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I'm fitting up a Laycock Type J overdrive to my 712M. Anyone have experience with using two Lobro CV's and a spline shaft for the short drive shaft? I've got about 5" total.

Thanks

Good luck, I hope you are using a scatter shield, not the strongest type of OD by any means. As for the shaft, remember the engine and trans are on 3 mounts, not 4. The shaft must have sufficient play, but you may be able to mod a VW 960 CV joint,boots and shaft to fit, but it will be hard to balance.

Jim,

Thanks for the heads-up. This particular OD was built up with a GV sump and some beefed up innards. The mount to the tranny is sound.
See below rendering.

Finally have the OD hooked up and functioning. Boy, its nice! 56mph at 2950 rpm. I still have power to accelerate. I'll post a complete write-up soon after some more testing.

Looking forward to it.

That sounds really interesting. Can you post what it took to do it,
and how it's working?

OK, just got back from a 100+ mile test drive with the OD unit. Temperature was 85 degrees plus, climbed over 1000' pass and on the way back I had some stop and go traffic.

All I can say is, I would never drive the Pinz again without it!

On the highway, I can cruise at 56mph at 3K rpm........all day long.....as long as it's relatively flat. I just have enough power to rise above the
overpasses without turning it off. I have a stock motor (unknown milage) on a 712 with 265/75/17 tires. This really makes the Pinz viable for long distance camping trips for us. We have to travel 100 miles of dead flat before we get to the foothills of the Sierra, so this makes the Pinz the perfect camper for us.
I can accelerate with the OD on up to 67mph before I get some minor harmonic vibrations in the vehicle. I'm not sure where they originated from, but that's plenty fast for me anyway. Honestly, this is the biggest improvement, in my opinion, one can make to the Pinz if overall utility is paramount.
I noticed in doing some research on this forum, that the same concept in Europe was being tested using the same J-type Laycock OD unit in a divorced fashion. There is no room to do this that way. By replacing the transmission end cover with the adapter itself, I had enough room for the dual Lobro joint "drive-shaft".

I just have to grin every time I hit that switch and the rpm's drop about 800 and the Pinz drops into purr mode !!

So very jealous!

I'm local to you and wondering what it would take to do the same to mine. 710K in Fremont area. Are you a shop? Know one that could do the work? I can do many things but this seems advanced for me.

PM me and we can discuss. I have been extremely busy so please be patient. Thanks

looks pretty cool. How much did it run you to do this?

The OD units can be had for $500-$1000, rebuilt. The Lobro joints and spline was about $500 total. I made the adapter myself, with about 100 hrs of development and research. ( I like the challenge of doing things people tell you can't be done) If there is interest, I can can make small runs of 5-10 pieces or I can post to Solidworks files and any competent machine shop can CNC the adapter. I'll post the write-up from another computer soon.

I would be interested in the adapter if you would make it available for purchase.

I like the challenge of doing things people tell you can't be done

I understand where your coming from!

Nice job on the overdrive, it looks very professional!

What is the ratio of the overdrive? Is it small enough to "split gears"?

Jim,

You can split gears providing you keep the rpm's high enough to maintain the hydraulic pressure to keep the unit engaged. I'm, playing with that now; determining minimum rpm's vs. gears vs. loads. It doesn't seem to be consistent. When I get a better switch in place (on the stick-shift), I'll post the results.
I also switched out the ATF for gear oil as it was shifting into OD too quickly with a jolt. I now get a smoother shift in and out of OD.

Question....I'm trying to upload a PDF or Word file and it won't allow it. What type of file is allowed?