Have been seriously considering building a Austin Cooper (NOT 'S') to historic race and have been wondering if they only came out with the 7" disc brakes, or could you get the 7.5" factory fitted as an extra

If not........ .........can anybody out ther make the 7" discs stop a car in race trim


Help

Minimad

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You can take the boy out of the racer.........but not the racer out of the boy!

No, the Cooper 997 or 998 never got 7.5 discs ex factory. But many people fitted them for rallying.

Yes you can make them stop, not quite as good as an S, but not bad.

997 Cooper had tiny little postage stamp pads. Forget 'em....!
998 Cooper had square pads like an S, but lots thinner and a bit smaller.
The split pins in both Cooper calipers are the same, but on a 998 they go thru the pads.

Calipers are really the same casting, but the 998 has a wider slot for the bigger pads. I milled thru a pair of 997 calipers to take 998 pads, then fitted Hardie Ferodo Metal pads and a VH44 servo. This lot went into an auto Clubbie that I drove pretty hard. And it didn't stop bad.

These days I think you can get EBC or Mintex race pads.

Throw away the dust shields too, they really impede airflow to the discs.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

That sounds pretty good

I have been toying with the idea of running an under 1000cc mini in the Nb historics.(pre1965)

The engines should be a hellavalot cheaper to build, and if you blow one up......isn't that hard to replace!!

The problem comes with stopping the car.
Need a light car. Ie 850 type body

Therefore only 2 choices.
1. Race an 850........Drum brakes ....and a magic wand gearstick

2. Race a Austin cooper......7" discs ... bit a decent gearstick

Anymore ideas


Minimad

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You can take the boy out of the racer.........but not the racer out of the boy!

When they used to race 998 Coopers here in the `60s they were pretty fast, and it took an S to (just) outbrake them.

Cooper discs are only 0.250" (6.35mm) thick. Legend has it that they therefore get too hot, but...
When I replaced my 7.5" S (were 3/8" thick when new) discs 2 years ago, the old ones had worn down to under 7.0mm and were still stopping me OK around Wakefield Pk with Ferodo Premium pads..
go figure..

These days, with good cooling and decent pads I reckon 998 Cooper discs could stop pretty well.

Forget the 850 with drums....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Just talked to a fellow at CAMS.

I can't change the "whept area" of the disk, but larger pads and thicker disks are allowed.

Has anybody ever turned down a set of cooper S 7.5" discs to fit on a cooper 7", with the extra thickness left on the dics

Dr mini,
I haven't ridden off the 850 yet.....I know a fellow that used to race a Morris Farinas(spelling??) and was only allow to use drum brakes......and it used to stop

But I want discs if possible

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You can take the boy out of the racer.........but not the racer out of the boy!

Hi Minimad,

Who did you talk to at CAMS? I'm 99% sure that you can run 7.5 inch disks on a 997\998 Cooper in Historics. There is a 998 running in Sydney that I am sure runs the larger disks. I can find out from our eligibility officer from CAMS if you would like?

If possible you should run the 7.5's as all the good stuff (rotors and pads) is only available for these. You wont believe the temperatures and pressures that you will end up applying once you get going. I'm running Brembo rotors with Carbon Kevlar pads in mine and I chew out a set of rotors every six or so race meetings. (and thats with being careful to bed them properly and warm them each time slowly).

HRS

I talked to one of the historic eligibility officers up here in Brisse.

He had not heard of any cooper running the 7.5" discs, and seemed to think that only the 7" would be allowed. Hence this line of questioning in this forum

If there is someone down your way running the 7.5" discs, then maybe there has been a ruling to that effect and this will solve all my problems
I would be very interested to know

Minimad

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You can take the boy out of the racer.........but not the racer out of the boy!

I have just sent an email off to an eligibility office who is a friend to ask his views.

I'll let you know.

HRS

Minimad,

I have confirmation of what is legal.

To run the 7.5 inch disks you need to run the car as a 970 Cooper S which is still 1 litre. To do this you need either a Cooper S motor or 1100S block with shorter stroke and longer rods (not easy). If you run a 997 or 998 block you have to run the 7 inch disks.

He also says that if you are trying to save money it is a mis spent idea as you can build a car of the same speed for alot less money with a 1275 than a 998. I have to agree with this as once you start racing all you want is more power and speed and will probably update in the end anyway which will end up costing you double.

Many people start with a 1275 but in just hot road trim and get the suspension and braking right then add a more powerful engine as their budget permits.

Hope this clears the matter up for you.

HRS

you guys are great

Thanks for all the great info.

I can get my hands on a set of 7" discs for little money off a friend. I also have many 998 engines lying around for nothing. I thought I might start with this and....you are right.....then go for the 1275 and 7.5" brakes as required.

The other consideration is that there is all the under 1 litre records around that hardly anybody is chasing. This could be fun

When I learn to drive the car, my son will be old enough to race and I can hand it down (know doubt a little secondhand looking ) and build myself a new one!!

Now....I can't use the 7.5" disc brakes.......can anybody make the 7" stop

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You can take the boy out of the racer.........but not the racer out of the boy!