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).
Engine tests comparing standard and two-piece cylinder blocks, with analysis of detonation and overheating effects.
| Identifier | ExFiles\Box 179\2\ img254 | |
| Date | 16th February 1932 | |
| -2- Ha/Yng/1/H1.16.2.32. Cont'd.{John DeLooze - Company Secretary} Results. The split pin tests have been reported on separately in Ha/LHM.2/HA.3.2.32. When the engine was stripped there were no signs of the sand blast effect which we associate with heavy detonation. The top joint rings of the standard block all looked perfectly good on the top face. On the face next to the cylinder liner, all rings were discoloured as though due to overheating on the diameter bisecting the diameter joining the spark plugs at right angles. On the two-piece block one or two rings showed very slight discolouration on the lower sides, but there were no signs of burning. As in the case of the standard block the discolourations were on the diameter approximately normal to the spark plug centre line diameter. (Prints A.{Mr Adams} and B. attached illustrate the above points.) SUMMARY. Running blocks of both types on the one engine gives us a comparison of durability and from the results obtained we can say that the top joint construction of the type and size as used on the two-piece block is superior to our standard design. Print C (attached) shows two top joint rings taken from Kestrel 1 - B - 165 which has run 142 hours in service. It will be seen that the marking is of entirely different character to that which results from detonation. The other sides of the rings are marked in a similar manner. It is interesting to note that in this case the marking occurs at one spot only. This spot is situated immediately over the exhaust spark plug and gas starter plug boss. From this it seems evident that detonation is not the cause of the poor condition of the top joint rings taken from the service engine, but rather is to local heating caused by the large mass of metal resulting from the exhaust spark plug and gas starter plug bosses being adjacent to each other. A modification has been put up which consists of drilling a .201 inch hole between the spark plug boss and the gas starter plug boss, thereby improving the water circulation at this point. It is hoped to run a cylinder so modified on a Type Test engine shortly. Ha/H.W.Young. | ||