Fuel Injection Valve

Stopped engine

Shut-off starting air

Shut-off cooling water

Shut-off fuel oil

Shut-off cooling oil

Stopped lub. oil circul.

Description:

Dismounting, overhaul, pressure testing and mounting of fuel injection valve.

Starting position:

Top cover on the cylinder head and front cover on the fuel injection pump has been dismounted.

Related procedure:

Antiseizure product.

(Copaslip, Molykote GN Plus or similar).

Replacement and wearing parts:

L23/30H

The fuel injection valve is the single component that has the greatest influence on the diesel engine condition. Various forms of operation and quality of fuel oil affect the overhaul intervals. In some cases it may be necessary to shorten the prescribed intervals.

Dismounting and cleaning:

1. Dismount the fuel injection valve from the cylinder head by means of the special tool as shown in fig. 1.

Fig 1 Dismounting of fuel injection valve from cylinder head.

2. Mount the fuel injection valve into the clamping bracket VTO-W020 (see plate 52014, item 025) on the pressure testing pump, and loosen the lock nut

(B) fig 2.

Unstress the nozzle spring by turning the adjusting screw (D).

3. Clean the lower part of the nozzle (J) from carbonized oil deposits before dismantling the nozzle nut (H). Remove the nozzle nut (H) and the nozzle

(J).

Fig 2 Fuel injection valve.

Attention!

Do not damage the lapped surface.

4.The nozzle spring (F) and the spring spindle (G), are to be taken out by loosening the adjusting screw (D), completely.

5.All parts must be cleaned with kerosene or gas oil and a hard brush (not a steel brush).

6.Clean the nozzle holes of charred coke by means of the supplied special drill (see plate 5201401H item 108) with holder.

7.Clean the cooling chamber and the cooling ducts in the nozzle guide and injector body by placing these in a cleaning liquid and then blow through the parts with dry working air.

Inspection of the parts:

8.Nozzles are matched by lapping and are therefore only interchangeable as units. Insert nozzle needle with gas oil in the needle guide. It must be controlled whether the nozzle needle slides down by its dead weight on its seat.

9.If the holes are oval worn, which is checked with of a magnifying glass, the nozzle must be scrapped.

10.The best way, however, to check if the holes are worn out is to control the flow rate of the nozzle which, in general, only can be made at the manufacturer's works on a special test stand.

11.Every effort to refinish will result in alterations of these values and malfunction of the nozzle. If heavy abrasion symptoms, respectively damages are observed at the visual inspection of the parts, the parts in question must be replaced.

Reassembling:

12.When all parts have been overhauled, found in good order and carefully cleaned, assemble the fuel injection valve again.

13.When assembling the injection valve, proceed in the opposite order compared to the disassembly. Pay attention to the following:

A.Lubricate the threads on the adjusting screw

(D)with lub. oil, and the threads of the nozzle holder for the nozzle nut. The shoulder of the nozzle which is in contact with the nozzle nut, must be lubricated with an antiseizure product.

B.The sealing plane surface of body and nozzle must be wiped dry with paper.

C.Renew the sealing rings (C) and (E).

D.Tightentorquefornozzlenut (seepage500.40.)

L23/30H

Pressure testing of fuel injection valve:

14.The most effective checking of the fuel valves is obtained through pressure testing, preferably carried out after each overhaul and also in case of irregularities in operation. The pressure testing is carried out in the following way by means of the pressure testing apparatus supplied.

15.Mount the fuel injection valve in the bracket VTO-W020 (see plate 52014 item no. 25) again. The bracket to be in such a position that the nozzle of the injector is pointing downwards.

16.For test of the injection pressure and atomizing mount the test pipe VTO-W021 (see plate 52014 item 049), increase pressure by means of the lever on the test pump, and adjust the opening pressure to

320bar, by the adjusting screw (D), see fig 2, then tighten lock nut (B) and check opening pressure again.

Do not expect chattering, but make sure that the nozzle spray from all holes in the same angle. The nozzle might chatter if the lever is worked very fast, actually by hitting it.

Do not expect a nozzle tip with more than 1000 running hours to perform like a new nozzle in the test pump.

Then increase the pressure to 300 bar and keep the pressure by working the lever slowly downwards. When the pressure is kept at 300 bar, there should be no more than one drip from the nozzle tip for approx. 3-5 sec.

WARNING: Keep out of the fuel jets as they will penetrate the skin. Fuel which has penetrated the skin can cause painful inflammations (blood poisoning).