Service Procedure: Notes

Remove air cleaner, check oil in carburetor damper. Make sure piston moves freely in chamber. Engine should be at normal operating temperature and all lights and accessories off.

1. Connect tachometer and timing light. Using a suitable carburetor synchronizer, balance air intake on both carburetors while maintaining an engine speed of 750 RPM (manual transmission in Neutral) or 600 RPM (automatic transmission in Drive). Set ignition timing to 5° BTDC (TDC with automatic transmission).
   Fig 1: Engine Modification System

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   • IGNITION TIMING NOTE (240 Z AUTOMATIC ONLY) - On models equipped with dual point distributor, the ambient temperature must be above 40° (1971 models) and 52° (1972 models) to set timing. Dual point distributor is temperature controlled, an advanced reading will result if temperature is not to specification. 
2. Disconnect control valve vacuum tube from control valve connector, connect servo diaphragm vacuum tube to control valve connector. Apply manifold booster to servo diaphragm. Turn rear carburetor balance adjusting screw (located on connecting shaft) to obtain an engine speed of 1200 RPM. Using carburetor synchronizer and maintaining 1200 RPM, turn front carburetor balance adjusting screw until air intake of both carburetors is balanced.
3. Disconnect servo diaphragm vacuum tube from connector and then reconnect and make sure engine speed is 1200 RPM. If not, repeat above procedure. Reconnect control valve vacuum tube to original position. Adjust each idle adjusting nut until best idle is obtained, or until a CO reading of 6% (5% with automatic transmission) is obtained with air injection pump disconnected.
   Fig 2: Datsun 240Z Engine Modification Dual Point Distributor

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   Fig 3: Engine Modification And Carburetor Linkage

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Fig 4: Temperature Controlled Carburetion

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