How is Counter Rotation done in 1988 7.4 Inboards?

[hottoddie]

Yes. I installed DUI (Davis Unified Ignition) distributors. When ordering they will ask many questions about the boat in order to create the best advance curve for your boat. You can even choose what color distributor cap. I also install electric chokes and removed the fast idle cam from the carburetors. When starting the engines I never touch the throttles. Just turn the keys and 2-3 revolutions the engines fire. Almost like fuel injection.

 

[Ken Wolkens]

Thanks for the reply. You have been very helpful.

 

[Doug Nelson]

OK I know it gets confusing but in the reverse rotation (RH) the crankshaft rotates clockwise and the camshaft, distributor and oil pump rotate the same as a standard (LH) rotation engine. That is accomplished by the camshaft being driven by two gears (no timing chain) off of the nose of the crankshaft. That way the camshaft rotates in the same direction of a standard (LH) rotation engine. The camshaft is machined to open and close the valves in the opposite order of the standard rotation engine while allowing the distributor and oil pump to rotate in the same direction (clockwise when viewing from the top). The plug wires are the installed in the opposite order in the distributor cap to coincide with reverse firing order. I know it's confusing and I even know experienced mechanics that can't grasp the concept. The main reason I get it is because 2 years ago I pulled both engines and had then totaled redone with mild performance camshafts to yield 380hp. I did the complete R&R of all components and both engines fired instantly when I turned the keys. That reverse rotation motors was fun to figure out.

Thanks Hottoddie this is the best I've read for content. The only other questions I'm reading is about the oil holes in the crank and the piston needing to be turned 180 deg. Neither make sense to me?