An M.G. Locost Build
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April 27, 2012
Transmission Tunnel

I figured out what I don't like about MIG welding. It's not the darkness. I thought the trouble we had seeing the puddle was just a too-dark thing. But that's not it. It's the torch. It's too big. It gets in the way. You're constantly trying to look around it to see what's going on. Maybe we're holding the torch too close, but better too close than too far away. The shielding gas is the only thing keeping the welds from turning into salt-water taffy.

  Big fat torch gets in the way of everything
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Sometimes you can only see the puddle if you lean over and turn your head sideways. The problem with that is, you may not be looking through the clearest part of your glasses. If your lenses are progressive, only the bottom half of the lens is any good for close-up work. So you may have a little trouble focusing, and sometimes you'll see two sparks unless you close one eye. Our best welds are made when we're looking down at the joint, with the torch angled about 15 degrees away from the puddle, pushing the leading edge. We'd like to do all of our welds like that.

I miss gas welding. With a gas rig you can see everything. You could read a newspaper. The slim torch tip shoots out an even thinner blue flame, and the bright yellow puddle flows with a glossy sheen. It's fun. You can make a perfect bead, or at least you could if you were any good at it. You can make a bead with MIG, but the steady feed of the wire makes it hard to produce anything but a slug-like lump. TIG welding is similar to MIG, with a too-dark helmet and a large nozzle spraying argon over a wide area. But you do have control over the filler rod, so the beads look better.

Combination transmission tunnel/arm rest  
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The good news is, the transmission tunnel is done. This is a big milestone because when you're sitting in the frame daydreaming about racing down the Mulsanne straight, you need a place to rest your right arm. The tunnel makes the thing feel more like a real sports car, and I also believe that the taller the tunnel, the sportier the car. I like the look of the 1"x 1/2" tubing. It was definitely easier to align than 3/4" tubing, and it makes the tunnel stronger and slimmer at the same time. And who wouldn't like that?

  Transmission tunnel under construction
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When we fit the engine and transmission in the mock-up frame, we found the forward cross tube interfered with the transmission turret. The tunnel was too low. The mock-up frame has a 9-1/2" tall book tunnel, and I figured we'd needed another inch. So we gave it an inch and a half. Which makes the tunnel in the new frame 11" high, just 2" shorter than the sides of the car, which is excellent. There's plenty of extra space for not only the transmission, but also the drive shaft, differential, and cup holders. And it's just about the ideal height for an arm rest.

Makeshift tunnel jig  
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Cutting and fitting tubes for the tunnel looked like it was going to be tricky, but turned out to be relatively easy. The frame is accurate enough now to be used as a reference, and we were able to use clamps and spare tubes for makeshift jigs, so the tunnel came out pretty straight. We built the sides of the tunnel, including the handbrake mount, flat on the table so it would've been difficult for us to mess that part up. But not impossible, as I think we've demonstrated adequately in the past. Luckily we're only tack welding.

  The almost-completed frame catching a few rays
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With the sides clamped in place, it was a pretty simple matter to cut the rest of the tubes to fit. Just to be sure, before we welded anything in and after tacking on each section, we took cross measurements of the frame from the back end of each B-tube to the corner of the opposite forward H-tube. Measurements were 65-29/32" left-to-right, 65-29/32" right-to-left. And those numbers are pretty much locked in now that the tunnel is in place. All that's left to do on the frame is tack on the 4 or 5 tubes that hold up the rear body work. After that, we weld the whole thing together.

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Comments:  
posted September 30, 2016 at 21:43:26  
hi, stumbled across your site, I also used wheel spacers in the rear, because I changed the wire wheels over to mini lites didn't think about wheel offsets the car was built back around 2001 buy my dad ken walton who liked the vintage look of wires and knock offs plus you can tweek wires for offsets he passed away not too long after building it so it lives with me now look in ron champions 2nd edition book theres some pixs of it during the build well one picture shows him also using the mgb motor to line up motor mounts,safety fast! ken walton 3  
posted October 10, 2016 at 23:41:25  
Ken, I'm totally honored to have you visit our site. You have no idea how much your dad inspired my build. There are only a few pictures of his car online, but I studied every one of them in great detail. I'm so glad the car is still around, and it's wonderful to hear from you. -- Nick  
posted April 27, 2017 at 18:55:14  
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posted September 20, 2017 at 09:30:57  
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