Dipped in green glass

[ferny]

Quoted from Nick Moore

I'm amazed that everything aft of the engine fits together so well - none of it is Triumph.

Fail to prepare and prepare to fail.
The worst bit (for me) is always doing loads of research, measuring a hundred times and then biting the bullet. Doing it properly is always worth the effort in the long run though!

[Mark Hammond]

I have to say, for me, this is one of the most enjoyable threads.  I can't wait to see this car completed.  It'll be one of the best GT6s around...

Mark

[Nick Moore]

Remember how I said how well all the non-standard components fit together? It looks like I spoke too soon.

One thing the GT6 has taught me is to check that everything fits, moves and works as it should. This morning I noticed that the clutch actuating arm was at the outer end of its travel. That's wrong, it should only be like that when the clutch pedal is depressed and the clutch is disengaged. So, gearbox off again. At least the engine/gearbox combo isn't in the car yet.

Everything in the bellhousing looks normal. The thrust bearing carrier slides easily along the input shaft's sleeve, and slave cylinder has a similar full range of movement. However, the thrust bearing isn't contacting the pressure plate's 'fingers'. That's not because the thrust bearing isn't moving far enough forward, or because the carrier needs to be longer. If it moved any further along the sleeve it wouldn't be properly supported - in the third photo you can see that it moves slightly past the end of the sleeve already. I wouldn't want it to move any further along without a longer support sleeve.

I've considered various options. There are two thicknesses of TR6 flywheel, depending on whether you have a long or short-backed crankshaft. Mine's a shortie, so the flywheel is deeper to compensate. The rear face of the flywheel is 1.5" behind the engine backplate, and the central recess is 1". Can anyone confirm that those are the correct distances? If it turned out to be a flywheel for a short-backed crankshaft, that could be the problem - but i don't think it is.

Looking at the clutch plates and flywheel, I noticed that the pressure plate's fingers were already depressed about 6mm below the rim of the pressure plate - see the last photo. I don't play with clutches very often, but I think the fingers usually stick out when bolted to the flywheel? When the pressure plate was unbolted from the flywheel, the fingers stuck up about 5mm, making a range of movement of about 11mm. That seems a lot simply from bolting up the plate. The driven plate's 9mm thick, which seems about right. And yes, the driven plate was installed the right way around!

My best guesses at the moment is that maybe Toyota flywheels aren't flat like Triumph ones, and that the driven plate sits in a slight depression or the pressure plate doesn't bolt up flush but rides on spacers. Or, the hybrid Toyota / Triumph clutch (which came with the kit) is wrong. Time to do some Googling, and contact the guy who sells this kit.

[Nick Moore]

A few more photos, showing the steel TR6 flywheel for a short backed crankshaft and its various dimensions. The ring gear seems to be in the correct position, as the starter motor's pinion moves out to engage the ring gear perfectly.

[junkuser]

Does the driven plate seem thicker than usual plates Nick?

[Nick Moore]

The driven plate is about 9mm thick. It could probably lose a millimetre each side before it's down to the rivets.

All the specialists are shut until next week, by which time I'll be back at work. But when I get back mid-month, I may take the clutch to a specialist. It has a driven plate with Toyota splines, and a pressure plate for a TR6. Possibly the plate thickness was overlooked. Googled pictures of Supra flywheels don't show stepped faces, so that's not it.

Another possibility - if the bellhousing is a few mm too thick it would produce this problem. Hmmmm....

[junkuser]

"if the bellhousing is a few mm too thick it would produce this problem."

Its the angle of the fingers when clutch assembled on flywheel that steers me to driven plate thickness Nick, but I could be misinterpreting what I think I am seeing.
i.e. problem appears to be well before bell housing considerations.

Would not take much variation to plate thickness to make a considerable change to finger position.

You could slip some thin washers under pressure plate mounting surfaces just to see how things change.

[Nick Moore]

You're on to something, Mal. I just tried refitting the pressure plate without the driven plate, and the clutch arm was in pretty much the correct position 🙂  Spacing out the pressure plate from the flywheel 3 - 4mm with washers would have had the same effect. It looks like the best solution will be to have spacers made up to move the pressure plate back.

I measured the driven plate properly this time. It's 10mm thick, and the rivet heads are countersunk about 1.8 - 2 mm. It could get away with thinner friction material and still have a decent service life. I'll see if there's a thinner driven plate available.

[Nick Jones]

Couple of thoughts from one who has been there......

1.  The thickness of the friction plate needs to be matched to the cover.  From the variants I have, most new Toyota friction plates seem to be 8.5 - 9.0mm.  Triumph ones are 6 - 7mm.  If you mix and match the thicker friction plate with std cover two things happen.  First, the diaphragm fingers end up nearer the engine and second, you need a massive stroke to clear the clutch.  They can work like this - my Vitesse worked like this for about 30k, though I confess it was largely a happy fluke and caused some head scratching when I was trying figure out why the more correct combo I tried next didn't work!

2.  I don't understand why you say the bearing carrier doesn't want to be longer.  In your current situation, to me it clearly does.  This is no big deal, there are different variants available (Sprint is the longest standard one) or you could have a simple spacer ring made up.

Cheers

Nick

[Nick Moore]

Thanks Nick, those thicknesses help a lot. I did a search of your postings about your W58, but didn't find any mention of plate thicknesses. Hopefully there are thinner ones available, or I can get a shop to fit thinner friction material.

As for the carrier - the sleeve it slides on isn't very long. When the carrier is fully forward (ie clutch depressed and disengaged) it overhangs the end of the sleeve by maybe 8mm. If the carrier were longer, its front edge would overhang even further and not be properly supported. The sleeve is part of the W58, but I'm not sure if the carrier and thrust bearing are Toyota parts, Triumph parts modified to fit the W58's sleeve, or custom made.

[GT6 M]

My self, would not shave the clutch face doon,
as that means it will have to be changed sooner.!!

If the clutch is disengade,n when its actually all bolted up, then leave it alone.
Butt if,t clutch arm is touch,n  or is restricted by the bell hosing hole, then elongate it further back

and if,t carrier slide is too short, then extend it. BUTT, it,ll soon no be too long,wen,t friction stuff is worn doon,
or am i missing some thing here,!!

m

[Phwoar]

M, you must be a Geordie, like!

[RedRooster]

Agree with M on this one, similar to my T9 conversion problems, an adjustable slave rod and a die grinder is your friend.

[Nick Jones]

Nick,

There's some on the subject here
http://sideways-technologies.c.....__st__20  (post 22 on)

Bottom line seems to be:
Although I crowed about finding a standard OEM clutch plate that would do the job when I first did the conversion, it's a compromise.  It's the only 215 mm clutch plate I could find that has the larger 29mm x 21T spline used on the W58.  It's original application seems to be light commercials such as Hiace vans - with 1.5 l petrol engines of 65 - 70 hp.
- Compromise one is that these plates have weedy torque springs (just 3 of them).  The Vitesse was easily able to bottom these out and eventually chewed them up (did take 30K odd though)
- Compromise 2 is that they are thicker by design than the OE Triumph ones which the covers are designed for.  As mentioned above, this can still work, after a fashion, but you may have trouble getting enough slave cylinder travel.  I had a 3/4" M/C on there, which I presumably put on to solve a non-clearing problem (though I don't remember doing so).  The increased travel does some strange things to the contact patch of the spring fingers to release bearing and highlights the fact that the Toyota release bearing isn't quite the right shape for the Triumph fingers.  
You will also find that the diaphragm fingers are closer to the flywheel face.  This might be solved by spacing the clutch cover from the flywheel by the same amount as the difference between the thickness of the Triumph friction plate sold with your particular clutch cover and the Toyota plate you are using.

I've just had a quick rummage through my collection of clutch parts.
The original plate I used was a QH 993AF (Hiace 1.5).  New thickness approx 8.6mm.  Mine wore to about 8.25mm in around 30k of fairly hard use.  This was enough to change the pedal action quite markedly, but it was still far from slipping - which is not surprising as it was used with an old style B & B pressure plate intended for a friction plate of around 7.8mm thick unworn.  This QH plate centre springs were insufficient for my 2L engine and certainly would die young behind your 2.5.

While I was hunting around for replacements I bought a complete new LUK clutch kit for a Hiace (it was cheap!) in the hope that the whole thing might bolt up to the flywheel.  It doesn't.  The cover is larger - looks like it is probably intended to be able to serve for larger friction plates as well.  It would physically fit on the flywheel but bolt holes/dowel holes etc would need re-drilling further out.
The friction plate supplied with this is actually made by Exedy and is a more robust looking item than the QH one, but still only has 3 springs.  Part nos on it are LUK 322 0111 60 or Exedy TYD063U.  It is 8.30mm thick new.

In the end I bit the bullet and bought a bespoke friction plate from Helix (Via Mardi Gras motorsport).  This is the correct thickness for the Triumph cover (7.8mm approx), has 6 beefy torque springs and the correct spline.    P/No. 703552/04 (centre plate 3552 + 29mm x 21T).  Wasn't cheap.....  but works nicely with an old style B & B cover.

Where did your clutch components come from?  If supplied with the kit then they ought to be able to help you (If Conversion Components then I've found Colin Dray helpful in the past).  Would be interesting to know what thickness of friction plate the cover you have was intended for!

From the pics, the release bearing carrier and release bearing look like the standard W series /Supra items to me.  They are pretty short - the OE bell housing is quite shallow and the OE flywheel/clutch is quite large.  Still reckon you could space the bearing forward if needed - you'll only be needing 5 - 10mm.

The release arm is different from the ones I have, which are nice looking forged items but is the same basic shape so they are probably interchangeable.

Law or unintended consequences gets you (and me) every time!  Good luck......

Nick

[junkuser]

You may find spacing out the cover much less than first thought will suffice due to the length of the fingers in relation to the point at which the pivoting action occurs Nick.

Triumph plate, from above post, 6-7 mm
Your plate about 10mm
So 4mm times the inverse of lever ratio would give you a guide to spacing required.

Possibly not all would agree with using spacers as an actual solution but if they were of the same shape as the contact surfaces it may well be the answer.  Have a look around and see if this could cause any clearance problems though.

("Spaced out" may be a poor choice of words at this time of the year.)

[Nick Moore]

Back in town and straight to the garage!

Although standard head gaskets are supposed to be compatible with a 76mm bore, the standard gasket's compression rings were only just big enough. If the gasket had been even slightly out of place, they would have protruded into the combustion chamber and the gasket would have failed. Also, the head stud holes were a fair bit bigger than the studs, so cement and luck would have been required to locate the gasket precisely before the head was fitted, and Terry warned me that gaskets can wander during the torquing process anyway. So, I stumped up the cash and ordered an oversize gasket from Chris Witor. It fitted a treat, and is much better quality than the original Stanpart gasket.

Once the head was on, the rockers fitted and valve clearances set, I was able to fill the sump with oil and prime the oil pump. That proved that the oil pump works, and that oil is getting to the rockers. It was good exercise!

I know I said I'd run in the engine using an original filter, but some of the powder coating started coming off the inside of the filter bowl. I'd asked the guy not to coat the inside for that reason, but he did anyway... The best solution was to fit a spin-on oil filter. I'd still like to run the engine for a while without a cooler, to avoid any swarf lodging in it and coming back to cause trouble later.

As for the clutch, I checked a Triumph driven plate, and it's about 3mm thinner than the Toyota one. The pressure plate's spring fingers deflect far less with the Triumph plate, so I'll talk to a clutch specialist tomorrow about making a thinner plate with the Toyota spline pattern. That should restore the correct geometry.

[Sheepy]

Nick, that looks beautiful!

Don't fit it in the car, sit it in the front room so you can just look at it!   .

Top work.

[Phwoar]

Quoted from Sheepy

Nick, that looks beautiful!

Don't fit it in the car, sit it in the front room so you can just look at it!   .

Sheepy beat me too it, looks like a work of art ready for exhibition in a gallery or museum. Looking good! I know it has to go into the car eventually but you should take a series of "well composed" high definition photographs suitable for enlarging and displaying.

I'll just have to pop up to BrisVegas for a look when she's running.

[ferny]

It's just pure porn.

[Hughbert]

Fantastic quality Nick well done 🙂

[tiggrr1]

It's a shame your going to have to fit it and get it dirty 😉

[JensH]

Hope you have a chance to get it DIRTY very soon  

[Nick Moore]

The clutch is slowly getting sorted. An engineering shop called Direct Clutches modified the Triumph pressure plate by altering its pivot point and grinding the 'ring' down slightly. Now it can accommodate the thicker Toyota driven plate, and the clutch fingers sit at the right level 🙂

That's half the battle won. However, even with the pressure plate's fingers at the right angle, the clutch fork is still in the wrong position. I've corrected that by moving the fork's pivot ball forward 3mm, and sliding the thrust bearing forward about 4mm on its carrier. That's just to work out the dimensions though, the thrust bearing needs to be correctly seated on the carrier. And that carrier is a pain - I don't think that part of the kit has been well thought through (and Colin Dray is ignoring me!). To disengage the clutch, it slides halfway off the guiding tube that surrounds the gearbox input shaft. I measured its overhang at 18mm! I can think of several solutions:

1. get a new carrier made which will move the thrust bearing 4mm further forward. The back side of the carrier could also be longer, so that more of it remains on the shaft when it's fully forward. That'd provide more support and make it more stable.
2. Machine a couple of mm off the front or back faces of the bellhousing, so that the carrier doesn't have to slide so far forward. However, there's a possibility that the input shaft might hit the flywheel. I'd have to measure that somehow.
3. Have a longer input shaft tube fitted to the gearbox's front cover.

Option 1 seems the best for now. Back to the machine shop to have a wee chat.

[junkuser]

Best not alter the bell housing Nick. Makes more work if you ever have to replace due to damage and not an easy machining job.

Agree new carrier to solve part of the problem.  Simple machining job.

Would suggest the longer fitting on which it slides also to get true support for carrier when up in its working position. Once again, easy machining job after fairly simple fabrication.  I actually made one for Datsun to VW box job out of an old hub that was knocking about, so your engineer may have something he can modify to save welding a flange onto a tube.

This car is sure keeping you entertained, but soon you'll be reaping the rewards.

Mal.

[Nick Moore]

Back to Direct Clutches this afternoon. Their suggestion was to lengthen the bearing carrier so that the thrust bearing sits further forward of the fork. If done right, it should keep the carrier on the guide sleeve. DC gave me a long list of dimensions to measure, so that they can modify the bearing carrier correctly - spigot length, bearing travel, flywheel depth and much more.

Yep, it's keeping me entertained, but I would have been much happier if i'd been installing the engine, not fixing some of the shortcomings of the conversion kit. Oh well, it'll be in soon enough.