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

Automotive Service

2. The two measuring systems commonly used in the auto shop are the:

A. ____________________ (STD) B. ____________________ (SI)

Customary & Metric

American & Asian

Global & Wentworth

Automotive Service

3. Math operations in the metric system often requires little more than

moving the _________ point.

Main

Decimal

Starting

3.004”

+ 3.250”

4.004”

- 4.000”

3.50mm

+ 3.15mm

4.95mm

- 4.80mm

Automotive Service 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

Automotive Service

Automotive Service 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.

Automotive Service

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”

Thickness of a Hair ≈ .002”

Thickness of a Dime ≈ .040”

Inch

Foot

Pound

Automotive Service 7. Both dial & electronic calipers can make _____________,

_____________, & ___________ measurements.

Inside

Outside

Depth

Automotive Service 8. A ______________________ can make measurements as accurate as

.0001” (one ten thousandth of an inch).

Micrometer

Plastic Ruler

Meter Stick

Automotive Service 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

Automotive Service 10. ____________ gauges of either the flat or wire type are used to find the

clearance between two surfaces.

Feeler Gauges

Dealer Gauges

Wheeler Gauges

Automotive Service

11. Dial ___________________ are delicate tools used to measure part movement

(play) in .001” or .01mm.

Calipers

Indicators

Testers

Automotive Service 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

Automotive Service 13. Temperatures in both _______________ Fº and ____________ Cº degrees

often need to be measured. (cooling systems, AC systems, exhaust, brakes, etc.)

Fahrenheit

&

Celsius

Automotive Service 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

Automotive Service

Ratcheting Torque Wrenches

Can be Mechanical or Electronic

Automotive Service 16. Both _______ and ________ gauges are used to measure engine conditions.

Pressure & Vacuum

Pressure & Distance

Suction & Vacuum

Automotive Service 17. Pressure is expressed in either ____________ per ___________ inch (psi) or

kilopascals (kPa).

Pounds per Square Inch

Pounds per Newton Meter

Pounds per Half Inch

Automotive Service 18. Vacuum is expressed in either ______________ of ________________ (Hg”)

or kilograms per cm2.

Inches of Mercury (Hg”)

Inches of Length

Inches of Lift

Automotive Service

1 Bar ≈ 15 psi

Automotive Service

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