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).
The engine, performance, and handling characteristics of an 8 Litre Bentley.
| Identifier | ExFiles\Box 21\2\ Scan082 | |
| Date | 2nd March 1931 | |
| R.{Sir Henry Royce} FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to PN.{Mr Northey} HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} re: 8 LITRE BENTLEY. Supplementing HS{Lord Ernest Hives - Chair}'s report on the bentley we attach herewith a print from a thumb nail sketch shewing the external arrangement of the engine. The point one notices most is the large distance between the rear crankshaft bearings flanking the eccentrics for the camshaft drive. Apart from the benefit conferred by the use of the double rear bearing this increase on the length of the shaft should be a disadvantage in some ways, but no doubt the dia. of the additional portion is large. The engine is 4.33 bore X 5.5 stroke, and it appears to be more or less the 6.5 litre model with 10 mm. on the bore. The mo mounting is 3 point apparently all on rubber and the gearbox is separate. The crankcase is well barrelled in shape with an external down looking lip but no great width of flange outside. This engine certainly seems to possess the ability to "rev". Mr. Bentley stated the master period was at 3800. and was equivalent to 111 MPH. but that he had run the engine up to 4400. The MPH. at 1000 appears to be 29. We ourselves ran the car up to 75 MPH. on 3rd. when the road stopped us. Assuming 3rd. gear to be .7 this would give nearly 3700 engine revs., at which speed the engine was remarkably smooth both driving and over-running. There is a wheel flying round at the front crossmember between engine and dynamo which might be some form of slipper utilising the dynamo armature as a damper flywheel since it would not be wise to rigidly couple the latter to the crankshaft. The slow running was not particularly good below 10 MPH. This is not inconsistent with the general behaviour of S.U. carburetters, which have a tendency to be sloppy when closed down. With regard to the springing of the bentley it is the worst example of pitching at low speeds ever encountered on a big car. The wheelbase if 13 ft. The springing was soft but held the road well at high speed. The front dampers were Hartford type with additional friction | ||