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).
G.M. Truck Co.'s bearing tests using lead bronze and leaded oil, noting the resulting surface deposit.
| Identifier | ExFiles\Box 173\2\ img287 | |
| Date | 22th March 1934 guessed | |
| PS from RHC{R. H. Coverley - Production Engineer} P. 2 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} M.{Mr Moon / Mr Moore} Truck Co., Pontiac, have standardized lead bronze for main and conn. bearings on all engines, lubricating system being combined low pressure and splash feed; for initial tests a thin mineral oil having 5% lead oil addition is used. Originally it was found that mineral oil caused considerable internal corrosion and scoring of pistons. The addition of lead oil not only overcame these troubles but proved more suitable lubricant for bearings. The conditions of tests on new engines with 275° F.{Mr Friese} oil inlet temperature being:- 4 hrs. light running at 1,200 RPM 1 hr. full torque at 1,200 RPM 1 hr. " " " 1,500 RPM 1 hr. " " " 2,000 RPM 1 hr. " " Max.speed 2,500 RPM Bearings do not normally operate under such high oil temperature conditions but these tests produce a beautiful ebony deposit on all bearings similar to that we have seen on Kes Conn. Rods. It is considered there is less risk of subsequent bearing failure if this surface condition is produced, in order to prevent foreign matter being circulated through lubricating system during test, oil is drained into a reservoir and thoroughly filtered. RM{William Robotham - Chief Engineer} informs me that he will not be through until March 20th and since there are still further matters I would like to investigate, we have arranged to sail on Berengaria, which leaves New York on March 21st and arrives Southampton March 27th. R H C | ||