Help - Position of cam gear when #1 Cyl. Fires

I don't see where it really makes any difference. With the valve cover off watch the intake valve for #1 open and then rotate the motor to where the harmonic balance timing mark of zero is directly under the pointer. You now are at TDC for #1 assuming that the timing chain is installed correctly.

 

When the timing marks are lined up properly, (The cam gear mark pointing down and the crank gear mark, aligned with the key, pointed up) No. 1 cylinder is at TDC with both valves closed, which is the ignition cycle. With the timing marks in this position, no. 6 the piston in no. cylinder is also at TDC, but both the intake and exhaust valves are slightly open as this is the "overlap cycle" or the beginning of the exhaust stroke.

 

Not a problem. Simply remove the no. 1 cylinder spark plug, stick your thumb into the plug hole and rotate the engine. When the compression pressure blows your thumb out, No. one cylinder is at or near the compression stroke. This is the only way to assure that the engine is on the firing stroke so the distributor can be installed properly.

Distributor intstalled Properly: Engine starts, runs, sounds normally.

Distributor installed 180 degrees out (Improperly): Engine attemts to start but since the spark plugs are being fired when both intake and exhaust valves are open, it sounds like WW111. Mucho backfiring, big flames coming out the carburetor, Every duck in the nearby area is dead and, since it now sounds like a major fire fight, the swat team is called out.