Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1920-08-22
UERR[ICH DISCUSSES
T. AND L HEAD MOTORS
|imcs-Dispntch Automobile Expert
Answers Pertinent Queries Pro-
pounded by Readers.
LECTURE NO. zoo.


ny FREDERICK &. GUERHLICH.
There arc a few questions which I
ish TO answer. as they are interest
Question from a. J. b.: The moor
my Buick car does not have The
alves placed as those shown n tn"
lSine In your second lecture, TEcy
al my engine - valvc-in- the head
hSinc. Gould you explain It's action
Question from T.. b. p: My engine
as not got valves on. both sides;
nc same AZ the engine you showed:
Answer: For convenience, when
<plaincd the cycle and valve action
the engine. l used what is known
T-hcad motor. that is. one in
hich the valves arc placed on OPP
ositc sides of the cylinder. F!gur.
In the drawing shows This mptor
1rns the letter T. from which II
cts It's name.
In addition to the Thead motor.
nSincs are also built in the form OF
ne L-hcad and also the valvc-in the
cad. or as II is often called. over
cad valve motor. Then there a"c
pecial types. such as the knlaht
!eeve valve and the ortary valve
rotor.
The L-hcad motor. shown in Fig
re 2. differs from the T-hcad motor
My in tho arrangement OF the
aivo,. In this motor, the valves
re all placed on the one side. the
ctlon otherwise being exactly the
me as that OF the T-hcad motor
II course, in the T-hcad motor. the
resh gases enter on one side aud tac
Nhaust gases go out on the other
ide. while in the L-hcad the Gascs
ntcr on the front or rear porti7n
ion OF tae cylinder respectively,
ut on the same side.
In most L-typc engines. the valves
re arranged thus: No. ! viii have
- N fns s,rI n.y Tor "a MI
Met rear: No. =. the inlet forward
nd exhaust rear; No. 3, exhaust for
rnrd. inlet rear; No. !, Inlet front.
Exhaust rear. The reason for .hig IL
hat II will permit the Inlet manifold
o. be built with only two branches
Tor the fou--cylindcr engine and
hree branches for the s!x-ciyiuder
Both tho T and L-hcad motors
ave their advantages and dIsadvan-
ages. The T-hcad motor can haze
nrsGr valve and these valves VIII
.sua!ly be moro accessible. II -.
Iiowc.er. more expensive 10 build
4'nd mas more parts. ag 1t Will haze
o have TWO cam shafts and two half
motor
The, I.:hcai viii require only one
am sha., and gear, and has the add
ia advantage OF having the exhaust
3nan!iold near the inlet manifold. so
nat the heat OF the exhaust VIII tend
heat the inlet manifold. and so help
7r,teha We con.Gsi'sat.on OF the gas
Ino'wIcver. is. limited. ana they are
liable 10 be less accessible
me overh ead-valvc engine has the
Ives paced on top, or in the head
II The cylinders. In both the II and
E--head motors the valves are opened
EE being pushed up against the
|, ring. but IN the overhead engine
liown. The cam shaft is the same. but
between the valve Hitter and the valve
= push rod and rocker arm are placed.
Figure 3 shows the overhead or
I q Ec-i!ticr guide. y the valve litter
|oihcsc parts you will notice are the
|sh'Ec Ia III. + and l.-head motors).
|inu !! is tho push rod. which rests In
l. hollow on tho valve lifter. while g
r. thc rocker arm. and TIL. valve
stem.
You VIII note that as 4 Is raised r.
go Is raised. and that. because OF the
aud therefore valve, IL pushed down
E'nd 20 The valve ia opened.
IN mos, overhead valve engines the
valve IS contained in 4 valve cage. as
is SHOWN in figures 4 and ). This
waive cage is simply cas-; iron cyiin-
dc having hole In the Side and one
In the bottom, which is closed by the
vaivc. These valve cages 1T snuIly
In holes bored In the mead OF the
cylinders each cylinder having an in
lei valve and cage and an exhaust
Y
by referring TO figure 6. you Will
note that this represents "A cross sec
ton Of the head OF Il single cylinder.
The hatcncd Qtned) rings L and V
represent The valve cages, while II
and ) are the holes in their bottom.
AS tho piston travels downward on
the suction stroke. due 20 the action
OF the cam. push rod and rocker arm.
the valve w! open the hole :. and
the mixture VIII come In through the
inlet manifold, passage l., hole o in
the side of the cage. and then down
iAtu The cylinder through =. On the
compression and power stroke the
valves will be closed. hut on the en-
haust stroke the exhaust valve viii
be pushed down, thus opening i, and
the burned gases Will come up and
GU, Of the cylinder through II. then
through the hole +, passage NJ, and
so out through the exhaust manifold.
When the valves are to he ground.
the entire cage. valve and valve
spring are removed assembled. This
is done by removing the rocker arm.
and the large nut which holds the
cage in place. and then inserting the
end OF a screwdriver or tire tool I'M
der the spring and prying the cage
out OF It's hole. y block OF wood may
have 10 be used as fulcrum.