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MG MGA - Rebuilt MGA 1600 Twin Cam Gearbox

All of the talk of the wonderfully warm weather and drive abouts down under has got me thinking about completing a couple of projects on my MGA before Spring arrives this side of the Equator. And this leads me to ask if anyone of you is in need of a freshly rebuilt MGA 1600 Twin Cam gearbox (10-spline first motion shaft) with standard gear ratios for their car?

I have one, and only one, Twin Cam gearbox available. I'm selling it to free up funds, and room, to continue restoration work on my MGA 1600 MkII. I'll only consider a local pickup and cash transaction; I'm located in South Jersey.

I would consider a trade for a recently rebuilt MGA 1600 MkII gearbox (w/ 23-spline input shaft) plus some cash, or would provide a discount for some other parts I can use, such as an empty MkII gearbox mainbox in excellent condition (I have plenty of MGA gearbox internals, and 1500 disc wheels, or so my wife says), or a recently rebuilt MkII head and/or dizzy.

If you have a serious interest, please contact me at mgagearboxes@verizon.net to discuss details.

If you have a question/comment related to this particular gearbox, or rebuilding MGA gearboxes, that you think would be of general interest to this BB audience, please consider to post to this thread.

Steve
Steve K

Here's a photo of the pretty thing. Of course, it's not covered in painted, but au natural.


Steve K

Yes, Yes, Yes

You have mail. I have a perfect 1622 MkII box to exchange
dominic clancy

Is this a very desireable piece of equipment? Even with the standard gear rations? I'm only asking because I have one too and never thought too much about it.
Mark J Michalak

Me too!!!!! More information, Please!
Barry
BM Gannon

Dominic, I've sent you a note.

Barry, I can send you a ton of information on the gearbox, including a summary of all the new and OEM parts used, as well as photos of every significant part used in the rebuild. Please note, however, as I mentioned in my original posting, you would need to make arrangments to have the gearbox picked up from me locally, as I prefer not to make arrangements to have it crated, shipped, etc. If you are still interested, please email me with the questions you have, and I'll shower you with details.

Mark, the desirablity depends upon whether one is seeking originality for a Twin Cam restoration. The rareness arises only in as much as Twin Cams are rarer than a typical push-rod engined MGA. Of course, many more gearboxes have survived than engines and cars, so while there is a differential for a TC gearbox, it isn't going to double the price compared to a similarly rebuilt gearbox original to a non-TC. (It could double the price with respect to a core that's not been rebuilt though.) Now, if it had close ratio gears, that would make it very rare.

The internals of the TC gearbox and tail end housing are otherwise mechanically identical to other MGA 1600 gearboxes. Only the mainbox housing and factory stampings on the unit differ. I'm pretty sure the 1600 TC and standard gearbox are physically interchangeable (the only question is whether there is an interference between the boss and bumpouts on the upper mainbox and the standard chassis. I don't think so, but you'd want to check before trying to fit it in a non-TC MGA.)

The value of this particular unit is that it is a Twin Cam unit, it's been throughly disassembled, cleaned, and rebuilt; and it's ready to go. Presently this TC gearbox is a backup for the MkII gearbox in my 1600 MkII, but the gearbox now in the car has been running great since I rebuilt it in 1976, so I don't plan on pulling it any time soon. And if I do, I'd probably want to remate the engine with the gearbox it was born with.

Steve
Steve K

I have the case for a TC transmission that I broke for parts if anyone is interested. It was was not a close ratio gear box.
Bill Haglan

Gents,

Always helps the twin cam registers if you could post the Gearbox numbers (stamped next to the dip stick) for our records.

Cheers
Mark.
499 & 801 !!!
Mark Hester

One of my 1600 mk2s came with a twin cam (style casing) gearbox. I don't know if it's the original gearbox, but I seem to remember that several mk2 owners have said the same. Maybe left over casings after the twin cam and delux? However I guess the number of splines on the input shaft would be different? Anyway I have it as a spare, if anyone is interested. However I have seen lots of these (various MGA gearboxes) go through eBay cheap or unsold.

Neil
Neil McGurk

Mark,

The S/N for the TC 1600 gearbox I posted is M2993. (See attached photo.)

Where can copies of the registers that include submitted information be found?

Steve


Steve K

Neil,

Yes, I agree with you. A very large fraction of the gearboxes appearing for auction on Ebay are in unknown condition from parted cars and go for $150-$450. Often a photo of the internals taken through the side cover is provided. While indicating the gearbox is not empty, such photos provide NO information regarding the condition of the parts. This is why they are cheap.

For example, even with the gearbox cover open for inspection there is no visibility to the roller bearings inside the laygear, the lay shaft, the synchro and corresponding gear surfaces and teeth, the straight cut gears, bearings, thrust washers, oil pump, seals, selector shafts and bore holes, detents and balls, etc., etc. More often than not two or more such cores and many new parts might be needed to complete a quality rebuild - not to mention the labor. This is why a NOS lay gear on Ebay will easily bring $100+. Certainly one would be ill-advised to install an undocumented gearbox as-is, unless pulling the gearbox out again is not an inconvenience.

In the case of the gearbox I've posted, I've personally rebuilt it and can speak to the condition of every part inside and out. (Even the tiny o-ring buried inside the speedo gear housing has been replaced.)

Steve
Steve K

Hi Steve, sorry I didn't mean that. I meant that my gearbox (that is not rebuilt) isn't worth much.

I also have a box that I have rebuilt completely and is as good as new that I would definitely not sell at those prices.

I was planning to rebuild the other box too. When I get around to it, maybe good gearboxes will be appreciated. Everyone seems to be fitting 5-speed conversions these days.

Neil
Neil McGurk

Neil,

Thanks for the clarification.

In 1999 I bought a new 5-speed gearbox too. ... Also, got disc brakes all around, anti-sway bars, limited slip differential, 1800cc DOHC engine putting out 138+ hp, over drive gearbox, electronic ignition, fuel injection, alloy wheels, ragtop with heated glass rear window, done in British Racing Green with tan leather interior ... A fully modernized mga twin cam ... One hot little roadster. Photo attached.

Steve


Steve K

Almost bought one back in the early 90s when they came out with BRG. At the time I was going to make a pair of cars an MGA to match the colors of the Miata. I ended up doing the A in its original colors. Iris Blue 1960 1600 #GHNL 90954. The car now shows on the Holland Register. I would like the current owner to contact me so I can return his original VIN plate.



R J Brown

RJ,

Beautiful MGA! It's never too late to construct a matching pair! They're wonderful to alternate between to appreciate them, the times when they represented the realization of the vision of a roadster, and the relationship between them.

When I started of thinking about adding performance upgrades to the 5-speed Miata, I left it as it was and decided to try a 6-speed Boxster S. I'm glad I didn't make significant changes to any one of them; however, if I choose to drive top-down on a high-speed, multi-lane highway, I feel the Boxster is most suited to enjoying the environment. On more relaxed roads the Miata and MGA are as enjoyable today as the day they were built.

Steve
Steve K

Mark, here is a photo (with number) of the Twin Cam gearbox I have - if the Registers are interested. Number indicates an early one. It is excess to requirements.
Barry
BM Gannon

And here's the photo!!!!
Barry


BM Gannon

For any wondering what this is all about, for reasons known to Abingdon, but not to we later acolytes, the Twincams received gearboxes that used the undrilled Magnette cases.

If you look at the picture you'll see the spot on top for a slave cylinder and the bulges for a cross-shaft.

Some people want to retain that specific case in a Twincam restoration, so such boxes should have a bit of a premium.
Bill Spohn

This thread was discussed between 01/02/2008 and 05/02/2008

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