Tuesday, January 29, 2013

BMW Switch Reconditioning

 Back to bikes!  This is the BMW headlamp pod with the reconditioned combination speedometer/tachometer unit that you saw in an earlier blog. This concerns reconditioning the handlebar switches, seen on the left and right in the photo above.
 Here is a close-up of the headlamp assembly with the combination gauge and the right switch. Of the switches, the one on the left switches on the stop lamp when the front brake is applied. The right switch controls the left/right direction signals and engine start.
 This is a close-up of the two switches for the right handlebar.
The drawing shows the component parts of the LEFT handlebar switch which controls high & low headlight beams and the horn. As the rider moves the thumb control the rotating contact plate decides which beam is "ON". When the button is pushed "IN", the horn sounds. Quite a lot of "stuff" in a very small switch body.

Other than a broken wire, the only thing wrong with this switch was 40+ years of built up corrosion between the brass parts. After I cleaned it all up and repaired the broken wire...VOILA!  Good for another 40 years! 

Sunday, January 20, 2013

Subaru, Saab and Great Designers

 Meet "Mr. B", my '87 Subaru Brat 2-4 wheel drive pickup. The other day the muffler [located just behind the rear axle] decided it was tired and got REAL loud. I replaced the rear section of pipe and the muffler and while I was at it, added a Monza dual outlet pipe tip. Hot ziggety!
 There you see the exhaust tip in all its exhausting glory. So what's the big deal, here, and what's the connection with Saab, you ask?  And what is this "Great Designer" business, anyhow?  The Subaru connection to Saab was Saab's 9-2, the badge engineered Subaru WRX wagon that Saab sold for a year or so. An excellent car, but not one the Saab snobs liked because it wasn't built in Trollhattan. Now for the designer part.
The Brat was designed by Alex Sarantos Tremulis, who also designed the '48 Tucker, added the chrome front fender exhaust pipes on the supercharged Cord, designed the '40 Chrysler Thunderbolt, a number of Ford show cars, and the world's fastest motorcycle, the streamlined, Triumph powered Gyronaut [ 245.667 mph at Bonneville] and managed to get a full sized motor home to 97.6 mph on Muroc dry lake in Southern California.

I was privileged to meet Alex several times at Art Center College of Design when I was an instructor there. He never stopped thinking, dreaming and designing and his knowledge of aerodynamics was amazing. At that time he owned three Tuckers and always drove one when he visited our school.

I've owned several "designer cars" but Mr. B is probably the coolest of all of 'em. 

SAAB Distributor Test Machine

 As promised, here is the SUN distributor test machine, with a Bosch/Saab V4 distributor installed for testing. When the machine is running, an arrow appears on the large black INNER ring below the distributor. Just outboard of that is another black ring with degrees etched into its surface. As distributor RPM increases [by turning the knob at the bottom, below the black rings] the arrow moves anti-clockwise, indicating degrees of advance for that RPM. The top meter on the right measures the RPM. I plot the RPM for each degree of advance, in order to see the mechanical advance curve.  
A typical advance curve--taken right from my distributor reconditioning records book--is shown in RED above, plotted over a set of minimum/maximum curves, as shown for that particular distributor, in the Saab V4 Service Manual.

When the actual plotted curve [RED] is NOT within the factory spec's, I have to disassemble the distributor and change one [or both] of the wee springs in the advance mechanism. Depending upon the distributor type, there may or may not be an additional mechanical adjustment that I can make.  Remember---there are at least a dozen different Bosch distributors used by Saab in their V4 model run from 1967 to 1980.
Without plotting the mechanical advance curve, using the SUN machine, you have no idea what the distributor is doing and I guarantee you--if the curve is significantly outside the minimum/maximums, the engine will run poorly, no matter what tune-up and/or repair you have done to it.

The bottom curve is a plot of the vacuum advance, also done on the SUN machine, or with a special machine I built for the purpose. Again, Saab shows the ideal minimum/maximums for that curve. The RED plot shows the curve of the vacuum advance unit I used for this particular recondition job.  One thing to note:  if the vacuum advance does not work, the engine will run like crap even if you have the timing and carburetion set perfectly.  How is YOUR V4 engine running?

One thing I have found out over the years of reconditioning distributors---the SUN machine never lies.    

Tuesday, January 15, 2013


 It all comes together! Above--seven reconditioned Saab V4 Bosch distributors. In the center, the last one, still in one of my holding fixtures. Each distributor has been re-bushed, and all new parts installed, including the vacuum control units.
Here are the seven reconditioned distributors. Depending upon the customer's needs, they may be delivered with points and condenser installed, or a solid state Pertronix unit, if that's what the customer wants. All will have a new rotor and new distributor cap.  If the customer wants a new spark plug wire set, he/she can get that too.  
Next step--I'll put each one on the SUN distributor machine and set the mechanical advance curve. The vacuum advance curves have already been plotted on the tech sheet for that distributor. I give the customer a copy of the tech sheet, which shows the advance curves and all the parts that were used for the rebuild.

The next blog--the mysteries of the SUN machine...heh heh heh.....