[TR] Zenith-Stromberg-new question

[jimmuller at rcn.com]

Time asked:
> If I set the timing at 10 degrees BTC dynamically, am I
> getting some influence of the centrifugal advance?

Not at idle.  Static timing and idle timing w/o vacuum retard or advance should be the same.  Most likely the centrifugal advance doesn't kick in until you get upwards of 2000rpm.  You can verify this after you set the timing by holding the timing light on and watching as you rev the engine slowly.

As far as I know, they never came with a vacuum advance but they did come with a vacuum retard active at idle only.  That's why your idle and static timing spec's are so different.  So with the vacuum disconnected just set it to the static timing value.

I'm not sure which breakerless ignition your Spitfire has, but mine has the Lucas CEI system (which has a late 70's GM ignition module inside).  The timing hasn't budged in 20 years.  I can't recall exactly what the setting is (it's been a long time since I looked).  With today's gas you may have to tweak it, probably backing it down a little, to avoid pinging.

Jim Muller