Caterpillar 3406 Generator Set

⚠ Valves must be fully closed.

Tools: Caterpillar Part Number 9S9082 engine turning tool, feeler gauge

1. Adjust valves with the engine stopped and cold.
2. Remove the flywheel housing timing hole cover.
3. Remove the plug.
4. Rotate the flywheel in direction of engine rotation until timing bolt can be installed in flywheel.
5. Install the timing bolt in the flywheel. This is the top bolt of the two bolts that secure the flywheel housing cover.
6. Determine if No. 1 piston is on compression or exhaust stroke. The cylinder on compression will have both inlet and exhaust valves closed. If valves are open, rotate engine 360° to obtain TDC No. 1 co
7. 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.
8. 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.
9. Set lash at .015 (0.38 mm) for inlet valves and .030 (0.76 mm) for exhaust valves.
10. Tighten adjusting screw locknut and check lash.
11. 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.
12. 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.

⚠ Valves must be fully closed.

1. Valves must be fully closed.
2. If bridge was removed, put engine oil on the bridge dowel in the cylinder head and in the bore in the bridge.
3. Install the bridge with the adjustment screw toward the exhaust manifold.
4. Back off adjusting screw several turns (counterclockwise), making sure it is not in contact with the valve stem.
5. Firmly press straight down on the rocker arm above point of contact with bridge.
6. Turn the adjusting screw clockwise until contact is made with the valve stem. Turn the adjusting screw an additional 30° (one-twelfth turn).
7. Hold the adjusting screw in this position and tighten the locknut to 22 + 3 lb. ft. (80 = 4 Nm).
8. Put engine oil at the point where the rocker arm makes contact with the bridge.
9. After checking the bridge adjustment, make the valve lash adjustment.

Tools: crane, dial indicator, shims, torque wrench

1. Loosen all bolts connecting base to foundation; loosen all bolts fastening engine supports and generator supports to base.
2. Ensure enough clearance between bolts and bolt holes in base, engine supports, generator supports at all locations.
3. Check clearance between base and foundation at all mounting locations; use shims to prevent deflection; tighten base-to-foundation bolts to final torque.
4. While generator supported by crane, loosen all bolts (2) fastening generator to flywheel housing; tighten alternate bolts to final torque; check clearance between base and engine and generator support
5. Tighten all bolts fastening engine supports and generator supports to base to half of final torque; loosen all bolts (2); measure gap between generator and flywheel housing; ensure bolts centered in c
6. Gaps at (E), (F), (G), (H) should be more than 0.03 mm (0.001 inch) and less than 0.13 mm (0.005 inch); adjust shims or move rear of generator right or left.
7. After shim correction, tighten generator support bolts to half of final torque 450 N-m (332 Ib ft); check gaps; repeat until 0.13 mm (0.005 inch) or less; begin with Step 5.
8. Install dial indicator on base with tip next to support mounting bolt (4); put tip on support (3); check while tightening bolt to final torque; if indicator moves more than 0.13 mm (0.005 inch), insta

Tools: shims, torque wrench

1. Loosen all bolts connecting base to foundation; loosen all bolts fastening generator supports and engine supports to base.
2. Ensure clearance between bolts and bolt holes in base, engine supports, generator supports at all locations.
3. Check clearance between base and foundation at all mounting locations; use shims to prevent base deflection; tighten base-to-foundation bolts to final torque.
4. Check clearance between base and engine, base and engine supports, base and generator supports over entire length; use shims to prevent support deflection; tighten all mounting bolts to final torque.

1. Drain crankcase and install new filters after normal operating temperature reached
2. Tighten crankcase drain plug to 70+/-14 N-m (50+/-10 lb ft)
3. Add oil per Refill Capacities chart and allow 5 minutes to drain into sump
4. Crank engine with filters installed before starting to avoid bearing damage
5. Start and run engine to circulate oil and fill filters
6. Stop engine, wait 5 minutes, mark ADD level on dipstick if different from actual
7. Add specified additional oil quantity (shallow: 3.8 L / deep: 8 L) and mark FULL level
8. Restart, run to operating temperature at LOW IDLE, mark opposite side FULL for warm/idle reading

⚠ Hot engine components can cause burns.

⚠ Only qualified service personnel should perform this maintenance.

1. Ensure the engine cannot be started; do not use the starting motor to turn the flywheel.
2. Ensure the engine is stopped and allow valves to cool.
3. Refer to the Systems Operation/Testing and Adjusting Manual for the complete procedure.
4. Set inlet valve lash to 0.38 mm (0.0150 inch).
5. Set exhaust valve lash to 0.76 mm (0.030 inch).
6. Perform initial adjustment at the first scheduled oil change.

⚠ Do not use starting motor to turn flywheel; hot components can burn

1. Disable starting motors so engine cannot start during procedure
2. Allow at least 20 minutes for valves to cool to block/head temperature
3. Clean area around valve mechanism covers before removal
4. Adjust valve bridges before adjusting any valves, per cylinder
5. Check/adjust valve lash to nominal value in Valve Lash Setting chart
6. Start engine at LOW IDLE and observe valve rotator rotation after setting lash

Tools: torque wrench, shims

1. Loosen the sixteen close coupled adapter bolts (2); visually ensure they are centered in clearance holes.
2. Check gaps at 3, 6, 9, and 12 o'clock positions; use 2, 4, 8, and 10 o'clock if 12 and 6 are inaccessible.
3. If gaps are between 0.03 mm (0.001 inch) and 0.13 mm (0.005 inch), tighten all bolts; alignment check complete. If not, loosen bolts fastening generator to base frame; adjust shims; move rear of gener
4. After adjustment, tighten generator mounting bolts to one half of standard torque 450 N-m (332 lb ft); repeat procedure starting with Step 1.

⚠ The VR3 regulator is protected by a fuse(s) and a solid-state overcurrent protection. If a fuse becomes open, contact a Caterpillar dealer.

1. Remove the access panel of the generator.
2. Loosen the locknut on the voltage droop potentiometer (1).
3. Remove the protective screw from the voltage level potentiometer (2) and from the voltage gain potentiometer (3).
4. Turn the voltage droop potentiometer (1) counterclockwise to zero droop. Tighten the locknut.
5. Turn the voltage gain potentiometer (3) counterclockwise to zero, then to about 1/4 of full range of clockwise travel.
6. Perform required maintenance on the engine before you start the engine.
7. Start the engine and allow the engine to warm up.
8. Increase engine speed to full governed rated speed (high idle).
9. Set the no-load voltage with the voltage level potentiometer (2) or the voltage adjust rheostat.
10. Close the load circuit breaker and apply full load gradually. Adjust governor control to nameplate frequency or rated speed.
11. If the voltmeter reading increases above no-load voltage, turn the voltage gain potentiometer counterclockwise. If it decreases, turn it clockwise.
12. Remove the load. If necessary, adjust the voltage level potentiometer (2) to obtain desired voltage.
13. Apply the load. Repeat Steps 10 through 12 until the voltage at no load equals the voltage at full load.
14. Tighten the locknuts. Install the protective screws and the access panel of the generator.

Tools: ammeter with capacity over 75 amps

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 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
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.

1. Remove the fuel filters.
2. Cut the fuel filters open.
3. Inspect the fuel filter before the filter warms. The inspection will show that the filter is filled with particles of either ice or wax.

⚠ Do not operate the generator set at a speed higher than one-half of the rated speed.

Tools: 6V-7070 Digital Multimeter, 12 VDC battery, Potential Transformer

1. Stop the generator. Connect the potential transformer's high voltage winding to generator terminals T1 and T2. Connect the voltmeter to the low voltage winding.
2. Disconnect wires F1+ and F2- from the voltage regulator. Disconnect the generator from the load.
3. Connect a 12 VDC automotive battery to wires F1+ and F2-.
4. Operate the generator set at half the rated speed.
5. Measure the AC voltage across the low voltage terminals corresponding to T1-T2, T2-T3, and T3-T1. Record the voltages.
6. Monitor the voltage between any two locations, then decrease the generator set speed by 10 percent and increase it by 10 percent.
7. The measured voltages should be nearly equal and should measure a minimum of 85 VAC.
8. When speed is decreased by 10 percent the voltages should decrease by 10 percent; when increased by 10 percent the voltages should increase by 10 percent.