View Full Version : Hood modified for breather clearance
One of my former classmates from high school caught up with me a few months back, and had some work he wanted done on a hood for his Tubbed V8 Plymouth Arrow. He said he wanted a more professional job over what was done back then..
https://i.imgur.com/HLgR4a7.jpg
A V8 in an Arrow is enough of a challenge, near impossible to fit it all under the hood. Here are some older pictures of the car just to show what we're working on...
https://i.imgur.com/9hlaX0b.jpg
https://i.imgur.com/Ay9A2iD.jpg
https://i.imgur.com/nJRNKNy.jpg
He had bought an NOS hood for it some years back, so at least he has something solid to work with.. He said the metal flopped a bit around the opening he cut, so I thought we'd add a wire edge around the opening and make some new bracing on the underside while we were at it. Here's the phenolic dies made for the Lennox to form the new bracing..
https://i.imgur.com/xkWYSWL.jpg
Here's a test sample run...
https://www.youtube.com/watch?v=QCoTMs0ANC8
...and a test fit
https://i.imgur.com/Kv2aRgu.jpg
Next, the bracing we wanted to install needed to go around the bigass hole, and some of the existing brace needed removing.
https://i.imgur.com/H85pPhz.jpg
https://i.imgur.com/9UR9mmH.jpg
Our new brace designed to go around the hole... cut in the flat and run through our dies..
https://i.imgur.com/Miq5USw.jpg
https://i.imgur.com/PqLFnTi.jpg
https://i.imgur.com/hBlrl8G.jpg
And here's about where it will sit....
https://i.imgur.com/lOxzwUp.jpg
Rather than screw up one of the last remaining NOS Plymouth Arrow hoods in existence, let's do a test sample first.. To strengthen the opening, we'll add a 1/8 wire edge protruding upward, which will also help to keep things out.....somewhat. Here's our new dies for the 1/8 wire... This is the "inlet" side...
https://i.imgur.com/F9YUtEI.jpg
Side view shows the ramps that will add the joggle
https://i.imgur.com/4eWKQCX.jpg
We're using a 22 x 22 piece of 19 gauge for our sample, and folding a 5/16 flange, which needs a bit of stretching to keep things flat. so a rounded hammer on the top of the stump adds a bit of stretch, then a linear stretch hammer and dolly to stretch further and fold things over..
https://i.imgur.com/ABicjt5.jpg
with the flange folded, the sample is run through our dies to form the joggle
https://i.imgur.com/ib2FRbD.jpg
1/8 stainless is rolled in our tubing bender/straightener, sized, and TIG welded to form a continuous ring. Then it gets laid in the channel and the flange staked over in various spots to hold it in place using the linear stretch hammer..
https://i.imgur.com/FP6hbJd.jpg
Hammering process to fold the flange over. Linear stretch hammer used to add a bit more stretch and to minimize marks left behind..
https://www.youtube.com/watch?v=WWIpwh0zZg4
Finished sample...
https://i.imgur.com/PgRmIYC.jpg
….and checked to the brace
https://i.imgur.com/E77l9RW.jpg
With the practice behind us, lets see what we can do to this hood. The outer circle is the mark for our fold, or opening size. The inner circle is the cut for our flange that will wrap around the 1/8 wire..
https://i.imgur.com/LFdradY.jpg
Getting our tin snips started...
https://i.imgur.com/3BwHpyh.jpg
Hole cut with no filing, no sanding, and absolutely no metal "splinters".
https://i.imgur.com/soMuJt1.jpg
If you have issues with tin snips AT ALL, I recommend Bill Gibson's tin snip video... One of the best training/refresher videos on tin snips..
https://www.youtube.com/watch?v=qAOQfUaRZyw
Next, on to the underside. We have four places where these areas of the old structure was cut out that need to go. Opening the hood to see these remnants would just kill the look, so let's see if we can mimic a factory look here.
https://i.imgur.com/R9Xb2Hp.jpg
A piece of 16 gauge was used as a heat shield and using the Meco torch and the barrel end hammer, reshaped the offset back to match the adjacent contour...
https://i.imgur.com/M6M8AXY.jpg
https://i.imgur.com/jV6MLDt.jpg
That'll do pig, that'll do.
https://i.imgur.com/9jl2RlG.jpg
With the hole cut now we need to fold a flange to wrap around the 1/8 wire. The linear stretch hammer and a heel dolly is used to stretch the flange that will be folded down, then a tipping tool takes the flange down about halfway. Then I needed to get in the thick of things, further stretching and hammering over to a 90* flange, all while checking the crown around the hole to ensure consistent stretch of the flange.
https://i.imgur.com/EBR5M2P.jpg
https://i.imgur.com/RoHIf8x.jpg
Once the flange is folded, the Lennox is used to add the joggle for our wired edge..
https://www.youtube.com/watch?v=TMk4myTDvmY
Bottom side....
https://i.imgur.com/qRnnpVz.jpg
https://i.imgur.com/bkhduMx.jpg
Top side....
https://i.imgur.com/1oaVHCh.jpg
https://i.imgur.com/h6S8hJ4.jpg
Our 1/8 stainless wire "ring" was formed using our tubing roller, the tool shown here in the vise when we were bending fuel line a few months back....
https://i.imgur.com/6w1XB1Y.jpg
The ring was then sized to fit, ends TIG welded together, filed, and media blasted for paint adhesion. The channel and surrounding area was abraded with some 120 grit and some SPI epoxy brushed into the channel. The wire gets laid into the channel and another brush coat on any bare spots. Then the flange is staked down using the linear stretch hammer to hold the wire in position...
https://i.imgur.com/hDZ9Ipm.jpg
Then the flange is hammered over as we did previously with our test sample.
https://i.imgur.com/jVZxvHv.jpg
After our initial coat of primer had dried, we brushed around the perimeter to seal the wire and flange.
https://i.imgur.com/LvacZsV.jpg
Looking at the bottom side of the hood, all of the structure uses a radius where the parts intersect, so we may as well follow suit.. Holes were cut in some 19 Gauge and corners cut out..
https://i.imgur.com/gpriIvL.jpg
Corners TIG welded and welds dressed..
https://i.imgur.com/iQ2x6KP.jpg
The area our brace will cover is abraded so we can get it covered with epoxy primer before installing the brace.
https://i.imgur.com/UhSBJP6.jpg
Brace is media blasted to prep for epoxy primer, and test fit to the hood.. Once the epoxy sets up a couple days we'll get the brace welded in..
https://i.imgur.com/OMikkMm.jpg
https://i.imgur.com/RT66GZG.jpg
https://i.imgur.com/t78EjWr.jpg
https://i.imgur.com/dZQINGe.jpg
Prior to welding the brace in, we used some 3M NVH dampening material and added a few dabs on the inner hood skin where the brace's flanges would rest (Thanks to Chris Hamilton for the recommendation).
https://i.imgur.com/YlZLdGW.jpg
16 gauge cold rolled steel was used under the brace as a heat block for welding. The brace Is clamped, then tacked in place using the TIG.
https://i.imgur.com/yPpiwly.jpg
https://i.imgur.com/Uw5aIvo.jpg
TIG welded in short beads and checked the outside hood skin for heat, let cool and continued in that fashion.
https://i.imgur.com/Qg7brw9.jpg
Welds on the flat area of the flanges were dressed smooth. Remaining portion of the weld will likely be covered in a slight amount of filler to mimic the radius elsewhere under the hood.
https://i.imgur.com/RSuExl0.jpg
https://i.imgur.com/7icWYe6.jpg
Video of underside:
https://www.youtube.com/watch?v=KvVjRLtrYZY
Topside with some epoxy on the bare parts....
https://i.imgur.com/Ag2fyYv.jpg
chevynut
01-31-2020, 10:36 AM
Great work as usual Robert, but if it was me I'd prefer nothing sticking through the hood in the first place.:eek: I would have looked for a different manifold and air filter solution, or even an EFI throttle body that's typically ~1" shorter than a carb. I'm sure there's something out there that would have precluded cutting a hole in the hood the only question is the cost. I had a concern about my EFI manifold being too tall but I would have never cut my hood to accommodate it. I guess everyone has their own objectives. :p
Again, awesome work!! That brace looks factory!
bigblock
02-01-2020, 06:43 AM
The Master has again showed why he is the Master!!!! Thanks
Belair-o
02-02-2020, 06:41 AM
Amazing work! I can't begin to do what you do, but do appreciate your craftsmanship.
Thanks Guys!
......if it was me I'd prefer nothing sticking through the hood in the first place.
CN, I'm with you, but he already has a running drivetrain. He's more anxious to get the little bit of body details fixed and not take anything else apart.
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