5 speed T9 conversions
Posted: Sat Oct 02, 2010 10:03 am
Hi
See my other post today- this one might specifically interest those with T9 boxes already in their cars.
At last I've got back a couple of parts I was having made by my local precision engineer.
Basically I've designed a system that reintroduces the spring loaded bias against 5th gear. An earlier version fitted in a boxed sextion on the top of the lid. That worked very well but some might have considered it bulky.
This one screws into the lid and is about an inch round and about 1.5 inches high.
I'll stand corrected on the last point but my understanding of the Alan Voights system (which also screws into the lid) is that a ramp/cam effect acts as limit on sideways lever travel in the neutral plane.
To obtain reverse one pushes the lever hard over leftwards to overcome the spring loaded ramp which is effectively a cut out in the interlock disc in the main casing. Selection of 5th operates in a similar fashion ie you have to overcome a stepped resistance.
I know this idea works because I have something similar in my own converted car. The problem (if that's what it is) might arise when changing from 5th to 4th. Pulling the lever out of 5th one needs to manually pull the lever leftwards to overcome the ramp/cam which usually leads in turn to having to move the lever back to the right to find 4th or 3rd.
You do get used to it but I think a spring system without a ramp is better. My idea does this and has the advantage of being adjustable for resistance by substituting springs of different rates. The cam effect is retained for selection of reverse but this is no bad thing since selecting reverse is only done when stationary anyway.
Unfortunately fitting this system requires the box to come out but minimal work is required to the box itself- basically a captive nut needs to be welded to the lid, a separate spring plunger installed for reverse (this is virtually flush with the lid and measures roughly half inch in diameter) and the selector rod needs to be freed from the selector forks. Assuming my understanding of the AV system is correct the interlock washer would need to be flipped over and a new small ramp cut out (an easy task- the ramp is only about 1/10th inch deep).
The system works on a test gearbox I have and provides a smoother selection of 5th, finding 4th or 3rd means merely pulling back out of 5th, the spring then naturally pushes the lever across the gate to the correct position for their selection.
Measuring the clearance on my own car there is ample room to fit and remove the device with the gearbox in the car- a bit fiddly but only as bad as removing/fitting the carbs and a lot qiuicker!
If anybody wants any info feel free to contact me- if there is sufficient interest I could get a few made. I'm not sure about the costs since the one I have was a one-off but I imagine making a couple would be cheaper than what it cost me.
My number is 0151 480 8400
Regards
John
See my other post today- this one might specifically interest those with T9 boxes already in their cars.
At last I've got back a couple of parts I was having made by my local precision engineer.
Basically I've designed a system that reintroduces the spring loaded bias against 5th gear. An earlier version fitted in a boxed sextion on the top of the lid. That worked very well but some might have considered it bulky.
This one screws into the lid and is about an inch round and about 1.5 inches high.
I'll stand corrected on the last point but my understanding of the Alan Voights system (which also screws into the lid) is that a ramp/cam effect acts as limit on sideways lever travel in the neutral plane.
To obtain reverse one pushes the lever hard over leftwards to overcome the spring loaded ramp which is effectively a cut out in the interlock disc in the main casing. Selection of 5th operates in a similar fashion ie you have to overcome a stepped resistance.
I know this idea works because I have something similar in my own converted car. The problem (if that's what it is) might arise when changing from 5th to 4th. Pulling the lever out of 5th one needs to manually pull the lever leftwards to overcome the ramp/cam which usually leads in turn to having to move the lever back to the right to find 4th or 3rd.
You do get used to it but I think a spring system without a ramp is better. My idea does this and has the advantage of being adjustable for resistance by substituting springs of different rates. The cam effect is retained for selection of reverse but this is no bad thing since selecting reverse is only done when stationary anyway.
Unfortunately fitting this system requires the box to come out but minimal work is required to the box itself- basically a captive nut needs to be welded to the lid, a separate spring plunger installed for reverse (this is virtually flush with the lid and measures roughly half inch in diameter) and the selector rod needs to be freed from the selector forks. Assuming my understanding of the AV system is correct the interlock washer would need to be flipped over and a new small ramp cut out (an easy task- the ramp is only about 1/10th inch deep).
The system works on a test gearbox I have and provides a smoother selection of 5th, finding 4th or 3rd means merely pulling back out of 5th, the spring then naturally pushes the lever across the gate to the correct position for their selection.
Measuring the clearance on my own car there is ample room to fit and remove the device with the gearbox in the car- a bit fiddly but only as bad as removing/fitting the carbs and a lot qiuicker!
If anybody wants any info feel free to contact me- if there is sufficient interest I could get a few made. I'm not sure about the costs since the one I have was a one-off but I imagine making a couple would be cheaper than what it cost me.
My number is 0151 480 8400
Regards
John