MGB MGB Axles & Hybrid Rear End

[tony barnhill]

My granddad told me that when I got frustrated with car to just walk away to another project....guess that's why I have several in various stages....I work on them as the mood hits.....somebody was wandering around in my garage the other day & asked why every car had some parts in it - I explained that the parts were to repair what was wrong with them...if I die, that way Jerri will know what each one needs to finish!

 

[artmck]

So to get an even up weight comparison, you need to estimate the weight of the pinion carrier that is used on the banjo since it is built into the sal. Is it aluminum on the banjo? The reason for my questions is I am planning this swap for my car, I have a friend with a '65 from which I can take the rear end.

 

[tony barnhill]

I don't think you're going to do the swap I did.....however, trust me - the weight differences between Salisbury & banjo are so major that whatever that little pinion weighs is nothing!

But, if you're planning on doing the hybrid thing I did, you'd better have either good machine shop skills of about $500 for Dave Headley to do it!

On a street car, though, you have to ask the question: why do it? I know why I did it on a race car....but, just swapping to a banjo, while giving you some weight benefit, isn't what you want to do...the axles aren't as strong as Salisbury axles, they're not lubricated as well - lots of reasons not to use banjo axles.

 

[tony barnhill]

YEA!! My 205x50x15 auto-x tires mounted on the Carroll Shelby 15" Saab minilite knock off wheels fit exactly in the center of the wheel well...& at their widest point (8.75") the tires do not rub!!

Now, I'm going to take everything back out & do some lightening on the rear brake setup!!

YEA!!

 

[DrEntropy]

OhBoi... Glad to hear the tires are "non interference". Other than putting holes inna backplate, what can you toss as "excess" on the rear brakes?!?! Hardly anything there I can think of that DOESN'T NEED to be there...

 

[Nunyas]

got something back there to keep it all centered while yer "hangin' 10" in the hard corners?

 

[DrEntropy]

Them "hard-mounted" pucks he's stuffin' into the butt-end guarantee it ain't wanderin' too much. Totally eliminates compression of bits that have "compliance" issues back there in road cars. Shock is a different issue, but as much as it'll be run, that issue is likely a dead horse. I look forward to finding out how this beast "feels" when wrung out at ten tenths... Gotta be about as much fun as one could be legally allowed.

 

[tony barnhill]

Gonna drill lots of holes in the backing plates - leaving all the handbrake stuf off...looking at trimming the lip on the drum & there's lots of extra metal on the brake shoes themselves

 

[DrEntropy]

Do us all a favor and glue some "pet screen" on the backing plates after you drill those holes... I may call you tomorrow and we can yack a bit about rear brakes and race cars... there's not much there to consider as "unsprung weight" compared to what you've reduced to this point.

 

[tony barnhill]

Call me, Doc...I've gotta drop off a few packages at FEDEX at 9 but should be home by 9:30

 

[DrEntropy]

Roger-roger.

 

[artmck]

I'm doing this for a street car just for lower unsprung weight, possibly using composite springs as well. I don't think I'll hit the limitations of the axle design for a low mile street car, so I'm not planning on the hybrid. You quote the bare banjo housing at ~40 lbs lighter than the sal housing, but the banjo does not have the diff/pinion carrier as part of it. I was wondering what the all up weight difference was. I would estimate the diff carrier at ~20 lbs, so the difference would be ~20 lbs I would guess. I didn't know whether the diff carrier was aluminum on the banjo, which would help.

 

[tony barnhill]

As I said earlier, the weight of that little gear is irrevalent (but its 2.8 pounds) - especially with all the other weight you'll be carrying around (rebound straps, park brake assembly, plus all the unsprung weight on the front end)...its also irrevalent on my car which will end up at 1,700 pounds including me!

 

[artmck]

I don't mean the gear itself, I mean the carrier. The carrier is built into the sal, while it unbolts from the banjo with the diff. I did some searching and it does seem that the banjo diff carrier is aluminum, so this is good, probably only weighs 10 lbs, so total banjo would be ~30 lbs lighter than total sal. Keep in mind that the lighter the car is, the unsprung weight is even more important. You could save another 15 lbs or so with composite springs if they are allowed for your racing rules.

 

[tony barnhill]

Banjo differential is not aluminum...the prices I gave were to stripped carriers - yes, the 3rd member of the bnjo includes the housing but the complete banjo 3rd member is less than the gears in the Salisbury...thinking you're chasing ghosts if you're worried about that....like I said, there's lots more unsprung weight to worry about...& I have a set of composite springs that'll go on the car after the GRM....trust me, I've researched lightening an MG from every view point....you might want to run over to my web site & read my racing page

 

[artmck]

https://www.chicagolandmgclub.com/photos/a_diff/index2.html

This was where I saw that the MGB carrier was aluminum. They were updating an MGA axle. Let me know if I am missing something. At the bottom they mention to be careful of the aluminum housing when torquing bolts. I need to look at the one I have to confirm I guess, but its in snow now!.

 

[tony barnhill]

Oh, you're talking about the 3rd member not the dif housing

 

[kennypinkerton]

I looked at Roger's Saab wheels yesterday too... They're just plain saab wheels.

 

[DrEntropy]

"Swing an' a miss...."

 

[tony barnhill]

Oh weill, Kenny - you've gotta kiss a few frogs before you find a princess!