Theory of Engine Operation - Delmar Learning

Engine Identification
Proper engine identification is required for the technician and/or machinist to obtain correct specifications,
service procedures, and parts. The vehicle identification number (VIN) is one source for
information concerning the engine. The VIN is located on a metal tag that is visible through the
vehicle’s windshield (Figure 2-33). The VIN provides the technician with a variety of information
concerning the vehicle (Figure 2-34). The eighth digit represents the engine code. The service
information provides details for interpretation of the engine code. The VIN is also stamped in a
number of other locations around the vehicle to make falsification more difficult.
AUTHOR’S NOTE: One day I was working on an older import vehicle and a police
officer walked up to the car and explained that he had reason to believe this was a
stolen vehicle. In order to check it out, he lifted the rear carpet in the trunk and compared
the VIN with the VIN located on the dashboard. Neither appeared to have been tampered
with, and the number did not match the VIN of the stolen vehicle. He left me to my work
and went on his way to search for the real stolen vehicle.
A vehicle code plate is also located on the vehicle body, usually inside the driver’s side door
or under the hood. This plate provides information concerning paint codes, transmission codes,
and so forth (Figure 2-35). The engine sales code is also stamped on the vehicle code plate.
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A B
C D
Figure 2-32 The stratified engine design uses a rich mixture in the precombustion chamber to
ignite the lean mixture in the main chamber.