[98GTW]

While we're on the topic, if I'm looking at it properly, the vacuum device on the distributor (at least on my 77 2.7) is most correctly called a vacuum retard, rather than a vacuum advance, no?
High vacuum, as at idle, with throttle closed, pulls on the diaphragm, retarding timing. Opening throttle reduces vacuum, allowing springs on advance/retard plate to pull points CCW, advancing timing.
I've been looking again at my timing (or a vacuum-related timing problem) as part of the cold-start issue I'm having. A PO had disabled the vacuum advance/retard for some reason. I've put it back as I think it should be. I set the timing to TDC (warm engine, vacuum hose on), but as an experiment I retarded the timing a few degrees by eye last night and starting cold was significantly easier.
I'm probably going to need to get a vacuum tester to track this down. Are there published specs for vacuum components? Any idea where I can locate a complete vacuum map?

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Dave
'77 911S
inari77s@911fanatic.com
Rochester, NY