Hello,
I am trying to find out if this is the Vac advance unit for the 2.0 L '74 distributor, 039 905 205 A .
It has one vacuum chamber, can someone verify this is the correct unit on the correct side?

Click to view attachment

Thanks,
Mike

...this is the closest I found since I don't have a 74'

page 134 of AA catalog (no plug - just what I found)...

Dave



Click to view attachment

Hey Dave,
Thanks for responding, I saw that ad along time ago, it does show the 1.7 vac advance, which has both advance and retard vacuums chambers, you just can't see it because it is rotated 180 degrees from the photo of my vac advance unit (later 2.0 L used only the retard portion of the unit), but I am not sure if this is the correct unit.

I see there is a photo in the factory service manual with the vac unit in this config but I do not know if it is correct and how it connects.

Thanks for looking,
Mike

OK, you need an 039 905 271 for that distributor according to the number you provided...

~$150 used (great condition).

Better picture of what it should look like is below...

Dave

Click to view attachment

Check the BMW distributors as well.

I believe their 76' had the same vac advance as the later 914 2.0.

Very close.

Hey Dave,
I see what you are saying, but these are from the Factory Service manual,

Early dizzy
Click to view attachment

Late dizzy
Click to view attachment

As you can see the photo shows only a single port for the vac unit, and it is on the advance side, I also read in the Factory Service Manual that "late 74" and up did not have the vacuum advance, just vacuum retard ('75 USA Model Year).
So is the second image a generic photo, or is it the correct config?

Thanks again,
Mike

OK.

Per GH's Tech Tips 700 (G.Hussey, Pg. 79)

Check the Dizzy Vac. Adv. Mech . The arm should state "603" for the 74-76 2.0.

...and...

"...1974.5 - 1976 models had only vac. retard connected, and a 3-inch piece of vac hose connected to the advance port breathing to the wind. To test for proper operation, evacuate each port and observe that the points plate twists smoothly each way and holds. If the unit will not evacuate or vac leaks down, replace it..."

See if any of that helps.

Thank George

Thanks Dave and George,
I see that the Bosch vac unit number is 1 237 122 603 as per PBAnders info, so the 603 on the vac unit arm is for the last 3 digits, I assume.

The unit in my original photo has 265 as the number on the arm.

Mike

Mike,
Did you get it running? Injectors opening? Checked your other thread and didn't see anything new as an update.
Tom

Hey Tom,
Been busy working on wife's pick up, leaking power steering fluid, have to make sure she is ok. Just a little progress, this is just another bit of the puzzle, I have to find someone who really knows this part?
Thanks,
Mike

ps: check the other tread for info.