Installing tachometer

[ripley]

Hi ,s class, do you still can organize a tacho for 280SE ?

[floyd111]

and me!
I also want tachos in both my Euro 280S and SE.
Already found out I can't switch out the complete instrument cluster from a 350/450, due to the speedometer difference.
Wasn't sure the swap of a 350/450 RPM counter-only, into a 280, was possible.
So, if you have 2 such RPM counters available that will surely work in a 280, please send me 2 units.
PM me for address and payment details.

Stan

[floyd111]

Updates?

[s class]

Geez talk about a thread dug out from the dusty archives.  I have stripped several 280SEs in the last 10 years, and I can scratch through the boxes of clusters and see what tachos I have.  Definately, you must use one from a 280, the V8 ones will not work correctly.

[floyd111]

Looking forward!

[floyd111]

Still hoping someone may sell me 2 tacho's for my 280!
Any updates?

Another question..
I do like the idea of installing a factory loom for the tacho, ensuring a longer life span, or better looks.
How much more difficult is it to use such a loom?
Can I use the W126 loom for this?

[s class]

I have just been too busy to scratch through my box of clusters.

Replacing the wiring harness in a W116 is and ENORMOUS project.  It is one unit that covers everything from the K-jet injection, headlights, hooters, rear screen demister, fuel pump assembly, tail lights, aircon apparatus.  Replacing the harness requires you to remove the fuse box, and ENTIRE interior including the dash, and headlining.  Ask me, I've done it, when I converted a 280S to K-jet injection.

The harnesses are all different, depending if its for a carb engine, 6cyl or 8 cyl, K jet or D-jet, and what options the car is equipped with.  The only semi-separate component is the electric window equipment which is a separate harness that ties into the fuse box. 

And no, I really don't think a 126 harness is the way to go. 

[Guillaume C]

Some options use separate harnesses, like tacho, headlamps washer, sliding roof...

I have at least one (maybe to) 280SE tacho and some separate tacho harnesses for W116.

To install a tacho in a 280S, you have to use transistorized ignition from 280SE and later (post 1977) 280S.
That's why there was no tacho in 280S before 1978.

[floyd111]

I was indeed talking about the Tacho harnas.
I thought I read that installing such a tacho harnass was a terrible job.
I can get one now, so I wonder whether to take it.

About the ignition thingy..
Does that mean a pre-1977 280 can not have a tacho? Can I not modify/change the transistorized ignition around?

[Guillaume C]

I thought I read that installing such a tacho harnass was a terrible job.

No, it's easy because it uses a special harness with only two wires. You just have to pass it under the dashboard and in the fuse box and attach it to the original harness with original plastic cable ties on front fender.
The most difficult thing is to connect one wire to a fuse in the fuse box, but it's the same job with the original harness or with an aftermarket one.

On pre-1977/78 280S, you can modify the ignition system by using 280SE transistorized unit, ballast résistors and distributor.