Clean Carbon and Grind Valves
The all steel valves used in the model “A” engine are accurately ground in at the factory. They form an ideal seat in the cast iron block, consequently they should require no further attention for some time.
Loosen radiator stay rods at radiator.
Pull radiator slightly forward and lift off hood.
Unhook spark and throttle rods. (See “A,” fig. 445.) These rods are connected with ball and socket joints and are disconnected by holding the rod stationary, and pulling back on the cap.
Disconnect carburetor adjusting rod “B” at carburetor and pull rod back into front compartment. Do not misplace locking sleeve spring and washer which will drop off when adjusting rod is pulled back.
Shut off gas and disconnect fuel line at sediment bulb.
Remove carburetor by screwing out the two carburetor to intake manifold bolts “D.”
Remove fan belt by loosening the generator arm stud nut and generator support to engine bolt and pulling generator towards engine as far as it will go. Fan belt can then be removed from fan.
Disconnect spark plug connectors and lift off distributor cap and body.
Screw off all cylinder head nuts. Loosen distributor set screw nut “C” and back out set screw until distributor base can be lifted off.
Pull radiator slightly forward and lift off cylinder head complete with water pump and fan assembly. Cylinder head gasket can then be slipped off over ends of studs.
Screw out oil return pipe bolt upper “E,” and loosen the lower bolt. Push pipe out of way so that valve chamber cover can be removed.
As a quantity of oil is always standing in the valve compartment it is a good place to place a drain pan under the rear end of the right hand engine pan before removing valve chamber cover.
Screw out the 10 valve chamber cover bolts and lift off cover “F.”
With a valve lifter compress the valve springs until the valve spring seat retains can be withdrawn (see fig. 446). It is not necessary to remove the valve springs. When compressing the springs the valve lifter is inserted between the lower coils of the spring.
Next lift up the valves as far as they will go and carefully examine both the valve seats and the beveled face of the valves. If the valves and seats do not require refacing of resealing, the valves can be ground in without removing the valve guide bushings. As the tops of the valves are machined smooth, it is necessary to use a vacuum cup type valve grinder (see fig. 447). The grinder holds the valve by suction. Extreme care must be used to prevent any carbon or grinding compound getting into the valve guide bushings; also make sure that all compound is removed from valves and valve seats when the grinding operation is complete.
Should the valves require refacing or the valve seats need reseating, it will be necessary to remove the valve guide bushings in order to withdraw the valves. To remove the bushings lift out the valve springs; the bushings can then be withdrawn through the valve chamber. If the guides bind in the the cylinder block they can be removed by tapping them out with a brass rod inserted through the valve opening in the face of the block.
After the refacing or reseating operation is completed, replace the valves and insert the valve guides into the cylinder block. The valves should then be lightly ground in to insure a perfect seat. After grinding, always check the clearance between valves and push rods; a thickness gauge is used for this purpose. The clearance should not be less than .013” or more than .015” The gap must be measured with the push rod on the heel of the cam.
Next, replace the valve springs, valve chamber cover, cylinder head, etc., making sure to close drain cock and refill radiator.