Steel Flywheels

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Steel Flywheels

Postby pbove » Wed May 11, 2016 8:15 am

As many of you will know, this subject has been rattling on for some time. However, subject to approval from the Race Committee (which I fully expect to be forthcoming) we will amend the Technical Regulations to allow steel flywheels for 2017. The details are:

1. The flywheel must have the same overall diameter as a cast Iron flywheel (i.e. the ring gear must be in the same place).
2. The existing clutch cover regulation will appply (i.e. a minimum of 180mm)
3. Flywheel must weigh a mimimum of 3.5kg

This allows flywheels to be made for both crank bolt pcds and to suit both standard and race clutch covers and organic and sintered drive plates.

I will be trying to find a supplier of such items, but equally, you would be allowed to source one from wherever you choose. Please contact me or any of the other committee members if you have any questions.

Peter
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Re: Steel Flywheels

Postby hcd » Wed May 11, 2016 3:23 pm

Hi Peter,

Would a different mounting solution be allowed with the proposal? Specifically, can larger diameter bolts be used to mount the flywheel?

Huw
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Re: Steel Flywheels

Postby pbove » Wed May 11, 2016 4:03 pm

Huw,

That would require a crank modification so probably not. Why are you interested in this?

Peter
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Re: Steel Flywheels

Postby hcd » Wed May 11, 2016 4:09 pm

Just my experiences from 2014 when two sets of flywheel bolts failed in succession.

The problem may have been related to my gearbox rebuild but it highlighted a possible weak spot in the drive line.

Huw
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Re: Steel Flywheels

Postby Martin Kemp » Wed May 11, 2016 6:09 pm

I had my flywheel bolts fail in race 2 at Silverstone. They were the original bolts at the proper torque and it is a standard flywheel.
It has not happened to me before though and I wonder whether lower grade bolts had been substituted at some earlier time in the engine's life.
I went to the FIAT dealer to find out exactly what they should be and was handed a set of ordinary grade M6 socket head cap screws.
When I laughed and said they had the wrong screws they got a bit upset and said they couldn't help .

Unless anyone knows exactly what they should be I would suggest using 12.9 grade high tensile bolts.

I think the steel flywheel is a good move and after all you don't have to have one. I think for me, not spinning on the first lap would have been a more effective strategy than lightening the flywheel

Martin
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Re: Steel Flywheels

Postby pbove » Wed May 11, 2016 6:42 pm

I have also had a set of flywheel bolts break, when I down shifted from 3rd to 2nd instead of upshifting from 3rd to 4th. I was pulling 7,250 rpm in third at the time and the bolts breaking (they were 10.9) probably saved the engine.
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Re: Steel Flywheels

Postby cartledge_uk » Sun Jun 05, 2016 1:53 pm

I'm really pleased with this move :+:

Martin, did you have a supplier for a 3.5kg steel item?
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Re: Steel Flywheels

Postby Martin Kemp » Sun Jun 05, 2016 7:48 pm

No. It was a few years ago that I looked into this.

Martin
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Re: Steel Flywheels

Postby F1300Tony » Mon Jun 06, 2016 3:24 pm

The same replacement bolt issue occurred with the Ford Kent engine. The 16 point bolts had a close fitting shoulder of a larger diameter than the thread that fitted the crank as well as the head and were up to the job without adding dowels, admittedly using Loctite. Then (as I remember) the 'replacement' bolts became ordinary capheads with no fitting shoulder. In my opinion they were not fit for purpose for a road car.
My point is that the important thing for a flywheel is that there is something of sufficient strength and total lack of movement to prevent the flywheel moving in the slightest. This means a tight fit, whether it is dowels of sufficient number and diameter or the shoulders of bolts.
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Re: Steel Flywheels

Postby ninja » Fri Sep 16, 2016 3:35 pm

hi,
if you want a steel flywheel for the formula contact TTV.
They are doing one for me.
nige
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