QuestionHow do you find top dead center on a 1993 Chevrolet G20 van, 350 5.7 with the distributor and rotor already removed and no reference mark was made? The timing marks in the front are lined uped and the 1st and 6th pistons are up.
AnswerThis from ALL-DATA.com
Engine Disturbed
Remove the No. 1 cylinder spark plug. Turn the engine using a socket wrench on the large bolt on the front of the crankshaft pulley. Place a finger near the No. 1 spark plug hole and turn the crankshaft until the piston reaches Top Dead Center (TDC). As the engine approaches TDC, you will feel air being expelled by the No. 1 cylinder. If the position is not being met, turn the engine another full turn (360 degree). Once the engine's position is correct, install the spark plug.
Align the pre-drilled indent hole in the distributor driven gear with the white painted alignment line on the lower portion of the shaft housing.
Using a long screwdriver, align the oil pump drive shaft in the engine with the mating drive tab in the distributor.
Install the distributor in the engine.
When the distributor is fully seated, the rotor segment should be aligned with the pointer cast in the distributor base. The pointer will have a "6" or "8" cast into it indicating a 6 or 8-cylinder engine. If the rotor segment is not within a few degrees of the pointer, the distributor gear may be off a tooth or more. If this is the case, repeat the process until the rotor aligns with the pointer.
Install the cap and fasten the mounting screws.
Tighten the distributor mounting bolt to 20 ft. lbs. (27 Nm).
Engage the electrical connections and the spark plug wires.
