MG Sports Cars

Jason,The only reason the 65-66 V8 Mustang hub outer race hole should be bored 1/4" deeper and trimmed on the outside is to set the bearing back in the MGB location so you can use the castle nut and cotter as intended. I wonder if the Mustang II halfnut threads are the same. In my setup I originally ground the castle nut down and drilled the cotter hole a little further out. The bearing is O.K.(before the threads) and the shorter nut has full threads. The machining of the hubs is the right way though. The track width comes out 3/4" narrower(about the same difference as the wire wheel rear axle. It would allow more room for wider 0 offset wheels. I am working on caliper brackets for various brake setups.



Edited 2 time(s). Last edit at 01/26/2011 12:18AM by mgb260.

O.K., I am getting questions on why you need a bigger master cylinder for some of these setups. Some of you know why,especially the racers or some who have put on bigger calipers and didn't like the longer pedal travel with the stock too small(3/4") master cylinder. On the other hand those that put the 1" Corvette or Lincoln master cylinder with stock too small calipers and need both feet to move the hard pedal any. Simply matching your caliper piston size with master cylinder size. The stock MGB 3/4" master with twin 54MM caliper pistons(108MM total). The small Toyota S12-8 caliper has two 42MM and two 36MM=156MM and Mazda RX7 caliper has four 38MM pistons=152MM so both would be better with a 7/8" master cylinder. The large Toyota S12W caliper(a favorite with Nissan Z guys) has four 43MM=172MM so size up again to 15/16" master. The Toyota T100 S13W caliper I'm using has four 45mm=180MM and needs a 1" master. It is all in matching the size. My aftermarket clutch slave cylinder(7/8") works best with a 7/8" master cylinder for the same reason. Hope that answers some of the questions.



Edited 4 time(s). Last edit at 01/26/2011 02:04PM by mgb260.

A quick update on the promised "How To".

I finished the write up and have most of the pictures but am waiting on a couple of small parts (caliper adapter, dust caps, AN line adapters) to arrive so I can wrap this up. Just to tease you a little further, I'll be including a couple of versions of the parts inventory - the down and dirty cheap version and a slightly 'upgraded' version featuring a lighter caliper. So far I'm into this for a little over $300 (sourcing everything with new parts). I know Jim has much less in his set-up but trying source parts out of a bone yard in the middle of winter in Vermont doesn't meet with the most success. The machine work needed to do this is minimal so far and the results are really nice - everything fits together like it was made to. Pretty cool. For those into the fancy schmansy rotors (dimpled, dimpled and slotted, slotted and cross-drilled, cross-drilled, anodized black or silver, etc.) I found a source that's very reasonable.

Stay tuned...hope to be posting this up next week.

Excellent, David!

More on brake balance. The smaller Toyota and Mazda calipers aren't that much bigger than stock to affect the rear balance too much,probably don't need a proportioning valve with stock rear drum(GT wheel cylinder recomended) or Scarebird rear disk kit. The Large Toyota and T100 really need a larger rear setup. The Nissan Z guys noticed and usually go with the street rod favorite Cadillac Eldorado rear caliper(GM Metric with parking brake) with slip on S-10 4X4 1" thick front rotor(drilled for Ford also)on 8" and 9" rears. I'm using 92-95 RX7 Rear 20mm thick vented rotors and 89-94 Subaru Loyale Front calipers. They have a large(54mm/2.34") piston and larger pads than the Cadillac as they were designed for a front brake. The neat thing is they have a cable operated parking brake. I'm also working on a Acura/RX7 setup for the stock 4 lug rear.



Edited 4 time(s). Last edit at 02/07/2011 06:29PM by mgb260.

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Edited 1 time(s). Last edit at 01/29/2011 07:03PM by mgb260.

Jim, I wonder how that balances out with Jag brakes on the rear? That's something I need to sort out. I don't have the area of the pistons but I can try to get it.

Jim

The Jag being a large car probably will be fine. Where we hotrodders run into problems most of the time is putting oversize front brakes on our smaller lighter cars and leaving the stock rear small drums or disks. That is what the Nissan Z guys found when they went to the large Toyota calipers in front with the stock rear brake drums in autocrossing. They first switched to small disks and still had problems. After they went to the large GM (pretty standard streetrod stuff) they had a matched killer setup. I think you will be happy with the Jag rear brakes as they are probably way bigger than the stock MGB drums. I still think the newer Camaro set up in the other thread on the front would work really well,those calipers are the same design as Baer and PBR racing calipers and the same as C5 Corvette except less fins and different mount spacing. 12" diameter,1 1/4" thick rotors. When you change your bolt pattern slip the rotor on, mount the calipers with slider bolts like GM Metrics to your custom bracket. Easy!



Edited 2 time(s). Last edit at 02/01/2011 12:28AM by mgb260.

Sounds really good, I'll look into that.

I have the gm metric with parking brakes on the rear of my sunbeam with an 8 inch ford rear. Those things are heavy. If I had to do it over again, I would try to use the mazda rear calipers from the rx7, as those are smaller, and are cable parking brake actuated also. I may change them down the road, since i have a clearance issue with the big gm calipers. If I hit a huge bump, the frame rail will hit the caliper. I cant make it happen trying to push the rear of the car down, but it has happened twice over the last year when I couldnt avoid giant potholes. I think the mazda brake cables pull towards the center of the car, which would be easier in my situation for a parking brake cable. The gm pulls forward, so with wide wheels with a lot of offset, you would have to angle it out around them.

Robbie, For your setup the small Mazda RX7 rear caliper is about right (you would also need a thinner rotor)for balancing out the small Toyota or Mazda front calipers. The GM rear would be a good match for the large Toyota front calipers . Like the larger Jag rear brakes would balance out the large LS Chevy front brakes for Jim.



Edited 1 time(s). Last edit at 01/30/2011 06:31PM by mgb260.

Keep in mind that cylinder bore and brake bias are very important. regardless of what heavy light caliper you use, either front or rear.
Piston dia of caliper front and rear, MC piston dia , bias of brakes and pedal ratio, weight of vehicle just to mention a few.
Just replacing calipers with ones that fit is a gamble.