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).
Falcon X engine test detailing issues with pre-ignition, valve wear, and water leakage after 14 hours of running.
| Identifier | ExFiles\Box 36\2\ scan 087 | |
| Date | 30th July 1926 | |
| R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} BJ. Wor.{Arthur Wormald - General Works Manager} RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} X2934 Hs{Lord Ernest Hives - Chair}1/K30.7.26. FALCON X. X3804 X2934 F.X.S. This engine has run 14 hrs. at 2200 r.p.m. developing 425 HP. the full power at this speed was 462 HP. After 4 hrs. running, trouble was experienced with pre-ignition, this caused drop in power and exhaust valves stretched and took up clear-ance. The clearance was adjusted to .020" and the engine run again, after a further 5 hrs. the exhaust tappet clearance was again all taken up and the power had fallen off. After adjust-ment the engine was run for a further 5 hrs. and after this all the adjustment for the exhaust tappet had been used up. It was also noticed that water was entering the engine and leaking from the exhaust ports. The engine was therefore dismantled. The exhaust valve seatings had worn badly, the exhaust valve guides had also worn, the most wear on seatings was in the position of the drag in the e valve caused by the rocker. Several of the exhaust valves had stretched, obviously due to pre-ignition. The worst feature on the engine was that on most of the cyl. bores there was water leaking from behind the valve seatings, the leaks occurred at the narrowest point in the band of metal between the inlet and exhaust valves. The water leaked from the back of the thread into the inlet and exhaust ports. It is possible that the cause of the valve seating leakages is due to the method adopted for fitting them. The seatings are left very solid for screwing in and the contraction on to the solid contd:- | ||