Usage:
NOTE: It is necessary to have an accurate record of the test results for each fuel valve tested. Record the results of each fuel valve test on a copy of Form SEHS8144, Nozzle Test Record. These test sheets are available through Miscellaneous Order Division. To obtain a pad of 50 sheets, order one Form SEHS8144. A copy of Form SEHS8144 is shown at the back of this instruction.
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When testing fuel injection nozzles, always wear eye protection. Fuel comes from the orifices in the nozzle tip under high pressure and can pierce the skin and cause serious injury to the operator. Always keep the tip of the nozzle pointed away from the operator and into the 8S2270 Fuel Collector and FT1384 Extension. |
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NOTE: Some of the tools shown in this instruction are not now available from Caterpillar. The tools are shown for reference only.
(1) Use the 5B1401 Cleaning Tool Group to clean carbon from the nozzle end orifice; use a .0175" drill for 3 3/4" bore engines with heavy rated springs, .0197" drill for other 3 3/4" bore and all 4 1/4" bore engines, or a .024" drill for 5 1/4", 5 3/4" and 6 1/8" bore engines. Cover the fuel inlet and overflow openings with the covers provided, and clean the exterior of the valve with cleaning solvent or diesel fuel.
(2) Use 5P7448 Adapter (1) and 5P4721 Tube (A) to connect the valve to the nozzle tester. Close gauge protector valves (2), (3) and (4) and on-off valve (5). Open pump isolator valve (6).
(3) Spray Pattern and Fuel Cutoff (Except 1P1795 Master Valves)
A. Pump the tester to remove air from the line.
B. Pump the tester with short, fast strokes and look at the spray pattern and fuel cutoff.
C. If the spray pattern and fuel cutoff are not satisfactory, see CLEANING, NEEDLE, NOZZLE BORE AND NOZZLE END OF FLAT-SEAT VALVES.
D. If, after cleaning, the spray pattern and fuel cutoff are still not satisfactory, install a new valve service group.
(4) VOP (Valve Opening Pressure) Test
A. Open the gauge protector valve [0-34500 kPa (0-5000 psi) gauge].
B. Increase the pressure until test oil flows from the nozzle tip.
C. Write down the VOP.
(5) Pressure Loss Test
A. Increase the pressure to 690 kPa (100 psi) less than the VOP.
B. Close the pump isolator valve (6).
C. Use the gauge protector valve (3), [0-34500 kPa (0-5000 psi) gauge] to adjust pressure to 690 kPa (100 psi) less than the VOP.
D. After 30 seconds, write down the pressure loss.
(6) Adjustment of Valve Opening Pressure
If spray characteristics are satisfactory, adjust the valve unseating pressure: Use 7B2591 Cap Wrench (7) to remove the cap. Remove lift screw locknut (8) and loosen lift adjustment screw (9) approximately three turns, so it does not interfere with the pressure adjustment. Loosen pressure adjustment locknut (10).
E. Install the nozzle on the 5P4150 Nozzle Tester.
F. Use 7B2601 Wrench (11) and adjust the VOP.
G. Remove the valve from the nozzle tester and put it in a vise. Install lift adjustment screw locknut (8).
H. Use the 6B1655 Wrench to turn lift adjusting screw (9) down lightly against the stem of the fuel valve spring.
I. Clamp the needle lift adjustment fixture to the fuel valve body.
J. Use a thickness gauge and adjust screw (12) until there is a clearance of 0.43 (.017") between screw (12) and lift adjustment screw (9).
K. Hold screw (12) in position with clamping screw (13).
L. Remove the thickness gauge and loosen lift adjustment screw (9) until there is 0.3 (.010") clearance between screw (9) and screw (12), after lift screw locknut (8) is tightened with the 7B2587 Wrench. The correct needle lift setting for all valves is 0.177 (.007").
Cleaning Needle, Nozzle And Nozzle End Of Flat Seat Valves (Except 1P1795 Master Valves)
(1) Remove cap (1), bonnet (2) or unseating pressure adjusting screw, spring retainer, spring (3) and spring stem (4). Put the correct needle extracting tool (5) through the valve body and tighten over the end of the needle. If the needle is tight, install a new valve service group, or disassemble and clean the valve according to the procedure that follows.
(2) If a fuel valve has a chip of scale, metal or foreign material on the seat, this will prevent the needle, from seating on the spray valve nozzle end, and cause the inner surface of the nozzle end and the needle end to become coated with carbon. Put carbon scraper (6) in the needle extracting tool and insert it into the nozzle bore and against the nozzle end; carefully turn the tool one revolution, with a slight pressure to remove the carbon.
NOTE: The cutting surface of scraper (6) has been lapped as perfectly flat and square with the center line of the tool as possible. Unless it remains so, it cannot effectively remove carbon. Handle this tool with care. Two scrapers are provided, so if one becomes marred, the second can be used while another is being obtained.
(3) Carefully wipe the needle with a clean cloth or chamois (7). Clean the bore of the nozzle with the nozzle bore wiper and a piece of chamois. Flush the fuel valve carefully in clean solvent, and blow out with air pressure through the fuel inlet connection. This forces foreign material out through the large bore instead of through the small fuel channels. Rinse the needle in clean solvent and insert it in the nozzle. Assemble the valve, making sure all parts are thoroughly clean. Check the spray characteristics as outlined under the topic, Testing Flat-Seat Fuel Injection Valves, in this instruction.
Installation Of Fuel Injection Valve Service Groups (Except 1P1795 Master Valve)
(1) Parts in the valve service group are: needle, nozzle assembly and nozzle end. Each service group is manufactured as a unit and must be installed as a unit; do not interchange parts between service groups. The correct service group part numbers, according to engine bore size, are shown in the chart.
(2) Remove cap (1) and the cap gasket, if used. Remove bonnet (2), or valve opening pressure adjusting screw (3), and the spring retainer, spring and spring stem (4). If there is a lock pin (5), remove it with the lock pin remover. Invert nut (6). If the spray valve does not fall out, tap nut (6) against a block of wood.
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Lock pin (5) is a hardened pin. Use care to prevent pin breakage or personal injury during pin removal. If the pin is broken, it can be removed by tightening and loosening nut (6) until the pin drops out, or it can be pulled out with needle-nose pliers, then remove nut (6). |
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(3) Thoroughly clean all valve parts in cleaning solvent or clean diesel fuel. Support the inverted service group in holder (7) and insert the service group into retainer nut assembly (6). Turn slowly until the groove in the nozzle is in alignment with the locating dowel; remove the holders.
(4) Turn retainer nut assembly (6) onto the fuel valve body by hand. Put the fuel valve in a vise in a vertical position.
(5) Assemble spring stem (4), the spring, spring retainer and bonnet (2), or screw (3), into the valve. Loosen the unseating pressure adjusting screw and the lift adjusting screw to avoid possible damage to the nozzle when nut (6) is tightened. Invert the valve in the vise and tighten retainer nut (6) with the torque wrench and the correct socket, to a torque of 95 N·m (70 lb-ft). Overtightening can cause distortion of the lapped nozzle bore and binding of the needle. If the retainer nut is not tightened enough, leakage may occur between the radius on the fuel valve body and the radius on the spray valve assembly. It is not necessary to install the retainer nut lock pin, because the hole in the retainer nut may not be in correct alignment with the hole in the fuel valve body. Any attempt to put the two in alignment will result either in overtightening or undertightening the retainer nut.
Parts Lists For Flat - Seat Fuel Valves
