Cosworth 4 Pots info

[clarenceboddiger]

I have acquired a pair of 4 pot cosworth front calipers and looking at them next to the hubs I will have to drill the hub bolt holes out to 12mm and use High Tensile bolts with nuts on to mount the calipers.
Question is I dont know which discs I should be using with this set up, I beleive I may have to machine a bit off the face of the caliper mount to line the discs up centrally in the caliper, but if anyone knows the correct (ie nearest match) discs to use it would save me from possibly machining more off than I have to, also any thoughts on the best master cylinder to use, or is the std one capable of feeding the extra 6 pistons as they are smaller.
I'm sure someone must have experience of this and any advise would be greatly appreciated.

Edited by clarenceboddiger on Wednesday 17th October 22:03

[z_chromozone]

Hi,

The 4 pot Sierra calipers require different fitment to the standard 2 piston (extra large) From my previous investegation in this area I was warned by the Sierra cosworth guys that the conversion was not worth the effort of making them fit, as they are not really much better than the standard Cosworth items (their words, not mine), so I didn't carry on. Not that that stopped me wondering about it, so I am very interested to see how you get on.

However, if you already have the calipers I am sure there are ways of making them fit. I have never actually tried myself. The plumbing should be fairly straight forward, just use Cosworth parts, or Princess parts, they used to be the standard upgrade and are available.

If you want to know what disks to use then try the Cosworth 500 disks, with the standard hubs and go from there.

RS 500 1993cc 87-88 F-V NBD 203 283.0 24.0 22.5 55.0 63.5 4

They are the same as the standard 2WD Sierra cosworth.

If you can't get the calipers to fit and you really want 4 pots, then look at swapping the calipers for some AP's, 500 Sierra calipers still fetch good money, and this may off-set the cost.

Good luck ande keep us posted.

S

Edited by z_chromozone on Thursday 18th October 17:33

Edited by z_chromozone on Thursday 18th October 17:34

[loudandfast]

I have this conversion on my v8s and i can say its well woryh it.i used black diamond grooved and drilled discs.the mounting holes needed enlarging and i needed to shave about 2mm off the mateing surface of the lugs to allow the caliper to sit centraly on the disc. i have used standard pads with braided hoses.the car stops on a sixpence with no excess pedel effort needed.i hope to be @ the cheshire tvr meet next month so you can have a look if you like
cheers andy

[clarenceboddiger]

loudandfast said:

i used black diamond grooved and drilled discs.the mounting holes needed enlarging and i needed to shave about 2mm off the mateing surface of the lugs to allow the caliper to sit centraly on the disc.

Andy
what car were the discs originally for? and did you keep the original master cylinder?
Were they as per z_chromozone's reply?

ps thanks to all for the replies

Edited by clarenceboddiger on Thursday 18th October 23:18

[loudandfast]

MY CALIPERS ARE 4 POT CALIPERS FROM AN RS500 COSWORTH. THEY FITTED STRAIGHT ON OTHER THAN HAVING TO ENLARGE THE MOUNTING HOLES ON THE FLANGES OF THE HUB AND SKIMMING ABOUT 2MM OF THE MAITING FACE OF THE CALIPER TO ALLOW IT TO SITT CENTRALY ON THE DISC. THE DISCS ARE FROM 2 WHEEL DRIVE SIERRA COSWORTH.I USED THE ORIGINAL MASTER CYLINDER AND SERVO BUT THEY WERE BRAND NEW AS PART OF A FULL REBUILD
CHEERS ANDY

Edited by loudandfast on Friday 19th October 20:17

[clarenceboddiger]

Great stuff, I'll get hold of some discs.Hopefully I will make it to the Cheshire meeting and have a nosy if your there.Thanks again