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+--- Thread: tachometer and speedometer in w123 + om606 (/showthread.php?tid=5441)
tachometer and speedometer in w123 + om606 - john - 03-18-2014
I am building a w123 + om606. whant the tachometer to work. Can i connect it to the "W" on the alternator or do i need the pickupthing from my om617.
How many pulses per revolution gives the old pick up vs the W on the alternator??
how can i sort out the speedometer?? i was planing to transplant a w124 speedometer and adding a sensor and pickup on the outputshaft from gearbox. Any inputs??
RE: tachometer and speedometer in w123 + om606 - CRD4x4 - 03-18-2014
Idk if this applies to your situation or not but the 1981 W123 300TD uses elecrtonic speedo while '82+ W123 uses mechanical.
(03-18-2014, 08:27 AM)john I am building a w123 + om606. whant the tachometer to work. Can i connect it to the "W" on the alternator or do i need the pickupthing from my om617.
How many pulses per revolution gives the old pick up vs the W on the alternator??
how can i sort out the speedometer?? i was planing to transplant a w124 speedometer and adding a sensor and pickup on the outputshaft from gearbox. Any inputs??
RE: tachometer and speedometer in w123 + om606 - john - 03-18-2014
WHAT?? superinfo, it made my day.
I will start locking for that. Where is the pickup placed on those? Maybe cara with abs have a electric speedo? I have a 79 300d and that i think have a cabel.
Any more exact specs on which one had electric?
RE: tachometer and speedometer in w123 + om606 - CRD4x4 - 03-18-2014
What transmission are you using?
(03-18-2014, 02:11 PM)john WHAT?? superinfo, it made my day.
I will start locking for that. Where is the pickup placed on those? Maybe cara with abs have a electric speedo? I have a 79 300d and that i think have a cabel.
Any more exact specs on which one had electric?
RE: tachometer and speedometer in w123 + om606 - john - 03-18-2014
(03-18-2014, 03:13 PM)CRD4x4 What transmission are you using?
(03-18-2014, 02:11 PM)john WHAT?? superinfo, it made my day.
I will start locking for that. Where is the pickup placed on those? Maybe cara with abs have a electric speedo? I have a 79 300d and that i think have a cabel.
Any more exact specs on which one had electric?
Bmw zf gs6-53dz
So no speedsensor there.
Where does 126 take there pick up signal from?
RE: tachometer and speedometer in w123 + om606 - aaa - 03-19-2014
The 126 and 81 TD had an electric pickup in the exact same spot where the cable pickup was on the tranmission. There was a toothed wheel inside for the pickup.
RE: tachometer and speedometer in w123 + om606 - DeliveryValve - 03-19-2014
If I am not mistaken, I do believe the '81 one year only electronic speedo only came in the US spec 300TD Turbo Diesel. Unless there are other 1981 300td Turbo Diesels offered in other countries, perhaps Canada, you won't be getting an electronic speedo in KM but in MPH.
.
RE: tachometer and speedometer in w123 + om606 - john - 03-19-2014
Any ideas why this is so exclusive?
RE: tachometer and speedometer in w123 + om606 - DeliveryValve - 03-19-2014
Here is my theory. Ultimately, it is cheaper to produce a speedometer inline with the other mechanical units offered in the w123 at the time. The decision was made to borrow the transmission from the 300sd for the 300td to bring it to production faster. They had no choice but to produce the electronic speedo unit until the mechanical speedo transmissions were built.
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RE: tachometer and speedometer in w123 + om606 - CRD4x4 - 03-19-2014
I was too slow to respond...
I heard it had to do with noise level. First year of a turbodiesel in the USA shouldn't have "noisy" cable driven instruments. Something like that. Then it was found unnecessary? Cable is cheaper? Idk.
(03-19-2014, 04:49 PM)john Any ideas why this is so exclusive?
RE: tachometer and speedometer in w123 + om606 - john - 03-20-2014
ok.
back to question number one.
How many pulses per revolution does the "W" phase on alternator give? one per revolution on alternator time its about 4 times smaller than the cranks pulley should make around 4 pulses per engine revolution??
how many does the w123 trigger give?
RE: tachometer and speedometer in w123 + om606 - Tito - 03-20-2014
The pulses are waaayyyy more. Like +40 per rpm.
The crankshaft pulley spins the alternator pulley about 3 or 4 times faster indeed. But, one rpm from the alternator gives about 15 pulses on the W phase (and the others) this is to give a smooth steady voltage. So 15 times 3 is 45 pulses.
RE: tachometer and speedometer in w123 + om606 - john - 03-20-2014
ok. and on the 617?
found this tachometer. whats the black thingy on the back? cant remember that i have seen it on any of my tachometers??
RE: tachometer and speedometer in w123 + om606 - w123love - 03-20-2014
(03-20-2014, 07:35 AM)john ok. and on the 617?
found this tachometer. whats the black thingy on the back? cant remember that i have seen it on any of my tachometers??
For the clock I believe
RE: tachometer and speedometer in w123 + om606 - raysorenson - 03-20-2014
I think the late '84 and '85 MY use the starter ring gear for the tach. The schematic shows the federal models have the tach wired directly to the 2 wire "engine speed sensor". The cali models look to have the 2 wire speed sensor wired to the egr box and a single wire from the egr box to the tach. Pre- 84 model schematic show a 2 wire "tdc sensor" plugged into a "tdc amplifier" that is connected to the tach with a single wire.
I can say with certainty that I have 2 '85 federal engines in the fleet and they both had sensors on the starter ring gear.
RE: tachometer and speedometer in w123 + om606 - aaa - 03-21-2014
(03-20-2014, 07:35 AM)john ok. and on the 617?
found this tachometer. whats the black thingy on the back? cant remember that i have seen it on any of my tachometers??
That is the speed pickup for the cruise control.
RE: tachometer and speedometer in w123 + om606 - swampmonkey - 03-26-2014
if you have a gasser tachometer, go to dakota digital and order a converter, get w+ to dakota digital part, and sync it with a strobelight to the crank, and then connect to the tachometer....
i plan to get a early generation tachometer from a w123 300tdt from the us with the pickup on teh front of the engine, and somehow mod it onto my engine, and use that. if i can make that work.
RE: tachometer and speedometer in w123 + om606 - oldbeaver - 04-11-2015
(03-19-2014, 03:07 PM)DeliveryValve If I am not mistaken, I do believe the '81 one year only electronic speedo only came in the US spec 300TD Turbo Diesel. Unless there are other 1981 300td Turbo Diesels offered in other countries, perhaps Canada, you won't be getting an electronic speedo in KM but in MPH.
.
Hello, just in case we may share info of value for both.
I have a 1993 MB 300D turbo, sedan. It was made for Japan, has metric signals I think.
I am on my way to attach a trip computer to it, looking to determine how many pulses per mile or per km the VSS signal has.
Any info available?
On the other hand, I adapted a tachometer to a swap motor in another MB I have.
Oldbeaver
RE: tachometer and speedometer in w123 + om606 - bricktron - 05-01-2015
oldbeaver, i dunno anything about that setup but if you can get a friend with an oscilloscope to ride with you and record the signal, it should be clear afterwards how the pulses come. buena suerte, eres de santiago?