MG Sports Cars

Jared, Picture of Volvo template gives dimensions for bolt spacing on RX7 calipers. You can use 11" Corrado rotors also if you open up the center hole. They have neat little cooling windows in hat. Might need 1/2" spacer between hub and rotor to allow somewhat thick RX7 caliper to clear wheel. Basically allow 2 1/2" from wheel mounting face on hub to rotor. Bill, I think the small Toyota 4 pot would be excellent on the Midget! The bolt spacing is 3 1/2". Clock the lower caliper mount above the lower mounting hole. You might have to grind the inside edge of the caliper housing and pads because of the smaller diameter rotor. Also you would need shims behind the pads because of the thinner rotor.



Edited 1 time(s). Last edit at 01/28/2012 12:57AM by mgb260.

Robbie has mounted his RX7 calipers and Nissan pickup rotors on his Alpine. I'm sure he'll post information on this site.

Thanks Jim. Clocking the caliper isn't an option on the Midget, run into clearance issues with the lower control arm or the shock arm up top at full lock unless the caliper is basically dead center and on the short side as well. I have tried to fit the RX7 calipers and also some Volvo calipers without luck because of the clearance issue. Austin Princess caliipers are a bolt on but basically un obtainable here in the US. I've read that there are some early Land Rover calipers that also will fit but again hard to find here in the US but I'm looking into that now. Looks like I might have to go with the more expensive Wilwoods and have mounts machined for those.

Bill, Maybe you could offset drill the mounts and calipers to make up the 1/8" difference per side and use a larger diameter mounting bolt.

Or buy that Austin Princess on ebay and get the seller to just send you the calipers...

Jim

Heres a picture of the back view. I finally got to drive the car today after a few months of upgrades. I have 1 water leak t address and the turning on and off at the right temp of the electric fans, and ill be back on the road.

Robbie, Cool! How would you rate the brake upgrade compared to stock brakes.

Hi Jim,

I'm a little lost. What of all these cars share the same hub with the TR6? I know the MGB and Midget do not, what about the Alpine pictured above? Have the RX7 brakes already been fit to the TR6 hub by someone? Thanks.

All of the hubs are different but the principal is the same. A piece of aluminum or steel bar stock adapter from the stock 3 1/2"(3 1/4" MGB) mount to the 6 1/8" mount of the RX7. Thickness will vary. Look closely at the Volvo picture and Robbie's Sunbeam picture. The original (same as Toyota pattern) is in the middle of the adapter,RX7 are outer holes.



Edited 1 time(s). Last edit at 01/30/2012 02:20AM by mgb260.

Well, I only drove the car about a mile because I have a slow drip from the Saab thermostat t I put in, but the brakes have less pedal travel and I can actually lock them up now, which I was never able to do before. I'm using a Nissan F10 master, 3/4 bore. I also need to figure out if the back is getting enough braking. Any suggestions on how to do that?

Drive it in the rain and brake hard to the point of just about locking up the front wheels in a tight turn with a safe runoff area. This can be done in a large vacant parking lot. If your rear brakes are doing anything this is where they will put you slightly sideways. Mucho sideways is too much, no sideways isn't enough. Play with it until you get the feel for it, then you can try it on dry pavement.

Jim

Robbie, You are probably well matched, as that combination was designed by Mazda to work together. I'm curious if your master for the rear brakes had a built in residual valve you removed.(drum brake on rear Datsun pickup) If not your rear brakes may drag. I use a 2lb residual valve front and rear and throw away the anti-rattle clips on the front calipers. Also on alot of these conversions make sure you have a little freeplay on the master pushrod. Either wiggle it a little where it connects to pedal or have 1/4" freeplay at pedal. Did you use ceramic pads and the shims behind the pads?

No shims behind the pads. On the front I used Wagner thermo quiet pads, whatever they are.

To check the brake bias between the front to rear, is done in a straight line.
Have a friend stand on the side while you brake hard and observed if the front lock up first or the rear.
The ideal is for the fronts to lock up first and then the rear.

If you have an equalizer valve on the MC then doing its job.

Teh danger is to lock up the rears first, this may cause the car to spin.

If the rear locks up first, you will know it. ;)

Sorry to resurrect this awesome thread but I have one question; What did you all end up deciding for the MGB front brakes? I ended up getting lost and rereading and reading until my wife's friend just woke me up at the computer and now I can't figure out what my notes mean.

I'm just trying to create my parts list from your "best practices" and learn from your innovation. I don't own a machine shop and have little confidence in most of the ones around here so bolt-on and light weight and simple are good for me.

NCtim

Almost a bolt on. You will need 1/2" aluminum spacer either between rotor and hub (use MGB rotor as template)or hub and wheel (longer studs for 98-2002 Camaro/Firebird/Corvette 12mm) to allow wheel clearance for the thicker 4 piston calipers. The 4 holes in the Cressida rotor have to be reamed slightly to match the MGB rotor pattern. Also could use the slightly larger diameter (11") 89-91 VW Corrado rotor. It has cooling holes in the hub. You would have to open up the center hole to match the MGB rotor. Rotor offset would determine the thickness of caliper adapter. VW Corrado rotor pictures:





Edited 3 time(s). Last edit at 04/21/2012 08:18PM by mgb260.

Thanks Jim.

Cheers,
Tim