BUILD-OFF CHALLENGE: Tygaboy's '75 LS3, It seemed a good idea at the time... Options

[tygaboy]

After a fair bit of head scratching on the design, I've now (mostly?) thought through the " how should I actually construct the fire wall?" so today I got started on the first of the "real" pieces.

My plan is to build the lower, vertical wall, then frame the critical edge joints to be sure I have fixed points from which I can generate accurate measurements.

First I measured and determined the arch and cut the blank for the lower vertical.
Plasma table to the rescue!

[tygaboy]

I want to spot weld the vertical lower to the arched cross bar so I need to make a flange across the lower, curved edge.
I set up an appropriate set of dies in the bead roller and in 5 or 6 passes, I have my roughed in flange.

Note that when you tip a flange on an inside curve like this, you end up with a flange where the outer most edge is shorter than the rest of the flange, so as the flange edge tips over, that short side causes the piece to curve.

These are the sorts of moments where I start to wonder if this will be another "practice piece". (IMG:style_emoticons/default/lol-2.gif)

[tygaboy]

Next, it's off to the shrinker/stretcher. A bit of stretching on the flange (and shrinking when I go to far!) and... She's FLAT! (IMG:style_emoticons/default/cheer.gif)

I still have to tune up the flange edge to get it a bit more crisp but it's looking like this piece will end up in the car!

[tygaboy]

There's still a bunch of trimming and fitting (and you can see why I want that flange edge to be a bit more crisp) but I couldn't resist a very loose test fit.

At this point, I'm happy with how it's coming along.

[bbrock]

Whoa. Nice fit! (IMG:style_emoticons/default/pray.gif) I know what you mean about shrinking when you stretch too far... or when you meant to stretch but shrink but shoved the piece in the stretcher by mistake. Not that I've ever done that... (IMG:style_emoticons/default/unsure.gif)

[tygaboy]

Spent all day yesterday reorganizing the shop. I have a ton more room! I can use most everything without having to move anything. Much better...

So today was back to the lower fire wall piece.

I used a different set of dies on the bead roller and got a much improved, nice crisp edge. The fit is near perfect. Very happy with this!

Then it was trimmed to a rough fit so I could locate a bead that the upper pieces will land on. I didn't want "exposed edge" joints so the bead offset will give things what I think will be a more finished look.

And yes, I'll be cutting the center section out and routing it forward to form the ledge for the access cover. But I wanted to do the bead work across the entire piece to ensure symmetry.

Onward...

[Mueller]

I like that version, looks great

[tygaboy]

I like that version, looks great

Thanks Mike. And just to be clear, that's the same piece, I just "tuned up" the flange and added the bead.

[tygaboy]

An exhaust system for an LS 914. Some assembly required..? (IMG:style_emoticons/default/idea.gif)

The bends are mild steel. I want to fit everything up to be sure it all works as desired, then I'll redo it all in 304 stainless.

[Andyrew]

Redo it?

You are one strange cat! I found some good stainless 3" mandrel J pipes on ebay.

I found it really easy to weld with the mig and some stainless wire.

[Mueller]

Redo it?

You are one strange cat! I found some good stainless 3" mandrel J pipes on ebay.

I found it really easy to weld with the mig and some stainless wire.

No back purge?

[tygaboy]

Redo it?

You are one strange cat!

Andrew - Meow!
Yep, I've proved to myself I rarely like "version 1" of what I build so...
When are you coming over to bend up a roll bar? (IMG:style_emoticons/default/poke.gif)

And Mike -
Yes, it'll all be back purged during final welding.

[Andyrew]

Redo it?

You are one strange cat! I found some good stainless 3" mandrel J pipes on ebay.

I found it really easy to weld with the mig and some stainless wire.

No back purge?

I didnt back purge it at all and had no issues. I have some welds about 6" from my turbo that havent cracked and the stainless has already rainbowed. Is it medical grade welds? No. But it seems really strong. It welded JUST like standard steel. Lemme see if I can find a pic.

[Andyrew]

(IMG:http://www.914world.com/bbs2/uploads/post-172-1459193534_thumb.jpg)
About 1ft from the turbo, Stainless flange on stainless downpipe

(IMG:http://www.914world.com/bbs2/uploads/post-172-1459193267_thumb.jpg)
Bunch of these water pipes. All stainless.

(IMG:http://www.914world.com/bbs2/uploads/post-172-1458019575_thumb.jpg)
(IMG:http://www.914world.com/bbs2/uploads/post-172-1458019532_thumb.jpg)
5 welds here, No issues


I would confidently do this again the exact same way.

[mb911]

Chris looking good..

[Dion]

This is the current thinking re: the replacement firewall design. The center section (below the cross bar) will be removable. I get all the clearance I need for fuel lines, etc, it's easy to service things that would otherwise be a real pain to get to.

I'm still working on the design above the cross bar but I really like the "mini-tub" look that it has going on behind the door bar.

(Hey, it is the RaceRod, so I figure it's OK... (IMG:style_emoticons/default/happy11.gif) )

Now, can I duplicate all this in metal and have it look the way I want? (IMG:style_emoticons/default/idea.gif)

Wish me luck.

Just so cool. It looks evil in a Darth Vader way. Heheh. I really like the way the creases in the center section flow down. Really nice Chris.
Have you even determined a colour for this beast yet?

[tygaboy]

This weekend was spent on design and practice:
Design: working out the details around how to build the fire wall.
I didn't want the various panels to just butt up against each other in the corners, neither inside nor outside corners.

Practice: working on the bender, bead roller and shrinker/stretcher to see if I could get the bead I wanted on both inside and outside corners.
The good news is that I was able to get what I wanted!
In some cases, it was using "mismatched" dies on the bead roller.

For whatever reason, I ended up tackling what I figured was the harder one: Bead on an inside corner with a curve. Here it is! (IMG:style_emoticons/default/cheer.gif)

[tygaboy]

And again

[tygaboy]

And here's how the corner will look with the panels.

I think this will look far more "complete" than panels that just terminate in/at the corners.

[tygaboy]

Then I went after what will become the flange that will be spot welded to the chassis under the top of the door bar. Here's the sorta test fit. No, I haven't yet removed all of the original firewall... this piece will replace what's left there now.

Hard to see, but its got a bead right at the edge that the panel will sit down into.
The next pic makes it a bit more clear.