MG Sports Cars

I was nearing the home stretch before paint -- finished the modifications to fit the A/C & shifted to installing the cowl piece I'm grafting in to fit an early style metal dash. When I cut off the lip from the cowl, I noticed it buckled a little near the defrost vent holes. That was about 6 months or so ago. I had assumed I got it a bit too hot when cutting it. I figured I could fix that & worst case I have a spare cowl, so wasn't too worried about at the time...

Now that I'm looking closer, I'm pretty sure what happened was ~6 months or so before that I cut the bar that runs behind the dash to move the center console about 1" inboard to make more room for the A/C. It didn't bind or seem to move any when I cut that piece out... but I've left the console out to make it easier to work on while I was doing the A/C area. I think the bend at the inboard edge of the cowl was enough to keep the sides seperated. But when I cut that part of the cowl away to graft in the early piece, the sides of the car came together about 1/2" (see the pic). The problem is with so much time between the activites, I didn't put 2 & 2 together until now... and with the A/C mods I've done, it's not budging -- seems I've locked in that 1/2" delta.

Since the fenders & doors both connect to this piece they should line up so I thought rehanging them to verify & if so, just fixing the bulges in the cowl & moving on, but if I do that, the windshield is going to be 1/2" too wide between the mount points (I measured & it's consistent... 1/4" gap on each side between windshield packing & windshielf frame where it bolts in).

I don't want to make it worse so stopped for tonight (my wife always tells me the best way to get out of a hole is quit digging :) ). Two lessons learned here... I should have put a temporary brace in before I cut the original one out (I'd read MG added it to address a highway speed vibration so wasn't thinking it was structural) & I should have stopped & figured out what was going on for sure when I first noticed the bulges in the cowl. Won't make that mistake again!

I'll have to look at it some more tomorrow to see if there's an easy way to fix this. I really don't want to have to redo the whole fire wall area to correct it but my fear is that's going to be the only way. I'm definitely open to any suggestions. For now, I think it's time to visit Mr Beam.

Yep, got yourself a situation there. One thing for sure, if there was nothing else to consider, you want the windshield to fit right. Mounting that is arguably the most difficult job on the whole car and you sure don't want to make it any harder. Also, if you are considering just forcing those mounts apart, bear in mind that will warp the fenders along the top rear curve and probably throw off the fender to door match. I would suggest simply cutting a slit down each side of your A/C opening, re-establish your dimensions, fill and finish as suits you. Not a real time drain and a proper fix. You'll have to carefully choose the locations for the slits to allow the necessary movement in the proper plane.

I had a similar problem. Back in the Dark Ages when I did sill repairs on my roadster bracing the door opening was a relative unknown and I ended up with longer than stock openings. Eventually more sill work will allow a proper fix but in the meantime I've had to work around it. I've considered winching the opening closed, it's only a small amount, but that would likely cause buckling somewhere and loss of strength. I may try it though, very, very cautiously. The body is capable of giving some without compromising it. But in your case, it should be much easier to just fix it.

Jim

BlownMGB-V8 Wrote:
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> I would suggest simply cutting a slit down each side of your A/C opening, re-establish your dimensions, fill and finish as suits
> you.
>
> Jim

I think you're right, but it aint going to be easy. I made that area like Ft. Knox to be sure it was strong... Inside the open box for the A/C Evap I have 16 gauge sides that bend over to the floor where the drain tube goes through. They're solid welded all the way around including to the front & back of the firewall. I also have the lips of the opening rolled over & welded down so there's a finished edge & added strength. On the inboard side of the opening I have a 16 gauge plate welded on all around like a frame. It has 90* bends that tie into the sides of the opening & at the bottom it's also rolled over (at least I hadn't done that to the top yet -- hey, always looking for a silver lining...) And the right side where I dropped the box down to make room for the a/c line connections, I have square tube welded on at the inboard edge & a cover welded on the back that's also tied into the tranny tunnel & fresh air vent box.

Hate to hear that, Rob. When you do what you need to in order to fix it, I would make sure to test fit the windscreen before final welding, just so you know it will fit after. Maybe before you do any fix cutting though, see if you can round up an uncut under dash brace like the one you cut and use it as a go-no go gage to confirm your buckling suspicions.

I'll definitely check the windscreen fit. I looked at it some today & have some ideas... from what I was seeing, I'm going to have to...
-- ensure the windshield frame fits properly
-- rehang the fenders & doors & ensure they'll line up properly
-- reinstall the hood (bonnet) to be sure it lines up correctly --- gaps & hinges
all of that before welding in any changes.

But, you gave me a thought Jake... If a couple of you guys who don't the have interior vinyl panels installed wouldn't mind measuring the width from one side to the other (let's say referencing the outside edge of the metal on both sides), that would validate it. I have to believe they're all going to be close to 50" because the windscreen width is fixed... if that part of the body varied in with, different sized spacers would be needed for it & I've never heard of that. Anyway, if 2 or 3 of you wouldn't mind measuring it, I would appreciate it.

Rob

Surprising results here maybe.

Measuring the GT directly above the t-tunnel from flange inside to flange outside (centerline of the welded seam the weatherstrip attaches to) I got 49-1/4"

Same seam directly between the upper door hinge openings: 48-3/4"

I measured as well as I could with the body upside down, across the cowl between the rear fender attachment holes. This with the windshield out, following the hood line back towards the windshield pillar (GT) to the second hole. I got something between 43-1/4 and 1/2" as near as I could tell.

From this I'm just guessing that there can be an inch or more of variance anywhere except at the windshield attachment points. This would open up a lot of room for just spreading those points with a jack and putting in some bracing to hold it. There would be some very minor misalignment along the length of the cast aluminum windshield pillar stubs but I wouldn't expect this to cause any problems unless the windshield was already misaligned. Even cast aluminum (and obviously sheet metal) will tolerate a smidgen of flex. But if it was clearly visible misalignment you'd have to fix that with tapered shims or something. Overall probably the easiest fix you could hope for.

Jim

Just to add to the confusion, I measured my '64, same method as Jim, from the outer welded panel where the weatherstrip pushes on on the PS to the inner panel on the DS, right above the tunnel: 48 7/8"

Measured the same way right about where the door hinge screws are in the door: 48 5/8"

Sure looks like a taper is in some of the bodies, have you tried to fit the windscreen yet? Maybe it will still fit, who knows?

Rob,
I just measured the 70 that I'm converting. The distance from the surface where the top windshield bolt sits to the opposite side measures 48 1/4 ". The distance at approx. top hinge location is 48 9/16" and across the trans tunnel I've got 49 1/4". I think Jake is right. There is taper in the bodies and his recomendation of fitting the windscreen should be tried before any alterations are attempted.

Paul

Ok, guys, that's a huge help!!! plus, my numbers were way off... apparently my son pays more attention than I give him credit for! I'd told him not to rely on the tab of a tape measure & to always use the 1" mark as the starting point... he did that when he was helping me measure it... so the 50" at the bottom is actually 49". We just remeasured the whole thing & here's what we got.... compared to ya'lls measurements...


So looks like mine isn't that far off -- 1/16 - 1/4" so I think I'm actually ok & the bulges are from heat after all. I can fix that way easier! I'm headed out of town till Wednesday, but will be reconfirming the measurements when I get back & if it it is heat warp, I can have the cowl taken care of by the weekend & I might just be back on track.

I can't thank you guys enough for doing the measurements for me!!

Rob

I wondered about that. Rob, based on the chart's middle line it looks like you could be pulled in a little, say something less than 1/4". That is a lot more consistent with the warpage you are seeing and it should be around 1/16" or so based on numbers and appearance. As before, windshield fit is key. Make that right and the rest should be fine.

Jim

Got some time to work on the car Thursday & today... was able to verify the windshield fits so I took care of the cowl & the modification to install the early metal dash. Will post some pics tomorrow.

I do have a question though... anyone know about how deep the typical after market speedo is? Right now, I have barely 2" clearance & am thinking that's probably not enough so will have to change something to make more room.

Thanks again for the measurements last week. I got them right as I was headed out on a business trip -- was a huge relief!

Great to hear.

Rob,
I use a Classic Instruments electronic speed in my 70 BGT. It measures 3 in from the mounting surface to the end of the studs where the wires attach.

Steve

Thanks Steve. I was able to find some install literature for AutoMeter Gauges... Looks like their "Hot Rod" series is 2 1/4" deep & their other ones are only 1 3/4" (case depth, mounting studs are longer but I can work around that). I was looking at Classic Instruments, but given the depth I think I'll go w/the AutoMeters & avoid having to re-modify the area.

Here are a couple of pics of the cowl with the early dash portion grafted in...

This first pic is the cowl (which i replaced with a spare I had) and the early front section grafted on...


This 2nd pic shows the dash attached & my playing with gauge & A/C vent layout. Pretty sure this is how I'm going to do them; just looking for A/C vents that'll fit (the '76 MG air vents fit the radio hole perfectly, but they're too deep if I want to retain the 'flapper' that closes off the vent so I'm looking for something similar size but not as deep). The circles drawn on the ends will be round vents. & the guages suspended in mid air below the dash will be in the console when its done.