Valve Dimensions

Valve Dimensions

	1969-Model				From 1970-Model
	911 T & E 2.0 Liter Engines		911 S 2.0 Liter Engine		911 TC, EC, SC 2.2 Liter Engines
	Intake	Exhaust	Intake	Exhaust	Intake	Exhaust
a	42 +/- 0.1	38 +/- 0.1	45 +/- 0.1	39 +/- 0.1	46 +/- 0.1	40 +/- 0.1
b	8.97 - 0.012	8.95 - 0.012	8.97 - 0.012	8.95 - 0.012	8.97 - 0.012	895 - 0.012
c	114.0 +/- 0.1	113.5 +/- 0.1	113.3 +/- 0.1	112.2 +/- 0.1	114 +/- 0.1	113.5 +/- 0.1

Checking Valve Seats

To check valve seat depth, insert the respective valve in the guide and measure the distance between the valve stem end and the bottom of the shim cavity, without shims (siee dimension A in sketch).

If the dimension is greater than specified, measure again using a new valve, If the dimension still is beyond specification, it is an indication that the valve seat insert has been cut too deep and should be replaced or the cylinder head exchanged.

Dimension A, from 1960-models, and 2.2 liter engines from 1970-models, is 47.50 +/- 0.6 mm.