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).
Cadillac V-8 crankshaft distortion and downdraught arrangement improvements.
| Identifier | ExFiles\Box 173\4\ img161 | |
| Date | 16th December 1935 | |
| -2- Cadillac maintain there is some peculiar distortion in 8 throw crankshafts that causes lead bronze bearings to require large clearances. Their V-8 24 journal will run on ordinary Allison copper lead at 1 1/2 to 2 1/2 thousandths clearance. This peculiarity is I think explained by Griswold's researches into dynamic balance. He plots deflection curves of a 6 throw crank when supported on knife edges at the ends and loaded front at pins 1 and 6 then 2 and 5 and 3 and 4, getting results - He calculates the amount of balance weight required on each throw to correct this deflection curve. Under centrifugal forces the crankshaft will then run without bearing loads. On a 6 cylinder only 4 weights are required and the arrangement we use, although giving correct "mass balance" does not give the minimum bearing loads, and has an unnecessary amount of inertia. On an 8 cylinder shaft both methods give nearly the same result. As regards distribution on the V-8, Cadillac's new downdraught arrangement is fairly good and would be better if the riser was some 4" higher (not possible under their bonnet) and the heat was applied to the riser and not the bottom of the induction pipe. [Diagram Text] 3,4 1,6 2,5 IS BETTER THAN HEAT HEAT LARGE CHAMBER ALSO IMPROVEMENT. | ||