[David_Hayward (RIP)]

The London Public Records Office contains a file number ADM 227/316 of 1940 relating to the testing of G.M. 2-stroke Diesel engines by the British Admiralty that G.M. Limited were proposing to supply to meet a particular need. Limited had in fact submitted a marine version of the three-cylinder 3-71 design to the Admiralty for type tests. Clearly the location of the Southampton Plant operations was advantageous here. However the success of the trials came to the attention of the War Office as post-Dunkirk there was concern by July 1940 to ensure an uninterrupted supply of power units for the Vickers ‘Valentine’ Infantry Tank Mk. IIIA, orders for which had been placed in Canada. The Valentine was a 1938 design that initially used AEC petrol or diesel engines. The W.O. became interested in the Detroit-Diesel design in its 6-cylinder form as an alternative power unit and so Limited worked with the ‘Detroit Technical Staff’ in procuring a 6-71 engine which was redesigned into the tank to be interchangeable with British power units. Field tests carried on by the W.O. and presumably Ministry of Supply in collaboration with G.M. Overseas Operations and General Motors Limited resulted in the first application of G.M. Diesel engines to tank usage, as the Model 6-71S. This was later superseded by the more powerful 6-71A. The alterations and design called for the changing of the fuel, water and exhaust connections, mounting brackets and clutch and gear controls. The Ministry of Supply forwarded complete drawings of the modifications to G.M.O.O. in order to determine whether G.M. would supply the 6-71 in quantity. James D Mooney was still in his position at G.M.O.O. at the time and was presumable involved with the negotiations that took place over five months between the G.M.O.O., the Detroit Diesel Division, Canadian Pacific Railroad who had been commissioned to build the Canadian Valentines, and British officials. This culminated in an initial order from the British Purchasing Commission or B.P.C. on 27 September 1940 for 250 engines. G.M.O.O. consequently invested as a consequence $50,000 for a sample engine in Autumn 1940.

...from JAMES D MOONEY: A MAN OF MISSIONS by David O Hayward.

This is from my thesis relating to GM Limited, Southampton from 1947:

Many profitable activities had been developed by capitalising on uses for war-surplus stocks of G.M. manufacture remaining in the U.K. However, in addition to the U.K. Government supplies, lots of surplus parts acquired included the bulk of the U.S. Army vehicle stocks at their main base in the U.K., the Admiralty’s surplus Detroit Diesel marine engine parts, parts for Detroit Diesel Series 71 Diesels as used in ‘Sherman’, ‘Vanguard’ and ‘Valentine’ tanks [6-71 in the Valentine Mark III Infantry Tank] , and parts for the Cleveland Diesels. Series 71 parts from two depots alone was to amount to between U.S.$4 and $5 million U.S. list value [but in line with the disposal of U.S. parts, these would have been acquired at 25% value].