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 failure of con rod top bearings and oil pressure issues on a Cadillac.
| Identifier | ExFiles\Box 125\2\ scan0197 | |
| Date | 2nd January 1935 | |
| L1729A To Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} From G.W.H. Chateauroux. Indre. France 2 Jan. 1935. Cadillac We have been investigating the possible reasons of the failure of the con rod top bearings. In doing so we found that the oil pressure was increased when we cut out the release valve. This led us to investigate the oil release valve; We found that the plunger was partially sticking open thus dropping the oil pressure too low at slow speeds. It has been a hell of a job getting to the release valve as it is situated in the front timing case. To get at the valve we have had to dismantle the radiator and the front grid as the nut holding the plunger spring was behind the outside crankshaft damper and could not be withdrawn. we have managed to withdraw the damper and get at the valve . there was distinct evidence of it having been partially open.The oil pressure was 15lbs when motoring the engine over at approx. 500 revs. per min. before we released the valve, afterwards it was 25lbs and maintained it. We are reducing the head of the nut so that we can get it out without having to dismantle the front in the future.Having done this I am proceeding to Paris to finish off the connecting rods. We have withdrawn the old bushes and fitted the new ones.They now require reamering and milling the oil way. We are still of the opinion that more oil supply is needed to the guggion pins and will do no harm.We hope to have the car running again by the end of the week. For your interest the front grid or shell of the radiator weighs 45 lbs. and the Radiator with the bottom support which is bolted to the matrix weighs 93 1/2 lbs empty and 115 lbs full of water. The thermostat and shutters are also attached to the radiator. G.W.H. G.W.Hancock | ||