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MG MGB GT V8 Factory Originals Technical - Driveshaft

Hellow all, I am at the point of installing the driveshaft, i have the Rover SD1 unit that of course will need to be shorten, problem is the flange holes on the SD1 driveshaft are drilled at 90 deg. from each other and they do not match the MGC pinion flange holes actually only two of the four holes match. Should i have the SD1 flange redrilled to match the MGC flange? any sugestions?
Romney.
Romney

Romney - I am not clear whether you have an LT77 box and SDI shaft or just the shaft - if its the latter you may have problems with length, circumference and one incompatible flange.

As I recall, I ruled out the SDI shaft because of size and the modifications that would be needed - the V8 shaft because of length, one incompatible flange and the tendency of the UJs to run dry and fail. Instead, I found a light engineering outfit that built me a unit in a slightly thicker pipe with bigger and stronger UJs with grease nipples. Cost about $155 including 17.5%local tax.

I reasoned that 50% more power and a metric tonne in tow called for a bit more strength.

Finally - your specific question; if your flange really does match up with the MGC axle - re-drill and be dammed (on a dark and stormy night, miles from anywhere - it's only inconvenience - not necessarily fatal) However, if my memory serves me right - the MGB Hive sells props which are already modified for the LT77 box - not sure about the MGC end 'tho.

Good luck
Roger Walker

Roger:
Yes I do have the SD1 egine, trans, and driveshaft with the MGC rear axel and yes one of the flanges does not match to the rear axel, i can have a drive shaft made with matching flanges and u-joints and smaller diameter tubing i just do not understand how i am goin to be able to fabricate one that slides in and out to take the rear axel vertical travel, because, the rear flange at the end of the trans seems to be solid, by this i mean the flange does not slide in and out as in american transmisions, maybe i am overlooking something ?
Romney
Romney

Romney - If you give the job to an a driveshaft specialist they will provide the sliding section needed to allow for movement. They either buy them separately or cannabalise an old splined section for example off your original propshaft. Make sure The section goes at the front end where you will be able to reach the grease nipple. They may ask you for the SDI flange too but they will have to find the MGC connection
Roger

PS Let me know if you can't find the splines on your side of the pond.
Roger Walker

Romny,

My sugestion would be to use an driveshaft from a landrover 109" (flange will fit the sd1 trans) and have that shortened to fit under your car with the standard flange of the mgc axle welded at rear (and balanced). The thing is, having it shortened is less expensive than having it extended.
Guido Smit

Can anyone in the US tell me what UJ/flange to ask for that will mate with my MGB rear axle? I heard something about a rover of some sort that bolts up.. My friend has a 3.9 EFI in which he had a stock MGB UJ and that broke very quick. I want something stronger but know that if the local driveshaft shops are anything like most auto parts places they will not be able to find anything unless I tell them what to look for.. (no offense to any auto parts guys, just been what I have seen from local places..)
Larry Embrey

Larry,
From info that I've dug up in the past for future use, the Spicer flange #2-2-329 with a 369 ujoint is supposed to be a direct bolt-up to our MGB axle. You might look into that.
Good luck,
Joe
Joe Ullman

THANKS JOE!! Just what I need, some part numbers!! Do you find it hard to "get something that will work" from places up here?

It seems like every time I go to a store and ask for something to fit "a 302" etc they have to know what year, model and options of car. I miss the old days when you walk in and say I need a crank gear, they say can't get em, but you can use the timing gear off a 1953 chevy wagon as a substitute..
Larry Embrey

Larry - our local breakers don't see much interest from the younger folks - as a result there arn't many who know enough. Fortunately there are still enough specialists here.
Roger
Roger Walker

Roger,
It's not the breakers that are a problem it is the autoparts stores. Unless you can give them a number in thier database, they won't take the time to help. Maybe I just have bad luck or something, every once in a while I find a place that is like the old days, usually 1hr north in a place I never go except that one time..
Larry Embrey

JOE,
Can you do me a favor and double check those spicer numbers?? I called a guy, he was nice and helpfull, they just did a friends car, but he said that number didn't sound like the correct unit.

Meanwhile I am going to try to see if my big fat tranny yoke will fit in my tunnel..
Larry Embrey

I mated a Rover drive shaft to an MG diff flange successfully. I took a flange off a Rover & MG drive shaft to a machinist who lined them up & drilled the Rover flange to the same hole pattern of the MG flange. I then refitted the Rover flange back on the shaft, & bolted it all together. That was 10 years ago & it's still on the car.
Barrie E
Barrie Egerton

Larry,
Those numbers I got from the BBS archives one night when I was researching driveshafts. Sorry if it caused confusion. I think I searched under 'propshafts', and just copied the number that came up in one of the threads. It claimed that it was a direct replacement for the MGC flange, in other words, a heavy-duty flange for the B. I haven't actually tried to source the part yet. You know what they say about info from the internet.....
Joe Ullman

Larry,
I found the specific thread by searching the v8 archives under 'propshaft flanges'. The thread is 'driveshaft choices', and a comment dated 3 March of 2001 gave those numbers, 2-2-329 flange, 369 ujoint.
I quoted the right numbers from the thread, but if they're right or not, I don't know. Maybe there are several that will work.
Joe
Joe Ullman

Yikes, is my face red!! Three posts in a row! That flange evidently is a bolt-up to the Rover tranny, not the B axle. So sorry, Larry.
Joe Ullman

hrmmmm,
Thanks for trying Joe!

ANYONE ELSE? Maybe an MGC flange and u-joint would be stronger??? anyone have a number for that?
Larry Embrey

The factory part # for the MGB V8 diff flange is BTB 855. I think it's a direct replacement for the MGB 4 cyl.part. Barrie E
Barrie Egerton

Barrie is that the flange that slips over the pinion on the diff, or is that the flang (yoke?) that the U-joint connects to the shaft?
Larry Embrey

I remember hearing from someone about a Ford Courier or Falcon flange set-up fitting? Anyone have info on that?
Larry Embrey

Sure Larry, just let me go find the part number for ya; I know I've got it here somewhere!!:)
Joe Ullman

Larry, it's the flange that slips over the pinion.
Sorry to get your hopes up. I've just checked an old M&G International & a Moss UK catalogue & it seems it hasn't been available for many years.You might have to resort to drilling the shaft flange to the MGB bolt pattern as I did. Barrie E
Barrie Egerton

Did they chnage the rear axle in the V8's?? I am wondering what they did for a driveshaft? My car will have more power, but it is worth a look at least..

JOE,
Had you heard anything about a courier or falcon flange matching the MGB flange??
Larry Embrey

Larry,
No, don't have any info on Ford flange to fit, but would like to. In the factory V8, I believe they used the B axle, but with numerically lower gear ratios. I think they used the MGC rear flange, but am not certain, nor as to what actual driveshaft they put it on, probably Rover?

Joe
Joe Ullman

OK, I got mine done!! I just picked it up and have not slid it into place. but I took my rear axle flange with me so they could match it. Was $197 after tax!! That includes full dynamic balance, new front ujoint and fresh paintjob.

Here is info
They used a 12-10 series u-joint to get a flange yoke and weld yoke to match my dhaft to the rear axle flange. This ujoint size is what is used in Ford Ranger trucks, so it is tough. I recommend if you get a donor shaft for the front tranny yoke to find one that is a 2 or preferably 2.5" shaft. Otherwise you will need a reducer installed.

Flange yoke (matches MGB flange): 2-2-899
Weld yoke(welded to shaft):2-28-1947
u-joint: 12-10 size ujoint

Those here in WA i highly recommend NW drivelines, the Fife branch. Ask for Creighton, he will hook you up.
Larry Embrey

FYI - that Flange Yoke is a bit spendy. List is $84US and it is a SPICER unit. But I think it is worth it to make sure that it does not fail under power...
Larry Embrey

Thanks,Larry, that info will be a great time-saver for me. On my project, I'll soon be nailing my engine in place with the new motor mounts when they come back from the welder. He told me about a way where you make mockups, with the engine in exact position. You use plywood and bondo, then he reproduces them exactly in steel. Supposed to drop right in place; I'll give a report when I get them. Thanks again Larry!

Joe
Joe Ullman

In the UK you can go to the outlet from the original transmission supplier to MG and have anything you like made up. The V8 axle to prop flange is the same as the MGC and is a simple fit onto the spline of the axle input shaft. This is simple, but suince the parts has been NLA for so long your going to be looking at a second hand item. I did hear a while ago of someone touting to see how much interest there was in doing a small production run of V8 flanges, but this apparently didn't come to anything.

I have used the LT77 (SD1) series gearbox in several different MGB applications and needed specific propshaft (driveshaft) dimesnions. I have also retained the original flange size of the MGB on two of the most recent. It is the actual joint which is the problem area. If the joint hasn't the torque capacity then frequent replacement is likely to follow or in the worst cases a sudent failure. However the recent special jobs done by Hardy Spicer (parts of GKN) involved use of high capacity joints that allowed the original MGB flange to be retained.

Just another option to consider with the already proven routes.

Rog
Roger Parker

I bought my propshaft flange from what was the Bromsgrove MG Centre. They had a batch made up for the MGC( which is identical to the V8) to use the what I believe is the 1200 series joint-but this was over 4 years ago. I also believe that one of the Rover P6 uses this size of joint.
Roger is right -it is the size and area of the needle rollers on the joint spider which will limit the ability of the shaft to be reliable under the torque of the V8 for any length of time.
Other factors to consider are propshaft diameter and clearance to the floor reinforcer at the aft end of the tunnel.
Excessive angular movement caused by spring wind up will also shorten the life of the joints.

Regards

John Bourke
John Bourke

You folks in the UK have it a bit easier with much of the parts for a V8 conversion. We silly americans have to have completely different parts for every car it seems.. heh

The Spicer unit I mentioned above is a direct bolt on flange matching the stock MGB rear axle flange. It is outfitted for a "12-10" ujoint which is the same ujoint used in Ford Ranger Pick-ups, so it is strong. the stock B unit is another step or two below that size.

FYI - I highly recommend people getting a driveshaft made or altered get a 2" or 2.5" tube, DO NOT get the 3" tube, it is a super tight fit in the tunnel with the handbrake mechanism...
Larry Embrey

This thread was discussed between 17/09/2001 and 16/10/2001

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