Text and jpegs by courtesy of hathitrust.org www.hathitrust.org, compiled by motorracinghistory.com
THE AUTOMOBILE and AUTOMOTIVE INDUSTRIES, Vol. XXXVII (37), No. 2, July 12, 1917
Frontenac Aluminum Engine
Cast Iron Liners Inserted Into Cylinders from Below—Valve Seats Dovetailed In
ONE of the most interesting of modern racing engines is that in Louis Chevrolet’s Frontenac car, which has figured prominently in several racing events of the season. It really made its début late last fall by winning the Uniontown, Pa., hillclimb. This engine is of the overhead camshaft type and has aluminum cylinders. Two sectional views which illustrate its internal construction appear herewith.
Liners Inserted at High Temperature
Cast iron liners of thin section are inserted into the cylinder bore to take the wear. These liners are inserted from the bottom and held in place by friction only. As they are introduced while the cylinders are maintained at a high temperature, by means of steam in the water jackets, they are automatically clamped tight in place at normal temperature when the cooling water is in the jackets instead of the steam. Also, as soon as the motor is started up under its own power the temperature on the inside of the cast iron sleeves rises so much higher than that of the water-cooled aluminum which surrounds them that the cast iron sleeves expand and tighten up inside of the aluminum rather than the aluminum expanding away from the cast iron sleeves.
As will be seen from the end section of the Frontenac motor, the seats for the valves are made up from iron castings with dovetailed edges cast in the aluminum. This makes the cast iron seats an integral part of the aluminum cylinder casting and has been found to give absolutely no trouble during the life of these motors, which has extended over a period of nearly 18 months. One piece is used for each group of four valves. By the use of these individual cast iron valve seats, the difference of the expansion of the cast iron and the aluminum does not affect the alignment of the adjacent cylinders.
135 Hp. Developed
The dimensions of the motor are 3.875 in. bore and 6.375 stroke, making a motor of just under 300 cu. in. displacement. With 105 lb. per square inch compression pressure, it is possible to obtain 135 to 140 hp. from this motor, so Louis Chevrolet claims. It will be noticed that two valve sizes are employed, the intakes being made lighter and larger in diameter than the exhaust, as is clearly shown in the sectional drawing. The intake measures 2 in. in the clear, while the exhaust measures only 1¾ in.
Photo caption.
Page 56.
FRONTENAC ENGINE DETAILS
Showing the arrangement of the cast iron cylinder liners and valve seats in the aluminum cylinder castings, the large jacket plates at the sides and ends of the cylinder block, the tubular connecting-rods, ball-bearing crankshaft made in halves, overhead camshaft, double valve springs, bevel gear camshaft drive and other features.