Specifications

82 Preservation Specifications

Special packing

Special packing must be carried out for storage outdoors, immediately following preservation if possible, for

engines which are to be taken out of service for more than 36 months or which are to be transported by sea

or in polar or tropical regions, see Section (→ Page 78)and (→ Page 80). Likewise, special packing is also

usually advisable for protecting the engine against corrosion during shorter periods of storage.

General information on special packing

Engines / drive plants must be specially packed for transportation by sea or in polar / tropical regions and before

long-term storage. This means that the engine must be preserved according to Section (→ Page 78) or (→ Page 80)

(completely drain off coolant and preservation oil) and enclosed in special packing in addition.

The following types of special packing are available:

• Envelopes of bonded-layer material (e.g. aluminum bonded-layers).

• Hygroscopic (water-absorbing) materials (e.g. silica gel).

The engine is welded into a foil with limited water-vapor permeability, the enclosed air is then extracted by

means of a vacuum-cleaner, and is dried to the desired relative humidity with desiccant. Desiccant is used

to achieve a specific relative humidity inside the foil envelope. The climatic packing of bonded-layer material

hinders the formation of condensed water o n the metal surface and resulting corrosion.

Maintenance Intervals

Every 3 to 4 months

• Check humidity indicators (→ Page 84)

Note:

When storing the engine in special packing (with laminated-aluminum layers), note that the elastomers

have a limited life. The calculation of the total service life of the elastomers begins with either the year of

manufacture or last engine overhaul (see nameplate). Based on current knowledge, elastomer components

made of fluorocarbon rubber (e.g. O-rings) have a total service life of about 20 years and those made

of other rubber materials (hoses) have a total service life of about 10 years.

In cases of storage for more than 10 years (from date of manufacture on identification

plate) but before putting into service

• Replace all rubber parts on engine (hoses, sleeves, etc.)

Storage beyond 20 years (as of year of manufacture on nameplate) but before commissioning:

• Replace all elastomers during a major overhaul of the engine.

Note:

A long storage period shortens the time limit for an engine’s major overhaul (TBO) because of the limited total

service life of the elastomers. MTU recommends that engines should not be stored for more than 10 years.

Envelopes of laminated material

The envelopes consist of tightly-bonded layers of aluminum composite foil which has limited

permeability to water vapour and gas.

The material used by MTU is composed of polyethylene – aluminum and polyester, with the following properties:

• Temperature range for applications from +70 °C to –50 °C.

• Water vapor permeability (WVP): 0.1 g/m² per day at 38 °C and 80% relative humidity

(compared with PVC soft foil: WVP 6 g/m² per day)

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