7/29/2019 Csl 1083

1/2

250-Cl8 CSL-100 250-B17, B17B, B17C TP CSL-1250-C20, C20B, C20F CSL-1083 250-C28B, C28C TP CSL-2250-B15G TP CSL-40 250-C30 CSL-3

COMMERCIAL SERVICEDetroit Diesel Allison

LETTER

Indianapolis, Indiana 46206 Page 1 of 2July 6, 1979FAA-DER ApprovedSUBJECT: Use of Silicone Base Molybdenum Disulphideand Nickel Base Anti-Seize CompoundsThis edition completely revises the original issue.Minute quantities of silicone are commonly used as an anti-foamingadditive in approved engine oils. However, any excessive amount ofsilicone w ill cause foaming. To prevent inadvertent contaminationof the eng ine or airframe lubrication system, restriction is placedon the use in certain areas of the engine.

Synthetic oil base (MIL-L-23699) molybdenumdisulphide mixture (EMS 37611) does not offer significantcorrosion protection above 250F and is no longer recom-mended for use.Silicone basf+m olybdenum disulphide (Silicone DC-550-R)offers greater corrosion protection up to 450F.Nickel base anti-seize compound (EMS 27627) is to be used in arewith higher temperatures.Under high temperature conditions, molybdenumdisulphide can oxidize and cause corrosive attack onlow alloy steel parts.

The properties of each of these compounds restricts their application:l MIL-L-25681 or EMS 27610 high temperature lubricant

and anti-seize compound (Silicone DC-550-R Silicone-Molybdenum Disulphide, Dow Corning Corp., Midland,Michigan 48640):

Revision No. 2February 15, 1980

Rolls-Royce Proprietary Data Uncontrolled Printed Copy

7/29/2019 Csl 1083

2/2

250~Cl8 CSL-100 250-B17, B17B, C17C TP CSL-105250-C20, C20B, C20F CSL-1083 250-C28B, C28C TP CSL-201250-B15G TP CSL-40 250-C30 CSL-301Page 2COMMERCIAL SERVICE LETTER

Use on EXTE RNA L spanner nut, nut, bolt and stud threads,except:male threads and attachments and plugs installedin the outer combustion case, turbine supportsand exhaust collector.

However, MIL-L-25681 or EMS 27610 molybdenum disulphideanti-seize compound is specified for use on the No. 2 bearingretaining spanner nut (LH thread).CAUTION

Do not use molybdenum disulph ide lubricants on internalthreads or on any fuel, lubrication or air systems tubing,hose or fittings threads where contamination of engine orairframe systems can occur.0 EMS 27627 anti-seize compound, high temperature, highpressure (NS-165 Never-Seez Compound Nickel Special,Never-Seez Com pound Corp., Broadview, Illinois 60153):

Use on male threads of attachments and plugs ins talledin the outer combustion case, turbine supports and exhaustcollector. Use also on threads of bolts used at the splitlinesbetween the outer combustion case, the turbine supports andthe exhaust collector.

This information will be incorporated into the respective Operation andMaintenance and Overhaul Manuals.

L. 0. Davidson --Service ManagerGas Turbine Engines

JPW/clsRevision No, 2February 15, 1980Published July 6, 1979

Rolls-Royce Proprietary Data Uncontrolled Printed Copy