123 Distributor / Setting timing Options

[rjames]

For those that have a 123 Distributor, I need some help setting my timing. I'm probably over thinking all of this but I've read several different threads on setting the timing with this distributor and I have interpreted them all differently.

I'm running a stock 2.0 w/ DJet.
The 123 distributor setting I'm using is 'B' (negative advance), and has a max advance of 22 @ 2700 RPM.

With my new-school timing light that allows me to set the advance, (with vacuum line from the tb plugged) do I:

- Set timing light to 27 advance and rev to 3500 RPM and time to the TDC mark?
- Set timing light to 0 advance and rev to 3500 RPM and time to 27 degree mark (same as above, right?)
- Set timing light to 22 advance and rev to 2700 RPM and time to TDC mark?
- Something else? (IMG:style_emoticons/default/rolleyes.gif)

I feel like an idiot asking this question. Timing is such a basic thing and I had no problem with the stock distributor and an old school timing light, but I've read more than one thread on how to time with the 123 distributor, plus I've also read that there's 10 degrees advance added at static on these distributors.
Help!

[914_teener]

So I'm confused.

The original dizzy on the 914 had a dual vacuum pot which used two types of vaccum. The retard port used manifold vacuum while the advance port used ported or atmoshere vaccum just in front of the throtle plate to advance the spark curve for part throttle situations.

When I had first installed the 123 I used the vacuum port on the dizzy for vaccum advance and the appropriate curve for that engine....matched components for D-jet.

I know on later models they used different distributors as Porsche had to comply first with NOX and then emission regulations in the US nearing the end of its production run.

After 73 it's a toss up of what curve setting to use if it is a switched 123. Just use the one that gives you the most power.

I'm not sure if you have the vacuum port on your 123 dizzy and given your post I'd call them to make sure what curve to use. I don't have my car anymore but I posted the initial group buy years back and after I dialed it in it ran flawless for years. It idled rock solid at about 800 rpms when warm. I had the stock cam.

The first thing I'd check is to make sure of your ECU number and other components are matched for your engine.

Frankley who gives a whim about retard curves after the car is smogged.

I'll also asssume you have the stock cam...if not...it might idle higher depending on the profile as you may be aware.

Good Luck.