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).
Investigation into the oiling procedures and effects on the Watford IS.12 magnetos.
| Identifier | ExFiles\Box 43\4\ Scan044 | |
| Date | 6th January 1927 | |
| EFC. WB.{Mr Brazier/Mr Bell}122. 6.1.27. OILING OF WATFORD IS.12 MAGNETOS. On these magnetos provision is made for lubricating oil to leak from the front bearing on to the contact breaker bearing surfaces and from thence to the contact breaker lever pin bearing. It was thought that overoiling of this front bearing would lead to surplus oil being deposited on the lever and contact points. The distributor bearing appears to be efficiently drained by two pipes leading from the base of the bearing housing to the outside of the magneto gear case. We have now run a magneto (No. 83134) with a view of observing the deposition of oil due to overoiling the front bearing. The magneto was run at 2000 r.p.m. for 6 hours in the first instance, the oil well being filled with oil at the commencement of the run. At the end of this run it was found that oil had overflowed on to the locating bearing surfaces of the contact breaker but otherwise the contact breaker remained perfectly free from oil. The oil well was again filled up and the magneto run another 2 hours, after which it was found that oil had further percolated to the contact breaker lever and into the bearing recess of the lever pin, but otherwise the points and other parts of the contact breaker were free from oil. The oil would then appear to drain from this pin bearing to the base of the contact breaker and miss the contact points altogether. There is also what appears from external observation a drain hole for this front bearing at one side of the base so that it is unlikely that any excess quantity of oil would find its way to the contact breaker. These observations lead us to the suggestion that the bad performance of the platinum points is not primarily due to overoiling from the lubricator, but oil or oil vapour being forced through due to external influences, i.e. engine crankcase pressure or hot oil dripping from the engine on to the magneto and percolating through the joint between the contact breaker unit and the bronze bearing housing. In addition to the above, we do not exclude the possibility of the lubricating oil itself getting hot after a long run on the engine causing Contd. | ||