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TR8 brake aclipers on a Spridget

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Trevor,
Yes my kit uses a Marina hub. They are available in the UK as blanks that can be machined to what ever bolt pattern needed. A stock Marina hub or the Morris conversion hub will not fit on the Sprite/Midget. The kit that we make has tapered roller bearings in the hubs along with bearing spacers. It is fully assembled and bolted to the rotor when you purchase the kit. This then becomes a slide on, tighten the nut and go, very easy install.
 
"· Tire traction
· Brake disc sizes
· Pad coefficient of friction
· Caliper clamping force
· Weight shift
· Front/rear braking bias"

Bluemax You are correct in all you say. I have tried the MGB / Spitfire rotor setup and it sucks big time. When the Healey family used it on their Le Mans cars back in the 60's, it was probably the best solution there was to stop at Mulsanne. That does not mean it is good for a street car or easy to install. The kits we build took 2 years of playing around to get where we are at today. Brake disc diameter, caliper piston diameter, master cylinder diameter, pedal stroke, caliper fitment, pad compound availability, rotor fitment, hub availability, front to rear brake bias, steering rack clearance, Swivel pin clearance and much much more are all factors on making the kit work. We sold a few and discovered we were not total geniuses and had to make some changes. This kit now is very proven and works extremely well. We understand that building big brake kits is not something you just pull out of a hat and throw at a car. It takes dedication to detail to make these thing right and not create a on-off switch, lock your brake up kind of braking. What is nice is adding our rear discs to the car and you can really get some braking power. The rears actually work instead of just going along for the ride and acting like a heavy wheel spacer. The best part of rear discs is that you get a hand brake that works (and works like a current car). With the big kit on the front and rear discs the cars stop evenly and without wheel lock up or front nose dive. They truly become driveable.
 
The TR7 caliper is the same as a Midget except it is metric. Same pads, same size piston, same seal kit. The TR8 uses the same pads, same size piston, and seal kit as the MGB. It is also a metric caliper. What BL did was to reach into their parts bins to build the TR7/TR8 as they did not have $$$$ for development.
 
I went with the ol phartz setup on my sbc powered sprite... It is a huge improvement over the stock setup, and I've done several 140 plus mph blasts with the setup and it slows down a lot better than stock. Pad size is twice the size of stock. It's also much better at brake fade than the stock setup and you know you'll be able to stop in time of the car in front of you locks up their brakes in traffic
 
anarchy99 said:
I went with the ol phartz setup on my sbc powered sprite... It is a huge improvement over the stock setup, and I've done several 140 plus mph blasts with the setup and it slows down a lot better than stock. Pad size is twice the size of stock. It's also much better at brake fade than the stock setup and you know you'll be able to stop in time of the car in front of you locks up their brakes in traffic
Click to expand...

yeah, but with that engine you need a parachute too. :rolleyes: :jester:
 
Steve, I can certainly share your experience in every detail. I had the same issues in designing mine for the front and the rear. I chose not to market the kits due to product liability. Even if I was found innocent, the cost of litigation would be astronomical. If you carry product insurance you can also be hit with civil suits to follow, just not worth it to me. You manufacture a very nice kit and I wish you all the best. Photo of my kit installed on a Bugeye

I believe Le Mans Sprites used Girling calipers not Lockheed like the traditional Spridget's & MGB's that are driven on the street today..


P1040161.jpg
 
Gerard said:
He makes a variety of aftermarket parts for a variety of cars, including rear disc brakes setups. Here's the Midget page.

https://www.olphartz.com/midget.html

I looked into his machinist making my 5 speed kits. The guy is quite skilled and makes some very high end parts for some exclusive customers.
Click to expand...

Thanks for that....guess I'm out of touch. Not much to say except...WOW!

Kurt.
 
Bluemax. The first Sprites with discs were the cars that were built for Sebring in 59. These had Dunlop Brakes. This was about the time that Girling/Lucas was purchasing Dunlop and the setup used by DHMC was discountinued. DHMC wanted the Sprites to use their setup when BMC finally decided to switch to discs but politics in BMC management meant the all of the A-series engined cars that got discs got Lockheed and the big cars got Girling. This did not set well with Healey. Also the BMC engineers cold not figure out how to get a decent size brake into the 13" wheel. This problem has caused rapid pad wear on Sprites since day one. We have spent the time and solved that problem. 4 pot calipers and pads twice the size of stock pads on 9.5" rotors that fit 13" wheels.

When I referred that Sprites used the MGB brakes, this was on the very late cars that DMHC built for Le Mans 64-68. Total different deal than the Sebring Sprite or Speedwell Sprite. The Triumph Spitfires built for Le Mans in 64-65 used this setup also. Of course they did not require a 1" thick spacer to make the Spitfire rotor fit. The kit probably works better there than it did on the Sprites. Gerard spent lots of time getting the B calipers to fit up correctly with the Spitfire rotor on a Midget.
 
Kit.jpgrear axle edited.jpg Here are pictures of our rear disc brake kit for the Sprite/Midget. The kit is installed on an axle from a 73 Midget. The component picture shows everything we send to install our brakes. The attachment picture is our tube type MGB rear kit.
 

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Bluemax,

"I chose not to market the kits due to product liability. Even if I was found innocent, the cost of litigation would be astronomical. If you carry product insurance you can also be hit with civil suits to follow, just not worth it to me"

Well those are issues that I face. I carry insurance and insurance from my parts providers. I am very careful in what I produce and how I sell it. I have done brake kits now for 25 years and not one liability problem. If you build a good safe product you don't have to worry. There are some things that I can do but won't because I play it safe.
 
Size comparison between my stock front pad and the ol Phartz pad


the car is a blast still, I need to finish the winter work on it, but it's **** cold outside, and even being in a garage isn't much help. She'll be back on the road soon though.
 
Steve, Dunlop by far was the major contributor at that time supplying tires, calipers, pads ect, however I believe that Lockeed, Dunlop, an Girling work hand and hand with DMH motor sport group to provide calipers, rotors, pads, based on weight of car and the specifics of tracks they ran, as well the contract agreements. Some of the Targa Floria cars were fitted with Lockeed calipers. The Le Mans cars ran Dunlop light Disc, pads, & calipers. When BMC motor sport drop out of racing the privateers used Girling calipers.

Here’s a photo of cousins Butch’s factory BMC Sebring car with Dunlop’s front and rear calipers.

Cheers

52302.jpg52310.jpg
 
BlueMax said:
Steve, Dunlop by far was the major contributor at that time supplying tires, calipers, pads ect, however I believe that Lockeed, Dunlop, an Girling work hand and hand with DMH motor sport group to provide calipers, rotors, pads, based on weight of car and the specifics of tracks they ran, as well the contract agreements. Some of the Targa Floria cars were fitted with Lockeed calipers. The Le Mans cars ran Dunlop light Disc, pads, & calipers. When BMC motor sport drop out of racing the privateers used Girling calipers.

Here’s a photo of cousins Butch’s factory BMC Sebring car with Dunlop’s front and rear calipers.

Cheers

View attachment 36224View attachment 36225
Click to expand...

Cousin's???? Tell us more! Gorgeous car...even underneath.

Kurt.
 
Reverse thrusters weigh too much and the parachute may lift the car up... Might need to pull the ole triple x stunt and wear a parachute... Hopefully without the same result as the stuntman in the movie
 
(Note: I can't get the format/font/etc. below to be consistent, so kindly ignore the bolding and Lord knows what all else)

I did a search a couple of days back on the Spridget forum, looking for brake upgrade information for our BE, and Gerard's comments led me to the Ol Phartz Partz web-page mentioned above, specifically https://www.olphartz.com/applications3.html .


I dropped a note to Steve Christiansen, asking what he recommended for a master cylinder brake bore for his kit. This lead to brief conversation via e-mail, which I will attempt to summarize (accurately, I hope) below (I figured it would be inappropriate to copy/paste his comments in directly without getting permission etc. etc.):


He recommended the 3/4" bore master cylinder, as original to the disc brake cars 1963-1966. He felt that it gave better pedal travel and the pressure was lower than with the 7/8" cylinder from the drum brake cars.
He echoed Gerard’s earlier comments regards the original Spitfire/MGB setup.
The caliper is a poor fit to the swivel pin and the rotor has to be modified to clear, plus the system needs a large spacer to make it all fit. Additionally, he felt that the caliper was heavy, and you “really have too big of piston for the Sprite and not much bigger pads.” The MGB caliper is 2 pounds heavier than the Sprite; the piston are ¼” larger than the Sprite, resulting in greater pedal travel, but the brake pad itself is “only a tiny bit larger than the Sprite pad. Not much surface area to gain stopping power.”

His view is that the original combination developed in the early 60s was restricted to what the existing parts bin could provide in a limited time line, and his design approach without those limitations has resulted in a brake kit that works properly.
He uses 9.25" rotors (1/8" larger than the Spitfire; according to the various parts suppliers on-line, the original Spridget rotor is 8.3 inches in diameter), no spacer, the rotor bolts directly to the hub, tapered roller bearings with spacer in hub, light weight alloy calipers with 4 pistons of correct size (calipers weigh 4lbs loaded with pads versus 7 lbs unloaded for a Sprite caliper), 4" x 2" brake pad for 3 times the surface area (Sprite is 2" x 1-1/4"), stainless brake hoses, and the mounting hardware.

[h=1]I have a separate note to myself that he sources undrilled Marina hubs in England for his machining, but I can’t find my source and Mr. Christiansen didn’t mention this. I couldn’t find dimensions for an MGB brake pad, but Stapleton’s “The MG Midget and Austin Healey Sprite High Performance Manual” mentions that the B pads are 25% larger than the stock Spridget’s.
[/h]
 
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