Flywheel & clutch advice please.

[dougal9887]

Whilst awaiting return of cylinder head and pistons, I have turned my attention to flywheel and clutch.

The build is based on a tall block conversion. The gearbox is 5 speed.

The two available flywheels.

The bottom end has been balanced. The flywheel fitted is the crossflow, has been lightened (5kg so 1.5kg less than standard) and has a virtually new ring gear. It would require a 7.5" clutch kit and a specially made insert to take the spigot bearing.
So the advantage of using this is basically that it is part of the balanced set up.
The disadvantage is the special insert, possibly the lightening, and the 7.5" clutch. So, has anyone got experience of this setup and am I risking clutch slip unless I were to opt for a heavier duty clutch and would the lightened flywheel end up an annoyance.

I also have a Lotus flywheel and 8.5" clutch.
The advantage of using this set up is basically it's all ready to bolt on and is standard tried and tested.
The disadvantage is that I loose the engine balancing (however this may not be particularly important as I plan to run within the standard rev limit), the ring gear is worn and the flywheel mounting holes are slightly damaged (this damaged occurred when I spun the car, as a callow youth, shearing the flywheel bolts ); the damage is mainly to the extremities of the holes and the bolts feel a reasonably good fit. After the incident I obviously took the same view and bolted the flywheel back on. The car was then used, after necessary replacement of the chassis, offside rear suspension and wheel , as a daily driver for three years with no ill effects from the damaged holes. I could save changing the ring gear by fitting a pre engaged starter which I fancied anyway.

Looks like I'm leaning towards the Lotus setup, despite the damaged holes and loss of balance and putting the hard earned towards a pre engaged starter. The friction plate has 1.00 mm above the rivets, does anyone have a figure for a new plate. I'm thinking that with low annual milage there's sufficient wear left to re-use.

Views and comments and any advice welcome!

Thanks, Dougal.

[ericbushby]

Dougal,
Surely a new pre-engaged starter will still need the ring gear teeth to be in good condition to engage with, just the same as the inertia type starter would. It still has to engage cleanly even though it is not under power until fully engaged.
Perhaps you should think of fitting a new starter ring while you have the chance.
Eric in Burnley
1967 S3SE DHC

[PeterK]

The upper flywheel also looks like it could do with a slight surface skim.


Regarding the clutch friction plate - they cost so little and as you need to remove the engine to replace the clutch, I would replace regardless, while the box is out.

Peter

[dougal9887]

Eric,
Thanks for your reply.
A pre engaged starter engages from the opposite side to an inertia starter so I would be using the unused side of the teeth. Interestingly, the ring gear, which is original to the car, has chamfered teeth both sides. The gear on the X flow flywheel is chamfered one side and square the other. Lotus saving weight again . I believe pre engaged starters happily engage with the square side also.
Dougal.

[Craven]

Hi,
Couple of numbers that may be of interest,
Torque Capacity 215mm Clutch---- 165 lbs/ft
Torque Capacity 190mm Clutch----100 lbs/ft
Lots of info available on AP Racing Web site.
Ron.

[dougal9887]

Peter,
I know what you mean. The Lotus flywheel looks better now that I've cleaned it up, a bit glazed but quite flat and the pressure plate surface is also okay. Since the ring gear needs to be removed to take out the dowels for skimming then it would be new ring gear, a skim, new friction plate and a new pressure plate and release bearing. What I'm thinking is all or nothing and I'm not sure it requires all just yet. And that would make the case for considering the X flow flywheel!
Could be wrong of course .
Throughout the rebuild I've looked at every component and fitting to decide on replacement, repair/rebuild or good enough, rather than the replace everything approach, so that costs are kept within bounds. I aim for a serviceable car rather than a new one. I suppose I view this as a service item whereas chassis and body/paintwork/interior/chrome were seen as restoration items.
We'll see how the opinions stack up which will help me make up my mind.
Thanks for your input, it really helps.
Dougal.

[dougal9887]

Ron,
That's great information. I'm aiming for 150 lbs/ft so that would rule out the 7.5" clutch in standard form at any rate.
No doubt the reason Lotus went to the 8.5", so a point in favour!
Thanks,
Dougal.

[ericbushby]

Dougal,
Of course, as you say, the new starter would use the undamaged side of the ring. I didn't think of that and I have one.
Eric

[oldchieft]

If the box is a ford type 9 then I would go the whole nine yards and use the clutch that goes with it.

I fitted a type 9 to a crossflow engine, and used Sierra parts from fly wheel to back to the gearbox.

.

This was my parts list for the job

Jon the Chief

[AHM]

Dougal,

I understand the sense of re-using serviceable parts. It somewhat depends how daunting you find removing the engine. an afternoon job? or a month of worry!
On my spare (original Borg Beck) clutch plate the depth from the face to the rivets is 1.4 to 1.6 mm. So it would appear that yours is only 1/3 used.

On the other hand I can't work out why you would try to save money on machining, balancing and a ring gear, in order to spend twice as much on a starter that you probably don't need.

[dougal9887]

No, you're right, I most likely don't need a new starter motor but they do look nice and shiny . So back down to earth.

It was my view that the friction plate, flywheel surface and pressure plate looked less than half way to replacement time, hence my reluctance to replace now. The ring gear is however quite well worn so I would either replace it, then have to have the flywheel rebalanced, or use a pre engaged starter on the fresh side! With the low anticipated milage I expect more starter wear than clutch wear .

Regards balancing, I assumed the flywheel to be balanced as standard, lost if I replaced the ring gear, and the issue was that it wouldn't be balanced to the, currently balanced, crankshaft. And I wouldn't have to remove the crank except for this operation. The nearest place to me for balancing is 2 hours away and they've had my cylinder head for new guides for 6 weeks so far

If I don't need balancing then I would remove the ring gear and have the flywheel skimmed locally. But surely if the flywheel is to be skimmed then the pressure plate should also be replaced? It also looks ok. And of course the friction plate. So I'm back to the all or nothing question.

What may sway me is the PM I received suggesting that the damaged holes in the flywheel could be bushed. I hadn't considered this since there's not much of a bolt head to hold the flywheel past a bush. Has anyone had this done?

Please keep the advice coming and I'll get there eventually!

Thanks again,
Dougal.

[PeterK]

If you've used this flywheel for many years, then the hole distortion can't be that bad (can it?)

If you're not worried by engine removal, then my cheap option would be replace ring gear, retain standard starter and use new clutch friction plate.
Peter