17 replies to this topic

[Tyre biter]

Righto,

I have a couple of questions from a muppet with rudimentary mechanical know-how and bugger-all Torana knowledge.

Simply, after looking through a few helpful threads here on the subject I decided to go the UC pedal/cable type clutch arrangement. Thanks to a fellow club and forum member I nowadays have myself a UC pedal, and my gearbox has (supposedly) the correct bell housing and fork to accommodate the same.

So the past few days I have been turning my attention to putting the pedals into the car but hit a few problems it seems, and I am looking for a 'leg-up', especially from folks having done this UC pedal modification before please.

Here is my UC clutch pedal (left) versus the LX clutch pedal;







Apart from the hook on the top, the other notable differences and possible problems for me include;

1. The UC pedal is missing that return bump stop.
Q: Is the bump-stop required or can I easily do without it when using the UC pedal?

2. The spring on the UC pedal's pivot is oriented in the opposite direction to the LX, meaning when it is all bolted up and the spring latched in, the tension of the spring pulls the pedal forward against the firewall - this doesn't seem right to me...
Q: Do I need to (somehow) turn the spring around, or will the tension of the clutch cable over-ride the tension of the spring making for a 'happy medium'?

3. Is there anything else I have failed to consider?

Thanks in advance for whatever help you can give.

Cheers, TB

[yel327]

UC doesn't use a bump stop from memory, and the pedal should go to the floor when no cable is installed also from memory. I haven't done this for over 20 years so someone else here might have more recent experience!

[TerrA LX]

Sounds about right to me, UC cable needs constant tension on it otherwise you might drive over a bump and the cable end might fall off, leaving you with no clutch next time you shift.

[Struggler]

Correct guys, the spring keeps tension on the cable so it doesn't fall off the hook.

What engine do you have ? If its a V8 there are benefits to moving the hook a bit further from the pivot but this will need a gentle massage to the plenum floor to get clearance.

You will also need to drill a hole in the firewall for the cable, it doesn't come out of the LH/X hole.

Hope this helps.

[Tyre biter]

Thanks for your advice guys, much appreciated.
Makes sense what you all say re: clutch cable putting tension on the pedal - making for a 'happy medium' as I termed it.
Yep, a V8 to be re-installed.
Any tips of where exactly this extra hole is required and in the threads I have surfed here I've never heard of needing to move the pivot or the need to massage the plenum floor - any tips/photos/descriptions in this regard would be greatly appreciated please.
Cheers, TB

[Struggler]

The UC pedal is designed for a 6 cylinder bellhousing. The distance from the end of the fork to the input shaft on a 6 cyl is considerably shorter than the same distance on a V8.

Therefore the V8 fork moves through a greater arc than the 6cyl fork.

Therefore the cable has to have greater travel to effectively operate the V8 fork than the 6.

It will work with the 6 pedal but the pedal will be high and you may not have clearance at the throwout bearing.

To get around this I have chopped the hook off and rewelded it about 6-8 mm further from the pivot point, this in turn gives you more cable travel for the given pedal travel.

Hope this makes sense.

If you install the pedal as is you will see the hook travels very close to the plenum under the dash. When you lengthen the hook it hits the plenum and you need to tap it up a bit to gain clearance.

As for the hole in the firewall, I placed a square on the inside of the firewall and lined it up with the arc the hook travels through, marked where the hole should be and drilled on. I once messed it up and had to redrill another hole but fixed it by making a aluminium spacer for the cable outer that covered the misaligned hole. Looking at a UC cable clutch firewall should give you a good idea of the general area.

Hope this helps.

[yel327]

As above. V8 cable clutch pedals in VB-VK and HZ-WB have the hook further away from the pivot. As there was no V8 UC there are only the 6cyl pedals so to do it right you have to mod the UC pedal. IF GMH had built a V8 UC they'd have put in a pivot location for the pedal lower than the original 6cyl hole the same way they did it in late HZ and WB. Then the V8 pedal when sat side by side with the V8 pedal would sit in the identical location with the pedal pad and hook as per the 6cyl but the pivot would be about 20-25mm lower on the V8.

[308 Sunbird]

use a wb v8 clutch cable and a new vn v8 t5 Manuel through out bearing and just use the standard uc pedal and it will be great i had this on mine and was nice

Freddy, I use UC pedal, UC cable, and the rest (bellhousing, clutch, carrier & bearing) from early Commodore V8 and works well.
Whats the difference with using the WB cable and VN bearing?

[308 Sunbird]

Craig, as AJ & Yel have said, the pedal to fork ratio isn't perfect and it is a very fine line between
getting clutch clearance (pedal depressed) and bearing clearance (pedal up).
I found with the pivotball in the bell housing adjusted well out I was able to achieve both leaving the pedal about 3/4 inch
higher than the brake pedal. .
I agree extending the hook higher would give more adjustment up your sleeve and looking at my pedal, this would'nt go
anywhere near the plenum.
You do need to cut away a clearance hole in the cross tube brace that the brake pedal
bolt goes through and I guess this is what AJ is thinking of.
Hope this helps.

[Tyre biter]

Thank you all for your help - much appreciated.

When I bought the gearbox from 'Aussie 4 speeds' a while back it was fitted with a bell housing and fork with the UC set-up in mind and I was told all I needed was a WB cable (as mentioned in this thread).

I wasn't aware of the need to drill holes in the firewall and cut away at the brake pivot housing - wish I stayed with the rat-trap but I guess there is nothing like jumping into the proverbial deep-end!

It is good to hear the tension on the cable will overcome the tension of the pedal spring thereby lifting the pedal back off the firewall back to where it needs to be.

I will now try to track down a WB cable and follow your advice - see where I end up I guess.

Thanks again and cheers, TB

[Struggler]

You do need to cut away a clearance hole in the cross tube brace that the brake pedal
bolt goes through and I guess this is what AJ is thinking of.

Ooops, you might be right, I do remember touching something up, thought it must have been the plenum floor. I last did this conversion over 15 years ago !

Thanks for the correction.

[308 Sunbird]

Ooops, you might be right, I do remember touching something up, thought it must have been the plenum floor. I last did this conversion over 15 years ago !

Thanks for the correction.

HAHAHA Yeah I know what you mean, I did mine 25 years ago- thats why I had have a look!

[Tyre biter]

Just wanted to clarify a few things guys;

This image shows an arch cut away above the brake pedal pivot and clutch cable hook - is this the 'clearance hole' you referred to? I hope so - means I don't have to get in there and cut away into all that fresh paintwork...



This next image is of the shell before it was repaired;



You can see a hole cut in the firewall (circled in red) that we filled because we thought it had something to do with a hydraulic clutch set-up. Referring back to the top photo you can actually see the same circle from the inside having been repaired and painted - to the right of the clutch cable hook and below the screw hole (whatever that is for...).

Is this about the right place the hole needs to be for the UC/WB cable conversion?

Cheers, TB

Edited by Tyre biter, 07 August 2012 - 09:42 PM.

[308 Sunbird]

Craig, that is correct. The arch only needs to be modified if you extend the pedal hook.(optional)
The hole for the cable in the firewall is simply a straight line through the arch from the hook.

[Tyre biter]

Thanks Stuart - I appreciate your help with this.
Now to figure out how to drill through the weld to re-make the hole we welded up!
I am told it is nigh on impossible to drill through weld...
Cheers, TB

[308 Sunbird]

Your welcome- best of luck.