Main
Bearings
The main bearing secure the
crankshaft in its place. The largest number of main bearings a
crankshaft can have is one more than the number of cylinders, but it can
have one less bearing than the number of cylinders. Not only do the
bearings support the crankshaft, but one bearing must control the
forward-backward movement of the crankshaft. This bearing rubs against a
ground surface of the main journal, and is called the "thrust
bearing."
Manifold
to Exhaust Pipe Gaskets
There are several types of gaskets that
connect the exhaust pipe to the manifold. One is a flat surface gasket.
Another type uses a ball and socket with springs to maintain pressure.
This type allows some flexibility without breakage of the seal or the
manifold. A third type is the full ball connector type, which also
allows a little flexibility.
Muffler
The muffler serves to muffle the noise
coming out of the engine. Exhaust gases leave the engine under extremely
high pressure. If these gases escaped directly from the engine the noise
would be tremendous. Therefore, the exhaust manifold sends the gases to
a muffler where they go through metal plates, or tubes, with a series of
holes. The pressure of the gases is reduced when they pass through the
muffler, so they go out of the tail pipe quietly. Made of metal, the
muffler is located underneath the body of the car. It is connected
between the tail pipe and the catalytic converter. There are two types
of muffler designs. While one type uses several baffled chambers to
reduce noise, the other sends the gases straight through perforated pipe
wrapped in metal or fiberglass. This type of muffler is designed for the
purpose of reducing backpressure and, consequently, makes slightly more
noise.
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