MG Sports Cars

I'm thinking about and looking for ideas of ways to do it where I wouldn't have to remove the seats & carpet when welding. The way I've seen it done, the cross member is cut out, a plate is welded to each end and to each end of the piece removed, and it's then bolted back in.

I'm concerned that the heat from welding the plates on the ends will melt the carpet &/or be a fire hazard. So, I've been thinking about other ways to do it. One idea is to make sections of U-channel that are a snug slip fit inside the cross member. Weld the plate to that and bolt that assembly to the cross member. The cross member is pretty thin, but I'm thinking I'd use 16 gauge for the u-channel sections for strength.

Anyone have a better idea?

Here's another approach which might be carpet friendly....Bill Guzman's tubular xmbr from the British V8 photo gallery.




Edited 1 time(s). Last edit at 05/12/2018 09:15AM by ex-tyke.

I'd seen that Graham. It's welding the plates that cap off the cross member sections that remain on the car and become what that middle piece bolts to that concerns me.

Bill's design is pretty good. It's also possible to tack the nuts on. I've used thicker plates and tapped them. I've also used square tube with a thick enough wall to attach a transmission mount to it.

As far as your welds are concerned, you are not going to be able to weld the top, just the sides and bottom. So the only place you need to worry about it is at the top of the sides and you have a layer of sheet metal between that and your carpet. Just do short tacks there and let it cool. The rest won't be a problem.

Jim

Reuse the piece that was cut out. Weld a piece of 14-16 gauge on each end and front and back side. Drill two 5/16-3/8" holes into the tabs where they overlap the remnants of the original crossmember, mark the holes for drilling. Make four tubular sleeves about 2" long with 5/16 or 3/8 I'd. These will have an od about 1/2" so drill that size hole in the four marked holes in the crossmember remnants. Insert the four sleeves into each hole and weld into crossmember then grind smooth. Insert removeable section so four bolts can be inserted into sleeved holes and overlapping tabs on removeable centerpiece. Tighten nuts and bolts and done. The sleeves will prevent crushing the sheet metal crossmember from over tightening. The centerpiece is now easily removeable when removing the transmission without the hassles of the original crossmember

Stock fixed crossmember:

Removeble fixed crossmembers:

BillGuzman



Hank R



Grant70B



Jimmy N





Edited 1 time(s). Last edit at 05/14/2018 11:10AM by MGBV8.

What Dan describes & what Jimmy N did are along the lines of what I was thinking. But Jim B has me re-thinking about how much the welding heat would be a problem. Will decide which way I go when I get the car up on the lift & have another look at it but leaning toward the traditional approach. Makes for a cleaner looking solution.

Not sure that it is really needed, but Dan & Jimmy's approach could also be done with rectangular tubing that has the top notched on each end.

I like the appearance of that last one, best to size it so that it can spring out just a little when it is unbolted. That will make it easier to fit up. The spacer tubes are a necessity with that design. I'd close the top.

Jim

Rob, my setup is a little different because that crossmember is my transmission mount. But if you do your cut right, you would be tack welding in the tunnel area of your driveshaft . 3 tack welds right next to each other, like laying quarters, then have your air hose to cool right after, then repeat.


You may have seen this when you have come over on Brenda's GT. The box is made out of 1/4" plate for the T56. But for welding you get the idea.








Edited 2 time(s). Last edit at 05/16/2018 02:30PM by 74ls1tr6.

Wait, those pics imply you're actually making progress on Brenda's car... Could it be true?