Lightweight flywheel for S3 auto conversion

[shovelled]

I need your technical thoughts.

I'm about to change our S3 1973 E Type from auto to manual 5 speed. OK, why is another story but it also is supposed to be a manual car (heritage cert says so and the chassis number hasn't get BW after it).

I ordered the conversion kit in January and by the time I finish, its going to cost around £10k for the parts alone.
The gearbox is a Tremec 5 speed and took a lot longer to get here than was promised. To compound that, it was sent with the wrong 5 speed ratio so had to go back which took another 4 weeks.

I've just started looking closely at all the parts now, ready to start work for the winter months. I'm looking at the flywheel and then the clutch disc that was sent me and thinking this isn't what I was expecting.




The green wear surface on the flywheel sticks out about 2mm over the aluminium centre you can see.



What do you think, am are worrying about nothing!
It's a lot of time an effort to swop the parts not to mention cost so I don't want to get it wrong.
HELP!

[abowie]

I don't like what they've done to the clutch plate at all. I wouldn't use it.

Would it not be smarter to machine the flywheel to clear the clutch plate?

Alternatively find a standard flywheel.

[shovelled]

Thanks for you thoughts. Good input. I don’t want to comment yet as I’m just asking an open question to see what people think. Really value your collective thoughts, so keep them coming and don’t forget to vote.

[mgcjag]

Im not really understanding the problem....if you had a standard flywheel and the clutch plate wears then the metal surface of the flywheel would be worn.....so whats different ...im obviously missing something.....uh..ok think i see the problem now.....the central section of the clutch plate has had rivets partially ground down....dosnt look like a very good engineering solution......i know these green flywheels are reasonably common and i havent heard of a problem with them so i would look into the clutch plate.....is it correct? ....if you continue and use it.....then what clutch plate do you purchase when it needs replaceing?...one that needs its rivets ground down to use it? .Steve

[MarekH]

My observations are:-

1/ the green bit is wider than the friction surface of the clutch disc and that's the right way around. If the green bit were to have a wider inner diameter than the inner clutch plate diameter I'd have been concerned. That'd have led to an uneven (i.e. a step or ridge) wear on the clutch material and that'd clearly have been wrong.

2/ You express worry about eccentricity in the text in the picture insert. That's not how it works. The pressure plate and clutch disc are mounted onto the flywheel with a centring tool based on the spigot in the back of the crankshaft, so eccentricity is not possible.

3/ Filing away the clutch disc is a concern, not now, but in the future. This is because the clutch disc will wear, so whilst it may simply be ugly right now, what I'd really want to know is how much clearance (in the forward to backwards plane, as fitted in the car) is there now between metal to metal contact versus how much wear on the clutch plate do you have available to you. If it fits now, then all well and good for now, but what is the potential for metal to metal wear when the clutch plate has worn down? Put another way, you need to verify that a worn clutch plate still only contacts the flywheel and pressure plate at its friction surfaces, not by any metal to metal contact.

I don't think it is right to make the correction to the clutch disc if there is a concern that there is a mismatch. This is because you'll have to do it again when you change clutch disc in several years time. Altering the flywheel to fit a standard clutch would have been the right way to go. This "mod" appears to be telling us that the flywheel doesn't fit the clutch kit.

4/ £10,000 for parts sounds very expensive to me.

5/ Whilst you are there, check the number of teeth on the flywheel ring gear is compatible with your starter motor.

kind regards
Marek

[shovelled]

Hi Steve, Thanks for the comments, hopefully this will add to the post for you.

With a standard flywheel or even this lightweight one, the normal limiting factor would be if the clutch disk wears sufficiently that the retaining rivets come to the surface of the friction material and then rub on the flywheel and/or the pressure plate. But usually the clutch starts to slip first so you know its on the way out and you change it. Normally the flywheel side of the clutch disk either doesn't have any raised elements or it sits in a recess on the flywheel/pressure plate.


This is a picture of the new clutch disk (bottom) and an old disk from a Series 1 I replaced earlier this year, just so you can see what I mean. Those outer rivets on the series 1 disk (top one) are the same height as the friction material rivets so a nice amount of clearance.

The main issue as I see it is, the outer diameter of the body of the clutch disk is slightly larger in diameter then the inner diameter of the flywheel. Therefore if 1mm of wear occurs with the friction material on the clutch disk, then the flywheel will rub on the metal part of the clutch disk and generating noise and debris when pressing the peddle.

[shovelled]

My observations are:-

1/ the green bit is wider than the friction surface of the clutch disc and that's the right way around. If the green bit were to have a wider inner diameter than the inner clutch plate diameter I'd have been concerned. That'd have led to an uneven (i.e. a step or ridge) wear on the clutch material and that'd clearly have been wrong.

2/ You express worry about eccentricity in the text in the picture insert. That's not how it works. The pressure plate and clutch disc are mounted onto the flywheel with a centring tool based on the spigot in the back of the crankshaft, so eccentricity is not possible.

3/ Filing away the clutch disc is a concern, not now, but in the future. This is because the clutch disc will wear, so whilst it may simply be ugly right now, what I'd really want to know is how much clearance (in the forward to backwards plane, as fitted in the car) is there now between metal to metal contact versus how much wear on the clutch plate do you have available to you. If it fits now, then all well and good for now, but what is the potential for metal to metal wear when the clutch plate has worn down? Put another way, you need to verify that a worn clutch plate still only contacts the flywheel and pressure plate at its friction surfaces, not by any metal to metal contact.

I don't think it is right to make the correction to the clutch disc if there is a concern that there is a mismatch. This is because you'll have to do it again when you change clutch disc in several years time. Altering the flywheel to fit a standard clutch would have been the right way to go. This "mod" appears to be telling us that the flywheel doesn't fit the clutch kit.

4/ £10,000 for parts sounds very expensive to me.

5/ Whilst you are there, check the number of teeth on the flywheel ring gear is compatible with your starter motor.

kind regards
Marek

Hi Marek,
Thanks for the input and some really good points.
Your point 1, The clutch disk is wider but will only start to contact the flywheel once a 1mm of friction material has been removed.
Your point 2, I'm not too worried about any eccentricity, it is likely to be pretty small but will stick a clock on it to see how well that clutch disk is made.
Your point 3, its 1mm, then the clutch disk makes contact to the flywheel. Its 1.7mm of material before the holding rivets start to touch which is the max possible wear before normal metal to metal contact without this issue. It does seem that if there was no other clutch disk options then the flywheel should be different or have been machined.
Your point 4, Of course, it just is so lame as an auto although my wife really likes it relative to the S1 manual we have. Manuals used to sell for around £10k more than auto's but I think the market is changing a lot so who knows.
Your point 5, yes really good point, I'd actually like to bench test the whole power train but that might prove a little difficult .

[shovelled]

I don't like what they've done to the clutch plate at all. I wouldn't use it.

Would it not be smarter to machine the flywheel to clear the clutch plate?

Alternatively find a standard flywheel.

Cheers for the input, don't forget to vote!
If I end up getting the flywheel machined, they are either going to do it or pay for it! But yes, that would have been the more professional approach rather than compromise the clutch disk.

[Series1 Stu]

Wow!

Let's not mince words - this is a disastrous mish-mash of cobbled together parts.

For this kind of money I would expect a sweetly engineered combination of complimentary parts that work in harmony to give excellent service and peace of mind.

How anybody in all conscience can take an angle grinder to rivet heads and the clutch spring retainer seats is beyond me. I have seen the after effects of a clutch self destructing on a rolling road dyno. The bell housing was completely shattered and there were pieces of clutch plate embedded in the walls and ceiling. Fortunately, nobody was hurt.

Definitely not for me. I'm happy to say that my T5 installation looks nothing like this.

Regards

[shovelled]

Wow!

Let's not mince words - this is a disastrous mish-mash of cobbled together parts.

For this kind of money I would expect a sweetly engineered combination of complimentary parts that work in harmony to give excellent service and peace of mind.

How anybody in all conscience can take an angle grinder to rivet heads and the clutch spring retainer seats is beyond me. I have seen the after effects of a clutch self destructing on a rolling road dyno. The bell housing was completely shattered and there were pieces of clutch plate embedded in the walls and ceiling. Fortunately, nobody was hurt.

Definitely not for me. I'm happy to say that my T5 installation looks nothing like this.

Regards

Good feedback Stuart, I like it. Lets know how far you are away from Eccelshall? We need more E types on the road so finish off that S1 62 model

[George]

Hi Paul,

I don't know the date you purchased these items but as you bought them from Croydon the supplier comes under the UK long distance supplier rules (ie bought on the internet) and to quote them :-

"A buyer has the right to withdraw, free of charge, within 14 working days. Sellers have a 30-day period to deliver the product."

I hope this is helpful.

Cheers
George

[angelw]

Hello Paul,
Is the spline of your T5 First Motion Shaft, the same as the Jaguar Gearbox?

Its hard to tell for sure from the picture of the two clutch plates, but it looks like the spline diameter of the new clutch plate is smaller than the unit from the S1. If so, the spline of the First Motion Shaft of the T5 is probably a Ford 10 tooth spline. If that's the case, there are a myriad of clutch plates available to choose from to get one compatible with the clutch housing and flywheel being used.

If the spline is the same as the spline used with the Jaguar Gearbox, its my understanding that its not available as a standard part for the T5 and will either be a custom made First Motion Shaft, or more likely, a shaft made by welding the Jaguar spline section to the back end of a T5 First Motion Shaft. Welding is not totally taboo; if done correctly, it can be OK, but based on the workmanship applied to the modification of the clutch plate, I would be skeptical. There are better alternatives to a welded shaft, so I see no need to resort to that method.

Regards,

Bill

[shovelled]

Hi Bill

Yes the first motion shaft is the same, so that S1 clutch disk also fits on it fine. Just the wrong diameter.

I’m waiting to hear back from the supplier, hopefully a big apology and replacement parts. I measured the clutch disk and the flywheel and determined that they didn’t need to grind down the disk face and especially the rivets as they are in clearance until the disk is totally worn out. But the edge of the disk isn’t with the flywheel, so on a linear clutch wear out rate, you loose 50% of the clutch life and you damage the flywheel face edge.

I’m sure they will sort it for me as they have previously when we have had issues. Update you next week.

[angelw]

Paul Wrote:

Yes the first motion shaft is the same, so that S1 clutch disk also fits on it fine. Just the wrong diameter.

Hello Paul,
Its likely that the shaft is made by welding two sections together. It's easily determined just by examining the section of the First Motion Shaft between the rear end of the spline and the bearing journal; the weld is invariably harder than the parent metal and has a shinier appearance. If the width of the weld is circa 7mm at the surface, the depth of penetration will likely to be circa 3 - 4mm and insufficient.

Kind regards,

Bill

[shovelled]

Hi Bill

The first motion shaft has this concentric clutch slave cylinder on it. So without taking it off, you can’t see if there is a weld.
I do need to test the slave cylinder before I put it on the car, that’s kind of the downside with the concentric type, if it fails it’s an engine out job.

[angelw]

Paul Wrote:

The first motion shaft has this concentric clutch slave cylinder on it. So without taking it off, you can’t see if there is a weld.
I do need to test the slave cylinder before I put it on the car, that’s kind of the downside with the concentric type, if it fails it’s an engine out job.

Hello Paul,
That guide tube for the annular, throw out bearing actuator is only held on by 4 to 6 screws and then it lifts off. It has some type of silicon sealing applied to the interfacing faces of the flange and the gearbox that would have to be reapplied on assembly. If it were my car, I would like to know what I had before putting it into work. The owner of the car I'm converting from Auto to Manual using theT5 Gearbox, was adamant that he wouldn't have a welded shaft and I would have declined to take on the job had he accepted the welded shaft.

Regards,

Bill

[shovelled]

Hi Bill

I took the slave cylinder off, and this is what it looks like.
There is a number on the shaft T0120 15
What do you recon?

[Allrand]

Hi Bill

I do need to test the slave cylinder before I put it on the car, that’s kind of the downside with the concentric type, if it fails it’s an engine out job.

Interesting of that bleed nipple, how do you get to it?

[bitsobrits]

I took the slave cylinder off, and this is what it looks like.
There is a number on the shaft T0120 15
What do you recon?

Looks to me like an un-welded shaft, which is what you want.

[angelw]

Paul Wrote:

I took the slave cylinder off, and this is what it looks like.
There is a number on the shaft T0120 15
What do you recon?

Hello Paul,
That looks like a one piece shaft and if its the same spline as the E Type, then that's a bonus; I wasn't aware they were available off the shelf with the E Type compatible spline.

If its as it seems, yours is another example of there being much better options than resorting to welding two parts together. I've been using Tremec Ford Mustang shafts, with machining the spigot journal down to 0.499"being the only modification required. The spline is a smaller diameter, but there are a great assortments of clutch plates available to match up with whatever clutch housing assembly one may have.

Regards,

Bill