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).
Investigating complaints of sticking valves by comparing the valve mechanisms of Phantom, 20/25 HP, and Bentley cars.
| Identifier | ExFiles\Box 17\6\ Scan212 | |
| Date | 16th May 1934 | |
| To HS{Lord Ernest Hives - Chair} X7060 Hs{Lord Ernest Hives - Chair}/GWH{George W. Hancock - Head Chateauroux}/EO/KW.16.5.34. Complaints of Valves Sticking. This complaint is prevalent on Phantom cars, and not on the 20/25 HP., or up to the present on the Bentley. In looking into the designs of the valve mechanism of the three cars we find the following differences :- (1) Valve Guides. The valve guides on the Bentley and 25 HP. cars do not project out of the cylinder boss to the same extent as the Phantom, and are therefore less inclined to distortion. (2) The valves of the 25 HP. and the Bentley, the reduced neck of the valve, (i.e. smaller dia. than the stem) extends up to and inside the bottom of the valve guide. (3) The Phantom. The full dia. stem protrudes approx. .125 beyond the bottom of the guide. (4) The guide of the Phantom is tapered outwards at the bottom. (5) The guides of the 25 HP. and Bentley are left parallel. (6) The reduced neck extending into the bottom of the guide of the 25 HP. allows for expansion of the valve stem at the critical position. Hs{Lord Ernest Hives - Chair}/GWH{George W. Hancock - Head Chateauroux}: | ||