Service Bulletin RTA–3.430.03.98

(supersedes BulletinRTA–3.3 of 25.04.94)

1. Introduction 1

2. Design Features 1

3. Tightening Instruction for 22–Piece Nozzles

4. Tightening Instruction 2for Fuel Valve

5. Maintenance 2

6. Assessment Criteria 2

7. Improved Nozzle Tip with Sleeve 3

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Technical Information to all Owners /Operators of Sulzer RTA “-8 Series”and RTA “-2, -U and -C Series” Engines

(except RTA 38 and RTA 48)

Contents: Page

Wärtsilä NSD Switzerland Ltd PO Box 414 Tel. +41 52 262 49 22Wärtsilä NSD Schweiz AG CH-8401 Winterthur Fax +41 52 212 49 17Wärtsilä NSD Suisse SA Switzerland Tlx 896 659 NSDL CH

Fuel Injection Nozzles

1 / 3 Service Bulletin RTA-3.4

1. INTRODUCTION

The fuel nozzles are exposed to harsh working conditions and have to be regarded as consumableparts.

Since the introduction of the 2P-nozzles (two piece), we have gained positive performanceresults from vessels equipped with this nozzle design concept.

Based on this experience they were introduced as the new standard, which is fully interchangeablewith the previous shrink-fit nozzle.

The 2P-nozzle design naturally incorporates all advantages of the former design such as the veryimportant rounded-off inner spray hole edges, but enables a much cheaper exchange of wornnozzle tips only, instead of complete nozzles.

The RTA "�8 Series" comprises the following engine types in this Service Bulletin:

RTA 58, RTA 68, RTA 76 and RTA 84

The RTA "�2 Series" comprises the following engine types in this Service Bulletin:

RTA 52, RTA 62, RTA 72 and RTA 84M

The RTA "�U Series" comprises the following engine types in this Service Bulletin:

RTA 52U, RTA 62U and RTA 72U

The RTA "�C Series" comprises the following engine types in this Service Bulletin:

RTA 84C and RTA 84CU

This Service Bulletin should be kept in a separate file in the control room. The respective pages or tablesof the Service Bulletin with modifications to the Operating Manual, Maintenance Manual or CodeBook should be copied and filed in the respective Manual or Book.

2. DESIGN FEATURES

A comparison between the shrink�fit and the 2-piece design is shown on enclosure RTA-3.4�/�1.

Wärtsilä NSD Switzerland Ltd is continuously searching for improvements in design andmaterials in order to gain optimum injection conditions as well as increased lifetime for nozzle tipand needle seat.

THEREFORE, IT IS OF UTMOST IMPORTANCE TO CONTACT WÄRTSILÄ NSDSWITZERLAND LTD FIRST OR THE ENGINE BUILDER WHEN ORDERING NEWFUEL NOZZLES, TO ENSURE THE DELIVERY OF THE ACTUAL DESIGN ANDSPECIFICATION FOR BEST ECONOMY AND ENGINE PERFORMANCE.

The initial purchase of the 2P-fuel injection nozzle will be slightly more expensive than theshrink-fit type because of the different design.

But the later exchange of the 2P-nozzle tip, which is subject to wear and tear, will be much moreeconomical.

2 / 3 Service Bulletin RTA-3.4

3. TIGHTENING INSTRUCTION FOR 2-PIECE NOZZLESValid only for engines mentioned in paragraph 1

Experience has shown, that a tightening angle of 35�is on the lower side of the tightening rangenecessary for the 2� piece nozzle!

The above mentioned limit on the angle originated from the previous atomizer materialTITANIUM which was deformed when it was tightened at higher angles than 35�.

For the 2P-fuel injection nozzle made of the Wärtsilä NSD standard material which is usedtoday, it is practicable to increase the tightening angle back to 45�as instructed earlier withouthaving to fear that the atomizers will be deformed.

Therefore the new tightening instructions are as follows:

- First step: Hammer-blow or approx. 20 bar tightening pressure.- Second step: 45�TIGHTENING ANGLE must be adhered to.

If new 2-piece nozzle parts have been fitted, loosen the cap nut again and repeat step 1 and step2, in order to take up any initial surface roughness and to ensure the correct final tightening angle.

When fitting the nozzle holders to the cylinder cover, pay attention that the seating surface in thecylinder cover is properly cleaned. The injection valve must be lowered carefully onto its seat, inorder not to damage the nozzle tip, and care should be taken to tighten the holders correctly.

4. TIGHTENING INSTRUCTION FOR FUEL VALVE

The instructions in the Maintenance Manual ask for a tightening of the Allen screws until theirheads are flush with the top face of the nozzle holders.

Experience has shown that for a number of reasons, e.g. setting of spring washers, different sizesof bolt heads, change of dimensions of components due to overhauls etc., the tighteningprocedure for the fuel valve has to be modified. Therefore the following new instruction has to beapplied.

Press down the fuel injector evenly onto its seat with the two Allen screws. The correct pre�tensionis reached, when the spring stacks are fully compressed by the two Allen screws, to their blocklength, after which the Allen screws are again loosened by an angle of 90°. The so�called Blocklength is then reached, when a noticeable increase of the tightening torque is felt while tighteningthe Allen screws.

Amend the respective section in the maintenance manual if required.

5. MAINTENANCE

For the 2-piece nozzles the same maintenance work is to be carried out as for the shrink-fit type.

The respective procedures to be applied can be found in the Maintenance Manual section272/2�or 2722/2.

6. ASSESSMENT CRITERIA

For the operative assessment of fuel nozzles please refer to the Maintenance Manual section272�or 2722.

Check and ensure that the nozzle body is manufactured with a shrunk-in hardened needle seat.A characteristic of this nozzle body is a total length of the needle of 83 mm compared to 87 mm ofneedles in earlier nozzles. Nozzle bodies without this feature should be scrapped.

3 / 3 Service Bulletin RTA-3.4

7. IMPROVED NOZZLE TIP (ATOMIZER) WITH SLEEVE as per Fig. 1Standard on RTA ��U and �C Series" Engines

To improve the atomizer of the 2-piece nozzle the radius R at the base of the nozzle tip has beenincreased. Newly ordered atomizers will be of the improved execution with the enlarged radius.

On the previous sleeve, the chamfer on the landing surface for the atomizer of the 2-piecenozzle was only 1 mm x 45°.On the newly designed sleeve the chamfer is now large enough (Ø15.4 mm/ 45°) toaccommodate the larger radius R of the new improved atomizer.

Note: This must be checked before a new atomizer is used. Old sleeves can be modified.For more details please see insert-drawing in enclosure RTA-3.4/ 1

0-0.2

Fig. 1 Sleeve with New Nozzle Tip

Previous Design New Design

Sleeve

Enlarged Chamfer

Contact onthe radius R

R

Wärtsilä NSD Switzerland Ltd has issued this Service Bulletin with their best knowledge and ability.However, Wärtsilä NSD Switzerland Ltd can not take any liability for any or all information containedin this or any other Service Bulletin.

Changes of any nature to the form and or to the content of this or any other Service Bulletin as publishedby Wärtsilä NSD Switzerland Ltd, are not permitted.

Service Bulletin Enclosure RTA-3.4/ 1

2P-Nozzle

1

2

3

4

Shrink-fit Nozzle

1 Tightening nut2 Nozzle body with shrunk-in

needle seat and needle3 Sleeve4 Atomizer (nozzle tip)

Modification set from shrink-fitconsisting of:to 2P-nozzle type,

3