S4 V8-4.2L (BHF) (2004)
Checking piston
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Measure approximately 10 mm from lower edge, at 90° angle to piston pin axis using an external micrometer of 75 to 100 mm.
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Maximum deviation from nominal dimension: 0.04 mm
Nominal dimension
Measuring cylinder bore
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Using an internal dial gauge of 50 to 100 mm, measure at 3 points in diagonal sequence horizontally - A - and vertically - B -.
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Maximum deviation from nominal dimension: 0.08 mm.
Nominal dimension
Piston installation position
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Mark allocation to cylinder on piston head using chalk or waterproof felt pen.
Note: Do not use a center punch or scribe, since the piston head coating will be damaged.
Installation position:
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Arrows on piston heads point to belt pulley side.
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Valve recesses - 1 - point toward center of engine.