3406 TRUCK ENGINE Caterpillar

Every 100,000 Miles or 2000 Service Hours

Usage:

(16)Engine Valve Lash

Adjust valves with the engine stopped and cold.

If valve clearance is within ± .003 inch (0.07 mm) of the clearance given, adjustment is not required. If clearance is not within these limits, adjust the valves.

There are two rocker arms (A), per cylinder. One rocker arm for the two exhaust valves and one rocker arm for the two inlet valves. Each pair of valves is connected by a bridge (B), which is actuated by the rocker arm. The valves in each pair are adjusted simultaneously by the adjusting screw (C), in the rocker arm. Each bridge is adjusted by adjusting screw (D).

1. Remove the flywheel housing timing hole cover (A).

2. Remove the plug (B).

3. Rotate the flywheel in direction of engine rotation until timing bolt can be installed in flywheel.

The engine can best be rotated by removing the flywheel housing timing hole cover and installing an engine turning tool, Caterpillar Part Number 9S9082. Contact your authorized dealer for information.

4. Install the timing bolt in the flywheel. This is the top bolt of the two bolts that secure the flywheel housing cover.

5. Clean the area around the valve cover. Remove the cover.

6. Determine if No. 1 piston is on compression or exhaust stroke. The cylinder on compression will have both the inlet and exhaust valves closed. If the valves are open, rotate the engine 360° to obtain TDC No. 1 compression.

Valves must be fully closed.

Bridge Adjustment

Adjustment of the bridge will be necessary only after grinding the valves or other reconditioning of the cylinder head is done. Make an adjustment to the bridge using the following procedure.

Valves must be fully closed.

If bridge was removed perform steps 1 and 2 that follow. If bridge was not removed, proceed to step 3.

1. Put engine oil on the bridge dowel in the cylinder head and in the bore in the bridge.

2. Install the bridge with the adjustment screw toward the exhaust manifold.

3. Back off adjusting screw several turns (counter-clockwise), making sure it is not in contact with the valve stem.

4. Firmly press straight down on the rocker arm above point of contact with bridge.

5. Turn the adjusting screw clockwise until contact is made with the valve stem. Turn the adjusting screw and additional 30° (one-twelfth turn).

6. Hold the adjusting screw in this position and tighten the locknut to 22 ± 3 lb. ft. (30 ± 4 N·m).

7. Put engine oil at the point where the rocker arm makes contact with the bridge.

NOTE: After checking the bridge adjustment, make the valve lash adjustment.

Valve Lash Adjustment:

1. With No. 1 piston at TDC on compression, check lash between the bridge and rocker arm on exhaust valves of cylinders 1, 3 and 5, and inlet valves for cylinders 1, 2 and 4.

2. To adjust, loosen valve adjusting lock nut and turn adjusting screw to allow proper size feeler gauge to pass between top of bridge and the valve rocker arm.

3. Set lash at .015 (0.38 mm) for inlet valves and .030 (0.76 mm) for exhaust valves.

4. Tighten adjusting screw locknut and check lash.

5. Turn flywheel 360° in direction of engine rotation. Align flywheel timing bolt with the timing hole in the flywheel. No. 6 cylinder will be at TDC compression stroke (valves closed).

6. Check lash between the bridge and rocker arm on exhaust valves for cylinders 2, 4 and 6, and inlet valves for cylinders 3, 5 and 6. Adjust valves if necessary.

(17)Fuel Injection Nozzles

Whenever an engine performs in such a manner that a fuel injection valve is suspected of causing trouble, test all fuel injection valves by loosening the fuel injection line nut at the pump.

When a nut is loosened and the exhaust smoking is completely or partially eliminated and the irregularity in running is not affected, this identifies the probable location of a defective fuel injector.

Your authorized dealer has the proper tools for cleaning and testing fuel injection valves.

To Remove Injector:

1. Clean dirt from around valve cover and remove the cover.

2. Disconnect the clip and lead wire from the glow plug.

3. Remove the fuel injection line at the valve housing.

Immediately install plugs in the fuel line nuts to prevent dirt from entering the fuel injection line.

4. Remove the valve retainer nut, and nozzle assembly.

To Install:

1. Screw the valve body into the nozzle assembly.

2. Insert the nozzle assembly and valve body, as a unit, into the precombustion chamber.

3. Install the retainer nut and tighten to 55 lb. ft. (71 N·m).

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NOTICE

Do not overtighten. Use a torque wrench. Overtightening or undertightening can cause fuel nozzle and engine failures.

4. Connect the fuel injection line and tighten. Install clip and lead wire to the glow plug.

5. Install the valve cover.

(18)Air Compressor

1. Inspect the performance of the air compressor.

2. Rebuild or replace the air compressor if needed.

3. Thoroughly inspect all connections for tightness before placing the vehicle in use.

(19)Cooling System-Cleaning

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At Operating Temperature, engine coolant is hot and under pressure.
Steam can cause personal injury.
Check coolant level ONLY when engine is stopped and radiator cap is cool enough to touch with your hand.
Remove filler cap slowly to relieve pressure.

Cooling System Conditioner contains alkali. Avoid contact with skin and eyes to prevent personal injury.

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NOTICE

All water is corrosive at engine operating temperature. Use either Caterpillar Cooling System Conditioner liquid, or the attachment coolant conditioner group to treat either plain water or ethylene glycol (antifreeze) solution. NEVER use both the liquid cooling system conditioner and the coolant conditioner element at the same time.

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NOTICE

When changing antifreeze solution, replace the attachment coolant conditioner group maintenance filter element with the appropriate precharge filter element, Part Number 9N2366. Do not use Caterpillar Cooling System Conditioner or Coolant Conditioner Elements with Dowtherm 209 Full-Fill coolant.

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NOTICE

If the truck is to be used or stored in an area with below freezing temperatures, the cooling system must be protected to the lowest expected ambient temperature. Never add coolant to an overhead engine; allow the engine to cool first.

1. Loosen the radiator cap slowly to release the pressure. Remove the radiator cap.

2. Remove the cooling system drain plug, and allow the coolant to drain.

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Use all cleaning solutions with care.

Most commercial cooling system cleaners may be used. The best cleaner is chelate type alkaline cleaners.

3. Install the drain plug. Fill the system with cleaning solution.⁽¹⁾

4. Start and run engine for 1/2 hour. Stop the engine and drain cleaning solution.

5. Flush the system with clean water until the draining water is clean. Do not run the engine while flushing.

6. Install the drain plugs. Fill the system with neutralizing solution.⁽²⁾

7. Start and run the engine for 10 minutes. Stop the engine and drain neutralizing solution.

8. Flush the system with clean water, until the draining water is clean. Do not run the engine while flushing.

9. Install the drain plug.

10. Add the correct amount of Caterpillar Cooling System Conditioner, or equivalent, so that the cooling system will have a 3% concentration. Add 1 pint (.50 liters) for each 4 gal. (15.14 liter) of coolant.

11. To help avoid air locks, add coolant slowly, at 5 U.S. gallons (19 liters) per minute or less.

12. Add antifreeze solution. See REFILL CAPACITIES.

13. Start and run the engine with the radiator cap removed. Allow coolant to warm and level to stabilize.

14. Add coolant, if necessary, to bring the coolant level to the bottom of the fill pipe.

15. Observe condition of the radiator cap gasket. Replace if it is damaged.

⁽¹⁾2 lb. Sodium Bisulfate (NaHSO₄ per 10 U.S. gallons (1 kilogram per 10 liters) water.

⁽²⁾1/2 lb. Sodium Carbonate Crystals (Na₂CO₃·10 H₂O) per 10 U.S. gallons (250 grams per 40 liters) water.

(20)Batteries

1. Loosen and remove cable clamps from all battery terminals.

2. Clean all cable clamps.

3. Clean all battery terminals.

4. Install the cable clamps on the battery terminals. Make sure they are secure.

5. Apply a light coat of grease on the battery connections.

(21)Starting Aids-Checking Glow Plugs

1. Disconnect the wire lead from the glow plug terminal on the HEAT-START switch.

2. Install an ammeter with a capacity of over 75 amps, in a series, between the disconnected lead and the terminal on the HEAT-START switch.

3. Turn HEAT-START switch to HEAT.

4. Observe the ammeter. Each 12 volt glow plug draws approximately 12.5 amperes. The ampere draw of one glow plug multiplied by 6 will be 75 amps, the total ampere draw of the glow plugs in the engine. A low reading indicates one or more defective glow plugs.

5. If a defective glow plug is indicated, disconnect one glow plug lead at a time.

6. Turn switch to the HEAT position. Observe the ammeter. Reconnect the lead.

7. The glow plug that does not change the reading on the ammeter, when the switch is turned on, is the defective glow plug.

(22)Engine Mounting Bolts

Tighten the engine mounting bolts. See BOLT TORQUE CHART.

(23)Crankshaft Seal

1. Inspect for front seal leakage.

2. Inspect for rear seal leakage.

(24)Turbocharger

1. Remove the turbocharger air inlet and the exhaust outlet piping.

2. Rotate the compressor and turbine wheel by hand.

3. The assembly should rotate freely.

Feel for excessive end play and radial clearance.

4. End play is best checked with a dial indicator. End play should be between .003 inch (0.07 mm) and .008 inch (0.203 mm). If end play exceeds .008 inches (0.203 mm) rebuild or replace the turbocharger.

(25)Water Pump

1. Inspect the water pump. Rebuild it, or install a rebuilt pump if necessary.

Your authorized dealer is familiar with worn replacement limits and rebuild procedures.

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NOTICE

If engine oil has been mixed with the coolant due to a pump malfunction, drain the cooling system, flush and clean the system.

(26)Vibration Damper

Inspect for separation of rubber ring between inner hub and flywheel ring. Replace if damage is visible.

(27)Thermostat

The opening temperature of the thermostat (bench test in atmospheric pressure) should be 180°F (82°C). The thermostat should be fully open at approximately 197°F (92°C).