Huber2p18

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Crankshaft Assembly

Connecting Rod and Piston

THE valvc in head type four cylinder en-ginę used in the Huber Super Four is remarkable for its flexibility, power and economy. It is strictly a high grade job in every particular, built along lines of most ad-vanced gas engine design. It is not an automobile engine in any sense of the word—not even a truck engine—but is designed and con-structed especially for installation in heavy tractor and industrial units. A reasonable overload, even though continuous, will not in-jure it and it is proportioned to stand the knocks and abuse to which an engine in this class of eąuipment is sometimes subjected.

Ease of accessibility to all parts is one of the real features of this engine. Large hand-hole plates are provided on the side of the crank case for all minor adjustments and inspection. There is a piąte on the bottom of lower half of crank case that can bequickly removed toadjust all main or connecting rod bearings.

The heavy crank shaft is madę of chrome nickel Steel, heat treated, and bearing surfaces are accurately ground and lapped to size. The shaft and fly wheel are balanced on a Norton crank shaft balancing machinę. Large holes are drilled in the shaft for lubricat-ing all main and connecting rod bearings under pressure. There is a total of 12]Ą inches of bearing length in the threemain bearings and these bearings are broached . 002 oversize to per-mit oil film between crank and bearing surface. All bearings are madę of highest grade bronze with babbitt lining, and are provided with necessary shims for take up of wear.

Connecting rod bearings are each inches long and the bearing cap is held in place by four heavy bolts madę of chrome vanadium Steel. A Steel tubę that is a part of each connecting rod supplies oil under pressure to each wrist pin. The wrist pins are madę of .20 carbon Steel, case hardened and ground accurately to size. A bronze bushing in upper end of connecting rod forms the wrist pin bearing.

The cylinder is madę of a high grade, close grained grey iron, cast four en bloc. Barrels are reamed and accurately ground to size. The combustion chamber is reamed to within .001" in diameter which insures uniform compression in each cylinder. Pistons are madę of the same grade of grey iron as the cylinders. The piston top is well ribbed and wrist pin bosses well supported. Grooves are provided for four piston rings, lower one acting as an oil ring. Cylinder blocks, pistons and heads are roughed out, then annealed before finishing. This proc-ess relieves castings of all strains, and by elimi-nating warpage insures perfect borę and perfect piston fit.

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