Discussions related to electrical and fuel system, gasoline, etc.
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I have a 1950 Super 8 with the 327 engine and the Autolite distributer. I have some pinging under load and I have been trying to do some checks on the distributer. The distributer is held down by two bolts to the block. There is a screw on the lever from the vacuum advance that when loosened allows the distributer to turn. I have tried to get the vacuum advance to move using a vacuum pump. It will hold pressure, but I am not seeing any movement of the lever. With the vacuum line disconnected the timing does advance when I rev the engine, which is the centrifugal advance I suppose. I checked the points gap and opened them a little, which made the car hard to start and it ran poorly. I managed to break the rotor getting it off to get access to the points again and I am waiting on parts to be shipped to continue. Does anyone know how the vacuum advance works? Does it move a plate below the points plate? It has been many years since I worked at timing an engine. My experience has been with GM V eights and sixes.
The vacuum unit changes the position of the points relative to the cam on the distributor drive shaft. This can be accomplished in several ways including (1) using the vacuum unit to rotate the entire distributor body and (2) with the distributor body remaining in fixed position, using the vacuum unit to rotate the internal plate on which the points are located. Packard used both techniques at various times over the years.
I ended up pulling the distributer to get a better look at the unit. The vacuum advance definitely does not work. I also noticed that the shaft that fits down into the block with the slot in it is held into the hollow shaft of the distributer with a pin that is mushroomed over. This solid shaft is a loose fit and will flop around a fair amount. I cannot imagine this is normal. Is this shaft normally a tight fit?