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).
Investigations into failures concerning petrol supply, petrol gauge, oil pump, and battery box.
| Identifier | ExFiles\Box 5a\2\ 02-page144 | |
| Date | 5th July 1922 | |
| To Me. From C.S.M. Hôtel de France, Châteauroux, Indre. 5/7/22. To-day has been taken up in investigating various failures. Firstly we have thoroughly investigated the autovac to obtain some definite formula for the shortage of petrol at high sustained speed. We found in the first place that the stand pipe in the autovac tank allowed 5 pints for the reserve. We are under the impression that this should only allow 4 pints. With the stand pipe higher there is only approx. 1 pint of petrol for the main supply. Therefore, if the autovac does not keep up as much as the engine uses, we have only one pint of petrol to play about with. We have reduced the height of the stand pipe to allow for 4 pints reserve, thus giving us 2 pints for the main supply. We have also checked the amount of petrol given per stroke of the autovac. At an engine rev. of approx. 600, the amount given was on an average 62 c/cs. At the same engine speed the autovac gave one pint in one minute. We have, by weighting the float of the autovac, reduced the time for one pint to 55 secs, and the amount per stroke to 65 ccs. This should give us a better margin for high speed work on the main supply. This will be checked over during our next run. The petrol gauge on this car was out of action. The main pressure pipe and pipe to air pump were both broken off short at the nipples of the instrument. We have repaired these and made the petrol gauge read correct. The thin pipes had not been sufficiently supported under the dash, and too much vibration had broken them off. We have also found that the main petrol pipe from the rear tank to the autovac was loose all along the frame, no clips being fitted. The bijur oil pump on the dash during the run down here yesterday threw oil out as per usual down the inside of the dashboard. This is very definitely not due to the height of oil in the pump, as when measured it was 2" from the filler flange. We have dismantled the pump and drilled air release holes, as we previously reported to you on the 20-HP. in conjunction with the air release, we have made 3 slots in the face where the filter makes the joint at the top, so that any oil getting above the filter, instead of running out of the hole of the bracket and down the dash, will be returned into the tank. We have filled the pump within .3/16" of the top and will report its behaviour to you during the forthcoming tests. The rear flange of the battery box had broken away where it is held by the brackets to the cross member. This flange is a right angled piece of steel which is rivetted on to the battery box. We have made a new angle piece and rivetted it to the box, so that there will be no chance of [Handwritten note] Route by See report | ||