The EGR valve, and the EGR channels on the carb spacer and intake manifold on my 73 351C 2V were completely clogged. I've cleaned out the channels and have a new EGR valve on order (though from the picture at the parts store, I don't expect it to fit). As I'm doing this it has me questioning the purpose of why I'm doing it.
I notice many after-market intake manifolds have no EGR provision. Does this mean that it's simply unnecessary? If I understand this correctly, the purpose is to vent the gases from the top end of the engine through the carb (below the throttle plates) and burn them up. Are the gases somehow damaging to the engine if there is no vent, or if the system is clogged? Doesn't this stuff foul the spark plugs?
Finally, the EGR valve is vacuum actuated. Why is it actuated at all? Why isn't it just open all the time? It appears to me, if the engine is running, then there is a vacuum present and the valve is open (Unless there is something I don't see regulating this vacuum).
I notice many after-market intake manifolds have no EGR provision. Does this mean that it's simply unnecessary? If I understand this correctly, the purpose is to vent the gases from the top end of the engine through the carb (below the throttle plates) and burn them up. Are the gases somehow damaging to the engine if there is no vent, or if the system is clogged? Doesn't this stuff foul the spark plugs?
Finally, the EGR valve is vacuum actuated. Why is it actuated at all? Why isn't it just open all the time? It appears to me, if the engine is running, then there is a vacuum present and the valve is open (Unless there is something I don't see regulating this vacuum).