Setting up timing and point gap on 1972 911S MFI

[perry911113]

Hi.

I am looking for the correct set up specifications for my 1972 911T MFI. The car has been rebuilt to S specs and still retains the original MFI injection.

I am replacing the points and want to verifiy the correct gap and also want to check and verify engine timing.

Thanks for the help.

Peter Perry

www.peterperry911113@gmail.com
1972 911T Coupe (S spec) Albert Blue
1965 230SL Roadster

[cmcfaul]

Adjusting points, dwell and gap is a big pain in the As_. The best improvement you will ever make is to replace the points with a Petronics (or other) electronic ignition.

It takes less than an hour to install and your car will run perfectly, from that perspective, for ever.

My car used to run so sweet right after adjusting the points. Over time the tune would go away. With the electronic ignition it has that just adjusted performance all the time.

It's easy to do (easier to install then to adjust the points), looks stock and never needs adjustment.

Best mod ever.

Chris
73 911 E

[Grady Clay]

Peter,
First, welcome to Pelican
You will find a lot of help here.

Pictures please.


The specs for your ‘72T/S are:
Bosch distributor:
Dwell = 38° ± 3°
Breaker gap = 0.35 mm

Marelli distributor:
Dwell = 37° ± 3°
Breaker gap = 0.35 mm


Timing:
1000 rpm = 3.5° - 6.5°
1500 rpm = 4.5° - 14°
2000 rpm = 16° - 24°
4000 rpm = 24° - 31°
6000 rpm = 31° - 38°

Here it is in graphic form:

© Dr. Ing. h.c. F. Porsche A.G.
911 FWM, Vol VI, Section 9, p. 9.3 - 2/3, Supplement XXVIII, 1973.

Always, the last thing you do is to confirm the timing at 6000 rpm with a good timing light.

Chris is correct, the Petronics system is an improvement.
There are also improved CDI systems.
Our nice old 3-pin Bosch have very short rise-time (good for firing poor sparkplugs) but short duration (bad for lighting lean mixtures).
There is lots of discussion about the various systems.
The MSD seems to be on top of the short list.

Again, WELCOME.

Best,
Grady

[HawgRyder]

I would be the first to admit that the new systems using pointless distributers are better for the average driver.
However...try troubleshooting a stalled car in the middle of nowhere with such a system (at night..no flashlight...no meter) and you will quickly see why I use points.
MSD and Pertronix make good equipment, but the average mechanic can only sub the part if the system does not work.
On the other hand...I do use the original Porsche CDI box...but with a few mods to make it more durable.
I replaced all the capacitors with better ones...and the SCR with a 40 Amp unit rather than the original 6 Amp one (same physical size).
Having been on the side of the road many times with cars and bikes...you get a different outlook on technology.
Above all....maintain the car...drive it...have fun.
Bob

[perry911113]

Thanks to all. I will be replacing the points within the next few days and will report back on my results.
Peter

[chiroracer]

How did it go Peter? I am contemplating the install myself. Steve