Automotive Service
Modern Auto Tech Study Guide
Chapter 6
Pages 70 - 84
Automotive Measurement & Math
20 Points
Automotive Service
1. _______________________ or “specs” are the minimum and maximum ( + )
wear limits (tolerances) and dimensions of important parts as published by
the manufacturers.
Specifications
Tolerances
Dimensions
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2. The two measuring systems commonly used in the auto shop are the:
A. ____________________ (STD) B. ____________________ (SI)
Customary & Metric
American & Asian
Global & Wentworth
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3. Math operations in the metric system often requires little more than
moving the _________ point.
3.004”
+ 3.250”
4.004”
- 4.000”
3.50mm
+ 3.15mm
4.95mm
- 4.80mm
Main
Decimal
Starting
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4. ________________________ charts are used when changing from one
measuring system to another.
Note: The ALLDATA information system that we use has an auto convert
feature for measuring units & systems.
Conversation
Calculation
Conversion
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5. Fraction-to-decimal conversion charts are handy since _____________ are
more accurate than fractions and decimals are used more often when
servicing vehicles than fractions are.
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6. Customary rulers measure to the nearest fraction of an ____ & metric
rules measure in 1 mm increments.
Note: As a “benchmark”, 1 millimeter is about the thickness of a
dime or about .040” and 25mm is about 1”
Inch
Foot
Pound
Thickness of a Dime ≈ .040”
Thickness of a Hair ≈ .002”
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7. Both dial & electronic calipers can make _____________,
_____________, & ___________ measurements.
Inside
Outside
Depth
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8. A ______________________ can make measurements as accurate as
.0001” (one ten thousandth of an inch).
Micrometer
Plastic Ruler
Meter Stick
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9. ______________________ gauges and small ________ gauges are used
to take hard to reach internal measurements of bores which are then
transferred to a caliper or a micrometer to get exact dimensions.
Telescoping Gauges
Small
Hole
Gauges
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10. ____________ gauges of either the flat or wire type are used to find the
clearance between two surfaces.
Feeler Gauges
Dealer Gauges
Wheeler Gauges
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11. Dial ___________________ are delicate tools used to measure part movement
(play) in .001” or .01mm.
Calipers
Indicators
Testers
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12. ____________ of rotation often need to be measured or expressed when
learning about or when servicing vehicle systems, engines, and transmissions.
There are _____ degrees in a full circle.
There are _____ degrees in a half circle.
Digress
Degrees
Digital
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13. Temperatures in both _______________ Fº and ____________ Cº degrees
often need to be measured. (cooling systems, AC systems, exhaust, brakes, etc.)
Fahrenheit
&
Celsius
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14. A ___________ wrench is used to apply a specific amount of twisting force
to fasteners like nuts or bolts.
Torque
Twist
Turn
Note: Every Tire & Wheel leaving our shop
is always final tightened to the correct torque!
Do it right, or don’t do it at all!
Automotive Service
15. Three types of torque wrenches are: ________ bar, ________ indicator, and
_________________ types. The ratcheting type is often referred to as the
“click” type or the “micrometer adjusting” type. (Electronic are also available)
Flex, Dial, Ratcheting
Twist, Meter, Scale
Turn, Bend, Stretch
Ratcheting Torque Wrenches
Can be Mechanical or Electronic
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Ratcheting Torque Wrenches
Can be Mechanical or Electronic
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16. Both _______ and ________ gauges are used to measure engine conditions.
Pressure & Vacuum
Pressure & Distance
Suction & Vacuum
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17. Pressure is expressed in either ____________ per ___________ inch (psi) or
kilopascals (kPa).
Pounds per Square Inch
Pounds per Newton Meter
Pounds per Half Inch
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18. Vacuum is expressed in either ______________ of ________________ (Hg”)
or kilograms per cm2.
Inches of Mercury (Hg”)
Inches of Length
Inches of Lift
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1 Bar ≈ 15 psi
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19-20. 240 inch pounds = ______ foot pounds of torque.
30 foot pounds = ______ inch pounds of torque.
inch pounds ÷ 12 = foot pounds
foot pounds x 12 = inch pounds