Chapter 11, Engine Fundamentals

List three functions of an engine flywheel.

1. The flywheel connects the engine crankshaft to the transmission or transaxle. Either the manual clutch or the automatic transmission torque converter bolts to the flywheel. 2. The flywheel for a vehicle with a manual transmission is very heavy and can help smooth engine operation. 3. The flywheel generally contains a large ring gear, which is used to start the engine. A small gear on the starting motor engages the flywheel ring gear and turns the flywheel.

The crankshaft must rotate ________ complete revolutions to complete the four-stroke cycle.

2

Define valve face

A machined surface on the back of the valve head.

A(n) _________ is needed to turn the camshaft at one-half engine speed.

Camshaft Drive

What parts are attached to the engine front end?

Camshaft drive, a front cover, an oil seal, and a crank damper. It may contain oil pump, water pump, chain or belt tensioners, auxiliary drives or sprockets, and engine sensors.

The ________ is the hollow area between the top of the piston and the bottom of the cylinder head.

Combustion Chamber

_______ are small pockets formed in the cylinder heads.

Combustion Chambers

Name the two types of piston rings and explain the function of each.

Compression Rings- Prevents blowby (combustion pressure leaking into engine crankcase). Piston Rings- Seals the clearance between the outside of the piston and the cylinder wall.

The _________ changes the up-and-down motion of the pistons into a rotating motion.

Crankshaft

The ________ provides a mounting place for the camshaft drive mechanism, front damper, and fan belt pulleys.

Crankshaft Snout

The _______ are large, round holes machined through the block from top to bottom.

Cylinders

The engine ________ forms the main body of the engine.

Engine Block

What is engine top end?

Generally refers to the cylinder heads, valves, camshaft, and other related components.

Where is an engine camshaft normally located?

In the engine block or in the cylinder head.

On late-model engines, the fuel injectors and the throttle body mount on the ________ manifold.

Intake

The ________ route air or air and fuel into the combustion chambers.

Intake Ports

Which is usually larger, the intake valve or the exhaust valve?

Intake Valve

Name the four strokes of an automotive engine.

Intake, Compression, Power, and Exhaust.

Explain the function of an exhaust manifold.

It carries burned gases into the exhaust system.

Explain the purpose of an automotive engine's crank damper.

It helps prevent crankshaft vibration and damage.

Describe the function of the engine valve train.

It must open and close the valves at the correct time.

The ________ are holes machined in the bottom of the block to hold the crankshaft.

Main Bearing Bores

__________ bolt to the bottom of the block and hold the crankshaft and main bearing inserts in place.

Main Caps

Engine main bearings are inserts that fit between the block main bore and crankshaft _________.

Main Journals

The connecting rod transfers piston ________ and combustion pressure to the crankshaft __________.

Movement, Rod Journal

An engine's rear main _______ can be a one-or two-piece seal.

Oil seal.

________ transfer motion between the lifters and the rocker arms.

Push Rods

The split between the ends of a piston ring is called _______.

Ring Gap

Name six parts of an engine piston.

Ring Land, Ring Grooves, Skirt, Boss, Pin Hole, and Head.

Piston _____ must keep combustion pressure from entering the crankcase and must also keep ________ out of the combustion chamber.

Rings, Oil

________ clearance is the small space between the rod bearing and crankshaft journal.

Rod Bearing

The valve ________ is a long shaft extending out of the valve head.

Stem

Piston ________ is the distance the piston slides up or down from TDC/BDC.

Stroke

What components normally make up an engine valve train?

The Camshaft, Lifters, Push Rods, Rocker Arms, Valves, and Valve Spring Assemblies.

Why is an automotive engine called a power plant?

The engine is the source of power for the vehicle.

How does an engine convert fuel into a useful form of energy?

The fuel is burned inside the engine's combustion chamber. This combustion produces heat, which causes expansion of the gases in the engine. The burning and expansion produces pressure. The engine piston, connecting rod, and crankshaft convert the pressure into motion for moving the car and operating its systems.

What is main bearing clearance?

The space between the crankshaft main journal and the main bearing insert.

Define deck surface.

The top of the block surrounding the cylinders.

A main ________ limits the distance the crankshaft can slide forward or rearward in the block.

Thrust Bearing

What is the function of the crankshaft flange?

To hold the flywheel.

What is the purpose of crankshaft counterweights?

To prevent virbations

Describe the purpose of an engine piston.

Transfer the pressure of combustion (expanding gas) to the connecting rod and crankshaft.

Explain the function of valve seals.

Used to prevent oil from entering the combustion chambers through the valve guides.

The ________ cover is a thin metal or plastic cover over the top of the cylinder head.

Valve

A(n) _______ usually rides on the cam lobes and transfers motion to the rest of the valve train.

Valve Lifter or Tappet

_________ are coolant passages through the block that allow a solution of water and antifreeze to cool the cylinders.

Water jackets