Distributor without ability to turn
 

I'm trying to adjust the ignition timing on my 1971 911T (which seems to be completely off). Though my distributor doesn't seem to have the ability to turn to make the adjustment. Instead the distributor is just fastened by a bolt, like the picture in the Haynes book.

http://i67.tinypic.com/2m5bj2f.png

How to I adjust the timing on this kind of distributor when I cant advance or retard the timing by loosening the bolt and turning the distributor?

You adjust timing by loosening the clamp under the distributor body, allowing the unit to rotate.

Hi Steve.

What clamp is that? Could you help me pointing it out on the picture?

In your picture, the clamp is touching the bottom of the red circle.

That makes perfect sense.
So I just have to loosen this screw, that loosens the clamp right?
http://i67.tinypic.com/1zy7cdh.jpg
I tried to search around to find the solution, but everything pointed at the bolt.

How come that this distributor is different from the majority? Is it a very old design, or a newer one?

That screw, if I remember correctly, is what turns the distributor clockwise or counter clockwise. The 13mm nut (M8) is what holds down the distributor once it is in the right position.

Is that a marelli?

No, it's a Bosch. Here's a picture of the actual unit:

http://i65.tinypic.com/ok4kth.jpg

I noticed that the previous owner blocked the vacuum port. Does this has anything to say when adjusting the timing? Should it still be 5 degree ATDC at idle?

Revisiting this thread as I'm now struggling with this. Mine is a '71 2.2E in a 914, so I'm working on this blind. I've loosened the horizontal bolt pointed to by the white arrow, but I still can't rotate the distributor.

It's a Marelli,,,and its stuck, more force required.

Mine is actually a Bosch with the same clamp, but thanks so much for the advice. I ended up loosening said bolt, spraying the clamp with PB Blaster, and then driving around to heat up the motor and ultimately loosen the distributor so that it could rotate.

This forum rules.