Nozzle Body (Dsl): Testing and Inspection

Fig. 38 Injection nozzle & fuel return lines:

REMOVAL

1. Using a spanner wrench to hold injection nozzle in position, disconnect fuel injection and return lines from nozzle, Fig. 38.
2. Using tool No. MD998387, remove injection nozzle from cylinder head.

Fig. 39 Checking injector nozzle pressure:

INJECTION NOZZLE PRESSURE TEST

1. Position injection nozzle on a suitable injection pressure tester, Fig. 39.
2. Operate injection pressure tester at approximately 60 cycles per minute and note pressure gauge readings. The reading should increase gradually, with pointer oscillating when nozzle is injecting. The pressure gauge reading at the point where the gauge pointer starts to oscillate should be 1707-1849 psi. If pressure is below the service limit of 1565 psi or less, then nozzle must be disassembled and inspected.

Fig. 40 Injector nozzle spray patterns:

NOZZLE SPRAY PATTERN TEST

Refer to Fig. 40 when checking nozzle spray pattern. If an unacceptable spray pattern is obtained, the nozzle should be disassembled and inspected.

Fig. 39 Checking injector nozzle pressure:

NOZZLE LEAK TEST

Operate tester, Fig. 39 to maintain a pressure of 1422 to 1565 psi and check nozzle tip for leaks. If a leaking condition is encountered, the nozzle tip should be replaced.

Fig. 41 Disassembled view of injector nozzle:

DISASSEMBLY

1. Position nozzle holder body in a soft jawed vise, then remove retainer nut using tool No. MD99838.
2. Disassemble injection nozzle, Fig. 41. Use a piece of wood to remove carbon from nozzle component, then clean components in a suitable cleaning solvent. After cleaning immerse components in light oil. Use care not to damage nozzle tip needle tip valve.




INSPECTION

1. Position nozzle tip and plunger in fuel oil, then lift plunger upward and allow plunger to slide downward into nozzle tip, Fig. 41.
2. Plunger should slide smoothly within the nozzle tip, if not replace nozzle assembly.
3. Also check plunger tip for damage and replace as necessary.




ASSEMBLY

1. Clean all components with fuel oil before assembling.
2. Assemble fuel injection nozzle components, Fig. 41.
3. Position nozzle holder body in soft jawed vise.
4. Using tool No. MD998387, tighten injection nozzle retaining nut.




INJECTION NOZZLE PRESSURE ADJUSTMENT

1. Position injection nozzle on a suitable injection pressure tester and check pressure as described under ``Nozzle Pressure Test.''
2. Injection pressure should be 1707-1849 psi.
3. If pressure is not within limits, adjust by changing the thickness of the internal shim. An increase of .004 inch in shim thickness will increase pressure by 142 psi.

Fig. 38 Injection nozzle & fuel return lines:

INSTALLATION

1. Clean nozzle mounting area of cylinder head.
2. Install a replacement nozzle tip gasket.
3. Install injection nozzle on cylinder head and torque using tool No. MD998387 to 44 to 50 ft. lbs.
4. Connect return line, Fig. 38 and fuel injection line to nozzle using a spanner wrench to hold nozzle in position while tightening line nut. Torque fuel return line nuts to 33-39 ft. lbs. Torque fuel injection line nuts to 17-26 ft. lbs.