using a 915 shift tower backwards for a 901?

[haycait911]

did a search but couldn't find a reference. maybe I'm missing something. my thought is this:

- take out the shift rod from a 915 tower
- re-install backwards, at 180 degrees to where it was.
- install tower in car, backwards.

this would give a positive reverse lockout for a 901. the only issue I can see is mounting the tower in the car and attaching the shift rod guide in place at the (new) back of the tower. not insurmountable fabrication issues. easy with a drill and some spacers, washers, bolts, etc. or slightly harder by welding new mounting tabs onto the tower base. any thoughts? am I missing something obvious? Don.

[911pcars]

Don,
There are several variations of your idea.

What you're proposing is doable. However, the base mounting fasteners use an asymmetrical bolt pattern. In addition to reversing the orientation of the shift lever, you must redrill/rethread the tunnel to match the holes in the shift housing. See below (my apologies to the contributor for credit).



-------------------
Milt, in one of his manic creative episodes, chopped and rotated the top of this housing 180º relative to the base, then rewelded in place; we'll call this creative solution "Franken-Hausen" for now. The former 915 5th/rev gate and factory spring loaded mechanism is now on the 1st/Rev. side for the 901 shift pattern. The added "gate" on the now-4th/5th side helps define those gear positions (hey Milt, that part looks familiar).



--------------------
Objectively, I suggest this one . No mods to the shift housing are necessary save for a couple of drilled holes to mount the tension block. In addition, every gear position is now spring-defined.


Yep. That's one of our Gate Shift kit's carrier plates as used on Milt's Franken-Hausen.

The single modification needed for a 901 is the removal of the 915's reverse lockout pawl as seen in the images above. The lockout isn't needed on the 1st/Rev side. Instead, the added spring tension from our kit pushes the shift lever from 1st gear into the 2nd/3rd shift plane. Available as a kit (you supply the 915 shift housing) or as a complete 901/915 bolt-on assembly. A factory short shifter can also be fitted.

There are several ways to go in the DIY mode + one of several aftermarket options.

Sherwood
www.seinesystems
(also available from our host)

[javadog]

Sherwood,

Ever tried this on a 914-6?

JR

[911pcars]

Originally Posted by javadog

Sherwood,

Ever tried this on a 914-6?

JR

JR,
To answer your question, I feel compelled to describe the overall situation.

Adapting a 915 shift housing to a 901 gearbox depends on the type of 901 gearbox - sideshift or tailshift installed; it depends on the type of shift linkage arrangement.

The shift linkage for "Tail Shifter" 901 gearboxes is similar to 911/901 gearboxes. The shift mechanism to move the shift forks is controlled by the same type shift tube through the chassis tunnel. The shift lever housing uses the same type ball-end lever and shift bushing as in 911/901 and 915 shift linkages. The bolt pattern to attach the housing is the same.


Thus, tail shifter gearboxes can accept a 915 shifter housing with or without our Gate Shift kit. A minor modification is to delete the reverse lockout pawl (5th/Rev on a 915; 4th/5th on a 901).

Other 914s use a Side Shift 901 gearbox. They use a similar shift lever housing. However, the shift lever, instead of having a ball end, attaches to its matching shift tube with a threaded fastener.

914 side shift, shift housing:


Unfortunately, adapting a 915 shift housing to a side shift gearbox isn't a bolt-on affair. An owner determined to do this must modify the lever-to-shift tube connection to make this connection compatible.

Sherwood
www.SeineSystems.com

Addendum: 914-6 gearboxes use tail shifter linkage

[javadog]

Sherwood,

You sure a 914-6 has a side shift transmission? I could swear mine's a tail shift....

JR

[911pcars]

JR,
Not sure now that you've advised me. If so, installing a 915 shift housing should be less of an issue.

Sherwood

[PCA7GGR]

factory 914-6 = tail shifter

[haycait911]

if an original '70 or '71 914-6 should be a tail shifter. thanks for the info Sherwood!

[911pcars]

Thanks for the correction guys. My post has been revised based on your input.

Sherwood