3.4 l engine performance kit / X51: Differences: Valves

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Fig 1: Identifying Two Different Valves Versions

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Depending on the time of assembly, the engines of the X51 are equipped with two different valve versions.

further to Item 4

Fig 1: Identifying Valves With Valve Caps

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Version 1:

Inlet valve (standard) and exhaust valve (standard) are additionally equipped with valve caps.

further to Item 4

Fig 1: Identifying Inlet And Exhaust Valves Lengths

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Version 2: (Introduced in December '98)

Inlet and exhaust valves lengthened by 1.5 mm. Valve caps were omitted after introduction of the valves (version 2). The valve caps will remain in stock as replacement parts for the shorter standard valves of the 911 Carrera (996).

Identification of inlet valve:

Yellow dot on the valve disc

Identification of exhaust valve:

Black dot on valve disc

Item 5