Figure 4-15. Ram Induction Manifold
will serve no useful purpose outside of its designated
controlled by the manifold heat control valve.
operation is covered In paragraph 7-3.
c. Heating the Mixture. As stated in paragraph 4-
(2) Directing the engine coolant, which Is laden
5a(3), providing controlled heat for the In coming mixture
with engine heat, through the intake manifold on Its way
Is very Important for good performance. The heating of
to the radiator (fig. 4-17).
the mixture may be accomplished by doing one or both of
4-6. Air Filters.
(1) Directing a portion of the exhaust through a
passage In the intake manifold (fig.4-16). The heat from
a. Purpose (Fig. 4-18). The air filter fits over the
the exhaust will transfer and heat the mixture. The
engine air Intake to filter out any foreign matter. Any
amount of exhaust that Is diverted Into the Intake
foreign matter that enters the Intake will act as an
manifold heat passage Is
abrasive between the cylinder walls and the pistons,
greatly shortening engine life. The two types of filters
currently In use are the wet and dry type.
b. Wet Type (Fig. 4-19). The wet-type, or the oil
bath, air filter consists of the main body, the filter element
that is made of woven copper gauze, and the cover.
Operation is as follows:
The incoming air enters between the cover and the main
body. It is pulled down to the bottom of the main body,
where it must make a 180-degree turn as it passes over
the oil reservoir. As the air passes over the oil reservoir,
most of the particles will not be able to make the turn,
they will hit the oil and be trapped. As the air continues
upward and passes through the filter element, the
smaller particles that bypassed the oil will be trapped.
The air keeps the filter element soaked with oil by
creating a fine spray as it passes the reservoir. The air
then makes another 180-degree turn and enters the
Figure 4-16. Exhaust Heated Intake Manifold