W123: Tach/clock in instrument cluster.
 

I would like to find a parts car for our two 300D's, ideally one which has the instrument cluster with the tach/clock rather than simply the clock. I'm wondering in which model years this feature was found. Our '85 California model has this feature, but our '84 Euro does not. Swapping the clusters between the two cars is an option, but I'd rather keep the '85 as original as I can.


Phil

'84 Euro 300D, manual trans, needs a tach
'85 Calif 300D, auto trans, has a tach (but why?)

Geez I just threw out a tach/clock today as a clock hand was missing. Those that have a turbo have a tach. Those models without a turbo do not have a tach. I could get you either unit from the local yards here for about $40 packed and shipped domestic USA. Really won't do yo much good if you are looking for a tach for the euro, as you dont have the rest of the stuff needed to pick up the RPM, and it never had one in the first place.
William

i have this one i was going to list on ebay, it has 171K and is from a diesel, it is a little dusty, but is in good condtion otherwise

Yes, more than just the cluster.
 

I realize that I'd need the sender as well as the cluster, which is why I'm really looking for an entire car. Am I correct in concluding that all the 300D's with turbos ('81-'85, I think) have the clock/tach combo?

Phil

'84 Euro 300D
'85 Calif 300D

1982 to 1985 Turbos had the tach. There is a change somewhere in 1983 to 1984, as the first versions used an inductive sensor that sensed a pin on the crankshaft belt pulley and an amplifier on the fenderwell. Later versions used a sensor in the engine to transmission adapter that sensed the ring gear teeth and did not use an amplifier. And I've heard that models with an EGR system, aka California models, used a different setup again that ran off of an EGR computer.

Yup, sits in the passenger side kick. :)

Sensor retrofit?
 

Because the Euro has no sender, I'm thinking that a sender from one of the earlier models might be more easily installed, unless there's a plugged access in the bell housing which would give access to the flywheel. The Calif-model sender would be a very difficult installation.

This gets me to wondering how MB drove the tachs on the gas engines, by the ignition impulse or the alternator. Do any of the gas engine models have tachs? If so, I wonder what their diameter was.

And, I'm still wondering why Benz thought a diesel paired with an automatic trans needed a tach.

Lots of questions ... any answers?


Phil

'84 Euro 300D
'85 Calif 300D

I've seen a 230E Euro with a tach... infact it sits on my shelf. :D

TD's were made with the turbo in 1981 model year, sedans and coupes in '82.

81 TDturbo no tach
 

I recently acquired and 81 TD turbo with no tach. I wonder if the cluster was swapped?

Glenn

Only the 82-85 turbo cars had the tach.

Most gasser tachs run off the ignition signal.

So you was considering swapping out the clusters - then why not purchase the one offered, rather that dismantling the 85'? You will still have the issue of the 84' not having the sending unit.

Personally, I would find another and keep the 85' as-is. When you start messing with these things, always a chance of messing something up.

The 85' model is a USA model and they typically were more "luxurious" than the comparable "Euro" model. Most automatic cars have tachs (at least imports) and now even many large American cars (automatics) have tachs.

Just a thought. Good luck.

No, no swap in my plans.
 

I hadn't meant to suggest that I might swap clusters between the '84 and the '85. That's something I definitely do NOT want to do. Nevertheless, I'm reluctant to buy a cluster until I know how difficult it will be to find and mount a sender which will drive it. Thusfar, that's still a mystery to me. Wouldn't the sender and the tach best be bought as a set to ensure their compatibility?

Phil

'84 Euro 300D
'85 Calif 300D

P'bert,

From most of what I've read on this forum and from the cars I own, it appears that the 82 and 83 300D's have tach systems that are compatible. Some of the 84's appear to be like them, but some may be like the 85's which are for sure a different unit. However if you are looking for a cluster that can be considered universal, that will be difficult as well. The 82's had an 85 mph speedo while the 83 thru 85 had the 125-mph speedo. So you need to know what year the donor was from and all of the info that has been presented on this thread to make a good assesment when picking a backup. For totally replacing what is in the Euro, probably any complete set of parts would work as well as one from another year.