Valve clearance adjusting

The valve clearance is checked and adjusted with the engine cold (ambient temperature of approximately 20° C (68° F).


911 Valve Adjustment

The valve adjusting sequence is 1-6-2-4-3-5 — Drain oil from engine crankcase.


Do not remove the spark plugs to make the engine turn easier. Carbon deposits that have built up on the plug can fall between the valve and seat with the plug is removed. This can result in inaccurate valve adjustment.

— Raise rear of car and support safely on jack stands.

1984 Porsche 911 Spark Plug Wrench

Remove heater elbow and hose on left side of engine. — Remove air filter cover and filter element.

^ Remove A/C compressor from mount (arrows) and set aside without disconnecting A/C lines. Disconnect wire harness (A) before setting aside.

— Unplug all spark plug connectors and set aside.

— Remove distributor cap from distributor (do not remove spark plug wires from cap).

— Remove upper and lower valve covers.



Using a 23 mm socket on fan pulley nut, rotate fan in a clockwise direction until distributor rotor is pointing to cylinder no. 1 mark (arrow) on distributor body.

• Z1 mark on crankshaft pulley must also align with mark on lower fan housing. If all marks align, engine is at top dead center (TDC).

^ Check clearance of cylinder no. 1 intake valve by sliding a feeler gauge between rocker arm adjusting screw and the valve stem (arrow).

• If feeler gauge slides in easily, valve clearance is too big. If gauge will not slide in at all, clearance is too small.

• Repeat procedure for exhaust valve.

^ If necessary, loosen valve adjuster lock nut and turn adjuster with screwdriver until a light resistance is felt at feeler gauge.

— While holding adjuster in position, tighten adjuster locking nut.

— Recheck adjustment after tightening lock nut.


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^ Rotate crankshaft pulley 120° (clockwise direction). Adjust valves for cylinder no. 6 using above procedure.

The crankshaft is marked in 120 degree intervals starting with Z1. With the crankshaft at TDC, the Z1 mark will be at 12 o-clock, the next mark will be at 4 o'clock and the last mark will be at 8 o'clock.

— Turn crankshaft clockwise 120° and adjust valves for cylinder no. 2.

— Turn crankshaft clockwise 120° and adjust valves for cylinder no. 4.

— Turn crankshaft clockwise 120° and adjust valves for cylinder no. 3.

— Turn crankshaft clockwise 120° and adjust valves for cylinder no. 5.

— Clean valve cover surfaces on camshaft housing to remove any gasket material that may be stuck to the surface.

— Clean all gasket material and oil from valve covers.

— Install valve covers with new gaskets, washers and locknuts.

Tightening torques

— Replace engine oil filter and add new engine oil.

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  • ferdinanda
    How to adjust valves on 911?
    9 years ago
  • samuel
    Can i adjust 911 valves with oil in crankcase?
    7 years ago

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