Page 293 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

9 Position the stop pin so that the tighter wound end of the follower spring and keep the injector body flat the stop
pin.
10 On fuel pincher unit injector, place the clamp on to the body and the spring to the clampit.
11 Hook the plunger head in to the follower Align the follower slot with the stop pin and align the flat side of the
plunger with the gear.
12 Guide but do not force, the plunger through the gear and into the bushing.
13 With the plunger in position push the follower down ward and at the same time force the stop pin in place.
14 On the fuel pincher align the roll (spring) pin in the followers with the release slot in the body. Then press down
ward on the follower rotate it clock wise until the pin contact the guide slot, and then release the force from the
follower.
15 Remove the injector from the vise, bring the control rack to the full- fuel position and check the rock to plunger
timing the visible marks must be from flat side of the injector.
16 Next place the unit injector in the concentricity gauge, Adjust the dial gauge to zero slow turn the injector 360°
and observe the dial movement if total spray tip run out is more than 0.008 inch (0.2 mm) loosen the injector
nut.
17 Reposition the spray ti-re-torque the nut and recheck the spray - tip concentricity.
18 If spray - tip is more than inch 0.008 (0.2 mm) out of the concentricity if could cause the needle valve to stick
and or allow combustion gases to pass by the injector or cause reduced injector cooling.
Test carried out on unit Injectors
1 Fill the injectors with clean diesel fuel place the galary pumps. Under the tip and depress the follower. Sharply
observe the spary pattern No have should be blocked and the radial lines. Should be this and continues and
then should not be any drop have at the tip.
2 Mount the injector on the test bench and opreate the lever several times and see that there is drop let at
the spary tip. Depress the follower to bring down the tight of the follower from the body surface to 33.5 mm
Move the control rack fully into the body use the test pump and bring up the pressure to 50 kg cm² and hold it.
Observe the pressure drop, it should not drop below 19 Kg/cm² in 55 seconds. If it leaks the plunger and barrel
are worn out.
3 Place the plunger in upper most position more than control rack fillingout of the body build up of the pressure
to 25 kg/cm² and slowly increase the pressure in stop at 2 kg/cm and observe the fall of pressure detecting the
check valve opening. It should be between 33- 52 kg/cm². If required change the valve and spring.
4 Move the control rack fully in to the body operate the pump to bring the pressure to 100 kg/cm² and maintain
this pressure for 1.5-2 mints and observe the leak at on the joints.

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CITS : Automotive - Mechanic Diesel - Exercise 15.7