Vitesse weak dizzy advance springs?

[daverclasper]

Hi.  Cam spindle does not quite return to it's return stop position by spring pressure, by maybe a couple of mm (no idea what degrees this would be?).

Assume this not quite right, maybe affecting timing throughout the whole rev range, from idle to higher?.

What would the likely symptoms of this be please?.

Thanks, Dave  

[NonMember]

Are you testing that static? Perhaps by rotating the rotor arm and noting where it returns? If so, that's not actually representative of what happens with the engine running.

[Pete Lewis]

yes i wouldnt loose sleep over that , its quite common/normal 

as Rob says its rotor  rest point is not necessarily its back stop 

pete

[daverclasper]

Cheers chaps. Yes doing it static. I have a spare dizzy that does return, so though maybe not quite right.

Reason I asked was, I understand timing has an affect on mixture and never been sure if it's ok on my car.

I do some city driving as live in one.  When doing this my plugs colours are always a small patch of brown and the rest very sooty, though plugs are always a very pale grey when running a bit harder.

I now there's richer running when stop/accelerating in slow traffic. Don't think it's the choke so much as car will have sooty plugs after a Motorway run, then a few miles through town.  Fuel consumption is about the book for runs, though maybe more on the heavy side than it should be for city driving (I reckon about 15 mpg during winter and a bit better in summer).

Have read up a lot on tuning and correct condition and done work on carbs, so they should be ok.

Car does run pretty good, so not too bothered, more of a wondering thing, if you get me.

Thanks, Dave    

  

[NonMember]

Sooty plugs after town driving are expected!

Carburettors are only ever an approximate fuel metering device (although better than the Lucas PI was) and don't do a terribly good job at low air flow. Also, 1950s cylinder head design wasn't great at burning lean mixtures, especially at lower pressures. So all our cars run rich when idling, some more than others. You don't get a nice even grey on your plugs unless you key off mid-cruise, coast to a stop and then pull them out to look. Even slowing down to safely turn off the road into your drive and up to the garage is enough low-speed stuff to put a bit of soot back on the plugs.