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).
Analysis of oil thrown onto cylinder bores from drilled versus non-drilled connecting rods, and a discussion on piston seizure in Bentley engines.
| Identifier | ExFiles\Box 159\6\ scan0089 | |
| Date | 4th April 1935 | |
| -2- S.A.E. 20 OIL. DRILLED ROD. | | Oil Thrown onto Bottom of Bore. | Oil Thrown onto Top of Bore. | |---|---|---| | Non Pressure Side | 3 Sec. | 5 Sec. | | Pressure Side. | 3 Sec. | 9 Sec. | S.A.E. 50 OIL. NON-DRILLED ROD. | | | | |---|---|---| | Non Pressure Side. | 4 Sec. | 25 Sec. | | Pressure Side. | 4 Sec. | No oil after 60 Sec. | S.A.E. 50 OIL. DRILLED ROD. | | | | |---|---|---| | Non Pressure Side. | 3 Sec. | 16 Sec. | | Pressure Side. | 3 Sec. | 30 Sec. | The quantity of oil thrown onto cylinder bore with drilled rod is considerably greater than with non-drilled rod, approximately three times greater. With this set up of pistons, skirt cut away on bedding sides, oil was allowed to be thrown up to the top of cylinder bore, whereas with complete pistons this could not be so, as there is only 3.250" length of cylinder bore exposed beneath piston when on T.D.C. Piston Seizure on Bentley. The history of piston seizure on Bentley engines before the hole was drilled in the conn. rod is contained in memo to Sg.{Arthur F. Sidgreaves - MD} and Wor{Arthur Wormald - General Works Manager} - Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/KW.4.4.35. Briefly this states :- "We have now had about a dozen cases of piston seizure on the Bentley in customer's hands. A case of piston seizure on 20/25 is almost unknown. We have failed to reproduce the seizures on our experimental cars or test -Continued- | ||