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 failures during road tests, detailing correspondence and actions taken to source replacements.
| Identifier | ExFiles\Box 82\1\ scan0054 | |
| Date | 24th March 1933 | |
| Handwritten top left: As/Rm{William Robotham - Chief Engineer} Handwritten top center: E JW Ah Stay Handwritten top right: XJ V12 A Stamp: RECEIVED 28 MAR 1933 To Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} From CWH B/Y Handwritten below stamp: Seen B/Y Hotel de France Chateauroux Indre 24.3.33. BENSPORT The car resumed running after fitting the N°6 piston and after allowing it time to run in, we were carrying out the oil temperature tests before lagging the front timing case. The second piston broke while the test at 70 MPH was being carried out. The failure is not due to the pistons hitting the cylinder head. That was the first question I asked upon arriving here and careful measurements were taken. With the gasket there is .037 clearance as we reported to you. In our opinion the weakness is due to castings being used and the cross cutting. The holes at each end of the slot comes too near the under cut, of the bottom ring. We had built the engine up and the car was on the road when we received your telegram: EXAMINE DAMPER LEVERS FOR SLACKNESS ARE PISTONS HITTING CYLINDER HEAD. Upon the second piston breaking we sent you the following telegram NUMBER FIVE PISTON BROKEN DURING MORNINGS RUN FRACTURE SIMILAR TO SIX. We had dismantled the engine and fitted the spare piston using the copper asbestos joint and the car was again on the road when we received your telegram: OBTAIN STANDARD PISTONS E57122 FROM PARIS AND FIT STOP PREPARING REPLACEMENT TO OBVIATE TROUBLE. The car left early this morning to fetch the pistons, but Paris had only two in stock; therefore we telegraphed to you having received a memo from PN.{Mr Northey} - - - - - - NO PISTONS CAN BE OBTAINED FROM PARIS STOP CAR IS RUNNING WITH NEW PISTON FITTED AT REDUCED SPEED RECEIVED MEMO PN{Mr Northey} REQUIRES CAR MONDAY STOP WHAT IS THE POSITION. We have received your answer NORTHEY NOT HAVING THE CAR NEW SET PISTONS SHOULD ARRIVE CHATEAUROUX SUNDAY. The car has been up to Paris and back and is running very well engine revs. not exceeding 3,000. We shall in the meantime get the following particulars. (1) Dynamo output (2) Maxim. rebound (3) Acceleration tests (4) Braking tests (5) Prepare asbestos for oil temp. test. We trust by then the new pistons will have arrived. G.W.H. [Signature] | ||