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).
Causes and potential solutions for Bentley piston seizures.
| Identifier | ExFiles\Box 87\2\ scan0047 | |
| Date | 11th April 1935 | |
| To E.{Mr Elliott - Chief Engineer} Bentley Piston Seizures. I have made enquiries of Hd.{Mr Hayward/Mr Huddy} about the piston seizures on Bentley production cars, and he informs me that in most cases the owners of the cars where seizure has occurred are people who use their cars generally for short runs with occasional long runs. From this, one would suggest that the cylinder lubrication gets badly diluted or perhaps washed right away during the short runs periods, as the petrol from the carburetters and the induction manifold all drains into the engine. It is also very easy to leave the control for rich starting mixture in the starting position. The seizures are not confined to any particular cylinder. The engine water temperature on Bentley is if anything slightly lower than for the 20/25 HP. On one car where seizure had occurred, the Rolls-Royce pistons were replaced by Aerolite pistons. These were run in for about four hundred miles before delivering to customer, but even so one of these pistons seized after the customer had run about one thousand miles. Referring to Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/KW.4.4.35, Rm.{William Robotham - Chief Engineer} suggests drilling an oil jet in the connecting rod stem to supply extra cylinder lubrication, although he does not want to groove the big end bush. According to Hs{Lord Ernest Hives - Chair}/Mths.{Reg Matthews}15/KW.2.11.34, this groove seems to be essential to the scheme, so as to guarantee an oil supply to the cylinders. E/McSTAY. | ||