NineMeister

With the front differential out of the way, the pre-loosened front driveshafts were easily removed. Now quite obviously the stub axle ends of the drive shafts are all that holds the wheel hub into the wheel bearing, hence when removing then something has to be fitted to take its place. PET lists two choices: a bolt with ABS ring at 130 each side or the RS one-piece tension bolt at £230 each side (+VAT). My choice? Sacrifice the C4 drive shafts, cut away the cage of the outer joint to separate the stub axle then machine it down to make a perfect RS one-piece bolt. Total cost £0 per side.

NineMeister

Meanwhile, Robin has cut down the new gear lever console, prepared the tunnel and welded it into place, joining it onto the existing top section of the console as used on the factory C4. With careful cold welding techniques this method saves the time and aggravation of stripping the interior for full welding of the complete piece.

Gus

What is the gain from the replacement gear shift lever box and console. Is this for a short throw?

NineMeister

There is no gain Gus. Quite simply the 964C4 has a torque tube running through the tunnel so it only has the top section of the box welded in which is used to hold the gear lever rubber boot. On the C4 the gear lever mounts to the torque tube.

That said you raise an interesting point. If you look at the gear lever console you will see that it has oval holes at the ends, not round. These oval holes receive a pair of plastic grommets (item 26 on the illustration) which have offset holes for the shift tube (item 27): the fit them with the tube at the bottom for standard gear lever, or with the hole at the top for the RS lever.

On some early 964C2 (-1991) the console does not have a slot, just a hole at each end with a plain round grommet. To fit an RS lever to the early 964 you need to convert the holes into slots and update the mount with the 993 grommets. Please, please, please do not fit an RS lever onto an early car and modify the tunnel under tray for clearance, this changes the angularity of the rod to the gearbox, will wear the shift and to be honest, is just a complete bodge job.

boxsey911

+1 I've just bought the RS shift for mine and will be having the box modified just as you say.

Gus

Colin -
I understand all - and know the tunnel well. I was tired of the play in the plastic bushings at the bottom of the shift lever and the forward going rod and replaced the ball ends with bolts and fitted rod end bearings. I now have a very sharp and crisp shift pattern. In the process I also modified the stock shift lever length and tunnel housing. The modified tunnel hosing was done because I raised the position of the shift tube ( for the longer shift lever ) Because of this I had to also modify the metal flange at the bottom of the shift box to allow for adequate travel of the shift rod going to the transmission. I have a shorter and sharper throw now.

Gus

Sorry - here are a few pics. the ball is easy to remove in each case as all you had to do was grind of the well and knock it out. Then fit a bolt in the hole with a shim and washers.

Gus

Cloin - In the re-read I noted your comments -
"Please, please, please do not fit an RS lever onto an early car and modify the tunnel under tray for clearance, this changes the angularity of the rod to the gearbox, will wear the shift and to be honest, is just a complete bodge job".
When you say it "changes the angle of the rod to the gearbox, will wear the shift, etc." This made me think, as this is really what I have done to a great degree. But in checking the rear rod going to the gearbox it is linked to the gearbox shift rod by a universal joint designed to allow the shift rod attached to move up down, left or right. This is very similar to the set up used with a Hewland gearbox which we used to modify the shift linkage on when the cars came in from GB. We would move the shift lever from the center console area to the right hand side ( done because the steering was right side and we US folks have a hard time shifting left handed) But, I digress. I see no issue of wear if the rear going shift rod is clear and there is no binding as the rear attaching universal joint as the universal can handle the angel. Where do you see wear occurring?

NineMeister

The shift will work fine, the wear will be the result of the angularity between the shift rod to the gearbox rod, the angle will cause side thrust on the gearbox rod which will wear the gearbox end seal, internal bearings and the rod itself. It is simply not worth the risk for the sake of elongating two holes into slots and buying two new parts for £10.

Gus

Ok - Your point is that it is important to keep the shift rod going to the gearbox at the original angle to prevent lateral thrust on the gearbox end seal and internal bearings and rod itself. This would be created if the RS shift lever was installed ( in a 91 or earlier) without raising the shift tube into the upper position as on later models because the shift box does not have this design and must be modified.
Will this occur even though there is universal joint between the gearbox shift rod and the long rod from the shift leaver?/ Doesn't the universal joint allow for some misalignment of the rods?

kos11-12

Interesting point , thanks for sharing Colin,

Could you please explain how the GT2 short shift is working , thanks .

NineMeister

Sorry to go all technical on everyone here.
Yes, the universal joint will allow the shift to work perfectly well but it will introduce friction from the vertical component (normal to the bearing) of the shift force due to the angularity of the two rods to each other.
F (Friction) = μN where μ = coefficient of friction and N = normal force
If the angle is 0, N=0, F=0.
It's a simple decision if you are an engineer. Unfortunately this is a case of "just because it works does not mean that it is right".

NineMeister

The RS gear lever is longer from the centre pivot to the bottom ball joint.
To present the ball joint in line with the gearbox you have to raise the pivot.
You raise the pivot by turning the oval plastic grommets (item 26) upside down, this raises the shaft (27) and all is good again and the gear **** will be in the same place.

NineMeister

Here is a photo of item 26 in place and the new front rod pivot (which is on the torque tube of the C4). The 9m made RS stub axle bolts in place & RS engine mounts now fitted as well.

Gus

Colin -
In the short shift kits I have seen the swing pin ( part #11 ) is lengthened to allow the rear shift rod to remain at the same angle as it was before the shift tube ( 27 ) is installed in the upper position. If this is not done then the shift rod going to the rear will be raised changing the angel going in to the gearbox resulting in what we have been talking about.