Due to changing the motor to the 5-litre-V8 from the SL, it would be handy to have the SL-instruments in the car. Speedometre, Rev-metre etc. just fit and no adaptations would be necessary ...

BUT ... the Pickup-Cluster is much smaller ... so what to do?

Part 1: "Shrinking" the SL-Instruments

21. March 2017


Dismantling the SL instruments

The cluster of the SL is significantly larger than the one from the Pickup. So I took it apart. I got a defective W115 cluster cheaply and used the frame to somehow try to fit the instruments in. One thing I found out right at the start: the control lights of the SL would not fit.

SL Cluster before dismantling
Gauges original
Speedometre original
Rev-Metre and clock original


Next step was to modify those instruments (significantly), so they might fit. As the circuit board had to be cut, quite some wires had to be reconnected. Furthermore I got a W124 cluster to use the - smaller - control light compartments. Those had to be fitted with the SL instruments.

Rewired gauge with "new" control lights
And the speedometre ... its box was just too large ;-)
Same with this one ... new capacitors for the clock installed too

First prototype ...

So after a lot of glueing, grinding etc. a first prototype was finished. The reset mechanics of the trip counter was shortened and also the adjustment "gears" for the clock had to be modified:

Instruments in the W115 cluster
Test at the "still operational" SL ... everything's still working!

In the next chapter I will show you, why I was unsatisfied with the "unprofessional" look of it and how the 3D-Printer helped again ;-) ... stay tuned!

Part 2: 3D-Print of the Cluster

1. April 2017


The Construction ...

As mentioned before, the "hand-modified" cluster didn't look too professional, so I thought I try printing it in 3D. My first 3D-printer didn't have a printbed big enough, so the whole construction started with two pieces ... to be glued together.

After purchasing my second 3D-Printer - which has a printbed of A4-size - I had a prototype lying on my desk on a sheet of paper. By accident I had a look at it and saw that it might fit diagonally on an A4 sheet. So after fiddling around for a while, I found out, that turning the whole thing 25.2 degrees would make it fit exactly on an A4-sheet ;-)))


The Result ...

Here you see photos of the last prototype. Everything fits, however there's no grinding for a proper finish done yet. Also it's printed in the most rough resolution, i. e. 0.3mm layer height. Nevertheless the printing time was around 26 hours (!).

A good friend of mine also watercut the plexiglass covers; the construction of those came directly from my construction and were put straight into the machine. Openings for resetting the trip counter and adjusting the clock are fit in. The 14-segment LED-display is another story, which I will tell you ... ;-)

Future Cluster, 14-segment LED Display integrated ...
Same stuff with the future plexiglass cover ...