Discussion on idea for "air horn" fix

[Namerow]

2 hours ago, Elliott000 said:

Dude that's awesome and I really appreciate all the research! I've got my tower braced right now at about 907 center to center while I've been working on the rails and inner fenders. I'm currently re attaching the fenders to the frame and have confirmed number in the vertical on both sides are the same. I'm pretty confident that everything will line up. I laid one of my old fenders on there and bolted on the door. Checked gaps etc because of having to lift the one side, i was worried it may cause issues but shes spot on. I measured the hood just now and it "seems" as though there will be sufficient gap for it to close low n behold the gap is same front and rear in relation to hood width.thi g's are looking up! In the topic of this actual thread. Once I finish the tie in, I'll be onto the over wheel air things. Should be fun.... I still haven't decidied on what the plan is haha. Maybe full on tin basher, or I might do card board cut outs and basically replicate it but with square corners essentially boxing it.

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The 'air horns' (aka 'over the wheel air things') are apparently known in more polite circles as the 'upper beams'.  I suppose the ones on the bottom should therefore be called the 'lower beams', but we've all decided to keep calling them 'frame rails', because that's what they were/are called in body-on-frame designs ('side rails').

I'm pretty sure that these beam stampings were made from extra-heavy-gauge steel.  In fact, I've got a dimension of 0.054" in my notes (with a credit to Z-guru, Carl Beck).  That's at least 18 gauge (maybe 16), so considerably beefier than the wimpy 0.032" / 20 gauge stuff used on the exterior panels.  Remember that these upper beams take most of the vertical loads from the suspension, so there's a reason why they need to be strong.  According to Carl, the wall thickness of the lower rails is a bit less, at 0.050".  Maybe someone else can confirm or correct on these panel thickness numbers?

It would probably be tough playing panel-beater with 16 or 18 gauge.  Maybe -- as Grannyknot suggested earlier -- you could fabricate the piece from a set of smaller pieces.  I'm thinking bent-to-shape vertical strips (2" wide?), tack-welded together into a final form.  Maybe make a wood buck, then lay in the strips, one after another, bending in-place and then tack-welding as you go along.  To make it easier, you could perhaps used 20-gauge and then lay some lengthwise gusset strips along the inside surfaces to add some bending strength. 

Whatever you do, remember to post some pictures for the rest of us to look at.

[240260280]

NOS

[Elliott000]

I agree on using a thicker stock which I have already. I think ill go the route of multiple pieces attached to make a final form. At least it doesn't have to look amazing since she's covered up. I did get excited when I seen that one guy who just cut em off and layed flat stock over it. But I'm not going that way, I agree these are an important part of the front structure. I'll post up pics as I go along of whatever I create.

 

I tried finding nos for sale with those part numbers but no go, ill keep browsing

 

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[Namerow]

14 hours ago, Elliott000 said:

I think ill go the route of multiple pieces attached to make a final form.

Grannyknot did some comparable fab work when he modified the front crossmember on his 240 to provide clearance for the sump of the BMW he was installing.  Maybe he can post a sketch of how he'd go about fabbing this part.

Great reference pix posted by 240260280.  Notice the doubler plate that's installed in the region right next to the shock tower.

[grannyknot]

10 hours ago, Namerow said:

Grannyknot did some comparable fab work when he modified the front crossmember on his 240 to provide clearance for the sump of the BMW he was installing.  Maybe he can post a sketch of how he'd go about fabbing this part.

 

Thanks John but Elliott seems very competent.

Elliott, I was thinking about what you said and you could do it by using steel plate in the shape of a sideways T, 3/16th"  it would probably weight 4x as much as the air horn box but you could do it.

[Elliott000]

I appreciate the confidence! I'm new to the sheet metal game, im used to building for 37 or 40 inch tires and a v8 haha. I actually made some headway today. I cut the passenger side rust off the bulkhead and i can actually make this happen with about three pieces. I've bent a straight run for the middle section that maintains a width on top of about 1 5/8 inch. I don't have pics of that peice but I will tommorow. The two ends I'll have to get creative with a couple relief cuts and maybe a triangle or two to make things blend in. Overall I think ill be good to go. I do however need to make the two thin er parts that come along the end by the hood mounts. That will be the biggest challenge now.

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[Patcon]

I guess you could do this if you want to stay in your comfort zone...

[Elliott000]

Hahaha I'll never do that!

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[Captain Obvious]

5 hours ago, Patcon said:

The turn signals say 240, but those are clearly 280 bumpers!!  

[Elliott000]

Update, heres what I have conceived..... Hammering on a buck with heavier guage would suck so im bent the contour into some straight stock and ill do reliefs to follow the contour and then dress the seams with some welding. Where it make drastic direction Change on the right ill start with a fresh peice with a custom shoulder in it. Once I sew it up and grinder it will appear almost as stock aside from the square corner at the bottom where it ties into the wheel well.

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[grannyknot]

Nicely Done. Elegant solution just be sure to test fit the fender over it before welding the repair, there are a few places where the clearance is fairly tight between those two pieces. 

[Elliott000]

Good to know, thanks man

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