From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Investigation into oil cooler failures and radiator manufacturing methods with supplier John Marston.
| Identifier | ExFiles\Box 131\1\ scan0297 | |
| Date | 10th August 1937 | |
| -2- (2) Oil cooler failures - the fact was established that all failures which have occurred in service have been on coolers of the type which Messrs. John Marston were making for us prior to Jan. 18th 1937 i.e. the matrix unit was made by dipping the tubes in a frame and this unit was then soldered into the outer casing by means of hand soldering. Since that date however they have been dipping the tubes and outer casing as a complete unit. We decided on this when the first two oil coolers were experienced on chassis 3-AZ-88, 3-AZ-98. The dipping process gives a much sounder job, the solder penetrating to the full depth of the tube ends. We had a dipped cooler put up while at Wolverhampton and were able to satisfy ourselves that the soldering was satisfactory. Examination of two of the burst coolers by sectioning, indicated that the hand soldering in places was not satisfactory, the depth of solder at one point between the tube ends and the edge of the bottom plate being only approx. .040" instead of approx. .300". Messrs. Marston state however that they would not be prepared to guarantee oil coolers of our type to be 100% reliable in service in the case of every cooler supplied - they are using the best manufacturing methods of which they know and the coolers are subjected to a very rigorous pressure test. (3) Messrs. Marstons quotation for the inner Wraith radiator (i.e. complete radiator less shell and shutter assembly) is approx. £6.15.01 this compares with a corresponding figure from our cost office of £10.15.0. for a similar article made in these works. They are also making us up for trial a Wraith radiator shell in chromium plated mild steel. (4) In order to ease the position as regards the supply of reconditioned Phantom III MK.V matrices to us (the reconditioning is necessarily a slow process) Messrs. Marstons had arranged to make 15 new MK.V matrices for replacement use (free of charge) They have completed 10 of these and are making the other five in the MK.VI type of construction. (5) The writer inspected the sample Bentley radiator made up by Marstons and with the exception of certain details approved of same it will be completed and sent over within a few days. Actually this radiator has now ceased to interest us with a view to use for production, because of the likelihood of Bentley III being put on the market in the early future. | ||