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MG MGB Technical - GT to Roadster

Is it possible to convert a GT to a roadster? The only major differences I can see are the rear bulk head, outer rear wings, rear deck panel and the front shroud.

Has it ever been done before? I know it is a major task, but I was just wondering if it was possible.

Thanks
Joe
Joseph Phillips

Joe, Sure it's possible but not pratical, it would require lots of work and sheet metal fabrication. I suppose Monster Garage could do it in a week. I've never heard of one being converted. It would be much easier and cheaper to sell the GT and buy a roadster. Clifton
Clifton Gordon

I have never heard of anyone trying to convert a GT to a convertible. It would probably be cheaper and less problematic to sell the GT, couple that with the money you would have spent on the conversion, and buy a good roadster. I know one of the major problems with coupe to convertible conversions is once the coupes roof is gone there will be a considerable amount of body flex. Most convertibles are designed with extra structure support in the chassis to compensate for the body flex, thus a convertible will weigh more than a hard top. I'm sure the MG roadster was designed that way. The only cars that are usually converted are ones in which no roadster is offered. Don't waste the time or money, or ruin a good GT.
Hank

Joe,

Yes it is possible and has been done - but you end up with an MGB GT convertible according to the DLVA!
Chris at Octarine Services

This is most commonly done when the car is re-shelled . re the DVLA , a rose by any other name...
S Best

The front wings are also different on the roadster.....if you are attached to the car and want it to stay with you, then I'd have said that the only real way foward would be a reshell: but as to how much of the car's original character that would keep, it's difficult to judge.

Bruce
Bruce

So is the windscreen.
Jake

"I know one of the major problems with coupe to convertible conversions is once the coupes roof is gone there will be a considerable amount of body flex. Most convertibles are designed with extra structure support in the chassis to compensate for the body flex, thus a convertible will weigh more than a hard top. I'm sure the MG roadster was designed that way."





The MG is unique in that the roadster came before the GT. The body was designed with the extra structure support right from the beginning, when the GT was designed the factory basically stuck a roof over the roadster shell. The only major structural conponent that is missing is the rear bulkhead, the floors and sills are exactly the same.
The Wiz

Yes, it can be done. THe results however are far from attractive.

http://lbcnuts.com/hobby/mg/horrors/gtpickup1.jpg

http://lbcnuts.com/hobby/mg/horrors/gtconv2.jpg
Steve Simmons

Hi Joe
You must have a cunning plan to do with power to weight etc.
Are you going to the Classic day at Combe on Saturday?

Mark
Mark

First off, I claim no responsibility for the blue hack job. I bought it as a parts car for $100, with the intentions of using it 's bumpers, suspension and other body parts in a 77 CB conversion. The PO's kid had taken a Sawsall to it as you have seen, then gave up. BTW, the engine in was new enough that it had only a thin layer of carbon in spots on the piston domes, new water pump, radiator and full new clutch. When I bought it, it still had the roof and bottom part of the rear hatch. I considered welding the piece of the hatch in place and making a P/U but decided that the body was just not worth the effort to save because there was rust in the rockers and doglegs. Plus the windshield would not have supported itself unless it was braced bigtime. Oh, the kid said he wanted to make a racecar! Go figure!
gerry masterman

BTW, Steve, where did you find that picture? Is it on a website somewhere? It's amazing how stuff gets around on the internet! Notice the sign behind it says GEM Enterprises? That's me!
gerry masterman

Small world, this internet! Those photos are from my web site which is currently down as I change domains and rewrite the site from scratch.

Here are the other two photos I have of the car:

http://lbcnuts.com/hobby/mg/horrors/gtpickup2.jpg

http://lbcnuts.com/hobby/mg/horrors/gtpickup3.jpg
Steve Simmons

Yikes, those pics are ugly. Maybe not such a good idea, although those look like quite bad conversions.

Mark,

Yes, the reason I asked was to do with power to weight ratio.

I am going to Castle Combe on Saturday, I have three sessions booked. See you there if you are going.

Thanks
Joe
Joseph Phillips

The GT is a faster highway car due to better aerodynamics.
Steve Simmons

If power to weight is all you're worried about, just don't eat breakfast and don't wear any socks or underwear. That will like be a better way to lose total weight with less drawbacks.
gerry masterman

"The GT is a faster highway car due to better aerodynamics. "

A Roadster with a hardtop is even faster due to better aerodynamics and lighter weight. A much better choice for the race track.
The Wiz

I would question the aerodynamic superiority of a hardtop roadster versus a GT. A roadster is a lighter, faster track car but on the highway weight has less to do with top speed than airflow.
Steve Simmons

There are advantages in doing it that way. I have heard of a V8 roadster in France which is a factory MGBGT V8 rebuilt into a Heritage shell. Normally you have major problems getting a V8 conversion onto the road. Since this car was originally a V8, then the French authorities are happy about the V8 engine as it isn't a conversion. I seem to remember it is registered as a MGBGTV8 roadster.
Mike Standring

If it is power to weight you are worried about then the GT isn't such a problem. yes it does weigh more initially, but you have more weight loss options than the roadster - EG, side glass to perspex, rear tailgate to fiberglass+perspex screen. Etc.

Running no trim, no heater, lots of lightweight panels, other tweeks - such as not fitting the sill jacking points, etc - you can get them pretty light.

My own GT is down to the mid 800kg's and I've still a got 30kg to loose from it when I get around to it this winter. (And that's with a plumbed in extinguiser and full rollover cage) Doesn't make an ideal road car though :-D
In fact if I lighten the doors by getting rid of the window winder mechanisms, fixing door windows in place and then getting medieval on the inner and bottom of the door with a grinder I'd loose a bit more than that.

In fact the biggest disatvantage comes in sudden direction changes, as the GT has has a slightly higher centre of gravity and it would be very hard to match the roadsters without....cutting the roof off. It's not much of a disadvantage though. MG midgets are the real buggers on tight tracks. Like chasing mice!

Tony
T Crossley

Hurrah for the Midgets!!!

(can you guess I have one...)
Matt Wrigglesworth

This thread was discussed between 04/09/2004 and 07/09/2004

MG MGB Technical index

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