2. 2
Engine Block Assembly
Very sophisticated
casting.
Made of cast iron or
aluminum with cast
iron cylinder liners.
A great deal of
machining involved in
the process of
manufacturing.
Becomes the frame of
the engine.
7. 7
Crankshaft Terminology
Crankpins or throws
Main bearing journals
Rod bearing journals
Thrust bearing
Main caps
Oil passages
Flywheel flange
Vibration damper
end
Keyway
Rear main seal
Front crankshaft seal
Counter weights
Firing order
8. 8
Crankshaft Bearings
Known as friction or
precision insert
bearings.
Uses a steel backing
with soft metal on
crankshaft side.
(lead,tin, copper,
silver, cadmium)
Oil clearance between
crankpin and bearing
very critical. (.001”)
Oil Clearance
measured with
plastigauge.
10. 10
Flywheel
The flywheel (known as
the flex plate when used
with an automatic
transmission) carries the
engines inertia in between
power strokes.
It is the power take off for
the engine. The clutch or
torque converter bolts to
it.
Lastly it has the starter
motor’s ring gear.
11. 11
Vibration Damper
The vibration damper
smoothes the
vibrations caused by
the power strokes.
It has a pulley on it
the run auxiliary
systems.
It may contain timing
marks or crankshaft
timing sensors.
12. 12
Balancer Shafts
Used to counteract
the normal
vibrations inherent
to piston engines.
Found on 4
cylinder and 6
cylinder engines
mostly.
13. 13
Covers & Pans
Made of steel
metal, aluminum,
or plastic
materials.
Usually use
gaskets or seals.
14. 14
Gaskets, Seals and Sealers
Gaskets seal two
stationary surfaces.
Seals do it when one
surface moves.
Many types of
materials: rubber,
paper, aluminum,
steel, cork and more.
Sealers adhere
gaskets to one of the
surfaces.
18. 18
Piston Rings
Rings seal the
compression in the
combustion chamber
and the motor oil in
the crankcase.
Automotive engines
use 3 rings: 2
compression and 1
multi-piece oil ring.
19. 19
Piston Ring Wear
Causes a loss of
compression.
Causes excessive
oil consumption.
May cause blue
smoke out the tail
pipe.
20. 20
Types of Piston Rings
Rings are usually
made of cast iron
can be plated with
chrome or
molybdenum.
Help seal the ring to
the cylinder wall.
Shapes of the ring
vary to also help the
ring seal better.
21. 21
Piston Pin (Wrist Pin)
Hollow polished steel
pin.
Attached in a variety
of ways.
Pinned to piston.
Clamped to rod small
end.
Snap ring free
floating.
Press fit.
22. 22
Connecting Rods
I-beam style rod use
to transfer the pistons
force to the
crankshaft.
Small end contains
the piston pin and the
big end has a
removable cap to
install it to the Crank.
Nuts and bolts are
usually of a very high
quality.
23. 23
Installation of Pistons
Cylinder number
Piston number
Notch to the front
Position ring gaps
Remove rod cap check bearing inserts
Cover bolts with fuel line if needed
Crankshaft at TDC or BDC
Install ring compressor
Oil piston, cylinder wall, & crank journal
Carefully tap in piston with hammer handle.
Properly replace rod cap
25. 25
Weird Science of Engines
Free running and Non-free running
Crankshaft rotation versus piston
travel
Piston side thrust
Piston pin offset
Cylinder bore wear
Crankshaft journal wear
26. 26
Free and Non-Free running
Engines
Free running
engines can have
their piston at TDC
and their valves
wide open and the
valve won’t touch
the piston.
Non-free running
engines will crash
the valves into the
piston if the piston
is at TDC and the
valves are wide
open. This will
wreck the engine.
27. 27
Piston Travel Verses
Crankshaft Rotation
When the piston
move ½ way down
the bore the
crankshaft does
not turn a ½ a
turn. This will
always create
vibration.
28. 28
Piston Side Thrust
There are two sides to
the piston.
The thrust side and
the relief side.
Wear occurs mainly
on the thrust sides.
Skirt area is not even
needed on the relief
side.
Piston pin offset
counteracts side
thrust.
29. 29
Cylinder Bore Wear
Wears oval
shaped.
Cylinder wall
tapers.
Pocket forms near
the top.
A ridge forms at
the top.
33. 33
Cylinder Boring
Cylinders can be
bored to restore
them however
they will be larger
requiring bigger
pistons.
Usually bored to .
010”, .020”, .030”,
or .050”
34. 34
Crankshaft Wear
Wears out of round
due to the power
strokes.
Grinding can
restore the
journals, however
they are smaller
requiring under
sized bearings.