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).
Piston seizure tests, comparing standard E.B.1299 pistons with Aerolite pistons.
| Identifier | ExFiles\Box 87\2\ scan0054 | |
| Date | 17th April 1935 guessed | |
| -3- At this stage we discontinued our tests with the standard E.B.1299 pistons and fitted the cylinder block and pistons off a customer's car on which there had been a piston seizure. This customer had seized a set of standard pistons and these were replaced for him by a set of Aerolite pistons, but after approximately 1,000 miles the car had been sent back to the Works with one of the Aerolite pistons seized. The pistons off this customer's car that we used were the set of Aerolites which for all intents and purposes practically new, the cylinder block was also new, having been fitted at the time the Aerolite pistons were fitted after the seizure of the standard E.B.1299 pistons. At the same time that we fitted these pistons we also obtained the customer's petrol pump and induction system in order to make sure that pump was delivering at the correct pressure and that no flooding was taking place. We also rigged up a car's petrol tank at the correct height relative to the carburetters and fitted a complete car petrol system in order to reproduce car conditions in the way of fuel feed. Our first test with these Aerolite pistons and cylinder block consisted of running the engine for 15 minutes at 4250 r.p.m. after a normal warming up, in order to see if these pistons were thoroughly "run in" but in this respect the pistons appeared to be alright for there was no sign of seizure under normal high speed running conditions. At the end of this run we shut the engine down quickly and allowed it to stand over the week-end in order to let asmuch oil as possible drain away from pistons and cylinder bores. After standing over the week-end, the engine was opened up to 4,000 r.p.m. as soon as it fired with the mixture full rich; the carburetters were flooded before starting but we again failed to reproduce a seizure. Summed up briefly, our tests show that on an engine which has been run in thoroughly and in which there is an adequate flow of oil from the main bearings, we can say that the following running conditions will have no effect on seizing. (1) Boiling. Under these conditions we ran a considerable amount of time, but could not reproduce a seizure, and providing that the cylinder block is devoid of steam pockets it is hardly likely that this condition will cause a seizure, particularly when using Aerolite pistons, since as the temperature of the piston increases there is a tendency for the pressure diameter to decrease on this type of piston. | ||