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).
Letter from Alta Car & Engineering Co. Ltd. seeking advice on a connecting rod failure.
| Identifier | ExFiles\Box 27\2\ Scan210 | |
| Date | 14th May 1934 | |
| TELEPHONE-ELMBRIDGE 3157 TELEGRAMS-ELMBRIDGE 3157 ALTA CAR & ENGINEERING CO. LTD. Directors — G.{Mr Griffiths - Chief Accountant / Mr Gnapp} TAYLOR. L. TAYLOR. May 14th, 1934. FULLER'S WAY, KINGSTON BYE-PASS, SURBITON. Your Ref. Our Ref. GT.LV. Messrs. Rolls Royce, Ltd., Derby. R R Alloys, Technical Dept. Dear Sirs, We are writing to you for advice on a subject in which you probably have not a great deal of interest in the hope that you will give us the benefit of your experience. We had two of our ALTA supercharged cars competing at Donington last Saturday, both cars being to all intents and purposes identical, one car gained two seconds and one third in three races, the other broke a connecting rod in practice. The connecting rods are made from R R 56 forgings supplied by High Duty Alloys, and we have sent the broken rod to you under separate cover. It has, we think you will agree, broken due to a seized big end and we think the following particulars will help you in suggesting a likely cause. The engine is our own 4 cylinder 60 x 95 m.m. with a B.H.P. of 80 - 90 at 6000 r.p.m. on Petrol Benzole, the crankshaft is supported on three bearings and is of nitralloy, the big end diameter is 1.625" width 1.2". The rods run direct on the shaft and are fed with Castrol R.{Sir Henry Royce} pressure 60 lbs. temp. 60° - 70° C by means of a drilled shaft fed from both ends via a Tecalemit felt pad type filter, the holes to the big ends face the axis of the crankshaft, no grooves are used in the bearings and they were fitted with a definite .0015" to .002" clearance on diameter and .006" side float. The rod which broke was No. 4 but No. 3 was badly scored, Nos. 1 and 2 were in 100% condition, the oil ways were clear, | ||