Ok, so I can now resolve this one: definitely incompatible
As can be seen below, the long shaft is considerably longer than the corresponding X1/9 (4 speed) long shaft:
This photo shows the difference in total length (the outer CVs are parallel with each other):
As
@Lowtechprime kindly pointed out, the tripods are also bigger (although can be swapped for the smaller ones). See above, and below:
One interesting feature of these is that the boots are different for the long vs. short shafts. On the long shaft, there is a seal that fits snugly over the axle which rotates within a seal in the boot (rather than a seal that rubs against the axle, as per in the X1/9 variant). This would appear to be a superior design (the reason I'm looking into all of this is that despite two attempts, my inner boots still leak gearbox oil to a certain degree
).
Here are some photos of the boot on the long drive shaft. Note in the first photo there is a clamp holding the outer part of the boot with the seal:
Here is the same boot from the inside:
The shorter drive shaft is much more similar to the 4 speed X1/9 one, although again, too long:
In this case the inner boot is actually very similar to the X1/9 one (although on the X1/9 the boot is the same on both sides). So on the Ritmo / Regata, only the boot on the short drive shaft is similar to the 4 speed X1/9:
As on this side the boot has a seal that rubs on the axle, it is imperative that the axle has a perfect finish. For this "new" driveshaft, that was unfortunately not the case (I think it was remanufactured rather than new):
So the conclusion is that Ritmo / Regata driveshafts are NOT compatible with an X1/9. Some important lessons though:
- on the longer shaft, the inner boot / seal arrangement is vastly superior. So shortening one of these for both sides might be an interesting experiment.
- on the shorter shaft, the inner boot is similar but different to that used on the X1/9. It looks like it is listed for Pandas and even Fiat 127s. Some even have cross listings for an X1/9.
Basically it comes down to:
Standard style (4177472):
Alternative style (92601217 / 92601216 / 92601255 / 4220475):
The alternative would "appear" to be a drop in substitute with the advantage of having the seal sitting is a slightly different position. If you have a ring worn into one of your driveshafts from the rubbing of the seal, this might be a useful tip as the different boot will now rub on a different part of the shaft.
Cheers,
Dom.
