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).
The issue of popping and explosions in the exhaust of the New Phantom model.
| Identifier | ExFiles\Box 1\3\ B001_X 93-page50 | |
| Date | 10th May 1926 | |
| COPY. To BJ. from CWB. Copy to PN.{Mr Northey} Copy to H.{Arthur M. Hanbury - Head Complaints} CWB3/PD/10/5/26 Popping and Explosions in Exhaust. New PhantomCodename for PHANTOM I. This trouble is still a serious one and is the cause of much comment and adverse criticism of the New PhantomCodename for PHANTOM I amongst owners and others, see BJ4/E5/3/26., and Hs{Lord Ernest Hives - Chair}2/LG6/3/26. The effects have been minimised by the newer exhaust system and the ball bearings of the governor control shaft, but even with these the most frequent and careful attention, such as is given to our own Trials Cars, cannot produce a consistent condition of freedom from these noises while with ordinary good attention only they are serious. With special reference to R1/M30/3/26., it is not merely a question of popping and explosions when overrunning from high speeds; a New PhantomCodename for PHANTOM I in ordinary adjustment will continuously spit and pop in the exhaust when overrunning in the course of travelling about London, driven in a normal manner, and never exceeding 25 m.p.h. It is of importance even with the cut out shut. Cuts out are never opened in London and seldom at all in England, but the spitting and explosions are clearly heard. A sharp crack or bang, as with cut out open, is not produced, but the actual noise is sufficiently definite and audible to be objectionable and to cause this constant criticism and expense at our repair depots. At the same time attention is drawn to the unreliability of operation of the governor control which appears to be an allied question. The main objection in practice is the variability in the speed of idling of the engine with a given control setting when the clutch is disengaged, according to the conditions immediately preceding, and under which this is done. Thus, if the governor lever is set to give a reasonable speed of idling and the car is driven at any high speed and then has to be suddenly stopped and the clutch thrown out it will be found that the engine will not have sufficient throttle opening to continue running and will stop, and conversely if the governor is set to keep the engine running under these conditions (which will be 3 or 4 notches higher than setting previously referred to) and the circumstances of the road cause the speed to be reduced very gradually, it will be found that the engine will race badly if the clutch is thrown out and that the minimum speed of slow running will be 15 or 16 miles per hour. | ||