The design of small car engines

Motor Sport has been summarising a series of papers on this subject which were read at a Symposium arranged by the Automotive Division of the Institution of Mechanical Engineers, the last of these articles appearing in the September issue. It was our intention to continue them but, in fairness to the I.M.E., which has now published the entire series, with the subsequent discussion and authors’ replies, we have decided not to do so.

This book, “Design of Small Car Engines for Mass-Produced Cars,” contains the illustrated papers delivered by W. V. Appleby (B.M.C.), D. C. Eley (Standard-Triumph), R. A. S. Worters (Ford), R. Bachex (Renault), Messrs. L. Kuzmicki, A. C. Miller and P. G. Ware (Hillman), Dr. D. Giacosa (Fiat), Prof. A. Fessia (Lancia) and R. M. Strobel (N.S.U.). The discussion is highly informative and even touches on vintage history, because Georges Roesch, claiming to have pioneered the silent and reliable, lowcost, high-performance car in 1930, in the form of the Talbot 105, which gave 105 h.p. at 4,500 np.m. on a c.r. of 6.6 to 1, and 140 h.p. at this crankshaft speed on a c.r. of 10.2 to 1. Roesch claims 561 h.p. at 6,000 r.p.m. on a cr. of 8.5 to 1 from the 1,070-c.c. engine he evolved from the basic 10/23 Talbot design in 1922, and a maximum speed for this engine of no less than 7,650 r.p.m. He says Segrave lapped Brooklands in the car at over 90 m.p.h. but found the ride too rough for his liking, so interest was lost and, this single-seater sold, “never to be heard of again.” Surely someone else must remember a 1922 push-rod-o.h.v. light car capable of revving to over 7,600 r.p.m.? Could it have been the 10/23 converted into a 2-seater and driven in speed hill-climbs by Mr. F. W. Shorland, Clement-Talbot’s Sales Manager? Perhaps someone can tell us?

All of which rather departs from the I.M.E. book, which is of great interest to engineers and designers, especially as the discussion takes in such matters as whether it is more meritorious to vary the bore or the stroke, whether 5-bearing crankshafts are justified, Saab’s admission that the two-stroke engine “isn’t satisfactory for the future,” and indeed, on all major aspects of engine design, as leading designers tilt and Spar with one another!