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MG MGB GT V8 Factory Originals Technical - MGC axle swap question

Thanks Jim Stuart for telephone help today, too late to call back, hence this post.

I currently have a 3.9 rear with rostyle wheels. I'm lucky to have found a 3.3 C rear with wire hubs in good shape. My understanding is that the C axles will remain in the C housing while backing plates/hubs/drums from my 3.9 will bolt right up, thus giving me a narrower set-up by about 2 inches or so.

To those of you who have done this swap, will my rostyles still fit? My concern is I'm doing this at a friends house on Sunday with not much chance of finding spacers and or longer lug studs if wheels wont fit. Don't want to leave project half done.

If wheels fit tracking in back is still too narrow I'm guessing. Do most of you fit positive offset wheels in back or use stock wheels with spacers?

My ultimate plan is to fit 15" minilites.

Mabe some of you will read this by tomorrow.

Morgan Sellgren
Morgan Sellgren

You might consider using centre lock Minilytes..of course you would need to swap out the front hubs to do this completely.

I'm afraid that the track will be too narrow on the rear to use standard offset wheels, as you amy find that running will occur on the inner frame rails, especially at the bumpstops.

If you do swab out the rear hubs, please let me know...I could use the C hubs.

rick
rick ingram

Morgan,

I have done this job some years ago and have placed Nissan spacers of 5mm on each drum.
On my car, I use the wheels of a Reliant Scimitar GTE, that have a different offset, restoring the track to the normal dimensions. With Rostyles you should try spacers of 1/2 inch, I think.
If the 3.9 is still in place, you should mesure the inside distance of the tyre to the inner wheel arch.
Afterwards, take off the Rostyles and mesure from the outer flanges of the diff casting to the hub/brake backplate on each side (LH and RH do NOT have the same length!!).
Do the same mesurements on the C axle and calculate the spacers.
Take care that there are enough threads left for the wheel nuts (equal to the diameter of the studs!).

BTW, this axle is great fun with the V8, would not change it anymore.

Ralph
Ralph

Thanks Ralph.. How are you Rick?

Completed the axle swap today. Pretty smooth process with Jim Stuarts step by step directions. Only obstacles seem to be the E-Brake cable is mounted differently on the C axle, and lost the adjustment, I'm guessing this has to do with narrower stance.

My rostyles rubbed at the bump stop area, being Sunday 7pm, nowhere to get spacers, I resorted to using 3 fender washers on each stud to get clearance. I was just going to get home, a block away. Seemed secure enough so I had to take a spin. What a nice difference. Feels like a different car.

Since my tires are near new, I'll look for spacers and longer studs if needed. Anybody having problems using spacers?

Morgan
Morgan Sellgren

My C roadster was fitted with an MGC 3.9 crown wheel and pinion when I purchased it. Great for hillclimbs and sprints hut a disaster for touring.

I'm in the process of grafting a Borg Warner 2.92 limited slip complete housing into my C diff. My friend who is doing the job has a jig to support the outer axle tubes from the C while he welds the tubes together about half way along their length. Even though 2 new axles have to be manufactured the whole process including buying a Ford Falcon diff from a wrecker is less than the cost of a new 3-1 crown wheel and pinion from the UK. Plus I get a bullet proof LSD as well. Total cost about $1500 Australian.

This is a comon conversion in Australia.
John Caffin

Morgan,
Glad to hear you got yours up and running. I picked up a 3.07 MGC axle this winter, am in the process of converting it to run my V8 wheels. I plan on getting some ½ or ¾ inch spacers and longer wheel studs from Summit. The new studs require the stud holes in the hubs to be drilled out .050" but are ½-20 so the original lug nuts will still work. Did you replace the pinion flange or run the MGC one?
Jake Voelckers

You have the wrong studs. You should not have to drill the hubs. Summit sells several different studs that are 1/2-20 with differing groves or knurling at the hub end. Swap then for a set with a smaller hub end.I will try to find you a part number tomorrow.
im Stuart

Jim,
If you have the info you can send me on the ½-20 studs to use with spacers, I would really appreciate it. Unless I find something that will work better, I am planning on using the following:
http://store.summitracing.com/partdetail.asp?part=MOR%2D46220&FROM=MG
Would require the stud hole to be drilled out probably .040" to press in.
Jake Voelckers

I will try to get by th shop tomorrow night, and if here is no flare up of "Old Fart's Disease" I will get the part number. (one simptom of OFD is a poor memory)
Jim Stuart

Got to the shop tonight, remembered to check the wheel studs, but I had studs only, no package or part number, sorry.

My sometimes faulty memory recalls that they are for a Datsun. Overall length is about 4", and I cut them after the wheels were installed.
Jim Stuart

This thread was discussed between 30/04/2006 and 18/05/2006

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