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W123 Speedometer Upgrade
GREASY_BEAST Offline
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#1
W123 Speedometer Upgrade
Which W123's had electronic Speedometers?
05-17-2010, 08:32 AM
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ForcedInduction Offline
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#2
RE: W123 Speedometer Upgrade
Only the 1981 300TD.
05-17-2010, 08:59 AM
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GREASY_BEAST Offline
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#3
RE: W123 Speedometer Upgrade
Thanks Forced. After doing some reading on other forums, it appears that the 1985 300SD also had an electronic speedometer. However, I'm not sure whether the speedometer from the W116 fits in the W123 cluster. Anyone ever tried? If it doesn't I might as well just go to the yard and get whichever late-model MB electronic speedometer I can lay my hands on, because adapting is adapting.
05-17-2010, 11:45 AM
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DeliveryValve Offline
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#4
RE: W123 Speedometer Upgrade
(05-17-2010, 11:45 AM)GREASY_BEAST Wrote: Thanks Forced. After doing some reading on other forums, it appears that the 1985 300SD also had an electronic speedometer. However, I'm not sure whether the speedometer from the W116 fits in the W123 cluster. Anyone ever tried? If it doesn't I might as well just go to the yard and get whichever late-model MB electronic speedometer I can lay my hands on, because adapting is adapting.

Actually all w126's have the electronic speedo.

The w116 speedo head will not fit in the w123 cluster without major modification.

So late model adapting might be the way to go if your looking for an electronic option.


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05-17-2010, 12:14 PM
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ForcedInduction Offline
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#5
RE: W123 Speedometer Upgrade
The W116 used mechanical.
05-17-2010, 05:43 PM
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GREASY_BEAST Offline
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#6
RE: W123 Speedometer Upgrade
(05-17-2010, 05:43 PM)ForcedInduction Wrote: The W116 used mechanical.

Sorry, I meant W126. Good to hear the W126 speedometer heads are all electronic, there are some good pictures of a W126 speedometer and instrument cluster in this thread. It looks like I'll be able to cobble it together, I think I'll just go buy one and figure it out. The plan is either to try to hook something up using the speedometer cable to drive a device that will send either a pulse or a voltage signal to a board which will convert it to the appropriate signal for the speedometer, or just generate a pulse directly from the drive shaft or some other rotating driveline component. One idea is to hang a hall effect sensor near the front flex disc so it pulses each time one of the 8 bolts passes by. I would rather do something a little more "solid" like interface with something in the tailcone of the trans, though..
05-18-2010, 05:20 PM
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Greazzer Offline
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#7
RE: W123 Speedometer Upgrade
(05-17-2010, 12:14 PM)DeliveryValve Wrote:
(05-17-2010, 11:45 AM)GREASY_BEAST Wrote: Thanks Forced. After doing some reading on other forums, it appears that the 1985 300SD also had an electronic speedometer. However, I'm not sure whether the speedometer from the W116 fits in the W123 cluster. Anyone ever tried? If it doesn't I might as well just go to the yard and get whichever late-model MB electronic speedometer I can lay my hands on, because adapting is adapting.

Actually all w126's have the electronic speedo.

The w116 speedo head will not fit in the w123 cluster without major modification.

So late model adapting might be the way to go if your looking for an electronic option.


.

Richard,

If I got the M100 6.9 instruement cluster, how much of a PITA factor is it to use the W116 speedo in a W123 ???
Seventh Year Anniversary with STD on 1-9-2018

Project 2018: Really get the car finished -- Turbo OM617 greater than 175 MPH goal.

RED W123 - left Germany as 240D in 1982.  Full AMG body kit less rear apron, 2:65LSD, five speed Getrag 717.400, manual steering, read leather interior, manual brake conversion, electric water pump (EWP), and a bunch of other goodies ...
04-14-2014, 06:05 PM
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DeliveryValve Offline
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RE: W123 Speedometer Upgrade
(04-14-2014, 06:05 PM)Greazzer Wrote:
(05-17-2010, 12:14 PM)DeliveryValve Wrote:
(05-17-2010, 11:45 AM)GREASY_BEAST Wrote: Thanks Forced. After doing some reading on other forums, it appears that the 1985 300SD also had an electronic speedometer. However, I'm not sure whether the speedometer from the W116 fits in the W123 cluster. Anyone ever tried? If it doesn't I might as well just go to the yard and get whichever late-model MB electronic speedometer I can lay my hands on, because adapting is adapting.

Actually all w126's have the electronic speedo.

The w116 speedo head will not fit in the w123 cluster without major modification.

So late model adapting might be the way to go if your looking for an electronic option.


.

Richard,

If I got the M100 6.9 instruement cluster, how much of a PITA factor is it to use the W116 speedo in a W123 ???

It's been a while since I compared them, you would have to physically see the differences.
But if I recall the w116 speedometer's face is much bigger than the w123's. So I am not even sure how you would go about shoe horning it in a w123 cluster housing. If you decide to try to swap mechanical parts between the clusters, I do know the worm gears will not work because the w116's gears are longer and teeth are placed differently. Magnet and cable tail orientation are different. Not sure if you can swap the whole mechanism to a different face plate, because the ODO numbers may not line up as well as getting the needle to show the correct speed.

On top of that, the 6.9 came with larger outer diameter 215 70 R14 tires compared to the w123 which came with smaller outer diameter 195 70 R14 tires. So you'll need to sort out the tire choices also.

So the reality is I think a w116 speedo will not be doable.
Gota love Mercedes Diesels!



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04-15-2014, 03:36 AM
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Petar Offline
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#9
RE: W123 Speedometer Upgrade
http://www.benzworld.org/forums/w123-e-c...-dont.html
Found this.I guess it is possible to mount a VR sensor on the driveshaft with some tabs welded to it to produce a pulse signal ?
08-18-2014, 05:01 PM
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