This insures accurate centering of the valve and minimizes the possibility of gas leakage and loss of compression. It also reduces carbon deposits which cause sticking The Ford crankshaft is made of carbon manganese steel and is ground, machined and polished to measurements as fine as five ten-thousandths of an inch. Ford crankshafts receive more than 150 gage tests for accuracy. The main and connecting rod bearings are polished to mirror-like smoothness within a tolerance of one one thousandth of an inch. End clearances between the connecting rod bearing faces and those of the crankshaft are held to the unusually close limit of five one-thousandth of an inch.
Great care is taken to insure the proper static and dynamic balance of the crankshaft.
The machines used for the dynamic balance tests are set upon foundations of gum rubber and are so delicately adjusted that the very air which surrounds them is first cleansed and then held at 68 by thermostatic control. Though weighing many pounds, the Ford crankshaft is so carefully balanced that it will remain motionless in any position when placed upon two perfectly levelled parallel bars, yet will turn if but two grams weight is placed on any connecting rod bearing. This accuracy in manufacturing, combined with simplicity of design and the high quality of materials, has a definite bearing on the good performance of the Ford and its economy of operation and up-keep. Throughout, it has been made to give you many months and years of satisfactory motoring. For there, among the holiday gifts, will be a gleaming new Ford.