fuel inj timing

7/30/2019 Fuel Inj Timing

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Wärtsilä Italy, Service

Subject Engine type Ref. Date Document No. DLC Issue Page Fuel Injection valve adjustment ALL WIT-S 09.01.07 I-ALL.0002.GB 161 00 1/4

Wärtsilä Italia SpA Bagnoli della Rosandra, 334 Telephone : +39 040 319 5000

Service 34018 San Dorligo Della Valle (TS) ITALY Fax : +39 040 319 5647

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Fuel Injection valve adjustment

1 Application

ALL Wärtsilä diesel engines excluding solenoid controlled injectors

2 General

There are different practices on evaluating the injection nozzles. In order to unify the rules and practices howthe nozzles should be tested and evaluated this Operating Instruction bulleting is giving general instructions.

IMPORTANT! Please always refer to the engine instruction manual for operational maintenance.This service instruction doesn’t want to replace or supersede any specific bulletin.

3 Cleaning procedure and proper test fluid choice

When using new nozzle, it needs to be washed with clean fuel oil or similar in order to remove preservation oil.Before using a new injection valve use it is not required to dismantle the nozzle. The injector needs to beflushed and tested and, if needed, readjusted to the stated needle opening pressure mentioned in the enginemanual or according to specific engine instructions.It is recommended to perform the test with clean calibration oil.

NOTE! Very good cleanliness is required when working with injection components!

Wärtsilä recommends the following fluids:

- Molyguard Calibration ‘A’- Shell Calibration fluid S9365

Or similar fluid with the following characteristics:

Viscosity, cSt/20°C 3,8

Viscosity, cSt/40°C 2,6

Flammability, °C > 99

Density, kg/l /15°C 0,827



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4 Testing of the new injector valve

4.1 Checking NOP and tightness of the nozzle seat

After assembling the injector to testing pump, the NOP (Needle Opening Pressure) has to be adjustedaccording to instruction manual.The nozzle should be completely tightened at opening pressure: NOP-20/50 bars.No drops are allowed for at least 5 s.Check and readjust the opening pressure if needed

4.2 Atomization test

The nozzle atomization test is to verify that the nozzle spray holes are open.Check the flow-through pattern of the nozzle with a few test pump strokes with released spring tension. All the holes must be clear and produce an even distributed discharge.Test to be carried out with no spring load on the nozzle needle.If test is performed with spring load, it’s recommended to use pneumatic or hydraulic pumps.If performed with manual hand pump, the results can be sometimes unsatisfactory because its delivery is toolow and is not describing the situation in the engine.

NOTE: The nozzles are not needed to chatter when tested.

4.3 Back flow test

The test is not needed with new valve, but this value is a reference value in order to evaluate the nozzle after use. Different test devices can give different back flow values.

4.4 Handling

Be aware of hitting on the nozzle tip. Never lay the injector so that the nozzle tip is against the hard surface. Thetip is very sensitive and can break easily. Always store the injectors covered and protected in clean place beforeassembling.

5 Testing and inspection of used injector valve

5.1 Visual inspection

Clean the nozzle tip from carbon deposit. If possible, use a chemical carbon dissolving solution. If such solutionis not available, immerse the components in clean fuel oil or similar to soak carbon, and then clean the partscarefully. Do not use steel wire brushes or hard abrasive tools. Brass brush is allowed.Check the condition of the nozzle tip for wear of nozzle holes and possible corrosion of the nozzle.

5.2 Checking of opening pressure

After cleaned, increase NOP pressure and record it



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After reassembled, flush the injector properly several times, Increase the opening pressure gradually up to thestated opening pressure and record it. In case the nozzle seat tightness test fails, skip to chapter “Dismantle of the nozzle” in the instruction manual.

5.3 Checking of tightness of the nozzle seat

Check the nozzle seat tightness with reduced opening pressure in order to use the whole needle lift. The nozzleshould not leak. Anyway the nozzle should be completely tight at opening pressure: NOP-20/50 bars.No drops are allowed for at least 5 s.

In case the nozzle seat tightness test fails, skip to chapter “Dismantle of the nozzle” in the instruction manual.

5.4 Atomization test

The nozzle atomization check consists in verify that the nozzle spray holes are open.Check the flow-through pattern of the nozzle with a few test pump strokes with released spring tension. All the holes must be clear and produce an even distributed discharge.Test to be carried out with no spring load on the nozzle needle.If test is performed with spring load, it’s recommended to use pneumatic or hydraulic pumps.If performed with manual hand pump, the results can be sometimes unsatisfactory because its delivery is toolow and is not describing the situation in the engine.If some spray holes are clogged they can be opened, but if not possible the nozzle needs to be rejected.Open the spray holes with the required tools.

5.5 Readjusting the opening pressure

Readjust the nozzle opening pressure to the value according to the engine instruction manual.

5.6 Back flow test

It is not compulsory to do the back flow test. It gives some idea of guidance clearance, if done with the sametest device as new.

5.7 Notes

- Never recondition or repair the nozzle by lapping it into its needle seat- Some spill fuel may appear from the nozzle holder due to leak along side the needle. Small amount isconsidered to be normal, check that connecting piece is tightened. If suspected leakage from nozzle topsurface, recondition is not allowed as the surface is lapped.

6 Distribution

Wärtsilä Service Network

Owners of engines concerned



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7 Liability

NO LIABILITY WHETHER DIRECT, INDIRECT, SPECIAL INCIDENTAL OR CONSEQUENTIAL, IS ASSUMED WITH RESPECT TO THE INFORMATION CONTAINED HEREIN. THIS PUBLICATION ISCONFIDENTIAL AND INTENDED FOR INFORMATION PURPOSES ONLY.

8 Validity

This general instruction is valid until further notice.

fuel inj timing

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