I think what sean's describing has the rear of each gearbox facing the other, so the selector rod inputs would need to be inverted?

That way, having the pivot point in between the 2 sets of rods would do just that.

The clever part is knowing when to ignore the hard parts and take the easy one - Citroen didn't bother with a single rod, they stretched all three to the gear lever.




That last image is computer-generated, so chinese whispers, but it's really helped me understand how it works. Sean's right - move the lever left and forward. The front (upper left) box left rod moves forward. The rear box right rod moves backward. Since that box is the wrong way round, effectively the left rod moves forward. Both boxes get reverse.

To lock the rear box out, the white knob on the side of the selector box seems to be some kind of a disconnect inside the box to sever the upper and lower parts of the lever. I know the clutches are hydraulic on the Sahara, and presume there's no clutch lock-out, just both always work, whether the rear box is in neutral or gear.

So it looks like you can't drive rear-engine-only.

This little beastie is currently running 2x602s and 'boxes. We decided to keep things simple by not linking the clutches together, we can run each engine separately, or if we wanted to run them both together the rear clutch is operated by a mk1 escort handbreak leaver on the floor (car is wider than a 2cv) and link the two throttles via an old heater control beside the seat. With the untrained eye you wouldn't know it was a twinned twin, no fan hole visible from the rear, instead an electric fan mounted behind the spare wheel, the underside is covered with 'bash plates' with fins cut in the back to help airflow. Ill try dig up some pics from when it was converted, car is currently in storage as my dad has moved on to play with land-rovers :/

Been there done that,

take a look at my Sahara lookalike/replica topic.....

viewtopic.php?f=19&t=2504

any questions.......

1-2-engines?

The original has this very simple little solution to swap the selector rods from left to right, looks pretty too. But a single rod set up would be simpler in a home built version.

Just seen an article in my latest Deuche magazine and it has a double engine Briot 2cv and the gear linkage looks very simple compaired to what has been posted (3 rods). It has a conventional lever (from the floor) with a single rod connected to the front gearbox about 80mm up it. The rear single rod is down on the floor running exposed between the seats.

I can't work out how a single rod system would work? :s

The floorchange on a G or Wheezer uses a single rod - as do a stack of other similars. Rather than connecting directly to the three sliding selectors inside the box, like the Sahara one, it connects to a shorter version of the normal 2cv lever coming out the top of the box. As you move the lever side-to-side, the rod rotates, and since it's cranked, it moves the lever side-to-side, too. It'd be done in a similar way to that Sahara box - the front engine comes off above the pivot, the rear off below, which swaps the motion over.