Bob_Spidell
Yoda
Offline
I have a little different philosophy. I adjust using an advance light with the vernier centered (IIRC, it's 8 'clicks' total movement). You can get the timing +/- a half-degree this way, then you can tweak using the vernier for various qualities of petrol, but I've never actually bothered doing this, as the adjustment with the vernier is just a degree or two, and I don't think you'll notice any difference in 'normal' driving. Have considered setting the vernier all the way advanced, then set nominal with the advance light, and if I was forced to use a lower grade of petrol I could retard using the vernier to eliminate any pinging--I don't carry the advance light on trips--then restore to original setting when better fuel is available. Using higher octane than necessary is somewhat wasteful, but in old Healeys you can't damage anything. At higher elevations here in the colonies, sometimes you can only get 90 octane--with our R+M/2 method--but with the less dense air this doesn't usually present a problem, but if it did I could retard the timing with the vernier.