CONTENT
Section Description Page
10 218 Specifications . . . 23 Tightening Torques . . . 23 Special Tools . . . 23 Description and Operation. . . 24 Fault Finding . . . 24 Overhaul . . . 25
SPECIFICATIONS
INJECTORS LUCAS C.A.V.
Adjustment Variable
Quantity, nozzle holes 5 Hole
Pressure Setting 292–300 bar (4234–4350 psi)
Injector change interval 1200 hours
TORQUE VALUES
Application Nm ft. lbs. kgf/m
Injector Nozzle Retaining Nut 48 35 4.9
Injector Retaining Bolts 22 17 2.2
Injector Leak-Off Line Banjo Bolts 12 10 1.2
High Pressure Gland Nuts at Injector 32 23 3.3
High Pressure Gland Nuts at Fuel Pump 33 23 3.3
TOOLS
Application TOOLS
Injector Cleaning Kit* 29367
Includes Nozzle Cleaning Wires – Pressure Chamber Drills – Pressure Chamber Scraper – Valve Seat Scraper – Brass Wire Brush – Pin Vise.
Tallow Obtain Locally Obtain Locally
Polishing Sticks Obtain Locally Obtain Locally
Pump Timing Tools 297119 / 297194
Description and Operation
The engine injector function is to inject fuel into a pressurized cylinder in a fully atomized condition so as to burn efficiently with a minimum of smoke.
Each injector consists of a nozzle assembly, contain-ing a needle valve, and an injector body assembly housing the injector needle valve regulating spring.
Fuel from the fuel injection pump enters the injector fuel inlet and passes down through a drilling in the in-jector body to the needle valve seat.
The fuel, pressurized by the injection pump, lifts the needle valve off the seat against the action of a
spring. The fuel is then forced, in an atomized state, through the five holes in the nozzle tip. When the pressure from the injection pump drops, the needle valve snaps back onto the seat under pressure from the spring.
To provide lubrication of the injector, a small amount of fuel is permitted to leak up between the needle valve and the nozzle body. The excess fuel rises to the top of the injector and returns to the fuel tank via an injector leak-off line.
FAULT FINDING
PROBLEM POSSIBLE CAUSES CORRECTION
Engine emits black smoke 1. Faulty injectors 1. Overhaul or replace injectors
Nozzle does not “buzz” while injecting
1. Dirty or sticking needle valve
2. Valve seat leakage 3. Damaged nozzle retaining nut
1. Clean or replace needle valve and nozzle holder 2. Clean or replace valve and nozzle assembly
3. Replace retaining nut
Nozzle leak back 1. Worn needle valve
2. Dirty nozzle and/or holder 3. Loose nozzle retaining nut
1. Replace needle valve and nozzle holder
2. Clean or replace nozzle and holder
3. Tighten nut Nozzle opening pressure
incorrect
1. Adjusting nut loose
2. Damaged nozzle or seized needle valve
3. Blocked nozzle holes 4. Incorrect shims fitted
1. Tighten nut
2. Replace needle valve and nozzle holder
3. Clean nozzle 4. Adjust shim pack Nozzle seat leakage 1. Dirty nozzle and/or nozzle
holder
2. Sticking needle valve
1. Clean or replace nozzle and nozzle holder
2. Clean or replace needle valve and nozzle holder Incorrect spray pattern 1. Dirty nozzle and/or nozzle
holder
2. Restricted nozzle holes 3. Damaged needle valve or nozzle
1. Clean or replace nozzle and nozzle holder
2. Clean or replace nozzle and nozzle holder
3. Replace needle valve and nozzle holder
OVERHAUL
1. Loosen the high pressure fuel pipe gland nuts at the injection pump.
2. Clean the area around the injectors.
3. Remove the banjo bolts (1) and discard the two copper washers from each bolt. Remove the leak-off pipe (3).
4. Unscrew the gland nuts and disconnect the high pressure pipes (2) from the injectors.
5. Remove the two retaining bolts from each injec-tor and withdraw from cylinder head.
6. If a replacement set of injectors is not immediate-ly available, cover the ends of the pipes and the cylinder head openings to prevent the entry of dirt and foreign material.
7. Discard the cork dust washer (1) and the copper sealing washer(2).
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NOTE: The copper sealing washer may have to be extracted from the bore in the cylinder head.
8. To establish if overhaul or replacement is necessary, test the injectors according to the fol-lowing procedure. Before testing, install a protec-tive cap to the inlet union and clean the outside of the injectors with a soft wire brush and a car-bon solvent.
30 TESTING
WARNING
The spray from a fuel injector tester can pierce human skin with fatal results. When an injector is spraying, the nozzle holder should be turned away from the operator and any other persons.
During the Nozzle Opening Pressure and Spray Pat-tern Tests, collect the spray in a container partly filled with rags to absorb the spray.
When conducting the Nozzle Seat Leakage Test, re-lease the injector tester pump pressure before touch-ing the nozzle tip with a sheet of blotttouch-ing paper.
WARNING
The spray is flammable make sure no open flames are in the area of the tester and do not generate ex-cessive vapor.
1. Fill the injector tester with a calibrating type fuel oil and leave the filler cap loose to prevent a vac-uum forming during testing.
TA6010115
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2. Prime the tester until oil is emitted from the tester line, then connect the injector.
3. Make sure the control knob on the tester is screwed in to prevent the gauge being over-pres-surized if the injector nozzle is blocked.
4. Pump the tester and check the nozzle is free to open. Open the pressure gauge valve and begin injector testing. If the nozzle is blocked or the needle jammed, disassemble the injector.
5. Nozzle Opening Pressure Setting - Slowly pump the injector tester and observe the pressure at which the needle valve lifts and fuel is injected from the nozzle tip. By rotating clockwise or anti clockwise the adjuster located in the top of the in-jector, the pressure setting can be varied.
6. Spray Pattern - Pump the tester rapidly (80 to 90 strokes per/min.) and observe the spray pattern from the holes. An atomized spray free from dis-tortion and irregular streaks of fuel should be ob-served. The tester is not regarded as providing a suitable test for atomization under working conditions, but gives an indication of the working of the nozzle.
APB10004
32 7. Nozzle Seat Leakage - Wipe the nozzle tip dry
and apply a pressure to 282 bar (4089 psi), i.e., 10 bar (145 psi) below the opening pressure. The nozzle tip and bottom face must remain essen-tially dry and there must be no tendency for blobs of fuel to collect or drip. A slight dampness can be ignored. If there is any leakage from the nozzle seat, the nozzle assembly must be scrapped.
8. Nozzle Back Leakage - Apply a pressure of 282 bar (4089 psi) 10 bar (145 psi) below the opening pressure, then release the handle and the time/
pressure drop should be between 148-99 bar) within 45 to 6 seconds, if below 6 seconds, the nozzle assembly must be scrapped. If above 45 seconds, check for carbon on the valve and/or blocked back leak drillings.
NOTE: If the injectors meet the tests carried out then refit the injectors to the engine.
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DISASSEMBLY
1. Place the injector in a holding fixture with the nozzle uppermost. Do not clamp the injector body in a vise. Use a socket tool to loosen the nozzle retaining nut.
2. Remove the nozzle retaining nut, complete with the nozzle body and needle valve.
3. Remove the injector body from the holding fixture and invert, carefully remove the top nut, spring tensioner and seat. To avoid damage, place all dismantled components in suitable baths of clean fuel oil.
34 NOTE: To prevent corrosion of injector components
after cleaning, rinse in clean fuel oil and place in a suitable bath of clean fuel oil.
INSPECTION AND REPAIR
1. Clean the injector body by soaking in a carbon solvent and brushing with a brass wire brush. In-spect the body for damaged threads and pres-sure face, making pres-sure the holes in the injector nozzle are thoroughly clean with no signs of cor-rosion or pitting.
35 2. Clean the spring and spring seat using a brass
wire brush and check for scoring, pitting or cor-rosion.
3. Clean the dowelled adaptor plate using a brass wire brush. Inspect the plate for loose or bent do-wels, a damaged pressure face or corrosion.
4. Clean the needle valve and body by soaking in a carbon solvent and brushing with a brass wire brush. Using the tools included in the Injector Nozzle Cleaning Kit, clean the nozzle as follows:
36 NOTE: If the needle valve is in any way damaged or
blued, it must be discarded and a new matched needle valve and nozzle body assembly obtained. It is not possible to grind or lap the three special angles on the valve point.
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A Clean the spray holes with a nozzle cleaning wire held in a pin vise so that it protrudes for only 1.5 mm (0.06 in.), thereby giving maxi-mum resistance to bending. Insert the wire into each hole, pushing and rotating gently until each hole is cleared.
38 B Clean the needle valve seat using the valve
seat scraper by rotating and pushing the tool onto the valve seating.
C Clean the fuel port using the fuel port scraper. Insert the scraper into the port, press hard against the side of the cavity and rotate to clear all carbon deposits from this area.
39 5. Use a Reverse Flush Nozzle Adaptor, on an
in-jector tester and reverse flush the nozzle to re-move the carbon loosened during cleaning, Step 4.
6. After flushing the nozzle, polish the valve seat by placing a very small amount of tallow on the end of a polishing stick and rotate in the nozzle.
40 7. Clean the top of the needle valve using a needle
valve scraper.
8. Clean the nozzle retaining nut using a brass wire brush and check to see that the threads are not damaged and are free from carbon deposits.
APB10013
RE–ASSEMBLY
1. Make sure all parts are absolutely clean and un-damaged prior to re–assembly. Rinse all parts in clean fuel oil and assemble the components while still wet.
2. Place the spring and spring seat into the injector body bore. Place the injector body into the hold-ing fixture.
3. Refit spring tensioner and top nut then invert in-jector in holding fixture
42 4. Carefully locate nozzle assembly onto dowels
and retighten nozzle retaining nut to 48 Nm (35 lbf ft)
To set the nozzle opening pressure, connect the in-jector to the test rig as described in ‘‘Testing’’ and alter the adjusting nut until the specified opening pressure is achieved.
INSTALLATION
1. Remove any blanking plugs from cylinder head openings and pipe ends.
2. Insert the new/replacement injector in the cylin-der head, having used a new cork dust washer and a new copper sealing washer.
3. Secure each injector with the two retaining bolts and tighten to 22 Nm (17 ft. lbs).
4. Reconnect the leak-off pipe using new washers either side of the banjo fittings and tighten banjo bolts to the 12 Nm (10 ft. lbs).
5. Reconnect high pressure fuel pipes to injectors and tighten gland nuts to 32 Nm (23 ft. lbs).
6. Tighten high pressure fuel pipe gland nuts at the injection pump to 32 Nm (23 ft. lbs).
7. Bleed the fuel system as detailed previously.
8. If the injectors are to be stored before installation, clean in calibrating oil. Storage for longer than 6 months may result in the necessity of disassem-bling and cleaning the injectors before installa-tion.
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