Clutch and flywheel advice - Minispares

[Jono]

I need to purchase a complete clutch and flywheel assembly for my engine build.

It's a 1293 with circa 85bhp/good torque and I'm have the bottom end fully balanced. It will be used mainly for fun but with some possible 12 car events.

I am looking at the Minispares steel flywheel - the moderately lightened one for road use (unfortunately out of stock at the moment).

Is this the best to go for and what sort of pressure plate, clutch plate and diaphragm should I use? I have a blue diaphragm - would this be sufficient or should I go orange. There's a huge price difference in plates between std and rally - would a rally plate be advisable at my fairly mild state of tune or could I get away with the std Minispares plate?

Cheers

Jon

[Richspec]

orange and rally plate are my default options for everything.
I really wouldnt want to go to Grey or paddle / race type plates as some of my mates have to as they can seriously spoil a road car.

[Jono]

brilliant, clear unambiguous advice - thank you.

Jon

[Vegard]

I'd fit an ultralight flywheel though.
There are absolutely no downsides with this vs. a "road" steel one.

I'd fit a blue diaphragm on that. What wheels/cam have you got?

[Spider]

I'd fit an ultralight flywheel though.
There are absolutely no downsides with this vs. a "road" steel one.

True, but there are many upsides, apart from better engine response, longer crank life for one.


In regards to the Diaphragm, I'd suggest fitting the softest you can get away with, your Crank Thrusts (and Crank & Block) will thank you for it. The Standard Cooper S Blue Dot is good for about 90 ft/lb, 85 - 90 HP in good but used condition.

[GraemeC]

What cam and gearbox?

[Jono]

It's a 276 cam and the gearbox is a straight cut with ST ratios and 3.4 diff

[GraemeC]

Then I would avoid the ultralight flywheel - with that cam and the high gears you'll have to slip the clutch to a degree to set off smoothly, this generates heat that the heavier flywheel will handle and dissipate better.

[ianh1968]

If you are going to optimise the setup, which you really should,
you need to make sure that the diaphragm spring is "flat" when
it's all clamped up.

With all brand new parts, I have found it necessary to have
the "horns" on the backplate machined to achieve this.

Additionally, if you follow the oft-quoted advice and fit 3 drive straps
between each horn and the flywheel and you don't compensate
for this by machining the horns by the same amount, you will be
de-rating the effectiveness of the spring by one strap thickness.

Whenever I have seen this "fit 3 straps" advice, there has never
been a mention of this problem. It can make a LOT of difference.

Check This:
http://www.minimania.com/Clutch_FAQ__non_Verto_

My setups:
Flywheel, Steel 4.3Kg (Approx)
Backplate, Steel C-AHT230
Disk, Rally C-AHT596
1330cc - Orange Spring
1480cc - Grey Spring

This was what happened when I used a "standard" type disk:

201211MiniClutch-003.jpg

Ian

[Spider]

ianh1968, mate, if you're hungry, I'm sure you'd find some biscuits in the cupboard. That would taste, well, YUK!

[Jono]

Many thanks for all the advice chaps in particular the bit about clutch set up from Ian - very interesting and I will certainly be following that advice.

I have ordered all my bits from Minispares now and am collecting on Monday - lots of nice shiny parts (don't tell the wife) As far as the clutch assembly goes, and based upon the comment here, I have decided on:

Lightweight steel road flywheel and back plate
3 ply drive straps (noting the advice to machine the pressure plate lugs back)
180 rally plate
Orange diaphragm

...and lots of good stuff for the head and top end

Will post on progress as the build progresses. This is my first proper A series build so I'm on a bit of a learning curve and there will be lots of questions

[AndyB72]

I used a 'blue' one on a similar spec engine I built and had no problems.

[ianh1968]

180 rally plate

Make sure that you haven't ordered a "Verto" one...
If you have ordered a GCP271AF, it's the wrong one.

You need a C-AHT596 for the "pre-Verto" clutch.

Ian

[Jono]

Thanks Ian...you had me worried, just checked and i've ordered the correct one

15% of this week which is well worthwile, just snuck in with the order