One of the big things I love about custom cars are the small details that builders put into a vehicle to make things simplified and flow. These type of modifications can take as much or MORE time than the larger, more common mods. My vision of Pile House from early on was a smoothed out 50's style custom with my own twist on it. Everything has been done with restraint and although some of the mods will be missed or overlooked when the truck is done, they're important to keep things clean and smooth. One of the big modifications on the truck I finished this winter was the one piece hood conversion.
The next part of the project was making the hood open on custom hinges. I was hoping I could find a pre-made hinge kit that allowed me to open the hood from the front like most cars currently have. Unfortunately all I found were kits for wild customs and street rods that opened from the back and tilted forward or to the side. As much as I like custom touches, making my vehicle look like a transformer is not one of the things I want to do this time around. I decided to take a crack at making my own hinges that disappeared behind the dash and share the process.
I promptly spent hours taking measurements off the firewall and making up crude models out of cardboard and tig welding rod. This is where it became blatantly obvious I suck at geometry and I was in over my head. I did know that I wanted a hinge that would tuck behind the dash when shut and and be strong enough to hold the fairly large one-piece hood I now had.
This is where I decided to consult with Evan S., one of our product engineers. Evan is pretty dang good with Solid Works and he agreed to help me draw up a design. Now I know not everyone has an engineer or designer friend, but a craigslist or similar ad could get you someone that would draw up hood hinge designs for a reasonable cost and save you wasted time and material. The nice thing I found during the process was that Evan was able to operate the hood in his drawing so we could identify potential issues that would arise before I cut, drilled, or welded. Once I had Evan's design printed out 1:1 I was able to mark out my slot in the firewall where the hinge would pass through and mark out my hinges on some 3/8" plate.
I first marked the center top and bottom of my slots and then I drilled holes with a step drill bit and pneumatic drill that matched the diameter of the slot. From there I used a cut off wheel on the angle grinder to connect the edges of the holes to make an even slot. I smoothed out the edges and blended the holes to the slots with a crosscut hand file.
Next I fired up the Versa-Cut 60 and rough cut the hood hinges from 3/8" plate. I clamped the hinges together and sanded them both down so they were exactly the same shape and rounded all of the edges. With the hinges cut out I was able to work on making the tabs that would hold the hinges in place. I used a prototype press-brake we're working on here in our R&D department to bend 1/4" plate into a U-shape. I then drilled holes in the brackets so I could slip a 3/8 bolt through. We then machined up a piece of round bar and bored the center out to allow the 3/8 bolt to slip through. Once I test fit all of this I was able to weld all of the pieces of the bracket together using the TIG 200 and the MIG 175 in the vehicle.
Once all the parts were mounted up I was able to double check the throw of the hinges with an angle finder to make sure I got the full lift and drop I needed. Luckily all the calculations worked and I got the -4 degrees when dropped and the 45-50 degrees with the hood lifted I needed. Now I had to figure out how I could securely mount the hood to the hinge. This is where things got interesting again. The hood on the truck hardly has any flat areas and it's full of compound curves. I needed to mount the hinges as far apart as possible so the hood was supported properly but that put the hinges on the downward curve on the outsides of the hood. I decided to try my hand (and prove my manliness) at shaping some 3/6" plate to mount to the hood. This meant I had to go back to basics and use the panel beater bag and a custom heavy duty shaping hammer that I made using the cap of welding gas bottle. Once I roughed in the shape I used the oblong shaping dolly to fine tune the corners and get the two mounting pads shaped to match the hood. This made A LOT of noise and wasn't easy on my hands, but it was the only good way to do it myself.
I then made up the other mounting pad that would be welded to the hinges and drilled 4 mounting stud holes in each. This gives me hood alignment adjustment and the ability to remove the hood when needed. I took some grade 8 bolts and cut the heads off so I could flush mount them in the hood mounting pad. I then welded them into the pads using the TIG 200 and flattened the welds out so they wouldn't interfere with where the pads mounted on the hood. I then fit the pads for the last time and slowly used the MIG 175 to stitch weld them in place. I have a couple spots where the welds on the corners of the plates pulled in a little, so I'll need to spend some time hammering and dollying those areas later on.
Finally I was able to weld the flat plates to the hood hinges. This required mounting the hood and squeezing myself under the fenders of the truck to tack weld the mounting pads in place. Luckily our SMD retractable flashlight has strong magnets that I could position the light just right so I could make a couple tack welds on each plate while in the engine bay. Once I got a few tack welds laid down I finish welded the hinges with the hood off and was able to mount everything back up and adjust the hood.
I'm happy to report that the hood opens well and moves the full range I needed. I realized I do still need to add some additional bracing under the hood to keep the hood from flexing a little when you first open it, but otherwise I'm extremely happy with how it all turned out! Check out the short clip below of opening and shutting the hood! Im also glad the hinges hid behind the dash nicely. My next projects for this part of the build will be building a removable "slam panel" that will house the female portion of the hood latch and cover the radiator and working on bracing the hood a little more. Make sure you check back to see how this progresses as I try and make Pile House an actual vehicle with opening, shutting AND latching body panels!