Successful clock calibration possible?

[Jim Donati]

I recently sent my original 1970 280sl clock in for repair and calibration.  Before I sent it in, it was operational, but lost several minutes each day.

I received the clock back and was told the clock was repaired & re-calibrated, but after reinstalling into back in to my SL, it still looses 5 to 10 minutes a day.

Before I remove the clock and contact the company (The Clock Works, Eagle River, Wisconson) that repaired it, I am interest in learning about others experience in having work like this done.

How successfull was your clock calibration?. Can anyone recommend a good repair shop?

Jim

[bpossel]

Hi Jim,

I never had my clock professionally calibrated.  It runs a few minutes slow during the cold winter months.  It then runs a few minutes fast during the heat of summer.
I recall reading that to calibrate these, you need to remove the clock and connect it to a battery source "on the bench".  Then do very small adjustments over many days.  I believe its possible to calibrate and get it to run fairly accurately.  The problem is that temp and humidity may then impact the clock over time, and it then becomes either slow or fast again....  I am just happy my original clock works, and I can hear the clunk of the clock as I work in the garage and while driving....
Bob 

[280SE Guy]

I sent an email off to Palo Alto a year ago about the calibration for the clock on my car, I can't imagine that it would be any different than yours:

I have a 1971 Mercedes 280SE and have a question about the mechanical VDO KIENZLE clock. Do you know what the beats per hour (BPH) for this clock are?

Their reply:

They are 16,200 BPH.  Please let us know if we can help you with any repairs or quartz conversion.
 
 
Hartmut C. Mees
Palo Alto Speedometer, Inc.
718 Emerson Street
Palo Alto, California 94301-2410
tel : 650.323.0243
fax : 650.323.4632
www.paspeedo.com

Just have your clock repair place confirm the correct beats per hour.

280SE Guy

[Peter van Es]

Mine is a couple minutes fast all the time... I just reset it every time I use the car.

Peter

[scoot]

I occasionally salvage clocks from the junkyard and recently obtained a clock out of a 108 which much to my surprise, worked!  It was a little slow.  I left it on the kitchen counter next to the oven clock for days, each day making a minor adjustment.  I got it to within a minute per day after about 4 days.  I was using a 9 volt battery as the power source, but I don't think that is relevant because in this clock design the power actuates a "winder" not a "motor" so the voltage being low isn't relevant.  (The winder arm moves closer and closer to the contact, then it hits the contact and the battery moves the winder arm and spring tighter again and the process repeats).  My assumption is that the spring in the clock (which is what we are adjusting - the tension in the spring) is going to vary according to temperature, so my guess is that my clock will run faster when it is in an environment that is warmer than my house, and slower when it is in an environment that is colder than my house.  I'm assuming that this would be a couple of minutes variation at the most, but I"m not sure.    I would run it on a bench for a few days and make tiny adjustments and then check back with it a few hours later. then a day later, making finer adjustments until you get it "pretty close" and call it done.

In my pagoda we had a conversion done internally to quartz, which seems to pretty much keep perfect time.

[graphic66]

I read an article on these clocks once and the person pretty much said that they will always be fast or slow. Once you calibrate them on the bench they seem to run differently in the car. I adjusted mine many times without success. I tried 3 different older style clocks with the same results.  I bought the Quartz version and only touch it twice a year for daylight savings time. I keeps perfect time right through storage. I did like the occasional click of the winder, but the accuracy of the Quartz is way nicer. I don't think perfect calibration is possible with most of the older style clocks

[Jim Donati]

Thanks everyone for the details of your past experiences with these old mechanical clocks.  I do not want to change the clock out to a quartz, I am happy to keep the original clock even if it does not keep accurate time.   Now that I know how difficult it may be to have this clock maintain accurate time throughout the year, I will probably leave it alone and just be happy that it runs.

Thanks for all your help.

Jim

[Atazman]

I recently went through the exercise of calibrating my clock.  First, it was loosing 5 min/day.  I took it out from the dash, and left it connected to the electrical supply from the battery to make fine adjustments.  Over several days, I got it down to gaining about 1/2 min/day.  I called it "good" and reinstalled it in the dash and tightened the retaining clip.  To my surprise, the clock began gaining about 5 min/day after being buttoned up.

All I could figure out was that the tightening of the retaining screws to hold the clock in the dash affected the time keeping.  So.......I removed the clock and made an adjustment, and fully installed it again.  After two cycles of this, the clock has gained only 3 minutes in 13 days.  Plenty good for me.

[douglas dees]

I have had the clocks in both the 280Sl and 280SE coupe re calibrated on the bench twice but they still go back to the old problem so I gave up and now it gives me something to do when I get in the car like a pilot's pre flight check. I adjust the time on the clock to my cell phone, put on my sunglasses, adjust the mirrors and take off.

 Having a quartz mechanism is not the same as you do not hear the famous clunk
Doug Dees

[merl]

retired watchmaker just repaired mine 280sl  i have a watch/clock timer 16200 bph is correct   mine worked great on the bench but took it out twice to make small adj as it ran differently when installed   the 10 min slow can happen as the points may not make perfect contact to wind the clock had to polish mine to correct now keeps + - 30 sec per day parked + - 1 min when driven

[Jim Donati]

Is it possible to adjusted the clock while it is in the dash, or do I need to remove it in order to get to the adjustment screw?

Jim

[bpossel]

Hi Jim,

Sorry, not that easy on our cars.  The clock needs to be removed.
Refer to clock section of our Tech Manual.  Its pretty good.
http://www.sl113.org/wiki/Electrical/Clock#Removing

Bob 

[Atazman]

But, Jim, it is not that difficult.  After the first time, it takes all of 5 minutes to remove the glove box, reach in and unscrew the two little nuts on the backside of the clock.  Once the two little nuts are removed you remove the "U" shaped clamp that holds the clock in position.  I had enough electrical wires to leave them connected to the clock, and just slip the clock toward you out of the dash.  You can then tilt the clock to see the small adjustment screw.

I'm not sure if all the clocks are the same, but my clock has the adjustment screw protruding through the clock cover along side the wire connections.  For me, moving the adjustment one of those little marks (about 30 Deg. as I recall) changed the speed of the clock about 2-3 minutes/day.

Another 5 minutes for assembly.......and you're ready for another pleasure drive.

[thelews]

Very easy, replace it with a quartz and save the other for originality.

[hauser]

You can keep the original look by replacing the mecanicals with a quartz movement.

[Jonny B]

I had purchased a replacement clock some years back, but wanted the look of the original, with the right face, and the beveled trim. I used Palo Alto to do the quartz conversion and could not be happier with the result. The clock is absolutely dead on. Yes, yes, yes, I know it does not have the little click of the reset, but I was willing to sacrifice that (in my mind, very small bit of originality) for a functioning and correct appearing clock.

[al_lieffring]

The VDO-Kienzle clock at best can be calibrated to + - 5 min per week. I have even tried rebushing the plates in several of these clocks to see if repairing the excessive wear on the 2nd. wheel that is common to most of these movements would make them run more accurately. There was some improvement, but it does not eliminate the changing of rate with temprature variation. The balance wheel and hair spring of the escapement are not temperature compenasted.
Last year I found a New-Old-Stock VDO-Kienzle clock on E-bay, still in a sealed box with a production date of December 1969, when I first plugged it in on my workbench, it ran about 5 min a day slow.

As a foot note I would like to add that the dash board clocks installed in most cars of the same era were of such poor quality that they were excluded from the new car warranty. Compared to these the Kienzle clocks were of much higher quality.