Larry,
I've got a Factory GT V-8 here in California, so I can address some of your
questions. The thicker rotor was used to dissipate more heat and to be more
resistant to brake fade (although I would have thought a ventilated rotor
would have done a better job, but the factory was working on the cheap when
they designed the GT V-8).
If you were to install the rotors on a 4-cyl car, you would also need the
V-8 calipers that allow for the thicker rotor. These were an amalgam of MGB
and Triumph 2000 calipers, and can be "fabricated" by combining one half of
the MG with one half of the Triumph units. You of course need the hardened
bolts and the square section fluid seal if you split calipers. I have heard
dire warnings from some folks that you need a special jig to reassemble
split calipers, but I have done it several times with no problem (as long as
the bolts and seal are replaced).
You will be hard pressed to find a set of Triumph 2000 calipers here in the
States, they sold only a few of that weird looking sedan over here. Of
course, you could buy new V-8 caliper assemblies in the UK, but I'm sure
they are hellishly expensive (I was able to rebuild mine). You are right
that the V-8 pads will fit the 4-cylinder calipers, and they give you a
better swept area. I got mine (original Lockheed pads) from either Brown
and Gammons or Moss UK (I don't remember which), and I paid about $35.00US
for them. Moss USA sells Mintex competition V-8 pads for around $80.00 a
set, but they probably need to be warmed up before they work effectively - I
don't want that on a street car.
The rotor and caliper are a direct bolt on to the MGB front uprights/hubs,
although the rotor splash plate needs to be cut away slightly to clear the
V-8 caliper (I bought a set of replacement splash plates, and they were
obviously 4-cylinder units that had been cut up). The brake lines are the
same as late MGB with the spiral protector, but I found that non-OEM
Lockheed brake lines will not fit, the hex end that screws into the caliper
is too fat to clear the caliper casting - make sure you use OEM Lockheed
lines. You also need longer cotter pins to hold the pads into the caliper,
these are not automatically included with brake pad sets any more.
As for whether the V-8 setup is worth it, IMHO I think that a set of cross
drilled MGB rotors coupled with the V-8 pads in the 4-cyl. calipers will
give you the same fade resistance as what the Factory intended with the
thicker rotors. Of course, I am going for concours originality in my V-8, so
I am stuck with the original system.
Cheers,
Paul Kile
1974 Factory MGB-GT V-8 (Formerly The Rustbucket, renamed The Phoenix)
-----Original Message-----
From: Larry Hoy [mailto:larryhoy@prodigy.net]
Sent: Monday, January 31, 2000 10:07 PM
To: MG V8 List
Subject: MGB v8 front brakes
This is not a new subject but I wasn't listening! Don't
tell me you didn't "drift off" in school occasionally.
Can any of you set me straight here? Tell me about the
factory MGB V8 front brakes. Here's what I think I know.
The rotor is the same diameter as the 4 cyl rotor, but it
thicker. 1/2" vs. 3/8" (approx).
The brake pads have a slightly larger foot print.
V8 pads will fit the 4 cyl cars without modification.
V8 rotors will not fit the 4 cyl cars unless the calipers
are modified.
Here are the questions:
What is the advantage of the thicker rotor?
What is needed to install the thicker rotor?
Would I get the same benefit by just using the V8 brake
pads?
And for our English friends are the V8 brake pads available
in England for less than 50 pounds?
Larry Hoy
http://pages.prodigy.net/larryhoy/
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