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).
Issues and comparisons regarding Cadillac hydraulic tappets, steering, and springing.
| Identifier | ExFiles\Box 125\2\ scan0157 | |
| Date | 21th November 1934 | |
| X1729A Hotel de France, Chateauroux. Indre. France. 21st November 1934. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From GWH.{George W. Hancock - Head Chateauroux} We have received your memo of the 19/11/34 and note your remarks. Re the Cadillac hydraulic tappets. The NS.{Norman Scott} set we dismantled and cleaned are now quiet. The trouble is due to the valves in the plungers not making an oil tight seating. These are the mushroom type and not the ball type as used on 28 EX. The cause apparently is due to the excessive amount of carbon sludge that is prevalent on the outside as well as in the oil passages. The rocker shaft and rockers are considerably more dirtier than experienced with our own engines. There is a filter (knife edge) in series with the oil feed to the rocker shafts, which is turned automatically by the brake pedal, similar to our main filter which is operated by our clutch pedal. Instructions are also given to give it a turn by hand daily, which has duly been carried out. The OS. tappets which we did not clean, and are occasionally noisy, we have quietened momentarily by pouring oil on to the plungers. We shall have to dismantle this side and clean the plungers, etc. to obtain satisfactory results. Re the Steering. We have stressed the point of the low gearing to be unsatisfactory for cornering and manoeuvering, and realise the difficulties one is up against to obtain the most satisfactory combination; but the fact remains that, for absence of road shocks, the steering of the Cadillac is beyond reproach. We are naturally disappointed with the steering of 21 G 1V after having become used to the Cadillac, and it is forcibly impressed upon us. The more direct steering of 21 G 1V is certainly an advantage in manoeuvering, cornering, and for high speed work it is definitely safer. It is a considerable improvement over the previous steering, but there is still that irritating joggle. It is free from shocks, i.e.- rapid oscillation which the RR. is prone to. We are, however, of the opinion that a gear ratio between what was on, and what is now fitted would be better. Springing. We have come to the conclusion that the roll rod has immense virtues, other than preventing the rolling of the car. We have, as you are aware, always over here increased our shock damper loads to obtain road holding qualities combined with speed. | ||