Automotive Engines 2
Connecting rods often have holes drilled into the big end to ____________.
"squirt" oil onto the cylinder wall
A dial caliper is accurate to _____ inch.
.002
The maximum amount of cylinder taper normally allowed is:
0.006 in. (.15 mm)
Each number on the sleeve of a metric micrometer represents _____ mm.
5
Technician A says a piston pin is sometimes called a wrist pin. Technician B says the piston pin is always centered in the piston. Who is correct?
A only
Technician A says the maximum amount of cylinder out-of-roundness allowed in most cases is 0.0015 in. (.038 mm). Technician B says that a cylinder can have a taper of up to 0.010 in. (.254 mm) and be acceptable. Who is correct?
A only
Powdered metal connecting rods ______________. -have no visible parting line -are more cost effective to manufacture -are lighter than forged or cast rods -All of the above
All of the above
Each half of a split bearing is made so that it is slightly greater than an exact half. What is this extension called?
Crush
T or F An oversize main or rod bearing insert is thicker in the inside (journal-side) than the original bearing.
False
T or F When installing a segmented oil control ring, the end gaps of the three pieces must line up.
False
T or F Fractured connecting rod caps can be installed in either orientation to its respective big end.
False
T or F The bottom ring on a piston is a compression ring.
False
Which type of connecting rod needs to be heated to install the piston pin?
Interference fit
A hypereutectic piston has a higher ________.
Silicon content
Two technicians are discussing the drilled passages in a crankshaft. Technician A says they provide a path for lubricating oil to pass from the main journals to the rod journals. Technician B says the holes are drilled to lighten the crankshaft. Which technician is correct?
Technician A
What is true about checking bearing clearance using Plastigage?
The journal should be clean and oil free The cap should be torqued to factory specifications The wider the strip means the narrower the oil clearance All of the above *** Correct Answer
T or F Aluminum blocks normally have sleeves or steel liners placed in them to serve as cylinder walls.
True
T or F Most cylinder wear occurs at the top of ring travel.
True
T or F Old core and oil galley plugs are normally removed and replaced as part of cylinder block reconditioning.
True
T or F Certain engines feature only two rings (one compression and one oil control).
True
Pistons for modern engines are made of _____
aluminum
A measurement must be made within one ten-thousandth of an inch. Technician A uses a machinist's rule. Technician B uses a micrometer. Who is correct?
b only
A cylinder bore can be checked for out-of-roundness with a _____.
both "dial bore gauge" and "telescoping gauge and micrometer"
A full floating piston pin _____.
both "rotates in the piston" and "rotates in the connecting rod"
Technician A says a vernier caliper can be used to measure the outside diameter of something. Technician B says a vernier caliper can be used to measure the inside diameter of a bore. Who is correct?
both A and B
Technician A says engine blocks are made from cast iron. Technician B says engine blocks are made from aluminum. Who is correct?
both A and B
Technician A says piston ring grooves should be cleaned with a piston ring groove cleaner. Technician B says piston ring grooves can be cleaned with a broken piston ring. Who is correct?
both A and B
Technician A uses a micrometer to measure the connecting rod journal for taper. Technician B uses a micrometer to measure the connecting rod journal for out-of-roundness. Who is correct?
both A and B
Two technicians are discussing undersized bearings. Technician A says a 0.001 in. or 0.002 in. bearing can be used on a stock crankshaft journal if the oil clearance [difference between the bearing diameter and the journal diameter] is slightly excessive and the journal is not excessively tapered or out of round. Technician B says 0.010 in., 0.020 in., and 0.030 in. undersized bearings are only used when the crankshaft journals have been reground (turned). Who is correct?
both A and B
Babbitt, a mixture of lead and tin, is used in _____
connecting rod and main bearings
Which of the following is NOT a core plug design?
contraction-type
The reciprocating movement of the piston is converted into rotary motion by the _____.
crankshaft
One main bearing will feature a flanged "skirt" on each bearing half; this is to limit ________.
crankshaft thrust
Main bearing journals are __________ the centerline of the crankshaft.
in line with
Plastigage is best used to check the clearance between _____.
main bearing journal and main bearing
Proper bearing-to-journal clearance is essential for _______________.
maintaining adequate engine oil pressure
The ___________ of the rod accommodates the piston pin (wrist pin).
small end
