Operation IDIocracy: So the Heavy Thing is Done… Now What? Driveshaft Fitment and 38 Gallon Fuel Tank Mounting

With the IDIot finally having landed in Vantruck, the project has passed what I called “Peak Entropy” – when it’s the most taken apart and dysfunctional. To be fair, Vantruck is plenty dysfunctional still, but at least the two largest planetary masses have collided and combined.

Every other part from here on is a small and annoying piecemeal activity or side quest in comparison, and it’s what these last couple of posts about IDIocracy will cover.

Making a Mix and Match Driveshaft

For some reason, I found myself owning several van driveshafts. There’s Vantruck’s original two-piece, which was partially re-used when I had my vanstylist install the Gear Vendors overdrive a few years ago. There’s the one I salvaged off Snekvan, for a conventional 138 inch wheelbase van. Then there was also one I plucked from a junkyard van. I figured between all of these, there was at least one I could actually use on Vantruck in lieu of having another one manufactured.

I dragged these out so I could start making measurements and seeing what spline and what U-joint fit where.

I made many scientific drawings and measurements such as this one. Vantruck has two center hanger bearing supports – one from Centurion when they extended the frame (closer one to the transmission) and one added by my van salon when the Gear Vendors overdrive was installed. I collected dimensions from the transmission to the hanger bearing supports, then from there to the differential.

To my amazement, I could combine the …uhh, foreshaft that came off Vantruck (A) with the back half of Snekvan’s OEM driveshaft (B). The E4OD output spline adapter (C) could be mounted on the foreshaft (A) if I bought a Dana “converter” U-joint since the cups were different sizes and spans.

This exercise reminded me once more that I really hate U-joints and the procedures needed to press them in and out. Especially when they’re gross and rusty from being under a truck for who knows how long. I rented a U-joint press for this purpose to minimize my pain compared to when I did it for Mikuvan and made shit up on the spot.

The shaft lengths matched up well enough, but I had to slightly change where the hanger bearing support was. It was close enough to just make a bracket for instead of cutting the support off and moving it. I made this support using a leftover chunk of steel channel that I’d picked up for Boxcar. It was cut in half, milled down, and had appropriate holes drilled.

I drilled mounting holes into the existing hanger bearing support and bolted the bracket in.

Sorry, I lied. You know exactly what I did instead. I’m not sorry.

Anyways…. now I bolted the hanger bearing support bracket in, after the paint dried. Everything lined up great! Installing the driveshaft was simple since the slip yoke’s spline could extend enough that I just bolted it up on both ends and then lifted it upwards. I also took this opportunity to clean up and coat the otherwise pretty rusty steel channel that formed the hanger bearing support.

Fuel Tank Mounting

Modifying the fuel pump bracket and gauge sensor was easy enough, but actually mounting this thing was a different question entirely. It’s too large to fit in the rear cavity of the frame (something something Not A Direct Fit For Vans…), so I’d have to cut the existing straps off and remake them.

Here’s what it looks like when I lifted it into place at first – It got stuck here and wouldn’t go up further! The plan was to cut that forward cross-member (on the left) off and make newer, longer straps across the top, and then weld it back into place.

I positioned the tank where I thought it would work well and marked the location to make measurements. This is almost right up against the rear differential, making me question if I had to drop the tank if I ever wanted to service the differential or something.

The bracket was drawn up in Inventor sketches enough for me to make the measurements. The new cross-member is made from 1.5″ angle steel, the same as what came off. Two 1/4″ thick tabs will attach the new custom straps on the bottom, and the straps across the top are 1/8″ thick mild steel strips.

I blasted these together quickly with Limewelder. Easy enough here in the garage, where I ran 240V from the breaker panel without telling my landlord, so I could have welding power.

Outside, though, was going to be a different question. I’d have to run Limewelder on 120V through an extension cord and I doubted it could push enough power to properly penetrate into sections of 1/4″ thick steel. It will probably be enough, but it won’t be pretty.

This is what the setup ended up looking like. I set up The Sun™ as a work light running off an inverter powered by Coronavan, since it does draw a pretty healthy amount of power. I wanted as much available for the welder as possible. After doing some tacking tests, I decided okay, this was going to be bad.

In the middle of winter, running on 120V through an extension cord. The welds would need to be preheated for several minutes with a heat gun or torch first.

Preheating the work zone to 200-something degrees with the heat gun made for some satisfactory results, though. In retrospect, I could have rented a generator-welder. This is certainly their use case!

I guess the ultimate test is standing on it and jumping up and down a bunch of times.

To make the bottom strap, I pulled a trick out that I hadn’t used in a very long time. I used a stiff mechanic’s wire, I think 18 gauge stainless steel or whatever they sell for hanging brake rotors and stuff. I attached one end to the new mounting ear and pulled the wire around the bottom of the tank, forming it as I went, ending where I think the OEM strap hangers will be.

Then I released the wire from the mounting ear, trimmed it, and recorded the approximate lengths and angles of each segment. I promise there is a small, rigid wire that’s been bent to a J-ish shape in that picture. It’s just well camouflaged!

The sketch was flattened out to obtain a length. Little 1″ cuts of angle steel will interface with the strap hangers.

A little action with my bench vise, hammer, and cheater bar later, and these 1″ wide steel straps have been formed.

With the help of the Code Enforcement Strike Team that weekend, we lifted the tank into position and mounted the straps. The fit is pretty spot on!

Because I have all of these brackets modeled and dimensions recorded, I’ll publish them here once the project summary page is made. Now we know how to stuff the 38-gallon F-series tank onto the van chassis! But not Directly.

This is the state of Vantruck after that weekend in February ’23.

Make no mistake, it’s far from complete here, but will fool an inattentive city worker. The bed and bumper were mounted loosely, for if we had to jump back in to do something. Nothing was hooked up yet. From here, work on the subsystems and remaining parts was very lightweight in comparison, just involved a lot of rolling around on the ground.

Operation IDIocracy: Correcting the Driver’s Side Engine Mount With a Custom Bracketry

In the last episode of Operation: IDIocracy, our heroes were on the brink of defeat by the forces of subtle year-to-year manufacturing changes that aren’t really discernable at a glance.

For one reason or another, the driver’s side of the engine cross-member was too high, causing the engine to sit off-kilter and hit the passenger side of the compartment. To proceed further, I had to redesign the mounting bracket on that side to accommodate. Here’s how that whole quest happened!

I removed the driver’s side engine mounting bracket again so I could pivot the engine from the passenger’s side one using the crane to hold it. The error source seems to be entirely here: Raising the passenger’s side to level it out will put it too high up in the compartment and still too close to the wall. I had to lower this side instead.

It seemed like the raised, stamped metal bracket had to become a flat plate with the same hole pattern. This is a standoff distance of about 1/2″.

Here’s the overview of the arrangement showing the use of the Attitude Control Ratchet Strap purely as a sling. I had the passenger side mount only somewhat tightened down, so I could see if the motion was going to cause any undue deformation on the rubber core. Too much initial twist and engine mount life could be negatively affected.

I stuffed a bunch of spare metal cast-offs from the shop into the gap on the driver’s side so I could see what the whole thing looks like once it bears weight. The items shown are cuts from 30haul’s Shiny Metal Ass and some 1/4″ steel strips, with the total height being 5/8″.

So I started getting the impression looking at it from underneath that the mounting studs coming off the engine should be centered in these big holes in the cross-member. That entailed a standoff distance of 3/4″, which looked correct. If this is in fact the case, then for some reason in 1986 the mounts for the 6.9 IDI (which would have been correct for that year) must have been 3/4″ shorter or more.

Yet I couldn’t quite see where Spool Bus (a 1984 6.9) was different in this regard. Maybe one day if I have to take it apart in depth, I can go find out.

So where do I go from here? It was time to reverse-engineer the engine mounting bracket. I’m going to duplicate the essential mounting holes but compress the raised stamping into a single plate. Since it’s a 2D part, I just took a really long-zoom picture of it.

Simple as that. The long zoom flattens out the perspective – not entirely, but better than being up close. I imported the the picture into Inventor and just started drawing a part using my scale reference.

The two mounting holes on the right and lower edge were reused directly. The third mounting hole is one that fit the 460 bracket but which the IDI bracket does not use. I replicated the teardrop slots for the engine mount studs.

Here’s the solid part! I had one of the Enders print out a few layers of it as a validation of the hole pattern.

Looks like I was off by some amount. Nothing a quick eyeball-caliper measurement and some marker can’t fix.

Using the original sketch elements now as reference-only geometry, I made new features that were the measured offsets from the fit test.

The fitment was amazing! So all it took was one revision. All bolts threaded in by hand with how spot on the centers were.

And the engine rested with all of its weight on the mount basically dead center in these access holes.

There’s one slight change that I think is fine. Because the original studs were supposed to be bolted through about 1/4″ thick stamped sheet, and I’m putting them through a 3/4″ thick plate, there’s no more “stickout” of the stud. The nuts actually tighten on completely flush with the end of the stud. All of these coincidences made me believe I had reverse-engineered the actual geometric difference between the two cross-member versions.

Here is what things look like from afar. The engine sits level and there is still the tiniest quantum of clearance to the passenger side of the engine tunnel, but it was much closer to the “Every part of a Ford Econoline is 0.25 inch away from every other part” guideline.

I sent the flat cut file of the new bracket to OSHCut to be made in 3/4″ thick regular vanilla steel.

Not going to lie, I kind of wanted to find out if a Markforged print could actually work as an engine mount… Given the loading is mostly compression from the weight of the thing, and in-plane shear from torque, I feel like a fiberglass-backed Onyx print may very well have worked. But maybe I will try that for a vehicle with an easier-to-access engine mount.

In 10 minutes, the plastic prototype mount was replaced. Up the engine goes, the bolts come out, and the metal part is substituted in.

And here is the final fitment – as on-the-money as I cared to achieve. At this point, all of the bolts were tightened to specifications, and I finished drilling and mounting the transmission cross-member. The crane, jackstands, and blocks were removed.

Next up: Well, I have a heavy thing living inside another heavy thing, but with no metaphysical connections to it. I now began the “1000 little things here and there” stage. First up, fitting up the driveshaft to the transmission and mounting the 38 gallon modified fuel tank.