No, notice the red line at 4600 rpm and the sign saying "4-Zyl-Diesel, alle Anbauteile, org. DB, sehr selten!" (4 cylinder diesel, alle parts, original Daimler-Benz, very rare!)

I think very rare says it all. I would be interested to see the mechanical fitting in place running through the bulkhead - the bulky metal ends of the "speedo cable" look about right for the parts that fit on top of the oil pump / intermediate shaft connection.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Okay, first time I've seen a red line on a diesel tach.

The max horse power on my diesels clock in at 4350 rpm.

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83 SD

84 CD

Hi all,

Yeah, checked the cars and all seems ok.
The 300TD has a bracket for the pulsgeber/sensor. Cool. Pic somewhere here:


The 300TDT has the bracket with the socket for the amp:


And has the sensor in place. Okidoki!



Now, if I am correct, I just need an
-amp, (will any work?...letīs wait for my tacho to arrive, and see...)
-some wires and connectors,
-the plug for the tacho,
-and a way to get the right current to the tach. (described in one of the threads)

Oh internet.....

And I found a torque graph with both the 617 an 617 A on it.



Even they are on a different level they look like brothers to me. It is the same peak for both the motors: 2200-2400 rpmīs
Then I can just go ahead and tweak all the factors and enjoy the jump in power with the same set up.

One thing I wonder about...Does the 617 turbo already have an advantage at low rpmīs?...letīs say driving-away-from-standstill-rpmīs? Even though it might be little?

Cheers, Jan.

For answers like that you might be interested in a SAE technical paper describing the development of the OM617 turbo.

The Turbocharged Five-Cylinder Diesel Engine for the Mercedes-Benz 300 SD

Other than that you need to chat with people like vstech who have owned virtually every 1980s Benz ever made!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Ok,

The tacho came in today and got a chance to check it out some more.



1985 3-pin model... is that an oops? Or not?
Good thing the plug and some wire are there.

The turbodiesel here is a 1986 ( pbb late 1985 model) so thought it would be ok. More digging to do. These variations with the euro vs US models...

See if the last thing to get is the amp,
or that the plans will be slightly different.

Laters,

Jan.

That is the 84 and later tach, post #49 shows the correct socket, should work, no amp, takes the signal from the transmission via an egr computer, I think.

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83 SD

84 CD

Hi,

Yes, that might be true...EGR....Hmm

The socket in post#49 is for such an amp I thought, for amplifying the signal from the crank-sensor.
Does that mean this 1985/86 model uses an old pre-84 model tach?
( because it is a euro model?)

My MB is a luddite version, no computer or advanced systems.

I plan to leave out as much of that as possible when transplanting the turbodiesel motor...even keep the car manual, transmission-wise.

Happy for info while digging around.

cheers.

Jan.

The pics shows a pre 1984 socket and amp, note the fewer female pins in the newer style.

Attached Thumbnails

 

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83 SD

84 CD

Ok,

Thanks,

Then I re-check the wiring. Sofar I found the obvious grey cable to the crank sensor. Maybe there is another cable to the tranny?

Or, the amp-style socket is for diagnosing and there is a different, or NO, cable for the/a tacho....since there is no tacho in this particular car.

If that is the case, I have to see whether the socket can be used for a pre-84 tacho, or that I (hopefully) can make it work with the tacho I have at the moment.

I reckon the tacho I have also operates with some kind of pulse of some kind. It must be a question of how to make it compatible.

You see I am a green-behind-the-ears-manalishi, eager to learn....

Jan

You have a 1984-1985 USA tachometer. That one uses the signal from the flywheel. That signal is put through the EGR "computer" and the EGR "computer" give the signal to the tachometer.

BUT: you probably have an Euro model, as you live in Norway. It could be an import from the USA, but probably not, as you don't have a tachometer at the moment. All USA models had tachometers.

The Euro model pre or post 1984 uses the crank sensor, diagnostic socket and tach amp for a tachometer. The frequency of the crack sensor is different from the flywheel sensor, that is why the two types of tachometer are not interchangeable. So yes, it is a big oops.

You might be able to make it work, but you need to change the electronics of the tachometer you now have. I don't know if that can be done or how it should be done, but I guess it must be possible.

The other route is finding a pre 1984 tachometer.

Allrighty,

Thanks Govert.

Like Too Many MB pointed out, the pre 84 amp socket has a different configuration. More pins. Would that be a challenge somewhere when using a pre 84 model tacho? Or maybe, beyond "challenge"....more like impossible?

Another question is, how many pulses per revolution does the flywheel give off, and what does the EGR do with that input?

Hahaha...This is getting quite nerdy. Fun it is, anyways...

See what comes up when searching for flywheel sensor based tachometers.

Jan.

The USA 1984-1985 models did have less connections in the diagnostic connection, because it only was a diagnostic connection. The pre 1984 models also had a connection for the tachometer. The tach amp connected and amplified the signal from the crank sensor to the tachometer. The signal wire for the tachometer runs from the diagnostic connection. That connection can (and should) be installed if you want to install a tachometer where there wasn't one, simply open the diagnostic connection and install the connection.

I don't know the amount of pulses, but a lot more than the crank sensor. Every tooth of the flywheel is a pulse. You need an oscilloscope to be sure. The EGR wants to know the rpm because it switches off the EGR at low rpm (below 1000 rpm) and at full load.

Ah,

Yeah, wasfraidso...
That means a stream of pulses. Boring.

POST 84 TACHOMETER ANYONE? hahaha.

And, has anyone a socket +amp+ pre 84 tachometer for sale?

I am not giving up yet. Thereīs more to see.

Thanks Gov, appreciate it.

Jan