Valve timing specifications and instructions for F.XI and F.XII engines.
| Identifier | ExFiles\Box 33\4\ Scan102 | |
| Date | 26th November 1927 | |
| To Mr. Wilkins AID. To RG. {Mr Rowledge} from Hs {Lord Ernest Hives - Chair} /VH. C. to HY. {Tom Haldenby - Plant Engineer} C. to [obscured] C. to [obscured] X1770 Hs {Lord Ernest Hives - Chair} /VH1/LG26.11.27. RR. F.XI. AND Xl1 - VALVE TIMING. From the experience gained in producing 30 engines, we give the following as an average timing :- Tappets adjusted to have .020" clearance, a .010" feeler used (.010" clearance actual). Inlet opening 6º B.T.D.C. Variation 1/9º B.T.D.C. Inlet closing 53.5º A.B.D.C. " 48/60º A.B.D.C. Exhaust opening 46º B.B.D.C. " 39/54º B.B.D.C. Exhaust closing 19º A.T.D.C. " 12/25º A.T.D.C. Hitherto the D.O. have called for a timing with .010" clearance. In the case of the RR.F.Xl. and F.Xll engines, this has the merit of simplicity - a .010" feeler has merely to be inserted in the standard working clearance and involves no alteration in the tappet setting. It is understood that the timing given is for checking purposes only. We are sending further instructions for timing engines. Much smaller variations [handwritten above 'variations'] are obtained when using .030" clearance - an average for these can also be quoted but no check is obtained on the toe of the cam. Hs {Lord Ernest Hives - Chair} /V.Halliwell. | ||
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).