Does anyone here know a lot about MGB's?

#1
Hi - Apart from the engine, I'm trying to find out how else the V8 version was different to the 1.8? Specifically brakes and diff. I haz a plan a-hatching.
 

cobraboy

Well-Known Member
#2
Here's what I know, which is minimal in the grand scheme of things.
Front brakes are 1/2" solid discs, upped in thickness from std B
Front pads are bigger surface area.

Rear shoes I believe are the same, but cylinders I believe are bigger.

B diff is commonly 3.909 ratio, BV8 diff is 3.08
 
#6
Hi, Early MGB's had 'banjo' type axles with removable diff heads, later ones had Salisbury type axles with integral diff which are stronger.

Colin
I've just had one of these (3.9) fitted in my Morris Oxford to give taller gearing. Much easier & cheaper than installing an overdrive gearbox for practically the same effect.
 

cobraboy

Well-Known Member
#7
Hi, Early MGB's had 'banjo' type axles with removable diff heads, later ones had Salisbury type axles with integral diff which are stronger.

Colin
Yup, I was forgetting that the BV8 used the later tube type axle - grey cell failure - again !
Mine is a tube type.
 

cobraboy

Well-Known Member
#8
To further answer your question on strength Rob - A tube axle diff fitted to a non V8 is the same as a tube axle diff fitted to a V8 bar the ratio, they did not beef up the V8 diff. I don't know what car you are intending fitting a B axle to, but bear in mind, a B is a light car and the longevity of a B axle in a heavy car with a lot of torque is going to be questionable.
I have severely abused my axle over many many years, but as I said earlier regular maintenance keeps it going, I cannot blow it up.
This weighs about the same as a B roadster.
IMG_3164.JPG
 
Last edited:
#11
Hnnnngggh! Excuse me.

Rob, what plan are you a-hatching then?
Oh, I don't know if people here will like it *evil laugh*


Ok - now I have more time to write, I'm weighing up the merits of 'borrowing' my P6's Engine and transmission to convert my Mk2 Cortina to a v8. It's a long story, but finding a 3.5 locally I can trust to run properly is a big part of the decision. I'll either keep the Rover in the shed awaiting a suitable 3.9, or 350 Chev, or sell it as a roller to help fund the conversion. Sacrilege I know, but the 3.5 isn't original to the car anyway. I'm yet to speak to an engineer (thanks lockdown) but I have a good handle on what's required and it looks attainable for full rego.
 
Last edited:

colnerov

Well-Known Member
#12
Hi, Sounds interesting!! Thinking back to another thread about a member down under wanting to put a bigger engine in a car and there being limits on a capacity increase above the original size. Does it get more involved above that criteria. Over here cutting the shell about to make it fit means you get the pleasure of submitting it for BIVA (basic individual vehicle assessment) and possible re-registration (new reg number usually a 'Q' plate) at DVLA's whim. Is it the same there?

Colin
 
#13
There's a formula for assessing largest engine size for NA and force fed. It's a clear line that anything above that is a no-no. With the Cortina I can go up to 3.6L. I'm hoping to getaway without cutting anything structural....
 
Top