Rennshift install / 901 spring pressure, Are the springs pressing on bits in the tranny? Options

[smdubovsky]

I installed the Rennshift last night. Nice piece of kit to be sure. It spring loads the 4/5 plane just like the factory shifter spring loads the R/1 plane. My question is, what are the springs pushing against in the tranny?

The stock 915 (in a 911) uses a little tab on the 5/R side to keep the springs from pressing the shift linkage against stuff in the tranny. Here is a pic from Seine systems (he makes a 915 kit that also springs load 1/2 and adds the tabs to both sides).



You can see the little tabs and the hook on the shift lever that relieves the spring pressure when your anywhere other than the center plane (3/4 in a 915, 2/3 on our 901s). The reasoning is that you can spend alot of time in 5th gear in a 911 and its putting pressure on the linkage & couplings. The stock 914's stock shifter doesnt have it, but you'd never spend alot of time in 1/R either.

What is the spring loading in the 4/5 plane doing to the tranny? Are the 901 shift fork internals that much different from a 915 (doesn't look like it in the pics I've seen)?

Just looking to keep the tranny healthy,
SMD

[smdubovsky]

James/Mike - Thanks guys. I thought side loading the 915 pushed one of the selector forks against the slider/syncros/etc. Maybe it was the fore/aft that you were mentioning Mike that I remember. It has been years since I've seen one apart and played w/ it. Its why I said I partially bought into the tab idea and was asking the question.

Mike, I wasn't talking about the wevo shifter, but the gateshift - the gate that goes in the tranny.

James, you should do a FAQ w/ pictures on why sideloading the levers in the tranny doesn't wear the sliders. I figure Im one step ahead of most in that I've actually played w/ the internals of a tranny, but there must be others out there who thought the extra tabs were also a good idea. I wouldn't target starting a war between companies, but it would dispel some myths.

All that being said, I went out to the garage and shifted the 915 (in the 911) w/ its weltmeister shifter. There is no mistaking youre in 5/R. If you engage those little tabs, the shifter got the right gear. You can both feel it and look down and see it. It may just take practice, but when I shift into 5th (or 1st) in the 914 - I *know* I made the correct movement, but the lever moves back towards 3rd when I let go. When I put my hand back on it or even look down at it, it seems like its in 3. Just a little disconcerting.

I ran out to the car and measured (from knob to the door), Even though I can push the shifter >2" (3rd->5th) it springs back >1" until its only 3/4" over from where it would be in 3rd. Is that normal? Maybe my shift rods are slightly worn on their sides if it isn't? Some sort of tabs/gates would definately help the perception of hitting/keeping the right gear though.

James, Im in no way knocking the rennshift. I mentioned in my first post its a fine piece. When I get the 911 back together, I'll likely buy one for it too.

SMD