Evening times-Republican. [volume] (Marshalltown, Iowa) 1890-1923, 1920-09-29
The Auto Quiz

/. When the word degree" Is en-
pIoyed in connection with engine
valve or magnetic timing, what does
the word imply?
The word degree" as used In con-
nection with engine valve and mag
neto timing implies the unit used In
tho measurement Of angles, or one
three hundred sixtieth OF circle.
2. What are the average gear
ratios of four speed transmissions?
Average gear ratios for each OF the
four speeds OF transmission are. for
low speed. s.24 revolutions OF the en-
CINE to one revolution OF the rear
wheels; for second speed, los to /:
for third speed. 1.i9 to !. and fourth
speed. / to /. The reverse ratio
averages to /.
3. Are double exhaust pipes and
muffiers necessary for eight or
twelve-cyllnder v type engines7
Dauble exhaust pipes and muffiers
OF eight and twelve-cylinder cars arc
commonly used but not absolutely
necessary. A separate exhaust pipe
| running back to separate muftler
for each set Of cylinders offers more
freedom for burned gasses to pass to
the open air.
4. What is the purpose OF the SAFE
ty spark gap on a high tension mag
neto?
The safety spark on high tension
| magnetos acts as a safety outlet for
secondary current In case it's path
OF flow was closed. For instance II
| wire was detached from distributor
| or spark plug. the current designated
| to flow thru this wire would pass
| thru the safety gap instead of ruin
| ing the arinature by forcing q pas
sage thru It's insulation.
8. What is the average setting of
spark plug electrodes for various
conditions OF compression?
Average setting OF spark plug
| points for an engine with high COM
preston Is twenty -thousandths Of IN
| inch. For medium compression OF
| about sixty pounds the average is
| twenty-five thousandths and for low
compression, below fifty pounds the
average distance II thirty thou
sandths.
s. With what mixture should ex-
haust pipes and muffiers be painted /?
The following mixture makes a
paint for muftiers and exhaust pipes.
Nine parts Of Fullers earth mixed
| with three OF graphite and two lbf
oxide OF manganese (black), add ten
parts sodium silicat mixed with four
OF water and one OF glucose. Stir till
1t may be applied with q paint brush.
Aluminium paint can also be used.
Z. What Is a possible effect within
the engine of spark advanced too far
when the engine Is laboring uphill?
The possible effect OF spark ad-
vaneed too far when the engine is re-
CURED to move the car against load
or uphill is broken connecting rod
or oveEheating Of the engine. A
sharpI knocking Is the first sign of
laboring against advanced spark.
8. What is the difference between
| backfire into the carburetor and a
backfire in the muffler?
Backfiring In the muffler is caused
by too rich a carbureter mixture or
when the engine is not firing regular
ly. whereas backfire in the car
bureter Is caused by a leak In the
inlet valve. The former is when
unignited gases pass into the exhaust
pipe and muff1er and are then ig-
nited by the next explosion while the
latter occurs when after an explosion,
the ignited gases or part Of them
pas thru the intake manifold to the
carbureter instead Of. forcing down
the piston.
9. How does magnetic ignition
timing differ from that OF battery
ignition?
The spark created by magnetic is
timed SO that 1t will occur at top
dead center, or end OF compression
stroke Battery ignition is timed for
the spark to occur at about six
teenth Of an inch over top center.
10. Where is the differenttal To-