Tremec TR-6060 Gearbox

[ChimpOnGas]

Alexdaredevils said:

I think the heavy clutch issues are down to the pedal ratios Dave, as my clutch is stupid heavy!

Sat in a Vette with near enough same clutch but the pedal was longer by a good 3 inches and felt like as light as a Civic clutch

So maybe moving the clevis pin up 5mm and a pedal extension 1-2 inch might solve everything

Nice idea in theory Alex but remember the the objective of the pedal stroke is to move the push rod down the bore of the master cylinder in exactly the same plane as the bore.

If you think about it the location of clevis pin is more or less a fixed point dictated by where TVR mounted the master cylinder. The only way to gain a mechanical advantage while maintaining the clevis pin point (and the essential straight push rod stroke) is to increase the pedal length, IE the clevis pin centre to the point your foot applys the pushing force to pedal.

The obvious problem with this is that the bottom of the pedal will be become lower in the footwell and closer to the floor, unless you have tiny child like size 6 feet your heel will either be through the floor or you'll need to push the pedal with your heel

The limitations of introducing greater leverage are dictated by:

1: The fixed position of the master cylinder

2: The distance from the ball of your foot and your heel

3: The distance between the floor and the clevis pin

I's a nice idea to increase pedal length to increase the leverage but it isn't really practical given these fairly fixed perimeters.

And don't forget leverage is just another form of gearing, while increasing the length of a lever will reduce the force needed to move a given load, you will also need to move that lever further to achieve the same distance you move that load.

Even if you could squeeze a longer pedal in the Chimaera footwell you may just find the stroke required to disengage the clutch will either mean you'd need the pedal starting so high your knee will be up by your ear, or you'd need a six foot leg and pedal that went through the floor when you disengage the clutch.

Sadly and for all these reasons, trying to gain a mechanical advantage by increasing leverage is completely impractical.

It's the same packaging & leverage challenge with the brake pedal, actually without some help you would need very strong leg muscles indeed to apply the brakes of any modern car. Since the 1950's mnufcturers have solved this problem by using a servo which is why I explored the servo clutch idea extensively a few yers ago.

There is a clutch servo kit you can buy for the Land Rover that gives a very light clutch pedal indeed, you can't really use this kit on Chimera due to space, but you could fit a remote servo.

In the end I didn't follow through with this idea for the following reasons:

1. Cost

2. Potential loss of feel

3. No clutch until the engine is started, unless you fit a vacuum accumulator or electric vac pump (Diesel brake type)

4. With a correctly engineered clutch you really shouldn't need a clutch servo

But QBee took my idea and got engineer1949 to install a remote servo system, now I haven't tried the feel of Anthony's servo clutch but by all accounts it's as lovely and light as you might expect by there is the issue of it not working until you've started the car which makes leaving the car parked in gear impractical.

The reality is the solution to a lighter clutch for me is simply to ditch the heavy Helix and fit a better and lighter weighted unit, the truth is even with a supercharger 'Ol Gasbag' doesn't need a clutch with the insane ergonomically unfriendly clamping forces of a Helix.

I spoke with Lloyd Specialist Developments yesterday and they took me through all the work they've done quietly in the background to source a clutch that was both light on the foot and suitable for higher horsepower Chimaera's & Griffs.

They explained they have now settled on a unit that is both feather light and will happily doing service in many of their customer's higher horsepower cars including at least one running a supercharger.

TBH that's good enough for me, LSD have done all the work to find the right parts and they 100% stand by their work, so I'll simply have them do the swap and if their clutch doesn't last or work exactly as promised they will sort it FOC.

My guess is they would rather just do the job once and have happy customer than pull the thing down at their own cost until they get it right, which is why they've invested the time upfront in making sure they use the right parts in the first place, parts that are proven to give the desired result first time every time.

Works for me

[QBee]

I do park mine in gear, but I do mainly park it on the flat.
The reason I park it in gear always is that I hate the hand brake!
And on track days you can warp the disks using the handbrake.

If I start it in gear, with foot on clutch, the first lift of the clutch can feel clunky.
I either just put up with it, or knock it out if gear and give the clutch a couple of pumps.
It's worth it to have the lighter clutch - I have an arthritic left foot, and it's the ball of my big toe that hurts the most.
With the clutch lightened I can stand any amount of stop-start driving.

If anyone actually wants to try my lightened clutch, just ask. Always happy to help.

[ChimpOnGas]

QBee said:

I do park mine in gear, but I do mainly park it on the flat.
The reason I park it in gear always is that I hate the hand brake!
And on track days you can warp the disks using the handbrake.

If I start it in gear, with foot on clutch, the first lift of the clutch can feel clunky.
I either just put up with it, or knock it out if gear and give the clutch a couple of pumps.
It's worth it to have the lighter clutch - I have an arthritic left foot, and it's the ball of my big toe that hurts the most.
With the clutch lightened I can stand any amount of stop-start driving.

If anyone actually wants to try my lightened clutch, just ask. Always happy to help.

I'd love to try it Anthony, when are you next in the South mate?

[Bassfiend229hp]

ChimpOnGas said:

So I've done the sensible thing yet again and just pulled the trigger on an S10 tail housing which along with the Burton quick shift and a lighter clutch is going to me the most cost effective way to improve the one area of the car that lets it down in the aspect of driver enjoyment.

...and...

ChimpOnGas said:

Now I've bought that S10 tail housing all I really want to know is if the Burton Quick Shift is worth the extra £120 and should I drop my flywheel weight one more step and fit the 15lbs one from V8 Tuner?

Where did you get your tailhousing from? I had a hell of a time locating one!

Phil

[ChimpOnGas]

ChimpOnGas said:

I've bought that S10 tail housing

Bassfiend229hp said:

Where did you get your tailhousing from? I had a hell of a time locating one!
Phil

Hi Phil, easy as an EBay search mate.

I picked up a brand new S-10 tail housing from Paul Cangialosi of The Medatronics Corporation which is actually a small business operating out of Tequesta, Florida...

https://www.youtube.com/user/GearWorldTV

Here's Paul's website...

http://www.5speeds.com/

Paul Cangialosi is a respected US manual transmission specialist, I know him from the Jag E-Type T5 conversion kit he developed & sells. If you have a E-Type and want a five speed box he's your man, or you could just pay one of the UK E-Type specialists five times the price for the exactly same thing

Here's his EBay shop...

http://stores.ebay.co.uk/5SpeedsCom?_trksid=p20476...

Dave.

[NZ fan]

Alexdaredevils said:

I think the heavy clutch issues are down to the pedal ratios Dave, as my clutch is stupid heavy!

Sat in a Vette with near enough same clutch but the pedal was longer by a good 3 inches and felt like as light as a Civic clutch

So maybe moving the clevis pin up 5mm and a pedal extension 1-2 inch might solve everything

I altered my pedal ratio by boring out the 1" bore slave cylinder to 28mm and making a piston to suit. Made a big difference and still a good feel to the clutch.

[ChimpOnGas]

NZ fan said:

I altered my pedal ratio by boring out the 1" bore slave cylinder to 28mm and making a piston to suit. Made a big difference and still a good feel to the clutch.

Very interesting NZ fan, I haven't done the hydraulic ratio calculations but that sounds like a tempting mod if you say the stroke/bite point remained acceptable and there's zero clutch drag after doing it.

Obviously if the master cylinder bore remains the standard 0.7" diameter (this is what I have) and you take the 1" (25.4mm) slave out to 28mm you will lighten the clutch, but as with all things gearing/ratio you don't get something for nothing.

With a larger 28mm slave cylinder and the master cylinder bore unaltered at 0.7" the pedal stroke will definitely become longer to completely disengage the clutch, if you say the mod works well with no downsides then I may just try it when my new lighter clutch goes in as it sounds like it'll give further improvements.

The slave cylinder used on a Chimaera is just the typical old Girling type found on countless a Land Rovers so they are readily available, making trying a 28mm bore a relatively cheap experiment.

NZ fan, can you tell me if you changed the push rod length or kept the standard one from your original 1" cylinder?

Also here you say you bored it out to 27mm not 28mm...

NZ fan said:

Don't know how accurate this is or indeed if it will be of any help but I have just used a smooth piece of 3x2 down through the steering wheel onto the clutch peddle and some scales on top, it took around 35 lbs to "stroke" the clutch peddle through its travel. As stated on a previous thread I have bored my slave from 1" to 27mm some time back. Otherwise a standard 500 chimaera. I still wouldn't call it a lite clutch but I don't find it bothering me in traffic.

And here.

NZ fan said:

The ratio of clutch pedal travel to clutch release arm travel is part of the problem. I have bored out my slave cylinder from 1" (25.4 mm) to 27mm and made a new piston to suit. This improved things noticeably and it dosen't appear to be short on travel on the release arm. You could probably go even bigger - maybe 28-29mm and still have plenty of travel. The slave cyl. Is very heavy walled so can handle this mod no problem.

Can you confirm if you bored to 27 or 28mm please?

Also can you confirm you have a 0.7" master cylinder like me or if it's a different bore on your car?

Many thanks, Dave.

[NZ fan]

That's some good detective work there c.o.g. Looks like it was 27mm. It was over two years ago that I did the mod. And haven't had any problems. I have the part no. Of the seal I used Somewhere, I think it's in my old phone. I didn't modify anything other than the bore size. Pretty sure my master is .7"

[citizen smith]

Hi,

To lighten the clutch pedal, you could always move the Fulcrum Point on the pedal and have a standard AP Rover V8 Clutch assembly (suitable for a std 4.0 Chim) fitted.

I carried this mod. out on my 4.0 Chim and it totally transformed the feel of the Clutch Pedal (I have a very weak left foot).

[ChimpOnGas]

citizen smith said:

Hi,

To lighten the clutch pedal, you could always move the Fulcrum Point on the pedal and have a standard AP Rover V8 Clutch assembly (suitable for a std 4.0 Chim) fitted.

I carried this mod. out on my 4.0 Chim and it totally transformed the feel of the Clutch Pedal (I have a very weak left foot).

That's also interesting citizen smith

Sorry to be thick but can I clarify what you are referring to as the "Fulcrum Point"?

To me the "Fulcrum Point" is the point about which the release arm pivots, Ie this..



Or do you mean...

"A" The Pedal Arm Pivot Point?

Or

"B" The Master Cylinder Clevis Pin Point?



I'm just trying to understand what you did exactly, perhaps you have some photos of your mod?

If so I'd be keen to see them

Thanks, Dave.

[QBee]

Dave, I am bound to be around the softie south at some point. I will email you if I am. Same applies if you find yourself coming dangerously close to Yorkshire any time soon. Half the population of Newark on Trent seems to have Yorkshire accents.

[ChimpOnGas]

QBee said:

Dave, I am bound to be around the softie south at some point. I will email you if I am. Same applies if you find yourself coming dangerously close to Yorkshire any time soon. Half the population of Newark on Trent seems to have Yorkshire accents.

Thanks mate

[citizen smith]

Hi,

Sorry about the shortage of information, point "B" on your diagram of the Clutch Pedal to Master Cylinder.

[ChimpOnGas]

citizen smith said:

Hi,

Sorry about the shortage of information, point "B" on your diagram of the Clutch Pedal to Master Cylinder.

Thanks, that's the same as Alex's idea then.

So as I understand it you re-drilled the clutch pedal arm to move the master cylinder clevis pin up a bit, this had the effect of lengthening the distance from where your foot applys pressure to the pedal to the where the pedal arm acts on the master cylinder push rod.

You've effectively given yourself some more leverage.

Questions:

1. How much further up the pedal is your new clevis pin hole (taking your measurement from the original hole)?

2. Have you had any issues with seal failures?

With this mod surely the stroke of the push rod no longer exactly follows the line of the master cylinder bore.

I know the push rod has a ball end and the the piston a concave face to allow for slight variances, but I was always taught the push rod should travel (as near as possible) down the centre of the master cylinder bore so as not to unduly stress the lip seal?

Wouldn't the new obtuse angle of the push rod increase the risk of cocking the seal over and causing premature seal failure/leaks?

Thanks for your clarification, Dave.

Edited by ChimpOnGas on Monday 5th October 15:15

[citizen smith]

Hi Dave,

You have a PM.

[ChimpOnGas]

citizen smith said:

Hi Dave, You have a PM.

Much appreciated Bill

I've just responded to your message and kind offer of help.