BMW used two different clock designs on the Tii.  The earlier model (used up until 1973) is the Kienzel clock, which is electromechanical.  It uses a mechanical clock mechanism with is wound electrically.  These clocks are usually pretty easy to fix when they stop working.  The other type of clock (used in 1974 and up), is a purely electronic clock, with a circuit board, transistors, resistors, etc.  Any one of these components can cause these clocks to fail, and I have not found a repair.  My solution was to swap a VDO clock into the case of the Tii clock.  It retains the original wiring harness, case and clock face, making it look totally stock from the outside, while achieving reliability.

 

The donor VDO clock can be obtained from an E12 5-series or E24 6-series BMW or from a 240 series Volvo.  The clock face uses the same mounting holes, so you can use the original Tii face.  The VDO movement has different wiring and case mounting layout, so some modifications have to be made to the original case.  Also, the Tii clock is about 60mm in diameter and the VDO clock is about 52mm.  This will not mater, as the clock movements are about the same size.

 

Let's dive into it...

 

 

1)      Obtain your replacement clock.  The two options that I found work are a Volvo 240 from the 80's or a BMW E12 5-series or E24 6-series from the late 70's and early 80's.  Once you receive your clock, connect it to a 12v power supply or car battery and run it for at least 12 hours to make sure it is working properly.  Here are a couple of pics of the two options:

      

 

 

2)      Dismantle the VDO Clock
 

     a)      Using a small flat blade screwdriver, I gently started to pry the back lip of the bezel away from the case. I started with a very small screwdriver as getting it started was a little more difficult.  After getting it started, I moved to a little larger screwdriver to minimize the marring of the bezel.  You will not be re-using the Volvo bezel, so no need to be super carful here.  Once I had the edge of the bezel pried away, I was be able to pull it all the way off.

 

   

 

     b)      Once the bezel was removed, I was able to remove the crystal (the clear plastic cover with the adjustment knob coming through it) and its holder. 

 

     c)       On the back of the clock there are 2 small screws that need to be removed.  They hold the clock movement in the case.  Remove these screws.
 

     d)      The ground then needed to be unsoldered from the case.  With a soldering iron, heat up the solder holding the ground pin to the case in the middle of the brass circle. This should release the movement from the clock case.

 

     e)      On the front of the clock movement, I removed the hands by gently prying up on the hands, evenly from the sides.  They should come off straight up.

 

 

     f)       Remove the clock face by removing the two screws.  If your VDO clock has it, you can remove the rear foam padding.

 

     g)      You now have the completely stripped VDO movement.

 

 

3)      Dismantle the Tii Clock - This part I needed to be careful with, especially removing the black bezel that surrounds the face on the exterior.
 

     a)      I removed the bezel from the Tii clock, mostly following the same process as with the VDO clock.  However, you will need to be more careful since you are re-using the bezel.  Once I started prying the bezel, instead of using a twisting motion with the screwdriver, I started prying straight away from the case.  This helped to minimize the damage to the bezel.  Remember, the ’74 Tii has a large plastic shroud the covers the clock.  This will hide most flaws to the side and rear of the bezel.  I also did some touch-up when I was finished to help minimize what is seen from the front.  Once I had the edge of the bezel pried away, I was be able to pull it all the way off.
 

     b)      I removed the crystal and its holder. 

      

 

     c)       On the back of the clock there are 3 small nuts that need to be removed.  They hold the clock movement in the case as well as the ground connection on the back of the case.  I removed the nuts and then removed the movement from the case.  I kept the ground wire spade connector, since I was going to use it later.  I was then able to remove the movement from the case.
 

     d)      I then removed the hands and face, just as above with the VDO clock.
 

     e)      You now have the clock case, face, bezel and crystal from the Tii clock.

 

Here are the two movements, side-by-side:

 

     

 

4)      Next, I attached the Tii cross-hair face to the VDO movement, using the screws from the Tii clock face.  Then I attached the white Tii hands, making sure to install the hour hand first, then the minute hand.  Install them both at 12 o’clock straight up.

 

5)      With everything dismantled, I made a template of the mounting and wiring holes so I could modify the Tii case.  I used a thin, but stiff cardboard, like from a USPS Priority Mail envelope.  I had to go back and forth between the Tii case and the VDO case to make sure everything lined up and marked it on the cardboard.  I then used a permanent marker to mark the hole and slot on the back of the case.  Attached below is a PDF of what I used.  It was close, but still required some minor modifications to make sure everything fit just right.

    

 

6)      I used a combination of a small drill bit, Dremel and a file to drill the extra mounting hole and the opening for the positive wire connection. The second mounting hole lined up just right with the existing hole on the Tii case that is marked “+ -”.
 

         

 

7)      I cleaned up the crystal, its holder and the bezel (this might require a light coat of spray paint to make it look nice again).
 

😎    I used some JB Weld to install the light reflector into the case, centering it over its original mounting holes.

       

 

9)      I purchased a couple of #6 x ¼” x 1/8” spacers from Home Depot. Everbilt sku number 398491.  These will space the movement out the proper distance from the inside of the case.  I used a little super-glue to attach these to the top of the treaded screw posts on the back of the movement.

 

      

 

10)   I then bent the ground post toward the screw post.  I then got a very small ring post terminal and soldered it to the ground post so that the ring was right over the screw post.  I also glue a very thin washer over the other spacer on the other screw post, in order to keep the two posts equal.

   

 

11)   Next, I used a little heat shrink tubing on the bottom part of the 12v positive spade connector on the back of the movement.  Leave enough room for the wiring connector.  This will protect the connector from accidentally shoring on the case.

 

 

12)   Insert the movement into the case and use the screws from the VDO case to attach the movement.  You will need to assess how everything fits.  In order for the time adjustment knob to work properly, and for the clock to look correct in the case, I had to make sure the clock was centered in the case.  This required so adjustment to the mounting screw holes and grinding down of the other 2 plastic posts on the movement.  Remember to install the spade connector for the ground wire under the screw.

 

  

 

13)   Once everything fits and is lined up correctly, I installed the crystal and its holder.  Make sure the time adjustment screw works smoothly, otherwise some more adjustment might be needed.
 

14)   I then installed the bezel over the crystal and the case.  I carefully used a larger screwdriver to press the lip of the bezel back over the lip of the case.  Once done, I touched up the paint on the bezel.

 

15)   I then finished up by installing the clock back in the black shroud.

 

   

 

 

Download the case template here:

Case Template.pdf