Part Two
More details of mods to shifter..
More details of mods to shifter..
- Attachments
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- 006Relocation of pivot tube.JPG (113.07 KiB) Viewed 14286 times
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- 004Insert stainless section.JPG (114.53 KiB) Viewed 14289 times
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- 003Relocated pivot fork.JPG (116.99 KiB) Viewed 14289 times
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- 002Selector fork.JPG (115.72 KiB) Viewed 14288 times
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- 001Extension to btm of selector.JPG (115.72 KiB) Viewed 14287 times
Transaxle Alfas Haul More Arse
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.)
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.)
- Attachments
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- 012New and Old comparison.JPG (118.06 KiB) Viewed 14284 times
Transaxle Alfas Haul More Arse
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.
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.
- Attachments
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- Shifter.JPG (195.18 KiB) Viewed 14229 times
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- Shifter mount.jpg (216.35 KiB) Viewed 14230 times
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.
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.
Transaxle Alfas Haul More Arse
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.
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:
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:
- Attachments
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- Bearing Seal 25%.JPG (23.69 KiB) Viewed 14078 times
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).
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).
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)
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)
Transaxle Alfas Haul More Arse