Cummins/Onan KTA50-G8 Engine

⚠ Over-tensioning of alternator belts can result in premature accessory drive bushing wear and seal leakage.

Tools: GT-1293 Burroughs Tension Gauge

1. Loosen the alternator and adjusting link mounting capscrews.
2. Loosen the jam nuts on the adjusting screw.
3. Turn the adjusting screw clockwise to tighten the belt tension.
4. Check the belt tension with a gauge.
5. Tighten the jam nuts on the adjusting screw to 55 Nm [40 ft-lb].
6. Tighten the adjusting link and alternator mounting capscrews to 55 Nm [40 ft-lb].
7. Check the belt tension again.

Tools: ST-669 Torque Wrench Adapter

1. Adjust the crossheads on the cylinder that has both valves closed.
2. Loosen the crosshead adjusting screw locknuts on the intake and exhaust valve crossheads.
3. Turn the adjusting screw out at least one turn.
4. Hold the crosshead down against its guide.
5. Turn the adjusting screw in until it touches the top of the valve stem but does not raise the crosshead.
6. Hold the adjusting screw and tighten the lock nut to the torque value.

⚠ The dipstick will break if the scribe mark is too deep.

Tools: scribe

1. Drain the oil from the pan.
2. Install the dipstick in the dipstick tube.
3. Use clean 15W-40 oil to fill the oil pan to the specified low level.
4. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the low level with an L.
5. Install the dipstick and add additional oil to the specified full level.
6. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the high oil level with an H.

⚠ The injector plunger is under spring tension. Do NOT allow the tool to slip.

⚠ Prevent damage to the indicator by allowing the lever to return slowly.

Tools: 3822575 injector and valve adjustment kit, 3822574 rocker lever actuator, ST-669 Torque Wrench Adapter

1. Assemble the parts of an injector and valve adjustment kit, Part No. 3822575, or equivalent, and install it on the cylinder.
2. Adjust the indicator so the tip touches the top of the injector plunger.
3. Lower the indicator 12.25 mm [0.5 inch] to allow for travel. Lock the indicator support to the post.
4. Use a rocker lever actuator, Part No. 3822574, or equivalent. Depress the lever until the injector bottoms two or three times.
5. Hold the lever with the injector plunger firmly bottomed and set the indicator to ZERO.
6. Turn the adjusting screw until the indicator reads the specified travel.
7. Tighten the locknut to the torque value.
8. Check the injector adjustment and repeat if not within specification.

⚠ Use the correct chart for the engine being serviced or the parts will be damaged.

Tools: 3376592 Inch Pound Torque Wrench, ST-669 Torque Wrench Adapter, feeler gauge

1. Select a feeler gauge for the correct valve lash specification and insert the gauge between the rocker lever and the crosshead.
2. Torque wrench method: use Part No. 3376592 inch pound torque wrench and tighten the adjusting screw to 0.68 Nm [6 in-lb].
3. Feel method: use a screwdriver and turn the adjusting screw only until the lever touches the feeler gauge.
4. The adjusting screw must not turn when the locknut is tightened.
5. Tighten the locknut to the value indicated.
6. The feeler gauge must slide backward and forward with only a slight drag.
7. Attempt to insert a feeler gauge 0.03 mm [0.001 in] thicker; the lash is not correct when the thicker gauge will fit.
8. Repeat until clearance is correct on both intake and exhaust valves.

⚠ Holes, loose end seals, dented sealing surfaces and other damage require immediate element replacement.

⚠ Pull the cover and element straight out to avoid damage.

1. Wipe dirt from the cover and upper portion of the air cleaner before disassembly.
2. Loosen the wing bolt and band clamp securing the dust pan.
3. Loosen the wing nut and remove the dust shield from the dust pan. Clean the dust pan and shield.
4. Remove the wing nut securing the primary element and inspect the rubber sealing washer.
5. Remove the dirty cleaner element and install the new primary element.
6. Make sure the rubber sealing washer is in place under the wing nut before tightening.
7. Assemble the dust shield and dust pan and secure with the band clamp.

⚠ Do NOT remove the radiator cap from a hot engine.

⚠ Do not allow oil to get in the filter; it will adversely affect the DCA.

1. Remove the coolant system pressure cap and close the shutoff valve(s), if equipped, before removing the coolant filter.
2. Push in the knob on the filter head or close the gate valve.
3. Lubricate the seal on the new filter with engine oil.
4. Install the new coolant filter. Turn the filter until the seal touches the filter head.
5. Turn the filter an additional 1/2 to 3/4 of a turn after contact.
6. Pull the knob on the filter head out or open the gate valve.

⚠ Do not use caustic cleaners in the cooling system. Aluminum components will be damaged.

⚠ Wait until the temperature is below 50 C [120 F] before removing the coolant system pressure cap.

1. Drain the cooling system. Do not allow the cooling system to dry out. Do not remove the coolant filter.
2. Add 3.8 liters [1 U.S. gallon] of Fleetguard RESTORE (or equivalent) for each 38 to 57 liters [10 to 15 gallons] of cooling system capacity and fill with plain water.
3. Turn the heater temperature switch to high to allow maximum coolant flow.
4. Operate the engine at normal operating temperatures (at least 85 C [185 F]) for 1 to 1 1/2 hours.
5. Shut the engine off and drain the cooling system.
6. Fill with clean water to flush and operate at high idle for 5 minutes above 85 C [185 F].
7. Shut the engine off and drain. Repeat flushing if the water is still dirty.
8. Refill the system with new heavy duty coolant and SCA.

Tools: dial indicator

1. Remove the fan belt.
2. Rotate the fan hub pulley to check for rough or damaged bearings.
3. Inspect the pulley grooves for excessive wear.
4. Check for grease leakage.
5. Use a dial indicator to check the bearing end clearance.
6. Replace with a new or rebuilt unit as necessary.
7. Install the fan belt.

Tools: 3375049 filter wrench

1. Clean the area around the fuel filter head and replace the fuel filter(s).
2. Use a filter wrench, Part No. 3375049, to remove the fuel filter.
3. Clean the filter head gasket surface with a clean, lint-free towel.
4. Apply a light film of clean engine oil to the filter gasket surface.
5. Fill the filter with clean fuel.
6. Install the filter on the filter head and tighten until the gasket contacts the filter head surface.
7. Tighten the filter per the filter manufacturer's instructions.

⚠ Avoid direct contact of hot oil with your skin.

⚠ Fill the oil filters with clean lubricating oil before installation.

Tools: 3375049 oil filter wrench

1. Operate the engine until water temperature reaches 60 C [140 F]. Shut off the engine.
2. Remove the oil drain plug and drain the oil immediately.
3. Clean the area around the lubricating oil filter head and the gasket surface.
4. Use an oil filter wrench, Part No. 3375049, or equivalent, to remove the oil filters.
5. Apply a light film of lubricating oil to the gasket sealing surface before installing the new filters.
6. Fill the oil filters with clean lubricating oil.
7. Install the filters as specified by the filter manufacturer.
8. Check and clean the oil drain plug threads and seal surface.
9. Install and tighten the oil drain plug to 100 Nm [75 ft-lb].
10. Fill the engine with clean oil to the correct level.
11. Operate the engine at idle to inspect for leaks; shut off and check oil level again; add oil to the high H mark.

⚠ Put a warning tag on the engine: The engine does NOT contain oil. Do NOT operate the engine.

1. Operate the engine at HIGH IDLE until coolant temperature is 70 C [160 F]. Turn the engine OFF.
2. Disconnect the fuel lines to the engine fuel filter and the injector return line.
3. Put both fuel lines in a container of diesel fuel and START the engine.
4. After the engine runs smoothly, transfer the fuel supply line to a container of preservative oil and operate until preservative oil flows out the injector return line.
5. Turn the engine OFF and connect the fuel lines to the fuel filter and injector return line.
6. Drain the oil pan sump, oil filters, and fuel filters.
7. Disconnect the electrical wiring from the fuel pump solenoid; turn the fuel pump manual shutoff valve counterclockwise until it stops.
8. Crank the engine slowly and spray lubricating oil into the intake manifold and air compressor inlet.
9. Drain the coolant and put a warning tag on the engine.
10. Store the engine in a dry area with uniform temperature and bar the crankshaft two or three revolutions every 3 to 4 weeks.