Hello everyone! I have a 200ci engine in my 70 Mav, with a holley 1940 carb that was already installed when I got the car.. Im not sure about the distributor, it looks like a dual valve loadomatic. Ive read those distr need a vac line from both the man and carb for the timing to be right. My Qs are; 1. Do the vac lines go straight to distr from the carb and manifold? Mine has a 3way valve the lines run to and "T" between carb & distr, and distr & manifold.. 2. Does this carb & dizzy match? 3. Whats the 3way valve on the thermostat? This is my first classic car and Im learning as I go thanks to GREAT sites like this!.. Thanks Guys
The dual distributor diaphragm is a two-chambered housing which is mounted on the side of the distributor. The outer side of the housing is a distributor vacuum advance mechanism, connected to the carburetor by a vacuum hose. The purpose of the vacuum advance is to advance ignition timing according to the conditions under which the engine is operating. This device has been used on automobiles for many years now and its chief advantage is economical engine operation. The second side of the dual diaphragm is the side that has been added to help control engine exhaust emissions at idle and during deceleration. The inner side of the dual diaphragm is connected by a vacuum hose to the intake manifold. When the engine is idling or decelerating, intake manifold vacuum is high and carburetor vacuum is low. Under these conditions, intake manifold vacuum, applied to the inner side of the dual diaphragm, retards ignition timing to promote more complete combustion of the air fuel mixture in the engine combustion chambers. Ported vacuum switches have been used in most 1970-77 models to switch vacuum signals with varying engine coolant temperatures. They may have two, three, or four vacuum ports, and, on 1975-77 models equipped with a catalytic converter and Thermactor air pump system, a set of electrical contacts. On some late model configurations, there may be as many as three or four separate ported vacuum switches, each with their own special function. PVS switches may be used to switch vacuum signals on an ignition spark control system to improve cold start drivability or lower emissions, to cut off exhaust gas recirculation until a predetermined engine coolant temperature is reached, to vent Thermactor air pump air to the atmosphere under certain engine conditions, to regulate a vacuum operated heat control valve in the exhaust manifold, or (especially on air conditioned cars), to provide extra ignition advance and subsequent higher idle speed should the engine begin to overheat.
I read all that in one of my Maverick manual and really still dont fully understand it after reading it a dozen times( I mean the port valve)... I get vacuum advance and retard.. Just wasnt sure if my set up is hooked up right or not.. I take it, it is, right?
The advance vacuum (outside port) is connected to the carb. The retard vacuum (inside port) is hooked to the PVS.
I think I get it now!.. Seems to be hooked up right, I guess.. Its connected pretty much how the illustration of the pvs shows.. The TOP port of the pvs has a hose going straight to the side of the carb.. MIDDLE port of the pvs has a hose going straight to the outside valve of the distributor. And the BOTTOM port has a T fitting in the line where one hose is connected to the intake manifold, and the other to the inside valve of the distributor.. Hows that sound? I also just ran out and took this picture to give you a better idea..
