113 replies to this topic

[JohnTurbo]

More likely meant to be an upgrade for the cooper s - or at least i can't find much on them if it is stock?

[CocoPops]

Ok, so I keep looking but what is the crossbolt issue? It only needs two bolts to mount right? (As shown with johns threaded bar for now)

[techieboy]

But it should have 4 bolts holding the two halves of the caliper together. The holes John has drilled transect two of the original cross bolt holes.

[CocoPops]

Ahhhh ok. So if pressure was applied, the calipers would force the 2 halves apart? Oops.

[JohnTurbo]

Apart as-in flex - it wouldnt burst in half. Materials ordered so watch this space.

[slindborg]

Fairly sure we suggested someone didn't cock about with the cross bolts on the oem calipers recently... Surely similar should occur here too

[techieboy]

AP certainly did.

[NickB787]

I had better dig mine out as they have been sat in the shed for a few years

[JohnTurbo]

If I could be arsed id model them, run an fea and find a central bridge is stiffer. There is always vockys route anyway if you dont mind adaptors. Will find the necessary dims for that if I remember. Of course the best position for the cross bolts is between the pistons ;-)

[JimmyJamJerusalem]

I don't like the idea about using helicoils, they're nowhere near strong enough for me to feel comfortable using them for the cross bolts. Repositioning the crossbolts could work out ok though but I must admit its starting to look like more work than its worth given the two other options identified. Great to see some proper old school machining skills though, impressive!!

[cnrandall]

I don't like the idea about using helicoils, they're nowhere near strong enough for me to feel comfortable using them for the cross bolts. Repositioning the crossbolts could work out ok though but I must admit its starting to look like more work than its worth given the two other options identified. Great to see some proper old school machining skills though, impressive!!

Nothing wrong with helicoils, in fact they are stronger than an straighforward thread in the alloy usually as they are a much bigger pitch.

[JohnTurbo]

Pretty sure helicoils would improve the strength of tapped cast alu. They are fitted as standard in the stock mgtf mounting holes - the bit I cut off. Im really tied between the coils and the bridge today.

[starlight]

I like the idea of your option 1. Although more initial machining, will keep pad changes easy, and I too am an advocate of helix oils in cast alloy.

[JimmyJamJerusalem]

Fair enough gentlemen. I work with stainless equipment so the use of helicoils has always been a last resort and far from ideal. Appreciate Ali is a much different beast and my inherent distrust is unfounded lol

[TheRealVXed]

Or just get a set of Mini Cooper s set

more info Lee please

[starlight]

I like the idea of your option 1. Although more initial machining, will keep pad changes easy, and I too am an advocate of helix oils in cast alloy.

That should be helicoils, not helix oils! Damn spell checker!

[starlight]

Or just get a set of Mini Cooper s set

more info Lee please

Although not much in the way of second hand availability for the Mini kit.

Edited by starlight, 03 May 2013 - 10:32 AM.

[Exmantaa]

Pretty sure helicoils would improve the strength of tapped cast alu. They are fitted as standard in the stock mgtf mounting holes - the bit I cut off.

Im really tied between the coils and the bridge today.

Seeing the problem in your earlier post, reversing the 2 clamping bolts and tapping some helicoil threads was the 1st thing that sprang to my mind. (providing there is enough meat there.)
Don't like the extra brackets and there's nothing wrong with threaded inserts in aluminium...

Interested in the outcome. ;-)

[JohnTurbo]

Helicoils it is. Hopefully the mail-man will bring these tomorrow. Just drilled one of the holes through with a hand drill but decided to to the rest on the VMC.

[kipper]

I don't like the idea about using helicoils, they're nowhere near strong enough for me to feel comfortable using them for the cross bolts. Repositioning the crossbolts could work out ok though but I must admit its starting to look like more work than its worth given the two other options identified. Great to see some proper old school machining skills though, impressive!!

Nothing wrong with helicoils, in fact they are stronger than an straighforward thread in the alloy usually as they are a much bigger pitch.

Second that. Have been fitting my rebuilt B275 engine during the last few days and all of the head bolts are secured by heli coils. The head has been on and off more times than I can remember, and the HC's are in perfect nick. They work well in cast and Ali applications with course threads.. In the case of my engine good old Whitworth