Engines, Blocks, Cranks & Cams

Plasti-gage is used to measure:

crankshaft to bearing clearance

piston to liner clearance

camshaft to bearing clearance

all of the above

Correct! Wrong!

Upon inspecting liner counterbores a technician finds that the bore seat is rough and pitted. The correct procedure is to:

install salvage sleeves

replace the block

use lower press fit liners

recut the counterbore seat

Show hint

Correct! Wrong!

A liner with excessive pitting on the outside liner surface, opposite the major thrust area would be an indication of:

casting sand deposits

cavitation

corrosion

water pump pulsation

Show hint

Correct! Wrong!

Technician A says that liner protrusion is measured with the liner clamped down in the block. Technician B says that liner protrusion may be calculated by subtracting the depth of the counterbore from the liner flange thickness. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Show hint

Correct! Wrong!

Which instrument(s) should be used to measure the liner counter bore depth?

outside micrometer

telescoping gauge and outside micrometer

small hole gauge and outside micrometer

depth micrometer

Show hint

Correct! Wrong!

Which instrument(s) should be used to measure the camshaft bores?

outside micrometer

telescoping gauge and outside micrometer

small hole gauge and outside micrometer

depth micrometer

Correct! Wrong!

A semi-floating wrist pin is one that:

float in the piston and is pressed into the rod end

floats in the rod end is pressed into the piston

floats in both the piston and the rod end

is pinned to the piston and floats on the rod end

Show hint

Correct! Wrong!

Technician A says that crosshatch pattern is controlled by the speed of the stroke and the RPM of the hone. Technician B says that deglazing of a cylinder will remove its taper. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Show hint

Correct! Wrong!

When checking bearing clearances, plastigage becomes _________ as the clearance decreases.

narrower

wider

longer

shorter

Correct! Wrong!

Installation of a non-drilled lower main bearing shell in an upper main bearing bore will cause:

improper nesting of the tang

no oil to enter the main bearing

inaccurate plastigage measurements

the bearing set to "spin"

Correct! Wrong!

A technician finds a badly worn main bearing in the center position, all other bearings appear to be in progressively better shape toward each end. The most likely cause of this would be:

insufficient oil pressure

bent crankshaft

overheating

all of the above

Correct! Wrong!

Witness marks on piston rings indicate:

which side of the ring faces up

where to place the ring gap

the wear on the rings

all of the above

Correct! Wrong!

A preliminary inspection of engine parts should be done at the time of engine:

disassembly

assembly

when cleaning the parts

when you have all the parts organized on the bench

Correct! Wrong!

After properly torquing the connecting rod bolts, what step can be taken to ensure the rod bearing has been installed correctly and the tangs are properly nested.

rotate the crankshaft over to be sure it will turn easily

rock the rod from side to side on the journal by hand

remove the rod cap and recheck the bearing

twist the rod on the cranckshaft to feel the clearance movement

Correct! Wrong!

After removing an engine''s main bearing, a technician finds that the back of the bearing insert is shiny and has etch marks on it and the inside of the main bearing bore is also shiny and has etch marks. The probable cause for this would be:

contaminated engine oil

insufficient bearing spread

insufficient bearing crush

any of the above

Correct! Wrong!

Upon inspection of a bonded type vibration damper a technician finds that the index marks do not line up. The proper procedure is to:

rotate the members so that the index marks line up

grind of old timing marks and install new ones

replace the vibration damper

this is an acceptable condition

Correct! Wrong!

Piston ring groove wear accelerates when the cylinder walls are:

oval

tapered

honed

deglazed

Correct! Wrong!

A technician finds signs of seizure on one piston when performing an engine overhaul. What would the most likely cause be?

faulty water pump

low oil pressure

low coolant level

faulty piston cooling nozzle

Correct! Wrong!

Parent engines are those that have:

dry sleeve

wet sleeves

no sleeves, the cylinder is machined into the block

original sized pistons

Correct! Wrong!

What is being calculated by the following formula: displacement volume + clearnace volume/clearance volume

engine dislacement

mean effective pressure

compression ratio

clearance volume

Correct! Wrong!

When the total of the cylinder volume at BDC is measured, we are referring to

compression

clearance volume

compression ratio

displacement

Correct! Wrong!

The last check(s) after installing liners into the block is to check for:

counterbore cracks

deck trueness

correct liner protrussion

liner distortion

Correct! Wrong!

New cam bushings should be installed with the use of the correct cam bushing driver and with the use of:

a driver guide

go bar

four pound hamme

all of the above

Correct! Wrong!

After installing new cam bushings you should check for:

oil passage alignment

coolant passage alignment

fuel passage alignment

all of the above

Show hint

Correct! Wrong!

The term "line boring" refers to:

boring of the cylinders in a straight line

machining the surface of the block to perfect flatness

trimming the size of the main bearing caps and re-cutting the bores in a straight line

boring of cylinder on a production line

Show hint

Correct! Wrong!

Liner "O" rings should be coated with ___________________ prior to installation

clean engine oil

liquid dish soap

vasoline

any of the above

Correct! Wrong!

Cylinder taper refers to:

angle of the cylinder to the crankshaft

angle betweencylinders on a V block

cylinder wear greater at the top

cylinder wear greater at the bottom

Correct! Wrong!

When a new bearing shell is placed into a rod bearing cap, but being wider than the bore, it must be pressed down into place. This is called bearing ______________.

crush

embedability

conformability

spread

Show hint

Correct! Wrong!

The template or torque and turm method of tightening bolts refers to torquing the bolts:

in the proper sequence

to a specified torque and advancing them an additional number of degrees

in three steps or stages

to maximum torque, loosening and retorquing the bolts

Correct! Wrong!

Prior to removing connecting rods and pistons you should:

check to see if the rods and caps are numbered

record the direction in which the rod numbers face

remove the ring ridge or carbon from the cylinder

all of the above

Correct! Wrong!

Crankshafts and camshafts should be stored:

flat on a clean bench and covered

safety supported on end in a clean location

in a container filled with oil

any of the above methods is acceptable

Correct! Wrong!

When measuring a cylinder bore, you find that it is larger at the top end of the ring travel area than at the lower end of the ring travel area. This difference is known as:

taper

ovality

barrel shaped

concave

Correct! Wrong!

When a machine shop is grinding a crankshaft, sharply radiused fillets should be avoided between the cheek and journal to prevent:

premature bearing failure

premature bearing wear

crankshaft breakage

premature journal wear

Correct! Wrong!

Referring to engines and their babbit bearings, premature bearing failures are more often traced back to:

misalignment

corrosion

insufficient lubrication

contamination during assembly

Correct! Wrong!

Due to rough counterbore seats, a technician finds it necessary to recut the counterbores. To compensate for the material removed from the seat, the technician must use:

liners of a different flange thickness

liner shims

different head gaskets

oversize water grommets

Show hint

Correct! Wrong!

Too little liner protrusion will often cause:

excessive compression

head gasket failure or coolant leakage

distortion of the heads machined surface

incorrect torquing of the head bolts

Correct! Wrong!

When installing cam bushings care must be taken to make sure that you:

have thoroughly cleaned the bushing bores

have the correct bushing for each particular bore

align the oil passages in the bushing to the bore

all of the above

Correct! Wrong!

When removing connecting rods and pistons, damage to the __________________may occur if the cap bolt threads are not covered.

connecting rod

camshaft lobes

cylinder liner

crankshaft journals

Correct! Wrong!

When measuring a cylinder for wear you should check for

taper

out of round

scoring

all of the above

Correct! Wrong!

When honing cylinder sleeves you should:

wrap them with a rag and place in a vise

have another person hold them while you hone them

insert them into the block to hone them

cylinder sleeves should not be honed, only replaced

Show hint

Correct! Wrong!

When measuring bearing clearance with plastigage:

crankshaft should be rotated

crankshaft should not be rotated

journal taper will not be evident

cap bolts do not need to be installed

Correct! Wrong!

An undersized connecting rod bearing is one that has a:

larger outside diameter and a standard inside diameter

larger inside diameter and a standard outside diameter

smaller outside diameter and a standard inside diameter

smaller inside diameter and a standard outside diameter

Correct! Wrong!

A technician removes a cylinder ridge to:

facilitate new ring installation

prevent the piston from striking the ridge

ensure proper piston to cylinder clearance

prevent ring groove damage on the piston

Correct! Wrong!

The purpose of the chamfer at the top edge of the lower bore on an engine block using wet cylinder sleeves is to:

prevent cracks in bore of block

aid in machining of block

guide liner o rings into bore

guide piston into liner

Correct! Wrong!

A rolled or twisted o ring on a liner may result in ______________________when installed.

the liner being deformed slightly out of round

extreme likelyhood of o-ring damage

coolant leakage into crankcase

all of the above

Correct! Wrong!

A piston assembly consisting of a separate crown, skirt, slipper bushing, pin, and pin seal expansion plugs would be known as a _______________ piston.

cam ground

crosshead

billet

keystone

Correct! Wrong!

Dye penetrants and sprays developer are used to:

seal liner "o" rings

locate oil leaks

locate coolant leaks

locate hairline cracks

Correct! Wrong!

If a dry sleeve goes in too tight the result will be:

excessive piston to liner clearance

distortion of the sleeve

increased ring end gap

poor heat transfer between the sleeve and block

Correct! Wrong!

Gallery plugs and frost plugs should be instaled:

dry

with the use of a sealant

by the gentle use of a hammer

by using the old plug as a driver

Correct! Wrong!

After honing a cylinder, the crosshatch pattern should be approximately ______________degrees (included angle)

25-40

30-40

45-90

40-60

Correct! Wrong!

After carefully cleaning a counterbore in a cylinder block you should measure it in______________location(s)

one

two

three

four

Correct! Wrong!

An improperly installed cam bushing may result in:

a blockage in the lubricating system

early camshaft failure

engine block damage

all of the above

Correct! Wrong!

Reducing the size of the main bearing caps and recutting the caps and block in a straight line is known as:

counterboring

crankshaft rezoning

line boring

really boring

Correct! Wrong!

Upon inspection a technician finds that the deck on the top of the block is warped by .004" (maximum spec. is .008") The block should be:

discarded

reassembled as is

draw filed" to level a bit better

sent to a machine shop for resurfacing

Correct! Wrong!

A minimum measurement of a crankshaft journal is specified to be 3.4960. This specification is to be read to the_____________ of an inch.

tenth

hundredth

thousandth

ten thousandth

Correct! Wrong!

A cylinder liner with a permissible amount of taper has had the ridge removed and has been deglazed. At which location in the bore do most manufacturers recommend that the new ring''s end gap be checked?

near the top

near the center

near the bottom

all locations are satisfactory

Correct! Wrong!

When measuring cam ground pistons for normal eccentricity, which location would have the smaller measurement?

across the crown at 90 degrees to the pin bosses

across the crown in line with the pin bosses

across the skirt at 90 degrees to the pin bosses

across the skirt in line with the pin bosses

Correct! Wrong!

Excessive ring groove wear on a piston may cause:

excessive oil consumption

ring breakage

hard starting

all of the above

Correct! Wrong!

Excessive pin and guide hole wear on crossheads (valve bridges) would be an indication that the:

the crosshead has not been matched to the pin

material in the crosshead is inferior

crosshead has been incorrectly adjusted

engine has been overheated

Correct! Wrong!

In the figure below, what is being performed?

Removing a scratch in the bearing with crocus cloth

Using a special tool to remove the bearing insert

Measuring the thickness of the crushed Plastigage

Determining if the crankshaft journal has been machined

Correct! Wrong!

While observing the tool shown below, Technician A says that it is used to straighten the connecting rod bend. Technician B says that it is used to measure connecting rod twists and bends. Who is right?'

A only

B only

Both A and B

Neither A nor B

Correct! Wrong!

Removing press-fit piston pins is being discussed. Technician A says the pin can be driven out with a hammer while securing the securing piston in a vise. Technician B says removing the pin requires a press and special adapters. Who is right?

A only

B only

Both A and B

Neither A and B

Correct! Wrong!

The volume into which air is compressed in a cylinder in an engine is know as:

compression ratio

clearance volume

expansion ratio

engine displacement

Correct! Wrong!

The term used to describe the heat generated through the cast iron block of an engine is known as:

convection

radiation

conduction

Correct! Wrong!

What engine performance measurement is found by using the following formula: TORQUE x RPM = 5252

torque

horsepower

mean effective pressure

volumetric efficiency

Correct! Wrong!

The difference in torque at governed RPM full load, and torque expressed as a percentage of torque at governed RPM, full load, is know as:

horsepower

torque rise

frictional horsepower

high idle

Correct! Wrong!

The lbs. of fuel per brake horsepower per hour that an engine uses is known as:

thermal efficiency

volumetric efficiency

horsepower

brake specific fuel consumption

Correct! Wrong!

The most common type of combustion chamber used in diesel engines today is the:

pre-combustion chamber

direct injection chamber

turbulence chamber

air cell chamber

Correct! Wrong!

During construction, crankshaft rod bearing journals are:

surface hardened

drilled for lubrication

indexed at 120 degrees for 6 cylinder in line engines

all of the above

Correct! Wrong!

Exhaust valve temperatures may reach

1300 to 15000 degrees F (7040 to 8150 C)

130 to 150 degrees F (70 to 81 degrees C)

900 to 1300 degrees f (500 to 720 degrees C)

none of the above

Correct! Wrong!

As an engine crankshaft rotates, the lubricating oil between the bearing and the cranksahaft is drawn into the high stress or pressure area. The term used to describe this process is sometimes known as:

oil vacuum

oil wedge

film strength

viscosity

Correct! Wrong!

An engine bearing must be designed so that it is soft enough to absorb minute particles of foreign materials. This feature is known as

crush

embedability

comformability

saturation

Correct! Wrong!

An engine crankshaft bearing is designed to be slightly larger in circumference than its bore so that when it is assembled it will fit tightly in its bore to improve heat transfer and prevent movement. This feature is known as

crush

embedability

conformability

press it

Correct! Wrong!

Valve overlap occurs between which of the following strokes?

intake

power and exhaust

exhaust and intake

compression and power

Correct! Wrong!

At 2000 RPM each valve in a four stroke engine opens and closes how many times in five minutes?

1000

4000

5000

10,000

Correct! Wrong!

Whenever a piston fires, especially when under full power there is a twisting of the crankshaft. To smooth out these power impulses and prevent crankshaft breakage from this twisting a ____________________ is used.

flange

counterweight

vibration damper

yoke

Correct! Wrong!

In the adjacent illustration, the rocker/pushrod design would mean that the valve would travel:

more distance than the push tube

less distance than the push tube

the same distance as the push tube

Correct! Wrong!

Technician A says that the parting line chamfer on an engine bearing is to provide space for any swelling in the area because of the bearing crush. Technician B says that most engine bearings are made with a steel backing, copper overlay and a babbitt coating. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

In the adjacent illustrations, the arrow points to a ______________________type piston

M.A.N

concave

convex

flat top

Correct! Wrong!

The compression pressure usually found in a diesel engine is:

125-145 psi

450-600 psi

1000-1200 psi

2000-2200 psi

Correct! Wrong!

The figure below shows a sequence of numbers. these numbers are used for what purpose?

To tell the technician which bolts to put in first

To tell the technician which bolts to tighten first

The serial number of the head

the part number of the head

Correct! Wrong!

The bore of an engine refers to its:

cylinder radius

cylinder diameter

piston movement

cylinder volume

Correct! Wrong!

What causes combustion air to enter a four stroke cycle, naturally aspirated diesel engine?

atmospheric pressure

turbocharger

blower

supercharger

Correct! Wrong!

Oil flow in the crankshaft flows from the:

main bearings to the rod bearings to the block

rod bearings to the main bearings to the block

block to the main bearings to the rod bearings

block to the rod bearings to the main bearings

Correct! Wrong!

A crankshaft''s throw:

determines the length of the stroke

is located next to the rear oil seal

is located next to the front oil seal

fits into the main bearing bore of the block

Correct! Wrong!

he ratio of the amount of charge actually taken in per engine cycle to a complete charge is known as:

compression ratio

mean effective pressure

volumetric efficiency

brake horsepower

Correct! Wrong!

When assembling an engine, liner protrussion is very important, too little protrussion may cause:

excessive oil leakage at the head gasket

excessive coolant leakage at the head gasket

damaging loss of clearance volume

fuel leakage at the head gasket

Correct! Wrong!

Upon inspection of a disassembled engine a technician finds one badly scored liner and piston. All the other liners and pistons appear to be in good shape. The first place to check would be:

faulty turbocharger

faulty oilcooler

faulty oil filter

faulty piston cooler nozzle

Correct! Wrong!

Upon inspection a technician finds one out of the seven main bearing shell sets badly scratched. The most likely cause of this is:

coolant in oil

particles left in the oil galleries from last overhaul

too long of an interval between oil changes

low oil pressure

Correct! Wrong!

Technician A says that a nick on any of the crankshaft journals that can be caught with a fingernail has to be serviced. Technician B says that crankshafts can be checked for cracks magnetically by using magnetic particle inspection. Who is right?

A only

B only

Both A and b

Neither A nor B

Correct! Wrong!

A bent connecting rod may cause collateral damage to all of these EXCEPT;

uneven connecting rod bearing wear

uneven main bearing wear

uneven piston pin wear

uneven cylinder wall wear

Correct! Wrong!

The tools in the picture below would be used for what purpose?

To widen the piston ring grooves

To deepen the piston ring grooves

To remove and replace the piston rings

To remove carbon from the piston ring grooves

Correct! Wrong!

When measuring the piston ring gap:

measure with the ring positioned at the top of the ring travel in the liner.

if the liner has been properly honed, you can measure anywhere

should be measured below the ring travel area

if you are using new liners and piston sets, the ring gap has been done by the manufacturer

Correct! Wrong!

Technician A says that vibration damper counterbalances the back-and-forth twisting motion of the crankshaft each time a cylinder fires. Technician B says if the seal contact area on the vibraion damper hub is scored, the damper assembly must be replaced. Who is right?

A only

B only

Both A and B

Neither A nor B

Correct! Wrong!

To improve combustion in the cylinders, all diesel engines use:

air turbulence

turbulence chambers

pre-combustion chambers

fuel turbulence

Correct! Wrong!

The purpose of removing air box covers on a Detroit Diesel engine is to:

adjustment of the bearing clearance

adjustment of the fit of the bearing to the crankshaft

protrusion of the bearing shell above the parting face of the cap or the rod

the damage caused by overtorquing the bearing cap bolts

Correct! Wrong!

weight of the engin

firing order

combustion process and engine speed control

number of strokes per cycle

Correct! Wrong!

The purpose of removing air box covers on a Detroit Diesel engine is to:

inspect for blowby

inspect for wrist pin end play

inspect the condition of the piston rings

inspect the engine for excessive oil consumption

Correct! Wrong!

In a diesel fueled engine, when the fuel is burned, approximately how much of the heat energy generated by the fuel will be used to produce usable power?'

one third

one fourth

one eight

one half

Correct! Wrong!

Technician A says that it is more cost effective to rebuild an oil pump than to buy a new one. Technician A says that it is a good practice to replace an oil pump when rebuilding an engine. Who is right?

A only

B only

Both A and b

Neither A nor B

Correct! Wrong!