Evening star. [volume] (Washington, D.C.) 1854-1972, 1920-07-25

Answers to Last Weeks Questions.
1. The usual cause Of lost compress
sion in a motor are faulty valves
| or piston rings. A number OF troubles
would cause a leakage of compression
at the valves. such as sticking valve
stems or pushrods adjusted SO tight
| iy that they do not allow the valve
to close A valve will not seat prop
erly or not at all il the spring is
| broken or II carbon gets on the valve
seat Piston rings, worn, scored
broken or turned so that the openings
are In direct line will lose compres-
sion. II leakage does not occur
through valves or rings. IT must oc-
cur where valve caps. printing cups
or spark plugs are inserted In the
and cylinder head.
! 2. The sharp noise heard when an
engine exhausts Is caused by the ex-
haust valve opening suddenly under
pressure. and allowing expanded
burned gases after the explosion to
the outer air. The pressure ranges
from forty Ave to sixty pounds per
square inch. consequently the noise
when the gases are released. The ex-
noise. as the exhaust valve 10 opened
| after the explosion occurs.
| 5. Mileage capacity OF q motor truck
varies according to make and pur-
poses for which it is used and man
ner in which 1t Is handled. There are
some old trucks which have more
than 100000 miles to their credit and
are still in use.
4. The practical method usually
used In removing storage battery ter
minals Is to drill a hole. through the
terminal into the center OF the post,
then pry or the terminal with a nat
hle or screwdriver Use a seven
eishths drill for one-inch posts. and
nve -eiGhths drill for three-quarter-
inch posts.
5. The practical carburetors in use
by the average cars Of today are
quite similar in construction and OPP
Grafton. They are composed of the
following parts: Gasoline inlet. con-
trolled by a choke valve, float cham
Der. float connected to the choke.
ventura tube or mixing chamber
spray nozzle. auxiliary air inlet. con-
trolled by a seating disc valve. a
main air inlet. controlled by q disc
operated usually from the dash and a
gas outlet. The gasoline enters the
carburetor through the fuel inlet.
flows to the float chamber: The hoat
rises until the proper level is reach
ed. when it automatically closes the
inlet valve connected to it, shutting
of the flow. On suction stroke Of
each piston in the engine the gaso-
line Is Drawn IN VdpOTlxSQ 10TH lHto
the mixing chamber through the
spray noxxle. which vaporizes 1t and
mixes with it air drawn through the
main and auxiliary air inlets. The
charge is sucked into the cylinder
from the mixing chamber. past the
throttle disc and gas outlet. The
amount Of each charge 10 regulated
according to how far the throttle
disc is opened. the amount Of air reg
ulated by tension of the spring whtch
holds the auxiliary valve Arm. and
amount of suction is controlled by
speed of the engine, together with
the space left open by the throttle
disc. Most carburetors havk2 drain
At the bottom Of the float bowl. used
for flushing out sediment which may
collect in the carburetor. Some car
buretors have warm air passages
surrounding them, connected with
the exhaust manifold or pipe. The
purpose is to pass warm air from
the exhaust around the hoae> and
mixing chambers. insuring proper
vaporisation Of each charge OF gaso-
line.
6. Ignition troubles which will
cause a motor to knock are irregu-
lar spark from short circuiteo wires,
spark too late. spark advanced 700
far. plug points not adjusted 10 rlgnt
spacing or dirty, wrong timing, olrty
timer or distributor.
I. The system of insurance for AUTO
mobiles is based on cooperation OF the
insurance. companies, their total expe-
licences. rather than those OF the mol
vidual. used as a working basis. Inc
reduction of collision or accident pre-