Page:Ford manual 1919.djvu/12

12 now being properly set, the exhaust valve on No. 1 cylinder is open and the intake valve closed, the other valves being in the position indicated in Cut No. 3. The opening and closing of the valves being as follows: The exhaust valve opens when the piston reaches 5-16" of bottom center. the distance from the top of the piston head to the top of cylinder casting measuring 3 3−8". The exhaust valve will close on top centre. the piston being 5-16" above the cylinder casting. The intake valve opens 1-16" after top center, and closes 9-16" after bottom center, the distance from the top of the piston to the top of the cylinder casting measuring 3 1-8".



The clearance between the push rod and valve stem should never be greater than 1-32" nor less than 1-64". The correct clearance is naturally half way between these two measurements. The gap should be measured when the push rod is on the heel of the cam.

They seldom get out of order—but they do get dirty, as a result of carbon collecting on the valve seats. These carbon deposits by preventing proper closing of the valves, permit the gases under compression to escape, resulting in loss of power and uneven running of the motor. If, when turning the engine over slowly there is a lack of resistance in one or more cylinders, it is probable that the valves need re-grinding. As the "life" of the engine depends largely upon the proper seating of the valves, it is necessary that they be ground occasionally.

(1) Drain radiator; (2) remove cylinder head; (3) remove the two valve covers on the right side of engine; (4) raise the valve spring with lifting tool (see Cut No. 4) and pull out the link pin under the valve seat. The valve may then be liftedout by the head.