MGB: Twin-Cam Magnette

Hello All!

For years I have heard rumours of John Thornley's Development Z-Magnette
which was fitted with MGA Twin-Cam wheels, brakes and motor. I have been told that Thornley adopted this Dove Grey car as his personal transport and used it daily for quite some time.
Has anyone seen a picture of this car? I know that the factory often didn't record development car in film but it seems unique enough that someone would have taken a picture of it as there were always MG Car Club people at the factory.

Pretty much everybody has now seen my ZA with Twin-Cam wheels, and I am asked quite often if there is a precedent for the conversion I have done.

For interest here is a passage from the 1994 Z-Magnette Register Yearbook with BMC Competitions Manager Marcus Chambers' musings on a Twin-Cam Magnette.

"The blunt facts were that we had no cars capable of winning the Monte orany other international rally. This fact was suspected before the rallywas run and discussed at a meetingheld in early January. The suggestion of running cars in the Special Touring Class received approval, and it was agreed that certain models were worthy of consideration for extensive development. I urged that an ideal specification be drawn up. using parts which were either available or about to beso. To this end I suggested an improved MG Magnette fitted with the new Twin-Cam angine, disc brakes, "knock-off" wheels, a close ratio gear box and fuel tank of 300 miles range. As at this time it was necessary to manufacture six hundred of a particular model in order to qualify for recognition by the FIA, this suggestion never, as far as I know, received any serious consideration and the Twin-Cam engine took so long to develop for production that the problem of finding a suitable car was solved in other ways."

I wonder if the Thornley car was build to evaluate the production capability of an uprated Magnette. I would imagine that, like so many other development cars it was either broken up or passed off to an enthusiast friend of the company to be used in competition or as a road car.

If anyone has pictures of this car, or anyother information on it I would really appreciate your posting them here or sending them my way.
I would relly like to find out more about this special car.

Thanks very much,
Rich McKie
ZA 7477

Hi Rich,
Nobody has stepped up to your challenge yet? Maybe a twin cam Magnette is just an urban legend? Possibly placing this on Gunther's site may get more responses from the folks in the UK.

In my searching I did come across this interesting reference in Peter Thornley's "Mr. MG", a book about is father, John Thornley. Peter came over to our local Britfest a couple of years ago in promotion of his book. On page 80:

"Consider for a moment John's own ZB Varitone (RJB 365). This had the engine punched out to 1,800 cc, and MGA Twin-Cam rea axle ratio, suspension lowered one inch at the rear, Dunlop disc brakes all around and was painted a single colour, Gunmetal Grey; or 'light black' as John called it. This was a wonderful grand touring 100+ mph wagon which, with its willing and powerful engine, was rediculously easy to drive fast."

So your disc brake conversion on your ZA is applicable, its not clear if it had the T.C. wheels or not, and the planned conversion to a 3 main 1,800 is in line too! It's hard to tell if this is the same car you may be referring to however.

Regards, Ed

I remember a post a while back where someone in the UK, pulled a twin cam out of a wrecked Magnette in a junkyard years ago, and noticed that it also had allow wings.

Thanks for the input guys. Ed, thanks for adding Thornley's plate number, that may help in locating pictures. I have posted this on the MG Enthusiast's Forum as well but to date haven't got any replies there. I may just send an information request directly to Gunther. The register may have some pictures on file. Gunmetal Grey...That sounds good. My car was originally black and I have been trying to come up with a good colour for a repaint. I don't intend to replicate the development car but it would be nice to base my car on it.
Rob, I have heard that story too! Nancy Mitchell was disqualified from the Tulip Rally for entering a Magnette with alloy bodywork and I wouldn't be surprised if the Managing Director's car acquired a set! I read a story by the chairman of the MG Car Club in the 50's who drove a Magnette. Whenever he was at the factory on club business he would drop his car off at the Competition Department and they would do the latest mods on it for him gratis. It seems likely that John Thornley's car would have received the latest and greatest in the way of mods as well. I would think his car could have Twin-Cam one week and a 2-litre the next!

Thanks again,
Rich

It would be interesting to know of any more details you uncover. On the alloy panels and Nancy Mitchell I had thought it was the door panels but when I went back and looked the "MG Saloons" book just says alloy panels, and that 12 sets were made. Now a set of those would be a real find!!!

Rich, I have to say the Twin Cam wheels look incredibly right home on your Magnette. But it looks like you need to now get a second Magnette, a Varitone, to do your magic to!

Regards, Ed

sigh*
If I bought another Magnette I would be sleeping in it...alone!
I'm afraid the ZA will have to do.
It sure would be cool to come across some of those alloy panels.
I wonder what the weight saving would be?

Cheers,
Rich

BTW: I will post any additional information I come across.

Aluminum is about 1/3 the weight of steel, but the panels have to be thicker so I would guess it would be about half the weight. Body steel on most of my British cars seems to be about .040 inch, and most of the alloy I have used in motorcycle applications has been .060 inch. Anyway, I'd guess half the weight of the steel you replaced. If somebody has a better estimate, let me know.

There is a guy near our office who could make alloy panels from scratch, but bring money! I had an early Muntz Jet with alloy fenders and a serious front-end smashup, and his quote for just the metal work (to fix the frame and get the body ready for primer) was $60,000. Uh, no!

Twin-cam Magnette with overdrive trans, alloy panels and disc brakes would be awesome. A 300-mile touring range would be a bonus, too.
Mark

At that price alloy panels would certainly be well out of my reach. A friend recently had a body tub for a Lotus 11 locally made of alloy but that was much simpler than Magnette wings.
By next summer my ZA will have a blown 1800 with overdrive to go with the Dunlop wheels and 4-wheel disc brakes. That's probably as close as I will get without a lottery win.
It should go pretty good though.

Rich

Rich in Vancouver Wrote:

Bill, Rich, everyman,
Can you expand on rebuilding a 3 main with the possibility of adding the Moss supercharger? What needs to be considered?

Rodger Wrote:

I would also add; Quality rod and main bearings, balancing, and careful attention to detail during machining and assembly. I am also planning to lighten the flywheel.

The Moss Supercharger is designed to be installed on a stock motor for street use but it would be prudent to use the best components when rebuilding, particularly stress bearing parts like bearings.
The Moss kit is relatively benign to an engine as it typically only runs 6PSI boost. I have been running one on my stock Magnette 1500 for about 3000 miles. I installed it without even pulling the head first and it has operated very well with no negative effects on the motor. My motor is a very early 7.15:1 unit that lacks the external oil pipe and does not have a timing chain tensioner. These engines are generally considered more fragile than the later motors, but mine has stood up very well. If the boost was increased it would be harder on the motor, and would also void the Moss warranty on the blower so that would be something to consider.