retard timing mechanically?
I have a suggestion that perhaps you've already thought of. Since the vacuum advance on a distributor is sitting bolted down and very removeable, remove it and see if you can pull the pushrod out any further than it is while just sitting there. In other words, see if there is something blocking the rod from coming out when you pull on it. If it won't come out at all, see if you can modify it to come out a bit, like perhaps 1/8" -3/16". Try to make the diaphragm the stop point for when you set the timing with the vacuum hose off the distributor. Once the timing is set and you put the hose back on, the timing will advance. Once the motor starts making boost, the pressure in the hose will not only allow the timing to go back to a non-advanced position, but put it in a retarded manner. I was modifying a GM distributor for a Desoto hemi when I came up with this idea, but then decided to go with a Megasquirt system instead. One could also make a billet vacuum advance unit out of aluminum utilizing a spring on each side of the diaphragm for advance and boost. Pictured is a billet wastegate actuator I just sold on ebay. A vacuum advance unit could be built with a spring on each side of the diaphragm so that it would work in both boost and vacuum situatuions. Here's the motor we were gonna use the distributor on. Just a thought, BillI'm not sure. The motor is sitting on a stand right now... the turbo project won't start taking place for a few more months.
What are you guys running for timing? How much are you pulling? I'm aiming for the 12-14lb range...
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