Chain Drive - Audi 4.2-litre V8 FSI Service Training

Engine mechanicals

Chain drive

Illustration shows the Q7 engine
Chain drive B
Chain drive D
The timing gear concept is identical in all Audi vee-
engine series.
The chain drive runs on two planes.
Plane 1
Basic drive A:
drives idler gears to camshafts from crankshaft
Plane 2
Top drive B and C: drives camshafts from idler gears
Chain drive D: drives ancillary units drive module
from crankshaft
Correct chain tension is ensured by spring hydraulic
tensioners. The chain drive is maintenance-free and
designed for lifetime service.
The two engine types differ in terms of the type of
chains used and the reduction ratios in drives A, B
and C. The load on the roller chains was reduced in
the basic engine version by selecting a higher
number of teeth.
14
Chain drive A
Q7
The camshafts in the basic engine are driven
by 3/8" simplex roller chains.
Due to their acoustic advantages, the chains were
developed to meet the high comfort requirements.
In this case the idler gears have 40 and 24 teeth.
The camshaft sprockets have 30 teeth.
High-revving engine
3/8" simplex sleeve-type chains are used here.
Their advantage is their reduced wear and higher
stress resistance at high engine speeds.
In this case the idler gears have 38 and 19 teeth.
The camshaft sprockets have 25 teeth.
Chain drive C
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