ALFAGTV6.COM

Part Two

More details of mods to shifter..

Final Part

A comparison of the original "front section" and the modified one.

(The rod welded to the shifter above the ball joint was an experiment to brace up what I consider too much spring in the selector itself owing to it relatively small diameter but this is just personal point and has no bearing on the nature of the shift geometry. Anortherwords, just ignore it.)

I started going a similar way to this.
I pressed the ball up 25mm on the lever and tacked it in place and then cut the shifter mount out of the trans tunnel and lifted it up so that the linkage still cleared everything. Lever top stays in the same position but the lever ratio changes from about 7.5:1 to about 4:1. I still need to change the gearbox end of the linkage (as Mike did) to reduce the lateral distance between the gates.

How do these two easier mods (not including MD's top side job) compare to the later isostatic system. ie do these mods produce a better feel or as good?

Daniel, it looks as if your "packing"out of the shift mount, to raise it, would still fit within the original centre console and gaiter, hence no outward change to the interior. Any pictures of what you guys did on the gearbox end to reduce gate distances?

thanks

mjr

For your answer, go to page one of this topic. If you need more info, just ask. As for the isostatic assembly, it breaks the fundamental rule of engineering which is : the fewer the moving parts, the greater the reliability. Can't beat the reliability and simplicity of the original changer.

A combination of Daniels stick (pivot) (ball) changes and my mods to the rear crank should get you shifting short and precise.

ok so I presume that last photo is the final crank to the gearbox? Sorry not been under the car yet to have a good poke around, and familiarise myself with the rear half, but its something Im looking at modifying. So reliability asides, I take it the later iso shift is not much of an improvement, and is still fairly sloppy. I drove a late 75 with this system, and to be honest apart from the shorter shifting, it didnt seem much better than the original system in good condition. The combination of yours and daniels mods, look like a nice improvement for almost no cost.

thanks chaps.

The later iso shift is a really nice shift if it has good bushings throughout.

I have an 85 GTV6 --> old style non-iso. Mine is v good though, as I have rebushed the shifter - rod bushing.

Something worthwhile that I have done to a few Milanos/75s and GTV6s is to rebush the front shift rod-end using sealed needle-roller bearings. Trying to be enterprising, I bought a ton of these some time ago:

mjr,
I'm not sure if the centre console will fit - I haven't got to re-fitting the interior yet. When I do, I think fitting the dash around the cage will create more of a problem than the console. I will check the console this weekend and post a pic.

This is a topic that I have been thinking about for some time. I drive a 75, but I have worked on a GtV6 box and have often thought that the 75 iso static setup seems overly complex.

Wouldnt these front section modifications work with a 75 iso rear section?
Or would it be better to scrap the iso set and change the 75 box over to a GTV6 selector shaft.
Isostatic rebuild kit costs $150 from performatek, less than a used gtv6 box. That is one advantage of staying with the complicated 75 setup.

MD,
Not to sound critical, but your extreme linkage reminds me of an oversized (tuned) isostatic. Your system isnt exactly simplistic either...

What direction do you guys think I should go?

shifts like an mx5 miata
Amazing.

Thanks, guys, for sharing your work. I plan to follow at some point. (After you guys have covered all the heavy lifting).

One simple idea that has passed between my ears is using a tube to replace the original shift linkage rod. Might save some weight.

I rekon from a cost, efficiency and results point of view, Daniels front section modification and MDs rear section mod are the way to go. Daniels front mod, is very simple and effective, and MDs rear mod is the same. It amazes me that no one at alfa ever thaught of doing it, it would have cost them nothing to do it. iso seems too complicated. Im going for the same mods, but replacing the heavy semi solid steel rods with high temp duralite alloy rods, cross drilled at the ends for mounting the couplings and connectors, similar to light aircraft control rods, very strong and light. this eliminates the welds all together, but will mean running up the crank and centre connetors on a mill. Im hoping that with the original shifter ball set up, the decreased weight in the whole line, wont make shifting too light.

mjr

Stay focused. You're on a winner there. You have the handle on what you need to do this. Just one thing. If you are going to go to that much trouble, why not make a puporse built shifter selector with the fulcrum ball in the correct location straight up but here is the key, make it out of twice the size shaft and taper it down to the gearknob. The problem with the existing one is its too light and springy.

(and don't wory about the weight issue, it's irrelevant)

md, yes indeed, i wish I had the time to go the extra distance and move shifter back to a better position as you say, but alas, there just are not enough hours in the day, hence a big improvement on the original set up without going the whole hog.

Has anyone tried modifying the front section on an isostatic car?