Mounting a Composite box to E350 Cutaway Chassis?

[CalgaryMcLean]

Planning on completing exactly this in the fall.
Total Composites box kit to be ordered within a month or so.

Just starting to discuss things with the truck body people who will build the frame and mount the camper.

Will keep you posted with anything that I find out or learn.

[carringb]

IMO Ford publishes those body-mounting options for good reason. If you mount the body on a 3-point mount, the chassis will do the work rather than the suspension, and it's just not designed for that. You'll start getting slip at all the crossmembers, which can take a "set" and affect steering alignment. You might even end up with stress crack at critical frame joints. It's far easier just to tune to the suspension to be more compliant, and you can even add more frame torsional rigidity just by adding 1 or 2 tubular crossmembers (and the hitch receiver aids this a lot too).

By taking a "set"... What I mean is the fasteners will resist twist to a point, until the connection slips, but it'll stay in the new position until you twist it back the other way. This happened on one of my F650s roll-backs. Normally the chassis is stiffened by the roll-back deck. But they are only locked together when the bed is stowed. After doing a cross-ditch recover, the frame twisted with the bed extended. We actually initially thought it broke a leaf spring because it stayed twisted about 2" corner to corner. We ended up having to put the chassis up on jacks and break loose every single huck-bolt to straighten it back up.

[b. rock]

I pinged them on this a few years back. They didn't have any subframes designed and it was going to be a custom design so I punted.

It does seem like the ideal camper if you can deal with the height. When I did some napkin math on the flat subframe + wall thickness + over 6' standing height, it was getting pretty tall. Getting wheel well recesses and a mounting frame to deal with them too would lower it significantly.

[mk216v]

Ambo modules are like a FWC(Four Wheel Camper); "stick tube aluminum", except ambo's are even more rigid. Compare this to a composite cabin which still has rigidity, but not built like a brick sh*thouse ambo.

From my long road of composite camper musings, TotalComposites and Boxmanufaktur both state that mounting one of their "box" cabins to a fully-boxed-frame pickup is fine, but on an open c-channel rig (like a Ford chassis-cab truck, or an E-Series), you need a torsion-free subframe between the chassis/frame and the underside of the cabin/box/module, so that as the c-channel frame twists, the subframe takes it and not the cabin (compare to the fully boxed pickup where the pickup frame takes the twist and the cabin is ok. I received an estimate for $6-7k for a custom subframe engineered/built/installed, from one of TC's cabin/subframe builders.

The idea of the bellow (rubber boot between cab and cabin) is smart for when the 2 sections twist from each other; how the others like ER, EC, GXV, etc do it. Ambo's don't seem to have any bellow, at least that can be seen, perhaps because the 2 sections don't flex much independently.

I think the composite cabin on the E 4x4 would be rad. Considered it (and Type3/1 ambo's even more) for a long time. But, there are a lot of moving pieces to sort out, and most are full custom; subframe, cabin, interior build. Not just a build you can order up and wait for it to arrive all complete.

[fjefman]

Love the topic and I've also got this on my radar. I'm working on building a bigger garage first so I have a place to build this, but I'm seriously considering starting a project like this over the winter.

Here is my plan:
Buy a brand new E-350 cutaway chassis from Ford (157" wheelbase, dually)
Getting U-Joint to basically build a flatbed on the back using normal ford body mounts so the floor is even with the cab
Fabricate a box that will connect in some way/shape/form to the flatbed (still deciding on the construction method of the box)
When all done go back to U-Joint for there 4x4 magic.


Maybe I'm just ignorant/stupid, but I don't think there is too much need to worry about flex/3 point/4 point mounting with an e-series chassis.

My rational for this is that there are tens of thousands of campers on the road today with very simply box to chassis mounting..and thousands more being built every year. Many of them are built out of wood and AL siding, some with thick fiberglass side panels, slide outs, etc. Some fo these have ~25' boxes with more than 4" of overhang over the rear axle. And, almost all of them are cheaply built with little thought matching flex characteristics to the chassis/cab.

Go to any camper lot and crawl under a few of them and you will see how little thought when into design, construction techniques, flex/mounting, stability etc. Sure, they aren't made for "off-road" use but some do light off-road and hit a curb or three on every trip and they don't have catastrophic failure.

Mine will certainly be more off-road capable, but I'll be going super slow and there is only so much rough stuff I can get to before the I just can't fit 10' tall, 7' wide, 12,000lb vehicle.

Also, the chassis is designed to have a full one piece cab/box on the back (van body) that just rests on normal rubber body mounts so full box or c-frame doesn't matter, it isn't designed for serious flex. See Fuso for an example of a chassis designed for flex.

So, when I keep in mind that whatever I build will be smaller (13' box), stronger and more durable than 99% of the Class B+/Class C campers out there I think I'll be just fine with my plan.

Am I wrong for thinking this?

Jeff

[VanHallen]

I think knowing how much the E350 Chassis can / will flex after the 4x4 conversion will be the determining factor, imo. I don't think the body layout guide / factory mounts assume significant offroad usage nor a 4x4 conversion with the addition of a solid front axle. I believe UJOR offers a 4, 6 and 8 in lifts where you would likely see a lot of twisting in those slow deeply rutted road conditions. It's something I'd want to know sooner in the build process rather than after the fact. With the SMB, the body tends to have more flex than what a composite panel construction will have and I just haven't found any direct examples, only anecdotal.

[b. rock]

Have you pinged Andreas at Total Composites directly? I see that he's chiming in on your thread on Expo.

The passenger/cargo and c/c frames are different, but in a passenger van even with moderate flexing the interior lights will flicker on and off due to doors shifting. Sway bar disconnects would help to an extent, until you really start crossing the axles up. With a c/c that has multiple wheelbase options, the longer the wheelbase the greater the moment. But, as mentioned by @fjefman, not a lot of people are doing to do that with this big of a vehicle.

I really want to see this setup succeed because it checks all the boxes. Tight approach/departure angles, pass through (this is the big differentiator vs a truck camper), good insulation, and nice square walls. Someone is just going to have to cross the subframe/mounting bridge and be the first.

[VanHallen]

I have been in touch with Andreas directly. He suggests mounting using the standard body mounts to the front and cab area, and some sort of springs in the back. He stopped short of offering to test this or guaranteeing the box I'd love to see Andreas and Chris at UJOR and/or Field Van / SMB do a few prototypes...all suggestions I've made

There's also a bit of hurdle in being able to buy a Cutaway Chassis before registering it. Usually they go to some sort of body upfitter where it can then be registered or an Upfitter can convert to an RV with the right goodies. I'm sure individuals can do all of this, but it does complicate the situation.

[b. rock]

Is he able to make frame recesses for the hump over the rear wheels?

Having watched Bison campers spring up out of nothing, it certainly seems like the market is hot right now to start something. However comparing new to new, an Ecoboost high roof AWD Transit is about $48k and a cutaway E350 is $34k (just going off of Ford's website) so you'd end up quite a bit higher in overall price by the time you add the 4x4, subframe, and box. Obviously those of us thinking about it understand the differences between the 2 but that's a pretty niche market. I'm not sure what else you're competing with at the ~70-80k price tag, but you're definitely under the price of something like a Tremor or Power Wagon + FWC (new costs). You can also find new vans with a traditional box already mounted for roughly 40-45k and then add insulation and shave off some cost. It's not as cool though.

[VanHallen]

I think he's able to do the recesses / wheel wells

I'm not sure what Ford's commitment is to the E350 as for a bit it looked like it was going to be replaced and phased out with the Transit. However, since Ford added the V8 (in two models, a performance and economy version), perhaps the'll keep it around for a while. Having come from a Truck Camper and seriously considered a Fuso based platform, I just picked up a 2003 SMB v10 and really think the e350 has so much much potential. The overall short length, short sloped hood, high payload, short wheel base, great angles beats almost all pickup truck based platforms. With its lighter weight and much more powerful Hp/low end torque engine (even the economy version), easy pass through and more comfortable ride, I think it beats the cabover Fuso platforms, too if you value both highway and offroad capability, equally. The lighter weight makes it better for a lot of terrain but also opens the door for a lot more tire options than the heavier Cabovers. Of course the 4x4 conversion is critical to the e350 platform and most allow on the fly 4wd under 55 and some even decrease the turning radius. I know my limitations and I'm no builder. I'm good with systems and design and know what I'd like that I just can't find in the market right now