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).
Engine lubrication, seizure risks after cold starts, and piston design improvements.
| Identifier | ExFiles\Box 15\3\ Scan024 | |
| Date | 12th October 1928 guessed | |
| contd :- -2- would drain away from the cylinder walls and it is conceivable that an appreciable time would elapse after starting from cold before the cyl. bores would receive adequate lubrication by the oil thrown out of the bearings. The danger of under-lubrication and risk of seizure becomes more acute when employing a bottom scraper ring. It is the experience of the Test Dept. that with the present production chassis, both Phantom and 20 HP., partial seizure frequently results in new engines if they are raced too soon after a cold start, particularly so if the car has previously been run hard. With our aero engines the case is different due to the longer warming up allowed and greater clearances but with our cars where it is possible to obtain a quick 'get-away' from cold due to the good induction and hot spot systems, the danger becomes very real in the hands of customers. The lack of adequate lubrication when cold we consider attributes largely to cold knocks. A desirable feature is flexibility of the skirt and for experiment we shall remove the stiffening piece at the bottom of the skirts of these pistons. We consider the pedestal type piston to be a considerable advance on the previous type in avoiding distortion of the skirt due to the fitting of the gudgeon pin and should be a feature much appreciated on production where considerable trouble has been manifest due to distortion. The greater flexibility of the skirt allowed by this construction should also go a great way towards overcoming troubles due to knocks. contd :- | ||