Mazda Training manual - part 253

 

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Mazda Training manual - part 253

 

 

 
6 – COOLING SYSTEM 

 

97

Piston Engine Fundamentals

TC010-05-01S

REVIEW EXERCISE 9

 

 
Fill in the words that correctly complete these sentences. Check your answers with the 
answer key on page 98.

 

 

1. 

A radiator that has side tanks, rather than top and bottom tanks, is called a 
______________________ radiator. 

 
2. 

A coolant fan that is driven by the engine is called a _______________________ 
drive. 

 
Use the pressure cap illustration below to complete the following two items.

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

3. 

Item 

     

in this illustration is the ________________________.

 

 
4. 

Item 

     

in this illustration is the ________________________.

 

 

 
5. 

Which of these symptoms would you expect to find in an engine that has a faulty 
thermostat? More than one answer may be correct.

 

 

A. leaking oil

 

 
B. fan not rotating

 

 
C. overheating

 

 
D. noisy engine 
 

 
6 – COOLING SYSTEM 

 

98

Piston Engine Fundamentals

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Answers to Review 
Exercise 9

 

 
1. crossflow

 

 
2. mechanical

 

 
3. vacuum valve

 

 
4. radiator 

reservoir 

 

hose  

 
5. C — over- heating

 

 

 
7 – GLOSSARY 

 

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Piston Engine Fundamentals

TC010-05-01S

 

anti-drainback diaphragm 

— an oil filter 

component that keeps oil in the filter when 
the engine is shut off. 
 
BDC 

— See bottom dead center

 
bearing cap 

— a U-shaped component 

used to attach the crankshaft, connecting 
rod, or camshaft to its support surface. 
 
bearing clearance 

— the gap between a 

main bearing and a main journal. 
 
belt and chain drive 

— a camshaft drive 

in which a timing belt drives the intake 
camshaft, and a timing chain drives the 
exhaust camshaft. 
 
blow-off valve 

— See pressure valve

 
bore 

—the diameter of a cylinder, usually 

expressed in millimeters (mm). 
 
bottom dead center 

— the position of a 

piston at its lowest point in the cylinder; 
abbreviated as BDC
 
bushing 

— a circular, sleeve-type bearing. 

 
bypass valve 

— an oil filter component 

that “senses” back-pressure from a clogged 
filter and allows some oil to bypass the 
filter. 
 
cam follower 

— See lifter

 
cam lobe 

— an off-center bulge on a 

camshaft that pushes against a lifter or 
rocker arm to control the opening and 
closing of a valve. 
 
cam-ground piston 

— a piston that is 

slightly oval shaped to allow for heat 
expansion. 
 
camshaft 

— a solid or hollow cast iron 

shaft with offset lobes, or cams, that control 
the opening and closing of the valves. 
 

camshaft flange 

— a raised surface on 

the camshaft that matches a thrust surface 
in the cylinder head to control front-to-back 
movement of the camshaft. 
 
combustion 

— the process of controlled 

burning of an air-fuel mixture in the 
cylinders. 
 
combustion chambers 

— the spaces in 

the cylinder head where the air-fuel mixture 
is compressed and burned. 
 
compression ratio 

— the ratio of the 

cylinder volume at bottom dead center to 
the volume at top dead center. 
 
compression rings 

— the top two rings 

mounted on the piston that seal, scrape, 
and cool the cylinder. 
 
compression stroke 

— the part of the 

four-stroke cycle in which the upward 
stroke of the piston compresses the air- 
fuel mixture into a very small volume at the 
top of the cylinder. 
 
connecting rod 

— attaches a piston to the 

crankshaft; the connecting rod transfers the 
movement of the piston to the connecting 
rod journal on the crankshaft. 
 
connecting rod bearing 

— a split circular 

sleeve that wraps around a connecting rod 
journal on the crankshaft. 
 
connecting rod journal 

— a smooth 

round surface, offset from the center line of 
the crankshaft, that is used to attach the 
connecting rods from the pistons; also 
called a crankpin
 
coolant passage 

— a passage cast into 

the cylinder block or cylinder head to carry 
coolant around the cylinders. 

 
7 – GLOSSARY 

 

100

Piston Engine Fundamentals

TC010-05-01S

cooling system 

— the engine components 

that circulate coolant to maintain proper 
operating temperatures in and around the 
cylinders. 
 
counterweight 

— a weight cast into the 

crankshaft opposite a connecting rod 
journal; counterweights help balance the 
crankshaft and prevent vibration during 
high-speed rotation. 
 
crankcase 

— the chamber at the bottom of 

the cylinder block where the crankshaft 
turns. 
 
crankpin 

— See connecting rod journal

 
crankshaft 

— the shaft that changes the 

up-and-down motion of the pistons into 
rotational motion. 
 
crossflow-type radiator 

— a radiator with 

side tanks that allow coolant to flow through 
the core from side to side. 
 
cylinder 

— See cylinder bore

 
cylinder block 

— the main supporting 

member of the engine that contains the 
cylinders, pistons, connecting rods, 
and crankshaft. 
 
cylinder bore 

— a machined space in the 

cylinder block where the pistons are 
housed. 
 
cylinder head 

— a structural member of 

the engine that is bolted to the top of the 
cylinder block; the cylinder head seals the 
tops of the cylinders, and contains the valve 
train components and spark plugs. 
 
 
 

cylinder head gasket 

— seals the 

connection between the cylinder block and 
cylinder head; the gasket is usually made 
of steel coated with a softer material. 
 
dipstick 

— a fluid level gauge used to 

measure the level of engine oil in the 
oil pan. 
 
displacement 

—the volume of a cylinder 

between the top dead center and bottom 
dead center positions of the piston; the 
displacement of an engine is the total 
displacement of all the cylinders in the 
engine, usually expressed in cubic 
centimeters (cc) or liters (L). 
 
distributor 

— directs electrical current to 

the spark plugs as they fire in turn. 
 
distributor groove 

— a groove on the 

exhaust camshaft that drives the 
distributor. 
 
DOHC 

— See dual overhead cam

 
downflow-type radiator 

— a radiator 

with upper and lower tanks that allow 
coolant to flow through the core from top 
to bottom. 
 
dual overhead cam 

— an engine design 

in which the valves and two camshafts are 
mounted above the cylinders; one 
camshaft operates the intake valves and 
the other operates the exhaust valves; 
abbreviated as DOHC
 
electric fan drive 

— a radiator fan drive 

that uses an electric motor to operate the 
fan only when a thermoswitch senses that 
the coolant has reached a preset 
temperature. 
 
end play 

— movement of the crankshaft or 

camshaft from front to rear. 

 

 

 

 

 

 

 

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