MG Sports Cars

Here is the thread I promised to stop hijacking the fender flare thread. I have been working for the past 12 years on my project to widen my MGB roadster and most who are reading this will probably have seen the journal at one time or another. The bottom line is my build has been an evolution away from the original thought of just widening the shell to cover the C4 suspension to what it is now with nearly the entire car being fabricated and well under 300 lbs of MGB metal remaining. The event that took the project off the rails was after I cut the car apart and spread the two halfs apart and I took the Corvette front suspension on the original Vette crossmember and raised it up in place where the MGB crossmember used to be. It was an almost perfect fit and I could have had it mounted easily within a weekend and retained all the MGB front structure. The problem was that the A arms and spindles were beautiful forged aluminum pieces but the crossmember was really UGLY. Rather than do the smart thing and build a crossmember that looked good and would mount the Corvette aluminum pieces, I decided to build an entire front structure that incorporated the Corvette suspension pickup points. That structure had to be tied into the monocoque somehow which led to the building of a Lotus Elan style backbone chassis and the eventual elimination os nearly all MG sheetmetal inside of the outer skin. Am I happy with the way the car turned out? Absolutely! I love the proportions of the car now and I believe it will be a good platform for the 500 hp it will eventually have. Was it the easiest way to do it? Absolutely not!

A number of people have expressed a liking for the look of the car but don't want to take on that much work. I can't blame them one bit. The aim of this post is to show an easier way to create a wider MGB roadster that would be more practical than mine will be (no door glass or top) but could be completed in an amount of time not significantly longer than more conventional V8 swaps that have been done here on the board.

So what can be done differently to make it easier? Let's start with the mechanicals.

Try to choose a front suspension that is on a removable crossmember, it will make your life much easier by not having to make a custom crossmember and all the geometry and pickup points are already done for you and the steering is already mounted. I don't have much to offer for which one to get but just take your tape measure and spend some quality time at the junk yard. Look for something that requires at least a 6" track increase as that will give yoiu enough room in the tunnel to run the exhaust. What you select has everything to do with how wide you make the car so have the parts before you start cutting. Most removable crossmember suspensions I have seen would be very easy to adapt to the MGB front rails. For simplicity sake I would use a solid axle for the rear, they work well and are easy to mount with coilovers. When you are reinforcing that junction between the rockers and the rear of the car (see below), think about where you want suspension arms to attach and work it into the design.

Before you start cutting make sure you have all the mechanicals you are going to use. Remove everything right down to the bare shell. Fixture the car with something similar to what I used (see part 1 of my journal) so that you can slide the halves closer or further away from each other once they are separated. I would remove the battery boxes and mount the battery in the trunk. You will want the extra width all the way through the tunnel so you can run the exhaust up inside the tunnel for extra ground clearance. Just one more advantage to having a wider car. Remove the slam panel and vertical brace by cutting out the spot welds, you will be able to extend it on each side and reuse it with the stock latch. Cut out the top of the tunnel that contains the removable panel with the shifter opening. To bisect the car, start at the front with a 12" blade in your Sawsall and cut through the oil cooler panel on the centerline of the car and then through the cowl down to the opening on the top of the tunnel. Continue cutting along the top of the tunnel over the driveshaft and up to the top where the battery cover shelf begins. Cut 90* to the centerline 1" back from the edge along the front of the battery cover shelf to the front of the wheel well, the cut should go straight across. Next you want to make a cut just outside of the seam in the center of the rear wheel house separating each side into two pieces - an inner and outer half. The inner half has the interior panel attached and the outer half attaches to the outer fender skin at the wheel opening. Now it starts getting trickier because you want to leave everything intact in the center portion of the rear of the car between the two cuts you just made in the wheel wells. Don't cut the diaphram as shown in the picture though.



Next you want to make a straight, horizontal cut in the diaphram from the top of one wheel well to the top of the other. Then make a cut on centerline through the outer and inner body panels between the trunk and cockpit down to the horizontal cut in the diaphram. A good reference are the photos of the body being assembled here [www.chicagolandmgclub.com]

In the trunk, make a straight cut across the floor just to the rear of the rear reinforcing rib and cut through the very end of the "frame rail" . Then make two cuts, one on each side of the license plate, to intersect the cut you just made. These cuts will preserve the license plate holes and the latch bracket. Drill out the spot welds holding the outer trunk floor to the outer portion of the wheel well. You will also need to cut out the welded in crossmember and the loop under the driveshaft at the rear of the passenger compartment.

Now the only thing holding the two halves together is the frame rail area just ahead of the wheel well. Study the pictures in the link above to see where you need to cut - too difficult to try and explain.

Now that the shell is in two pieces you need to decide how wide to make the car. A lot of that decision depends on what suspension and drivetrain you plan to use and what it's track width is (see the section on mechanicals above). What I did was to set up the suspension at ride height with the wheels and tires I was going to use on a platform and then pull the body halves apart until it looked right. I left a little tire sticking out because I wanted a slightly bulging fender but you can have everything inside the stock body lines if you want. You then need to fill in all the gaps with sheetmetal. If you separated the body halves by 7" you will need to weld in 7" strips to fill the gaps and 3 1/2" strips of metal to join the wheel well halves back together and on either side of the license plate section in the rear. For the outer body panels at the cowl, rear of the cockpit and around the license plate you need to contour the metal slightly to blend with the body shape. Find someone with an English wheel or get one of the harbor Freight planishing hammers to create the contour. The less you widen the car, the less the compound curvature is an issue.

Make sure you reinforce the area where the rocker boxes join the rear frame structure. How you do this will vary depending on how much wider you make the car but there is plenty of room in the wheel wells and on the inside of the rail area. This is a critical strength area so use doublers and extra bracing. This is not how I did mine so I can't offer much first hand detail.

Some of the details:

Instead of putting bumpers on the car (trust me they are a pain to cut and weld into the right curvature and very expensive to chrome) just do rolled pans and nerf bars similar to what many have done here on the forum. They give the car a good look.

I would use a steel hood even though it weighs more, it is much easier to work with. Cut the outer skin down the middle on centerline. If you want to retain the badge bump on the front, cut it out first. On the inner structure, cut out the center section that has the latch and then cut the remainder of the inner structure on centerline. Like the rest of the car you will have to fabricate the filler pieces and weld them in. For the outer skin, pay another visit to your friend with the English wheel. The inner reinforcement fillers will require some metal forming so they match but nothing too difficult. When welding the filler pieces in, do it with a series of tacks skipping around so you don't add significant heat to the panel distorting it. Keep adding tacks in between until the entire seam is welded - it takes a long time but you don't warp the metal. Don't get too agressive grinding the welds for the same reason. Repeat the process for the trunk lid. The less the car is widened, the less you need to worry about contouring the outer skin pieces.The stock hood and trunk hinges and latches will still work as they did on the original car.

Run a fishmouth style grille (no frame) that is easy to fabricate with either vertical bars or a wire mesh

For the dash you can get creative sectioning a stock one or make one from scratch. Again, many folks on the forum have made custom dashes, this one is just a little wider.

Get another cowl air grille and cut the two to make one. You can weld it with some of the potmetal welding rods available and get it rechromed.

I saved the worst for last - the windshield. If you want to have a top you should probably modify a stock MGB frame. You need to find a windshield glass that has the proper contours and enough width that can be cut down to fit in a modified frame. Take a stock MGB windshield glass and cut it down the middle vertically. If you live close to San Diego,I'll give you one. Take that to the junk yard and start laying it on different windshields until you find one that has a similar curvature and the extra width you need. You will find that the MGB windshield has a lot more curvature than most. The top and bottom rails of the frame will need to be cut, bent and welded to match the curvature of the glass and extended to the right width. You will need two sets of rails. This will be the most challenging part of the build. If you run a top you may have to reshape the forward edge of the latching bar to match the new curvature of the windshield. The top bows can be extended by welding in sections of tubing and a good upholstery shop can make a new cover.

So what will you have when you get done? A better proportioned and better handling car with stock body lines. An engine compartment that will accept almost any engine you want to put in it (my vote would be an LS). Exhaust that runs inside the frame instead of out through the wheel wells. Exhaust that does not hang below the bottom of the car for good ground clearance. Wheel wells that will accept any size tire you want to run without flares. Enough room (width) for a decent size radiator and fan. A really high COOL FACTOR.

I hope this might encourage at least one of the more adventurous among you to take on the project.



Edited 2 time(s). Last edit at 04/22/2013 01:48PM by Jim Stabe.

Thanks, Jim!

If I ever get that garage built, I'm ready.

Get busy Carl, I want somebody to park next to in Colorado Springs.

Great writeup Jim. So I just have to ask though, how far are we willing to go to reduce the labor and cost? It seems to me that we are looking at a range and at the wider end we have cars like yours while at the narrower end we have flares. So far we've seen primarily the Rabbit flares which add maybe 3 inches to the width. Then there are cars like the MG-Roadmaster, my car and a few others which have been widened up to about 6" by various means usually involving either Sebring flares or hand formed sheet metal or both. Many think these cars look like deformed cartoon cars but others like them. I'll pose the question though, how wide can we go with this approach before it becomes unmanageable?

Along with that question, how far can we go with altered bodywork before altering the tub becomes the only practical solution?

If we take what has been done as the starting point it would seem that somewhere around 6-7" is going to be pretty close to the practical limit on widened bodywork, and while this does give you clearance for wider tires (up to a 315 is possible before tire diameter starts to create a limit) it does nothing for exhaust clearance. (and now I know why you made the tunnel wider) So it begins to look like the 6 to 12" range is where the sectioned tub really applies the most. Less than that could be said to be too little gain for the effort. And then of course there's the windshield. Nice solution on that btw, but I don't expect to see many follow ups. What can be done to retain the stock windshield? I have no idea, since the windshield is pretty much tied to the doors and wing glass.

So here is a thought. Considering that the width at the doors is the biggest limiting factor in widening just the fenders, what about widening the doors themselves? The sills of course will have to be made wider as well but that could give room for the exhaust to be tucked up inside if done right. I haven't tried this so it's just a jumping off place for another approach. There would be issues with the front and rear fenders of course. What I have done is section the front fenders beside the top flange and add a wedge of sheet metal tapered from a point at the rear to 3" wide at the front but this creates a "wasp waist". Because the fender is double layer at the rear and there is a curve to deal with keeping the straight lines would be more involved. The same issue with the curve would apply at the rear where the fender approaches the welt, and then the rear treatment is tricky as well. But it's something to think about.

Jim

Jim

I don't quite understand what you mean by widening the doors

Make the door itself a few inches thicker to eliminate the "wasp waist you get when you widen the fenders.

Jim

Not a bad idea but you would be pretty much limited to glass packs and pipes exiting in front of the rear wheels. You would also lose the extra width in the engine compartment

True. And as it stands I believe with a 17" wheel and the right offset you can fit pretty close to a 255 under the front fender without widening it any, possibly even wider. That's plenty of tire on the front of an MGB, and I am even toying with the idea of going back to a stock width front end on my car at some future time. (I think that would be number 6) Just kicking ideas around here, since any widening of the bodywork that way would involve changing the curvature of the upper 1/3 of the panels to match. Still it could be done. The front fenders only have an issue around the windshield but that cut could be just outside of the mounting points and I think it could be carried off pretty easily. The doorskins could be cut close to the weatherstrip flange. The rear fenders could be cut near the top welt. But at the rear the tail lights would be an issue. Perhaps the cut could be carried down the inside of the welt and follow the crease to the bumper, leaving the tail light mount intact.

Since rear tire width is really THE issue, I think it might not be that hard to taper the width of the car, keeping it at stock width at the front and going something like 6 or 7 inches wider at the rear with this method. In that way the stock beltline could be retained along with the smooth uninterrupted plane of the car's side. The angularity would be almost unnoticeable and in fact would very likely go overlooked except for the wide rear tires. At the doors the extra width per side would be about 2" give or take, and I don't think that much added to the door and sill would be any inconvenience. As for the exhaust, I've run it through the rockers for over 2 decades now and have a few new ideas. Two specifically, which I'll be adopting before long. First is a chambered pipe which should be better than the glass packs. This is an insert than can be slipped inside any size pipe. There is room for 4 chambers and the diameter could be anything up to about 3" while still leaving adequate clearance. On my car I use perforated stainless panels to form the rockers for cooling and that works reasonably well. At the rear, instead of turning the pipe out in front of the tire as it is now, I expect to go through the inner panel, coming out underneath the car just ahead of the wheelwell to the inside. You can look and see where this spot is. It'll be a little tight and will require a smaller diameter tail pipe but 2" will certainly work and it might be possible to go a little larger. From that point rearward I plan to follow the contours of the system on the MG-Roadmaster, as Dave VanWyck has done a masterful job of routing past the Jag IRS, adding a pair of resonators along the fuel tank in similar fashion.

Granted, that probably makes for a warmer package than tucking it up in the tunnel where there is more airflow, and if you consider all the work involved in modifying a car in this manner, is it really any easier than sectioning it down the middle? Perhaps not. The single biggest advantage I can think of would be leaving the windshield intact.

Incidentally I developed a way to splice two front bumpers that leaves a small discolored weld zone 1/4" wide behind the bumper overriders and that could be done on the rear as well. It basically involves a jig to position the pieces and hold a shaped chunk of dry ice against the chrome to narrow the discolored zone. (I may even still have the original jig around here somewhere) Then the bumper is mig welded from the bottom. A small amount of chrome infiltrates the weld bead and prevents oxidation, (10 years now and no rust) but running stainless wire in the mig would be even better as I think you would then be able to grind, polish and buff the very small exposed weld bead to an acceptable finish, as long as you could do it without going through the chrome.

Any way you look at it this is going to be a big job, but given the amount of panel replacement we've seen in conversions in the past is it really any more than what guys are already doing? Maybe not. By the time you're doing floors, sills and doglegs it isn't really much of a leap and a good bit of the work is either on top or on the bench.

Jim

The idea of tapering the width is interesting but I'm not sure how to pull it off. If you widen the car 7" at the rear axle centerline that is 3 1/2" per side. The distance from the front point of the beltline to the front of the door is 45% of the distance from the front of the beltline to the rear axle centerline so the front of the door would have to come out 1.57" to keep the beltline straight. The rear of the door is 81% so it would have to come out 2.83". You would almost have to keep the vertical contour of the body side stock all the way back to keep it from looking goofy. If you just added width to the body panels and kept the door top and the rear welt in their stock locations, the bulge would get progressively rounder as you went back or you would have to make it square like the old racing Porsches. To keep the vertical contour stock, you would have to move the hinge pillar out 1.57" and the latch pillar out 2.83" and the body would have to be cut inside of the welt, probably at the crease between the welt and the trunk, and the metal massaged so the lines flowed. You are starting to get into some major surgery and you still don't get the advantage of a wider engine/radiator compartment or tunnel.

I had considered cutting the bumper using your method and over riders but I wanted a really clean look on the front without over riders or bumper mounting bolts. I had to add 11 1/2" of width and I could not get the curve to flow smoothly with just two cuts. The outer 1/4 was OK as is but the center 1/2 required a lot of pie cuts and welding to get the contour so it looked right.

Another project that might be interesting would be widening a GT. The windshield would be less of an issue because the glass has less curvature and you could find an existing car that had a glue-in glass that was close and cut the entire frame out of the doner and weld it into the GT. The rear glass would not be much of a problem since it has very little contour and you could find a doner glass fairy easily. With the extra width, the too-tall top would look more in proportion with the car.

Yes, I think the GT would benefit greatly.

Don't think moving the door posts and latch posts would have to be done if the doors are just made thicker. Yes, this is more or less wasting the extra space but the cut could be just outside of the windshield mount, the idea being to move the skin out while leaving the frame in place. An inch or two at the front would ease the angle as well, and it may be that the taper idea does not help any. The car is remarkably easy to widen at the front with this method anyway, as the grille area is not affected. I see the inside crease or valley at the rear being usable in the same way.

`Clearly you gain a lot more in many ways with a split down the middle but I think both are viable for different goals.

Jim

I think I would try to compromise and allocate part of the extra room for the tunnel (two inches, maybe) & most for the cockpit. A bit more elbow room would be nice. Plus, a couple more inches in width would greatly open up the seat choices.

What is the width of a stock MGB well where the seats are located? I'm curious how much wider mine came out.

20"

I thought I posted this-but..use 2 MGB windshields, L/R. bonded in the middle, or a verticle center bar. Are aerodynamics important ? The wider the car= more drag. It's a compromise between ultimate handling , speed and aestetics. If your using irs., perhaps exhaust pipes may be routed inside the widened door cowl areas, and then routed under the irs, to central/rear mufflers, like Corvette ? Onward, roverman.

Carl

I did allocate extra room for the seats - between 2" and 2 1/2" because the tunnel tapers slightly. I built the whole tunnel so it wasn't a big deal but I think it would be fairly easy to widen the passenger wells on a simple split car as well.

Art

You can't just cut the windshields and join them as you proposed because the glass starts to curve back once you go past the centerline and you end up with something like this and it gets worse the more the car is widened. Same problem with the bumpers

Ok, so with your car, there would be 5 5/8" of curved/central area, per side ? Could the center ends be pushed forward, to compensate ? Cheers, roverman.

The height of the glass also peaks in the center. If you pushed the center forward enough to make a consistent curve you would have to allow more than the 5 5/8" and the front of the glass would probably extend into the hood, there is a lot more curvature to an MGB windshield than you realize. It's difficult to visualize until you actually try to do it.

I see some street rods, with aftermarket peeked/curved windshields,(named after the designer). Seems like they might lend a retro look, to the right LBC. Unfortunately, I think there is ample scope creep, with Hemi Healey, already. Cheers, roverman.

Hmm, wasp waist, I can relate to that. While I was halfway through my build, the guy you see in some of the pictures said in his punch drunk manner,, It looks like it was tee boned.

So could we summarize by saying that with the center section method the biggest issues are the windshield, grille and bumpers, while with the outer panels method the biggest issues seems to be matching curvature at the top of the panels, and difficulty in adding seat width?

Jim