Ford Manual
:
When the Valves and Push Rods are worn---what?
Answer. No. 26
When the valves or push rods become worn, so as to leave too much play between them, thus reducing
the lift of the valves and diminishing the power of the motor, it is best to install new push rods. If
replacing the push rod does not give the desired clearance, the valve should also be replaced.
Installation of new push rods or valves necessitates retiming the motor (See Answer No. 22.)
What about the Valve Springs?
Answer No. 27
When the valves fail to seat themselves properly, there is a possibility that the springs may be weak or
broken. Weakness in the exhaust valve spring causes a very uneven action. the symptoms are a lag in the
engine due to the exhaust valve not closing instantaneously, and as a result a certain percentage of the
charge under compression escapes, greatly diminishing the force of the explosion. Weakness in a valve
spring can usually be detected by the following method: Remove the plate which encloses them at the
side of the cylinder and insert a screw-driver between the coils of the spring while the engine is running.
If the extra tension thus produced causes the engine to pick up speed, the spring is obviously weak and
should be replaced with a new one.
What causes "Knocking" in the Engine?
Answer No. 28
There are several causes, which may be enumerated as follows: (1) carbon knock which is by far the
most common---resulting from carbonizing of cylinders; (2) knock caused by a too advanced spark; (3)
connecting rod knock; (4) crank shaft main bearing knock; (5) knock due to loose-fitting piston or
broken ring; (6) knock caused by the piston striking the cylinder head gasket. When the engine knocks
from any cause whatsoever, the matter should be promptly investigated by an experienced mechanic and
the difficulty corrected.
How may the different Knocks be distinguished?
Answer No. 29
(1) The carbon knock is a clear, hollow sound, most noticeable in climbing sharp grades, particularly
when the engine is heated. It is also indicated by a sharp rap immediately on advancing the throttle. (2)
Too advanced spark will be indicated by a dull knock in the motor. (3) The connecting rod knock sounds
like the distant tapping of steel with a small hammer, and is readily distinguished when the car is allowed
to run idly down grade---or upon speeding the car to twenty-five miles an hour, then suddenly closing
the throttle, the tapping will be very distinct. (4) The crank shaft main bearing knock can be
distinguished, when the car is going uphill, as a dull thud. (5) The loose piston knock is heard only upon
suddenly opening the throttle, when the sound produced might be likened to a rattle. The remedies for
these knocks are treated under their proper division.
How is carbon removed from Combustion Chamber?
Answer No. 30
First, drain the water off by opening the pet cock at the bottom of the radiator; then disconnect the wires
at the top of the motor and remove the spark coil; also disconnect the cylinder head outlet connection.
Remove the 15 cap screws which hold the cylinder head in place. Take off the cylinder head and, with a
putty knife or carbon scraper, scrape the carbonized matter from the cylinder head and top of pistons,
being careful to prevent the specks of carbon from getting into the cylinders or bolt holes. In replacing
the cylinder head gasket turn the motor over so that No. 1 and No. 4 pistons are at top center; place the
gasket in position over the pistons and then put the cylinder head in place. Be sure and draw the cylinder
head bolts down evenly (i.e., give each bolt a few turns at a time); do not tighten them on one end before
drawing them up at the other. After the engine has warmed up the bolts should again be tightened.
How are Spark Plugs cleaned?
Answer No. 31
