915 tranny: Help with figuring out custom shift linkage plz

NONO5.0 · 11-12-2003, 05:40 AM

Welp, I've mounted the 915 tranny out of a '72 911 into the DeLorean with no problems, however, now I'm having to figure out how to run the shift linkage. I'm just tryin to figure out how to make it work b/c the shifter is about 1 1/2 inches higher than where the tranny sits. Does anyone have any ideas on how to make the linkage work properly in this configuration? Here's the stock linkage:

and this is a simple diagram of how it is sitting in the car and how I'm *thinking* of cutting it to fit into the frame:

The rod is going to be cut about 2 inches shorter than stock, but I'm worried about the slight angle (being about 1 1/2 inches lower than the stock linkage as it seems the stock shifter makes a slight bend and then comes back straight.

Will this work? If not, does anybody have any thoughts or suggestions on how I can make this work?

Thanks in advance!

Tim Walsh · Tim Walsh's Garage

hmm.. can make a custom shifter rod (the vertial rod) so that it would be a straight shot down to the transmission?

old_skul · 11-12-2003, 06:25 AM

Given the fact that there's ball joints at the shifter end and the universal-style coupler at the tranny control shaft, you shouldn't have any problems. Joint like these are in place to help transfer off-axis loads into the axis the device operates in.

You're putting a 915 in a DeLorean? Engine too? Interesting. Pics.

BGCarrera32 · 11-12-2003, 07:54 AM

The shift lever pivots about an axle held in place in the casting that creates the shift tower. I would look at modifying the shift lever to drop it deeper or lower that 1 1/2" to make the shift shaft (with couplers) horizontal if you determine that having it angled is a problem. You will have to compensate your lever length (above axle/below axle) accordingly to obtain the correct aspect ratio. Hence, fabbing a new lever...

-BG

NONO5.0 · 11-12-2003, 07:57 AM

Quote:

Originally posted by l33t9eek
hmm.. can make a custom shifter rod (the vertial rod) so that it would be a straight shot down to the transmission?

I don't think a vertical rod would work b/c it has to be mounted to the shifter using that little bracket. Another thought I had was maybe putting in a u-joint where the bend down to the tranny starts. I wonder if that would help?

BTW, nope, I don't have any pics yet, but the engine I have installed is a Vortec 4.3 out of a Chevy S10. It worked ok with the DMC tranny, but eventually the tranny couldn't hold up to the power of the 4.3.

Thanks!

Eugene at Pelican Parts · 11-12-2003, 08:44 AM

What does that Vortec make? 1.21 Gigawatts? (Someone had to say it) Why don't you try mocking that orientation with some wood to see if it'll work. If it looks like it just needs more throw, modifying the shifter a bit could do it.

NONO5.0 · 11-12-2003, 12:00 PM

Quote:

Originally posted by AlwaysWong
If it looks like it just needs more throw, modifying the shifter a bit could do it.

Yea, I mocked it up with some PVC pipeing but of course, it wasn't a one piece item. I'm just lost on how to make a straight top rod, turn a bottom rod the same exact way without it being straight or with a different bend in it

911pcars · 11-12-2003, 12:52 PM

I thought I'd drop in here since we discussed your shift setup via email at some length a few weeks ago.

Angularity in the shift rod shouldn't pose too many insurmountable problems. I believe the 914 shift linkage, and many cars with a rear gearbox, share the same issues. Consider the driveshaft, as found on a RWD car. It's seldom when the engine and gearbox combo line up perfectly with the differential housing. That's why there's a CV or universal joint at each end to reduce the angularity and torque loss.

The factory shift coupling is already there on one end, so you've got one more to go. Go to the Aircraft Spruce catalog and find the desired CV or U-joint that you can adapt at that kink area of the shift tube. That should work. Don't mess with the shift lever pivot point by lengthening the bottom end at this time as you want the 915 to shift like .... a 915.

You could also be trick and orient the gearbox upside down as Porsche did in some race cars. This lowers the center of gravity as well as raises the shift shaft up a few inches - more in line with the shift housing. But you'll probably have to perform more mods to get the gearbox to work this way.

Sherwood
http://members.rennlist.org/911pcars