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).
Ventilation design for the J.III distributor head, comparing gauze-covered holes to drilled holes.
| Identifier | ExFiles\Box 61b\2\ scan0154 | |
| Date | 2nd March 1932 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Wst. c. Ry. c. Wor.{Arthur Wormald - General Works Manager} XG148 Hs{Lord Ernest Hives - Chair}/Wst.1/AD3.2.32. J.III DISTRIBUTOR HEAD. We have just seen drawing D.53023 showing the distributor head for Japan 3. and Peregrine and we note that it is still decided to use gauze covered holes for ventilating purposes. We consider this to be wrong in that in our experience the ventilating holes become clogged up and thus render the ventilation inoperative. We think this has also a bearing on the frequent seizures in the past of battery ignition levers on their pivots due to the corrosive effect inside the distributor head. Messrs. Lucas have confirmed this opinion in a report which they sent to us on tests they carried out on a standard R.R. distributor we loaned to them in exchange for one of theirs. An extract from their report reads as follows :- "The distributor top has replaceable nickel inserts and is provided with two gauze covered ventilation windows. This type of ventilation in our experience is very liable to become inoperative owing to the gauzes becoming clogged." We recommend instead of gauzes, two small holes drilled in the head directly under the securing clips for ventilation purposes. These holes would also facilitate the machining of the bakelite moulding die as it is difficult and expensive to machine out the small boss carrying the present standard gauze ventilated window especially as this is shown at an angle. We think this point should be further considered before the dies are made for the head. Hs{Lord Ernest Hives - Chair}/Wst. | ||