slapping a metric (KPH) faceplate on standard (MPH) cluster, w124 300D - PeachParts Mercedes-Benz Forum

scottmcphee · #1 06-10-2009, 12:47 PM

I want to move a Canadian metric speedo faceplate over to my American import daily driver that has both miles and metric scales. The metric faceplate is much less cluttered looking because it does not have a miles scale on it. And I live in Canada and only need kilometers per hour on the scale. I don't want to move the whole gauge, just the faceplate if possible. (The odo will say "kilometers" but will really be showing a number that is "miles" but I don't care.) There is no need to do this for import rules or anything... I just want the cleaner face look. Plus I think my current speedo error is off by as much as 10%. So I can correct that at the same time using a GPS to calibrate is good enough for me.

From a salvage car I got the metric faceplate off OK, pulling the needle, two screws.. and there you have it. Comparing the plates, they both have the same full scale reading in kilometers per hour. But the metric plate's whole scale is rotated a bit counter clockwise. It seems to me that setting the needle back on its pin slightly rotated in the same direction will make up for that. Seem reasonable?

Also, key question, what is the normal procedure for placing the needle in the correct position when putting a faceplate back on? I notice if you "jump" the needle over the zero-stopper the spring drops it further past the stop. It settles out in a spot that is ??? mysteriously calibrated to be the normal relaxed point. I notice on the MPH scale faceplate, there is a painted tick mark which may be the spot that says "hey place the needle here"... Is this the case? I'd assume the tick mark on the metric faceplate may be a smidgen different, to accomodate for the shift in the scale.

porkface · #2 06-10-2009, 03:18 PM

you need the whole speedo as the odometer will still read miles, not kilos. seen this in ferraris where the us face was installed onto a euro speedo and the "miles" click off in nothing flat. good luck, chuck.

pawoSD · #3 06-10-2009, 03:26 PM

Why not just get the proper kilometer speedo for your car off ebay or something?

Ivanerrol · #4 06-10-2009, 09:18 PM

I have been through this. Converting a dual KMH/MPH cluster to a singular KMH type.

If you get another off fleebay, make sure that the cluster or speedo you get exactly matches your car. Same series, diff ratio and engine type.

You will be surprised at the mount of differences. They all look very similar or the same from the front.

scottmcphee · #5 06-11-2009, 09:29 PM

Quote:

Originally Posted by porkface

you need the whole speedo as the odometer will still read miles, not kilos. seen this in ferraris where the us face was installed onto a euro speedo and the "miles" click off in nothing flat. good luck, chuck.

and to re-quote myself:
The odo will say "kilometers" but will really be showing a number that is "miles" but I don't care.

scottmcphee · #6 06-11-2009, 09:30 PM

Quote:

Originally Posted by pawoSD

Why not just get the proper kilometer speedo for your car off ebay or something?

I've got 3 identical cars, 2 are miles, one is metric. I don't need to shop on ebay. I just want to swap the faceplate.

scottmcphee · #7 06-11-2009, 09:32 PM

Anybody got any advice on where to put the needle back on... when you are reassembling a speedo. Suppose you put the same faceplate back on the gauge it came off. Where do you plant the needle with any degree of certainty? Is there a calibration dial somewhere that you diddle with when putting a needle back on?

Chas H · #8 06-12-2009, 12:35 AM

Quote:

Originally Posted by scottmcphee

Anybody got any advice on where to put the needle back on... when you are reassembling a speedo. Suppose you put the same faceplate back on the gauge it came off. Where do you plant the needle with any degree of certainty? Is there a calibration dial somewhere that you diddle with when putting a needle back on?

You put the needle back where it was. You did mark it- right?
Or did you pull the needle off while it was on the stop?

yhliem · #9 06-12-2009, 12:58 AM

I have done this with my 2.3-16 and for other readers of this thread: I concur with Ivanerrol. If you are replacing the entire gauge you MUST ensure that the 'new' replacement is from your exact model. Depending on whether there are driveline (ie gearing) differences between model years you might even need a model year specific replacement.

That having been said, if you are doing what Scott is attempting you need to know the following:

The speedometer needle spring is preloaded so you cannot just stick the needle onto the shaft at the stop.

If you look at the bottom edge of the gauge face you will see a small, thin mark (probably white in colour). When you put the needle back on you will need to line it up with this mark. Yes, the needle will be on the wrong side of the stop.

Once the needle is on, GENTLY lift the needle over the stop as you rotate it clockwise into position on the correct side of the stop.

If you do not follow this procedure the needle spring will not be properly preloaded and your speedo could register an incorrect speed.

If you want to be EXTRA precise, BEFORE you pull the needle on the speedo you are going to use, lift the needle over the stop and see where it rests when unloaded. Mark the position on the faceplate and then transfer your mark to the 'new' faceplate.

Bear in mind that regardless of how you go about it there is still going to be a level of uncertainty by virtue of the fact that there are many moving parts involved, the age of the parts and the fact that you tool it all apart. You should get someone to help you verify the accuracy of your placement by getting them to pace you in a second vehicle and compare what the speedos register at various speeds. You may need to do this more than once.

scottmcphee · #10 06-12-2009, 09:46 AM

Hey thanks. Needle not off yet, still planning for the job. I will mark the needle and observe the tick on the gauge so I can put it back correctly. I will compare the tick marks on kph vs. mph faceplates. I will measure the degree of rotation of the scales between the faceplates and compensate for that by offset in the needle. And also compensate for the error I am seeing in the speedo right now. Finally, when reassembled I will check my needle setting on the new faceplate with GPS to get a degree of certainty the speed is showing correctly, and if it's more than 5% out of whack - take it apart again and adjust to compensate. That the plan anyway.

TX76513 · #11 06-12-2009, 09:53 AM

There is a forum member that makes a very high quality face plate to what ever (almost) specification that you need. I replaced the KM to MPH/KM on my 500SE. They are not expensive, have good instructions and allow you to clean up all those dirty numbers and the inside of the cluster. Take a picture of your cluster in the "rest" position before removing the needles. Refer to pictures when replacing needles. There are some pictures of my conversion on the forum.