Sprint Concentric Slave

[Sprintparts]

Hoping that I can get some definitive answers to my question.

Has anyone successfully done their own clutch concentric slave cylinder conversion to a Sprint gearbox/clutch?

Have dug around on the forum and done searches, and although it has been discussed, can't really find any up to date info on a successful operating conversion. I am aware that there are several (UK) businesses that have concentric slave conversion for various Triumph gearboxes, and the price can vary enormously and the top end ones are expensive.

I am wanting to do the conversion to a couple of installations if it is successful. The machining of parts is not the problem, as I have some machining capability and If necessary have a good contact with someone who can make or do anything that I can't.

Ideally what I am after is the part number of concentric slave that has been used and proven to work on in a Sprint gearbox/clutch.

The internal size of the slave cylinder needs to be >33mm ( to fit over gearbox nose and make life easier than making a new nose)
Bearing contact diameter is approx 50-52mm, and bearing face should be radiused (as per original unless someone can prove that a flat face works OK and does not damage the clutch fingers).

Thanks
Mark

PS. Anything else that I am missing?

[Macleesh]

There's a kit available for TR6s, I assume it should work on a Sprint as the gearbox is the same (ish)

Bit spendy though....

https://www.racetorations.co.uk/product ... aring-kit/

Sean

[shaunroche]

Nope, that won't fit, the Sprint box is just different enough for it not to fit...

You want one of these off eBay...

https://www.ebay.co.uk/itm/196355367870 ... R7iV9qe2ZA

And one of these...

https://www.ebay.co.uk/itm/235148353013 ... R7yvg6i2ZA

And then you'll need to find a way of mounting it all....



If you've got access to machining services, the while lot shouldn't cost you close on a grand like that TR6 one!

That layout shown uses a concentric ring that squeezes the nose tube that is connected to the bearing cover plate - I think you can hang something off the four bolts that fasten the bearing cover down but haven't had time to work it out yet...may have a look at it now I have finished Sprinting and Hill Climbing for the year...

If you want to buy one off the shelf that's proven to work with proven quality then you want one of Rob's from Sprintspeed....

https://www.sprintspeed.co.uk/pages/pro ... ct-clutch/

[cleverusername]

Why do it? Concentric slave cylinders are a nightmare, if you end up with a bad slave cylinder you have to take out the whole grearbox to get at it.

[Macleesh]

The reason is getting rid of the troublesome cross shaft I assume. Certainly the reason for doing it in a TR6. Also a gearbox out job to fix properly.

I've had plenty of moderns with concentric slaves and they seem a sight more reliable than the types fitted to most classics. Their stroke length is much shorter so presumably that reduces the wear rate on the seal?

Sean

[cleverusername]

The reason is getting rid of the troublesome cross shaft I assume. Certainly the reason for doing it in a TR6. Also a gearbox out job to fix properly.

I've had plenty of moderns with concentric slaves and they seem a sight more reliable than the types fitted to most classics. Their stroke length is much shorter so presumably that reduces the wear rate on the seal?

Sean

All I can say is the ones fitted to a Rover 75 are notorious for failing early, requiring gearbox out to fix. It isn't the only car with this issue, thanks to bad aftermarket parts.

[Sprintparts]

Nope, that won't fit, the Sprint box is just different enough for it not to fit...

You want one of these off eBay...

https://www.ebay.co.uk/itm/196355367870 ... R7iV9qe2ZA

And one of these...

https://www.ebay.co.uk/itm/235148353013 ... R7yvg6i2ZA

And then you'll need to find a way of mounting it all....



If you've got access to machining services, the while lot shouldn't cost you close on a grand like that TR6 one!

That layout shown uses a concentric ring that squeezes the nose tube that is connected to the bearing cover plate - I think you can hang something off the four bolts that fasten the bearing cover down but haven't had time to work it out yet...may have a look at it now I have finished Sprinting and Hill Climbing for the year...

If you want to buy one off the shelf that's proven to work with proven quality then you want one of Rob's from Sprintspeed....

https://www.sprintspeed.co.uk/pages/pro ... ct-clutch/

Great info, thanks for your help. Will do a bit more digging and report back on my progress.

Why do it? Concentric slave cylinders are a nightmare, if you end up with a bad slave cylinder you have to take out the whole grearbox to get at it.

Numerous people have asked me that, because I want to, and also enjoy the engineering challenge and the purist will hate it.

Like a lot of things these days there seems to be a lot of comments about failures and nothing about the good stuff. Lots of cars use concentric slaves which are reliable and trouble free, until they fail! I know of many cars that have had to remove Triumph gearboxes (and particularly Sprint) because of broken fork pins, worn fork pads, arms broken from cross shafts, worn cross shaft bushes etc etc, so what is the difference to remove to replace a concentric slave?

I have a Renault Clio race car and last year did a gearbox upgrade which uses a concentric slave cylinder. This required me changing from the cable operate clutch to hydraulic system and modifying the clutch pedal operation from cable to hydraulic, which was a bit or a mission. The cable operated clutch (Sachs competition item) was OK, but the hydraulic system is nice and smooth and progressive

[shaunroche]

The reason is getting rid of the troublesome cross shaft I assume. Certainly the reason for doing it in a TR6. Also a gearbox out job to fix properly.

I've had plenty of moderns with concentric slaves and they seem a sight more reliable than the types fitted to most classics. Their stroke length is much shorter so presumably that reduces the wear rate on the seal?

Sean

All I can say is the ones fitted to a Rover 75 are notorious for failing early, requiring gearbox out to fix. It isn't the only car with this issue, thanks to bad aftermarket parts.

I can only speak of my own personal experiences obviously.

At the risk of insulting people, I wonder if the majority of people driving Sprints on the road now are likely to be of an advancing age and will probably drive their cars in a somewhat sedate manner...I would also guess that none or few will drive them hard.

(I appreciate Steve (Carledo) that this does not apply to you because you are a Hooligan, I'm pleased to say! )

In that case the std master cylinder set up will unlikely be stressed much and only being used for a few thousand miles per year, and thus they will be perfectly adequate.

My Sprint is a competition car, it is driven very hard and in the course of an event where actual driving time may be less than 8 minutes, 100 gear changes would not be uncommon.

Therefore, sedate driving on the road is one thing and brutal beasting on the track is another. In 8 years of competition I have never had the actual concentric cylinder fail, only the copper plumbing which I have now replaced by plumbing the hoses directly in to the cylinder.

On VA138, my L reg Sprint restoration, I have done away with the master and slave cylinder and replaced with a concentric system.

Why? Because based on 8 years of very harsh 'testing' the reliability is proven. End of.

Interestingly, I did have a V6 Rover 75, and yes, the concentric cylinder did fail thinking about it.

[shaunroche]

Great info, thanks for your help. Will do a bit more digging and report back on my progress.

Why do it? Concentric slave cylinders are a nightmare, if you end up with a bad slave cylinder you have to take out the whole grearbox to get at it.

Like a lot of things these days there seems to be a lot of comments about failures and nothing about the good stuff. Lots of cars use concentric slaves which are reliable and trouble free, until they fail! I know of many cars that have had to remove Triumph gearboxes (and particularly Sprint) because of broken fork pins, worn fork pads, arms broken from cross shafts, worn cross shaft bushes etc etc, so what is the difference to remove to replace a concentric slave?

I have a Renault Clio race car and last year did a gearbox upgrade which uses a concentric slave cylinder. This required me changing from the cable operate clutch to hydraulic system and modifying the clutch pedal operation from cable to hydraulic, which was a bit or a mission. The cable operated clutch (Sachs competition item) was OK, but the hydraulic system is nice and smooth and progressive

Absolutely spot on and I couldn't agree more!

Numerous people have asked me that, because I want to, and also enjoy the engineering challenge and the purist will hate it.

No better reason for doing it then!

[Sprintparts]

[new to this]

This is my setup there’s a lot of adjustment if needed

[Carledo]

(I appreciate Steve (Carledo) that this does not apply to you because you are a Hooligan, I'm pleased to say! )

YEP! I'm a Hooligan! At 70, i've realized I don't have time to waste dawdling around! So I still drive 'em like I stole 'em!

For what it's worth, the Carledo has a concentric slave cylinder on it's Omega 5 speed, married to a stock Toledo master and yes, it has failed - ONCE.

But context is needed! Firstly, the gearbox was pulled from a scrapyard Omega, complete with the slave. The donor car had over 140K miles at that point. Then I made a mistake by fitting a too thin flywheel to the previously auto Carlton engine. This meant the slave popped to pieces the first time it was tried, OOPS! I just slapped it back together again. I DID consider a new slave then, but being broke and the slave being over £60, I left it alone. This abused 2nd hand slave lasted a further 8 years and 40k or so hard miles before it started weeping.

Replacing it was a doddle, The Omega box is short and light and the car has no parcel tray or carpets or any of that stuff that makes tunnel removal painful. It took me circa 3 hours, on a ramp, drive in to drive out. Another 5 years and maybe 30k or so more hard miles and the engine and box have been swapped to another shell and it's still going strong!

So, whilst i'm perfectly satisfied with the slave and the concept, there is one part still working that HAS truly amazed me, that being the Toledo master cylinder. When I bought the Carledo as a humble 1300, the master looked fairly new. It's never leaked, so it's still there through 2 bodies and 2 slave cylinders, over 13 years and maybe 70-80K miles of MY driving! If it ain't broke........

Steve

[Sprintparts]

This is my setup there’s a lot of adjustment if needed

What is the source for this slave?

Notice that it appears to have a flat face release bearing, how does that go with the Sprint clutch plate fingers?

How are you locking the adaptor on the gearbox nose?

Thanks
Mark

[new to this]

Mark

My slave cylinder came from a Mondeo, it lines up with the clutch plate okay, when it wears out ill use a Vauxhall omega next time, only reason is one of the threads on the Mondeo slave is an odd size, and i had to make up a hose just to take that thread, i didn't want to modify the slave every time it wears out

My mounting plate for the slave cylinder, slides over the gearbox nose, and its held in place by a pinch bolt

Hope that helps Dave

[Sprintparts]

Hi Dave,

Would you know know the part number of the Vauxhall concentric slave that is used for the conversion? We don't have Omega's in Australia, (could be the same or similar to our Holden Vectra), but in the aim of keeping this post a source of information for others, the part number would help.

thanks
Mark