CIS Distributor with PMOs?

[Phoenix]

Background: My Dad is and ex-foreign car mechanic (when foreign cars were truly foreign) and had repaired his fair share of original Porsches. I'm no expert only he and my mechanic are.

I've had the car converted from the '73.5 CIS to PMOs. It has L cams and Mahle 2.4 pistons / cylinders.

The issue is the distributor:

When looking at the distributor, it sits at the edge of its adjustment range and the vacuum advance is disabled. My Dad tells me this is incorrect. It's a vacuum advance dist. It was designed as such and should be used so. Also, it should sit somewhere in the middle of its adj. range (see pic.)

The only current symptoms the car has is that it is running very rich (deep black soot in the exhaust) and is getting low fuel mileage (10-12mpg). I've driven it roughly 900 miles since the PMOs were put in and am planning to have my mechanic look into the rich running at 1500 miles when he does a valve adjustment and checks to make sure everything is still tight.

My questions:
1 - am I using the correct distributor? (do you have enough info to tell?)
- if not, what should I be using
2 - could the dist. be the cause or contribute to the rich running and low fuel milage?
3 - what would the ideal setup be for my motor?


I don't want to approach my mechanic (whom I trust) with this or my Dad (who i respect) until I find out a bit more. My Dad's been out of the business for over 15 years and is/ was incredible on originals but has limited experience on modified "bastardized" motors.

Hoping you guys can help me increase my knowledge on the subject.

[Formerly Steve Wilkinson]

If your distirbutor is at the limit of its adjustability range and you feel it needs to go farther in the blocked direction, I'd move it a tooth at its juncture with the drive gear, if you're confident you can do that without semipermanantly disabling the car. As for whether the distributor can work with PMOs, as far as I know a distributor is a distributor is a distributor. It'll send spark to the plugs regardless of whether they're being fed fuel by FI, carburetors or whatever. The important thing is whether it's sending those sparks at the proper time. (My car is an '83 SC from which the CIS has been removed and PMOs substituted. I'm still using the original distributor, though it has been modified to accept a 12-plug cap and rotor since the engine has also been twin-plugged. And my vacuum advance is disconnected as well.)

Stephan

[john walker's workshop]

the distributor you have there has a vacuum RETARD. it doesn't need to be used. the advance curve should be sufficient to run your engine quite well, however there's always room for improvement if you sent it out and had it recurved. set the timing so when it's fully advanced, at say around 4000RPM, you have 35°. then whatever timing it idles at, is what it idles at. it you hear any pinging, retard it a couple of degrees. when a distributor cannot be rotated enough to get the timing figure you want, it needs to be pulled out and the rotor turned one tooth. the rich running is not related to the distributor. how is the float level? is there any drooling down the throats? black tailpipes are the norm these days with the crap fuel they sell.

[Phoenix]

Guys, please forgive my ignorance on this...

Stephan - thanks for the info. If I moved the dist. one tooth further along, will I not need to readjust the timing?

John - . What do you mean "have it recurved"?

[john walker's workshop]

yes, you would retime after moving one tooth.
recurving is when you modify the mechanical advance by changing/modifying the weights and/or springs to get a certain amount of advance at a certain RPM. usually for hot rods. yours should work fine as is.