Porsche 1972 911 Workshop Manual page 132

911
C r a n k c a s e a n d C r a n k s h a f t
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P I S T O N S FOR K J E T R O N I C E N G I N E S
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Pistons for K Jetronic-equipped engines of Type
cavity in the piston top. This provision ensures
a particularly thorough blending of the fuel/air
mixture.
I n s t a l l a t i o n n o t e :
T h e piston must always be installed so that the
flat spot in the piston top faces upward (towards
t h e intake valve).