Leakage of the induction system - Any leakage from the pressure side of the induction system should be repaired.

Inlet manifold leak - An inlet manifold leak can be caused by any one of the following problems:

• Loose fittings and loose plugs

• Missing fittings and missing plugs

• Damaged fittings and damaged plugs

• The manifold to cylinder head gaskets

Check all of these items, if necessary.

Aftercooler Core Leakage

Illustration 3	g00295702
FT-1984 Air-to-Air Aftercooler Leak Test Group (1) Regulator and valve assembly. (2) Nipple. (3) Relief valve. (4) Tee. (5) Couplers. (6) Aftercooler core assembly. (7) Dust plug. (8) Dust plug. (9) Chain.

Aftercooler leakage can cause the following conditions to occur:

• Low engine power

• Low boost pressure

• Black smoke

• High exhaust temperature

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NOTICE
Remove all air leaks from the system to prevent engine damage. In some operating conditions, the engine can pull a manifold vacuum for short periods of time. A leak in the aftercooler or air lines can let dirt and other foreign material into the engine and cause rapid wear and/or damage to engine parts.

A large leak in the aftercooler core can be found through a visual inspection. To check for smaller leaks, use the following procedure:

1. Disconnect the air pipes from the inlet side of the aftercooler core assembly and from the outlet side of the aftercooler core assembly.

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Dust plug chains must be installed to the aftercooler core or to the radiator brackets to prevent possible injury while you are testing. Do not stand in front of the dust plugs while you are testing.

2. Install couplers (5) on each side of the aftercooler core. Also, install dust plugs (7) and (8).

   These items are included with the FT-1984 Air-to-Air Aftercooler Leak Test Group .

   Note: The installation of additional hose clamps on hump hoses is recommended. This additional installation should prevent the hump hoses from bulging while the aftercooler core is being pressurized.

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NOTICE
Do not use more than 240 kPa (35 psi) of air pressure or damage to the aftercooler core can be the result.

3. Install the regulator and valve assembly (1) onto the outlet side of the aftercooler core assembly. Also, attach the air supply.

4. Open the air valve, and pressurize the aftercooler to 205 kPa (30 psi). Shut off the air supply.

5. Inspect all connection points for air leakage.

   The aftercooler system's pressure should not drop more than 35 kPa (5 psi) in 15 seconds.

6. If the pressure drop is more than the specified amount, follow this procedure:

   1. Use a solution of both soap and water to check all areas for leakage.

   2. Look for air bubbles that will identify possible leaks.

   3. Replace the hoses, or repair the aftercooler core, as needed.

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To help prevent personal injury when the tooling is removed, relieve all pressure in the system slowly by using an air regulator and a valve assembly.

7. After you test the aftercooler core assembly, remove the FT-1984 Air-to-Air Aftercooler Leak Test Group. Reconnect the air pipes on both sides of the aftercooler core assembly.

Dynamometer Test

In hot ambient temperatures, dynamometer tests for models with an air-to-air aftercooler can add a greater heat load to the jacket water cooling system. Therefore, the jacket water cooling system's temperature must be monitored. Also, monitor the inlet air temperature, which may need a power correction factor. These other measurements may also need a power correction factor:

• Fuel API rating

• Fuel temperature

• Barometric pressure

With dynamometer tests for engines, use the FT-1438 Dynamometer Testing. This tool uses an air-to-water aftercooler to control the inlet air temperature. This pressure is controlled to 43 °C (109 °F).

Measurement Of Exhaust Temperature

Table 3

Tools Needed
Part Number	Part Description	Qty
123-6700	Laser Infrared Thermometer	1

When the engine runs at low idle, the temperature of an exhaust manifold port can indicate the condition of a unit injector:

A low temperature indicates that no fuel is flowing to the cylinder. An inoperative unit injector pump could cause this low temperature.

A very high temperature can indicate that too much fuel is flowing to the cylinder. A malfunctioning unit injector could cause this very high temperature.

Use the 123-6700 Laser Infrared Thermometer to check this exhaust temperature. You can find operating instructions and maintenance instructions inside the Operator's Manual, NEHS0630, "123-6700 Infrared Thermometer II with Laser Sighting".

Turbocharger

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Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.

Check the turbocharger under the following conditions:

• 4800 hours of usage

• Any unusual noises from the turbocharger

• Any unusual vibrations in the turbocharger

A quick check of a turbocharger bearing's condition can be made without the disassembly of the turbocharger. Follow this procedure for this quick check:

1. Remove the piping from the turbocharger.

2. Inspect the following components of the turbocharger for any damage and for any deposits:
   • Compressor impeller

   • Turbine wheel

   • Compressor cover

3. Rotate the turbocharger compressor wheel and the turbine wheel assembly by hand. Take extra care to feel for any excess end play and for radial clearance.

   The turbocharger compressor wheel and the turbine wheel assembly should rotate freely without any rubbing and without any binding.

   If the impeller rubs against the compressor cover or turbine wheel rubs against the turbine housing, the turbocharger needs replacement or repair. For replacement, use a turbocharger that is new, reconditioned, or rebuilt.

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NOTICE
Do not use caustic cleaners to clean the air-to-air aftercooler core. Caustic cleaners will attack the internal metals of the core and cause leakage.

Checking for End Play

Use a dial indicator to correctly check the end clearance.

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Illustration 4	g00341132
Checking for Turbocharger Rotating Assembly End Play Typical Example

1. Attach a dial indicator with the indicator point on the end of the shaft. This can be seen in Illustration 4.

2. Move the shaft forward and backward.

3. Record the indicator gauge's total reading.

   Note: Refer to Specifications, "Turbocharger" for the correct end play dimensions.

If the end play is more than the maximum amount that is listed, replace the turbocharger. If the end play is less than the minimum that is listed, inspect the turbine wheel for any buildup. If any buildup is found, disassemble the turbine wheel for cleaning and for inspection.

A more reliable check of a bearing condition can only be performed after the turbocharger has been disassembled. Then, the following components can be precisely measured:

• Bearings

• Shaft journal

• Housing bore diameters

Crankcase (Crankshaft Compartment)

Table 4

Tools Needed
Part Number	Part Description	Qty
8T-2700	Blowby/Air Flow Indicator	1

Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition will cause the engine to run rough. There will be more than the normal amount of fumes rising from the crankcase breather. This crankcase pressure can also cause the element for the crankcase breather to have a restriction in a very short time. This crankcase pressure can also be the cause of any oil leakage at the gaskets and at the seals. These areas would not normally have leakage.

Note: The electronic service tool can be used to measure crankcase pressure.

Illustration 5	g00286269
8T-2700 Blowby/Air Flow Indicator

The 8T-2700 Blowby/Air Flow Indicator checks the amount of blowby. See Special Instructions, SEHS8712 for more information on using this tool.

Compression

An engine that runs rough can have a leak at the valves. An engine that runs rough can also have valves that need an adjustment. Use the following test for a quick, easy method to identify a cylinder with low compression. This test will also indicate whether a cylinder does not have good fuel combustion:

1. Find the roughest speed of the engine.

2. Maintain this speed until the test is completed.

3. Loosen a fuel line nut at the fuel injection pump.

   This stops the fuel flow to that cylinder.

   Note: Take great care to tighten each fuel line after testing a cylinder and before loosening the next fuel line nut.

4. Repeat Step 3 for each cylinder until a loosened fuel line makes no difference in the engine's performance.

   This is only an indication of a problem.

This easy test can also indicate that the fuel injection pump has a problem, so the cylinder must be checked thoroughly.

Cylinder Heads

The cylinder heads consist of three main components that can be removed:

• Valves

• Valve seat inserts

• Valve guides

When any of these components are worn or damaged, these components can be removed. Refer to Disassembly and Assembly, "Cylinder Head" for more information about these components.

Valves

Use the following tools for installing valves and for removing valves:

• 5S-1330 Valve Spring Compressor

• 5S-1322 Valve Keeper Installer

Valve Seat Inserts

The tools that are required to remove valve seat inserts can be found in the 6V-4805 Valve Seat Extractor Tool Group. See the Disassembly and Assembly, "Valve Seat Inserts" for this procedure. Remember that the valve seat insert is easier to install by lowering the temperature of the insert. This should be done before you install the valve seat insert into the cylinder head. Refer to Special Instruction, SMHS7935, "Use of 6V-4805 Valve Seat Extractor Tool Group" for more information.

Valve Guides

Table 5

Required Tools
Part Number	Part Name	Quantity
7S-8858	Bushing Driver	1
9U-7349	Valve Driver	1
9U-6954	Guide Collar	1
1P-7451	Valve Guide Honing Group	1

Use the tools in Table 5 to install the valve guides. The counterbore in the driver bushing installs the valve guide to the correct height. Use a 1P-7451 Valve Guide Honing Group to create a finished bore in the valve guide after you install the guide in the cylinder head.

Note: See the Disassembly and Assembly, "Valve Guides" for more information on installing valve guides. Also, refer to Special Instruction, SMHS7526, "Use of 1P-7451 Valve Guide Honing Group" for more information.

Checking the Valve Guide Bore

Use the 5P-3536 Valve Guide Gauge Group to check the bore of the valve guides. See Special Instruction, GMGO2562 for more detailed instructions for using this tool group.

Illustration 6	g00509317
5P-3536 Valve Guide Gauge Group

Valve Lash

Illustration 7	g00316303
Engine Design (A) Exhaust valves. (B) Inlet valves.

Use the following procedure to adjust the valves:

1. Put the No. 1 piston to the top center position on the compression stroke.

   Note: See Testing and Adjusting, "Finding Top Center Position for No. 1 Piston" for further details.

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   Table 6

   Valve Lash Setting with Stopped Engine
   Valves	Dimension of Gauge
   Inlet	0.38 mm (.015 inch)
   Exhaust	0.64 mm (.025 inch)

2. Adjust the valve lash on the inlet valves for cylinders 1, 2, and 4.

3. Adjust the valve lash on the exhaust valves 1, 3, and 5.

4. Turn the flywheel by 360° in the direction of the engine rotation.

   This puts the No. 6 piston at the top center position on the compression stroke.

5. Adjust the valve lash on the intake valve for cylinders 3, 5, and 6.

6. Adjust the valve lash on the exhaust valve for cylinders 2, 4, and 6.

7. After each valve adjustment is correctly made, tighten the nuts for the valve adjustment screws to 29 ± 7 N·m (22 ± 5 lb ft).