Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
What sort of car are you talking about that still has a dizzy?

most do. Or many do. No contacts but still one 25kv coil feeding one of
four (6 or 8) plugs..via a rotating rotor arm. there may also be a
sensor there to monitor crank position. But thats more generally on the
camshaft

As is the distributor itself sometimes. Depends really on packaging.

I ask again. Name one new car with any form of distributor. If one exists,
avoid it. As it has an ancient engine design best left for the science
museum.

All of them. Without a distributor you need at least one coil per
sparkplug, unless you want to take the risk of firing all the plugs all
the time and the possibility of a misfire ..

Additionally you need to tell te EFI and ignition system which part of e
4 stroke cycle you are ion to time the sparks and injectors correctly.
This means a divide-by-tow rotor and a sensor of some sort..since
camshaft is already needed to control the valves, is normal to tack the
distributor onto that and use it to do the two things it still needs to do
- distribute the spark to the right plug
and
- provide timing information for the injectors and the ignition.

So a modern distributor does less, - its doesn't have a mechanical spark
generator in it and it doesn't have centrifugal advance/retard and
vacuum advance on it - that's all done electronically, but it still
shuffles the spark around and provides a convenient place to put a
camshaft sensor.

Look in most petrol cars today, with an OHC and you will see a 5 wire
lump 4 a 4cyl engine) stuck on the end of the camshaft, and probably a
sixth small wire there as well that's the sensor. four wires go top the
lugs, and the fifth goes to a coil or coil pack, which is usually bolted
somewhere else

even if the car has one coil per plug, it STILL needs a way to selct
those..and the camshaft sensor is still needed.

That's as little of the distributor as you can get away with. Arguably
at some point its not a distributor any more - but that is when it stops
distributing the sparks and that means an expensive multi-coil ingnition
system that is not found much on cheaper cars.