moroza

How about a sign that says "Warning: proximity sensor for automatic toilet dump." And maybe have a little auxiliary holding tank for "warning shots"? There's also the classic, "Do not tailgate; vehicle sheds parts." Helps if the vehicle looks the part, of course. And my personal favorite:

Hey waitaminute, you've got a -78 cab in the first shot, and a 79-83 in the second... cab swap? Why? Staying tuned...

I don't own what came from a factory as a motorhome, but... 26.

Wouldn't that be weaker than the triangle structure I have now? Anyway, that upright member is for keeping the walls from flexing too much, and supporting a window. I don't see it supporting much other weight. Duly noted, anyway. More comments like this, please! 1. Good idea, and I will do something similar temporarily, but I plan on adding a second tank opposite the first, so other than little cubbies there won't be much room down there. I plan to keep at least some of my drinking water and all of my batteries inside the insulation layer, for function in extreme cold. I am considering making space for temporary mounts for the batteries as low and centered as possible, in case I ever really need to squeeze out an extra couple degrees of traverse angle. 2. There'll be exterior storage bins at least in front, if not also behind, the rear wheels. I did not include them in the drawings because they are outside the structural and insulation layer. The departure angle looks so good because I completely redesigned my project to maximize it. I can't get any better without getting real creative with the rear springs (not shown, but they are the drag point right after the full-sized spare). Right now, the spare sticks out a good bit, and I'm not sure if that's a very good thing (hang a steel plate under it and it's a very good bumper) or if I should relocate it to maximize the angle. I lived in my car for about a year, got hooked on that lifestyle, but decided that an old BMW wagon just wasn't appropriate for it. Carving corners at 200kph doesn't mean much when I get stuck on my way to a campsite, then spend all night freezing in the back of the car because there's no heat or insulation. I call this project a "tinyhouse", but it's not a house scaled down, it's a car scaled up.

I played with a few different configurations of skin material and thickness vs. stud material and thickness, and came to the conclusion that triangulation with studs is much lighter than with skin. At least, that's how it was with wood/plywood. I would think that triangulation is a lot more important in a structure that sees frequent side to side loading, rather than buildings.

Thermal bridging. See the first pic for how I'm getting around it. Well, I'm not using any fiberglass. The only heavy plywood is on the floor and a bit on the roof. The wood studs could probably be thinner; all they're for is supporting the windows, and keeping the thin wall skins from flexing too much. The alu studs might get thinner, too. Weight is the reason I redesigned the whole thing to use alu instead of steel. My previous scheme involved steel tubing of various shapes and sizes, plus the same skinning materials as this. I estimated 280kg before interior fixtures and whatnot. With this, I'm hoping for more like 230kg. I've yet to run weight calculations. For now, I'm looking for feedback on structural design. Like does it look adequately triangulated? Is part of it overbuilt? Underbuilt?

I've seen and studied the Super Camper. Nidacore is too expensive and underinsulated. I can take screenshots and upload them as JPEGS, of course, but you won't be able to fly around the model. I guess I'll try that. Here we go:

Any armchair (or actual) engineers around here? Or anyone else with $.02 to share about my plans to DIY a motorhome? I've got an '81 longbed 4x4. I want to build my own for several reasons, chiefly that I want it heavily insulated. Current plans are 3 inches of polyurethane or polyisocyanurate rigid boards all around, maybe more in the roof. Structural materials are mostly riveted aluminum, with some wood thrown in a few spots. For planning, I have it nominally as 2x1" beams, but actual pieces will depend on what I can find. It'd be great to come across a stash of broken aluminum ladders, and chop them up for beams. The "stove" refers to either the smallest Ammocan stove, or something very similar of my own construction. I plan to use propane only for cooking, and diesel only for moving the vehicle. Window shapes and positions are approximate; actual details will depend on what windows I salvage from something else. Really, that statement applies to everything in the design. Walls materials and their thicknesses, inside to out: 3.2mm plywood (1/8) inside, except around stove, where it's cementboard and alu skinning 50.8mm alu and wood studs, insulation between them 25.4mm more insulation 0.6mm (0.019") alu skin on outside floor: 15.9mm plywood (5/8) 50.8mm studs and insulation 25.4mm more insulation 0.6mm alu skin on outside (bottom) roof: 3.2mm plywood (1/8) inside, except maybe around the stove 38.1mm insulation 50.8mm studs and more insulation 12.7mm (1/2) plywood 0.6mm or thicker alu skin on outside (top) Here's my SketchUp model. I couldn't find a 1st gen cab, so I took a 3rd gen and fudged it to similar dimensions. The collection of stuff in front of the truck is a cutaway of the wall/floor joint, illustrating my positioning of the structural beams to avoid thermal bridging. Er...how do I upload a .skp?

I'm still in the planning stages of a DIY camper build on an '81 Toyota 4x4 frame. Right now I'm trying to decide between a side-door or rear-door layout, and hoping some folks can weigh in with their experience and thoughts on the relative merits of the two designs. The competing layouts I'm considering are 6.2 and 9: Bright red lines represent full-height floor-to-ceiling partitions (closets). Dark red are partial-height (bins). Dark purple is a sideways Murphy bed in half-out (couch) mode, light purple is in full-out (bed) mode. The gray X-ed box represents the floorspace taken up by the woodstove and everything it comes with. The cross-section view is looking forward. There, the blue is the shape of half the bed's mattress, the green is a fold-down table/counter, and the curved dark red is the shape of the cab cutout. The white boxes are the wheel wells. Constraints and externalities: * The space is 4' tall by 5' wide by 8' long. I will not make it longer, wider, or taller, for various reasons. * The back of the cab will be cut out and joined with the rear box. "Flow" between the cab and box is very important to me. I'll eventually have a captain's chair mount for the passenger seat. * The bed/couch design is pretty much fixed. It must be full-width and be able to fold away. What the pros-n-cons basically boil down to is this: a side door feels nicer to live with and has more cargo room. But much of its cargo room is at the back of the vehicle (real heavy stuff like water and batteries can still be in the center, though). Maybe I'm still stuck too much in performance-car-thinking, but that seems like bad design from a moving-vehicle perspective. Anyway... your $.02?

I've got a lot of steel tubing available here, as well as angle iron and some heavier C- and I- beams. The tubing is (I think) 2" x 2", 1/8" thick, the other pieces vary. There's also a lot of old leaf springs, some highway stakes, at least one big piece of diamond plate... and that's just what's here and otherwise trash, not counting whatever I buy. Should I make the whole thing out of steel, or just a rollbar-shaped core structure, or just the floor...?

That stove looks excellent. I've got a whole lot of old ammo cans laying around here, and I bet I could make something like it, but with an exterior air intake and maybe extra heat shielding. Work's been slow; I'm rebuilding the front axle, relocating the rear, and doing little this-n-that things to the rest of the truck. I've also been doing unrelated welding projects, which have made me realize that making a steel frame isn't out of my abilities like I initially thought. I know that steel is stronger than wood in some ways, not others. Who here can tell me what about making some of the structure out of steel, to gain strength or lose weight?

I like those ammo-can stoves; they're about the size I had in mind when first planning things. I'd want to add a lot more heat shielding to mine, though. Now that I've figured out a nominal value for how much heat output I need, I'm leaning towards a more complicated but compact heating system: a tiny stove, maybe the size of one of those ammo-can ones, with extensive heat shielding, that normally gets stored in some cubby, but that I can bring out and attach to two semi-flexible ducts: one for exhaust, one for outside-air intake. When I need heat, I bring it out, hook it up to the ducts, burn what I need, let it cool, then put it away and save some valueable floorspace.

Most commercially available LEDs are a balance between cost and output, with their "purer" light somewhat mitigating the lower actual output. You can get LEDs that are just as bright as incandescent or compact-fluorescent bulbs (Audi and some other cars are coming with LED headlights), and they'll last longer and draw less, but they'll cost you a lot more. I have two 5W LEDs in my yurt, and it's an acceptable amount of light for reading and cooking and whatnot. I'd say they're about equivalent to two 25W regular bulbs, while costing about twice as much and drawing five times less power.

Regarding insulation, here's the back of my envelope: Surface area of the camper box, including a hypothetical wall between the cab and rear, is 19.5 square meters. Rigid foam has a thermal conductivity of 0.035 W/(m*K), which for 89mm gives a thermal resistance of 0.089/0.035 = 2.54 K*m^2/W. Thermal transmittance is the reciprocal of thermal resistance, in this case 1/2.54 = 0.393 W/(K*m^2) With 19.5 m^2, I get 7.67 watts of heat lost through this insulation, for every degree Kelvin (same as Celsius) temperature difference. If I'm in a typical Norcal winter (5*C) and want it to be 25C inside, that's a gradient of 20K, so I need to be generating 7.67 * 20 = 153W to maintain that temperature. In a murderous arctic winter of -75C, that 100-degree gradient means I have to generate 767W, which is about 2618 btu per hour, which is about a sixth of the smallest woodstoves I've seen. A human body makes 80W of heat when sleeping, about 110W at rest, and over 1000W doing heavy work (the first two numbers are pretty consistent among sources; I'm not sure about the third, though). This isn't including the insulating value of plywood (very small), interior cabinets and whatnot (moderate), nor losses due to 2x4 framing (small to moderate) or windows (variable). But the back of my envelope suggests that me doing some pushups now and then will be enough of a heat source no matter how cold it is outside. So... I... don't... need a woodstove at all? Can someone check my math and reasoning?

Thanks, I'm glad to hear a space this size doesn't need much in the way of heat generation, more in retaining it. There'll be a smoke alarm, CO meter and alarm, at least two fire extinguishers, and variable vents in addition to the doors and windows. I do intend to seal it thoroughly, so outside intake air is a given. (Minimalist indeed)

GK, I'd really like to hear details of your splitting incident... My truck already came with the 86+ rear axle, which I'm pretty happy about. I might convert to a floating setup eventually, but it doesn't sound like that's a weak point. Not mine, just some inspiration. I have a feeling that's all it is, but I do want to hear GK elaborate on what was going on. Intriguing. Yes, it'll be lighter than wood. Stronger? I doubt it. My biggest concern is being able to take it apart later, to retrofit a pop-top, add doors/windows...

I'd say your biggest problem is going to be outright space for four people, especially sleeping. With a quad cab, you've got precious little frame length to work with unless you extend it, and you know better than I what that's going to look like. On that note, I'm still hoping you can give me some details of the frame splitting incident you mentioned in my thread. I like the idea of being able to convert the rear seat area into a bed. But then why not use a single cab and have the rear seat be full-width, as wide asthe camper as opposed to only as wide as the cab?

Holy expletives! Please tell me you were catching air while carrying a load of bricks with 22" rims mounted, not something more... mundane. I would think the springs, shackles, bumpstops would all get destroyed long before the frame did anything but flex, maybe bend. Just snapping?! Where was it, right behind the cab? Was the frame at all rusty, especially on the inside (you probably got a good look at it after the fact...)? That sounds... heavy. And way more welding than I'm comfortable doing. Good advice. I feel that's what I've been doing - this has been in planning for months, and I'm sweating as many details as seem remotely relevant. Some of the bigger-picture items, though, come only from experience I don't have. I've played with lots of road vehicles, but pretty new to offroading. I've learned how to get stuck, how to get unstuck, and the value of scouting on foot for hidden meter-deep ruts - all the hard way - but never had anything that serious happen. That's what's so valuable about reading others' experiences, especially the ones I'd rather not duplicate! I wonder if your cab and camper were rigidly connected, to distribute the load better, that it could've prevented that disaster? Or would you instead get them cracking from twisting forces? Hardwood, hockey pucks, nylon... do you think using soft rubber mounts would've helped? I'm toying with using BMW motor mounts, which are fluid-filled. Not cheap - about $60/per - but two of them hold a V8 making 335 ft-lb torque just fine, and they are certainly very isolating. I may have to rethink this entire d-mn project, having heard this. I won't be running quite as much weight as you (do I remember reading you were somewhere north of 5000 pounds?), but I do intend to take it off-road, and I was going to stretch the wheelbase with Ford springs, which isn't going to help the frame any.

I've read your restoration thread, and was hoping you'd chime in. Can you elaborate what you mean by "built in fireplace"? I want to keep weight down, so building an entire corner of the box out of masonry brick isn't going to work. The more I research stoves and safe clearances, the more this stove idea is crystallizing into something made out of a small beer keg, with several layers of well-spaced heat shielding to keep it from burning the whole truck down. I've seen where you've taken yours and how you've used it. I've got some questions about overall structural integrity. Is your frame a factory longbed 4x4, or is it reinforced in any way? Is the rear axle the stock one, or a 1-ton? I assume the fiberglass box is mounted rigidly to the cab, but how is it mounted to the frame? Same rubber mounts as the cab? Have you experienced any flexing or related damage from wheelin' it around with all that weight?

Oh, I know the story of diesels and vacuum. The problem is where the pump is: most diesels have it as a belt-driven peripheral, or on the back of the alternator. On the ALH, it's on the back of the head, driven off the cam. That's fixable, but the timingbelt-driven waterpump is a dealbreaker by itself, so I won't bother. I'm almost certainly not going to run the full suite of VW electronics, so I'd tune it like any other diesel. But really, I'd leave fuel alone and just advance the pump a bit. My concern with the TDI is that they're efficient and reliable in 3000 pound commuter cars, but 1.9 liters pulling a 2+ ton box through a 4x4 drivetrain on all kinds of bad/off-road terrain? Makes me a little wary, long term. If I were in Europe, a 2.5 or 3.0 V6 TDI would be on the short list of swap candidates, but I'm not. And frankly, every VW product I've ever wrenched on has been, well, horrible, which makes me additionally hesitatant regarding the TDI. The Chevy Luv and Isuzu P'up had the older indirect-injection C223 engine, a miserable 50hp wheezer. They later made a turbo version, the C223T with a whopping 82hp and rod bearing issues. I'm not interested in those. The 4JB1T engines I mention are direct-injection 1-wire 2.8 liter turbos (some intercooled). They came in Rodeos, Troopers, and some box trucks with 5-figure GWR's, so I think it'll do just fine in my truck. They also made industrial ones that go in some Bobcats and other applications. Something like 115hp/160ft-lb out of the box, which should be plenty. Pending fitment, it's just about perfect.

Any well-built diesel is easy to turn up, but in any case I want to preserve long-term reliabilty rather than squeeze out more power. The ALH has a timing-belt-driven waterpump, and a vacuum pump on the back of the head. The former is an abomination of unreliable engineering, and the latter is a fitment issue. A sorted TDI longblock with an mTDI pump would set me back roughly 3000 including adaptation to a Toyota transmission. A Toyota 2L2T or 1KZ would be about the same cost, easier fitment, less fuel economy and comparable reliability. An Isuzu 4J would be about 1000 less since it comes with its own trans, and I'm impressed by what I hear of their reliability and maintainability (replaceable cylinder sleeves, gear-driven camshaft). The only huge unknown there is physical fitment. What's your experience with the TDI or any other diesel motor? Great. Thanks to these two suggestions in particular, I'm now going to spend the next week of my life buried in reading about using composites for construction instead of wood. So much for free time... Other than that, the subproject I'm most focussed on right now is interior layout, which is going to affect door placement so I need it out of the way before starting construction. I'm doing all kinds of analyses, but it'd be great to get feedback on the various possibilities from people who've dealt with this before. Should I make a new thread for that?

I much prefer metric when it's not inconvenient (tire diameters, for instance). No, but I've spent some recent time traveling and worktrading in BC and Yukon, and lived in Manitoba about 20 years ago. Thanks, that's good to know about the heater. My theory is that with heavy insulation, I can use the stove in bursts rather than continuously. Light a fire and quickly get the whole space kiln-like, then choke off the fire and open ventilation to lower the air temp to the upper limit of Comfortable. The insulation should help it remain above the lower limit of Comfortable for a while, without lighting the fire again. I did some weight calculations - basically summed up the total volumes of dimensional lumber and plywood, multiplied by the densities - and got something like 200 pounds for the frame (2x4's with some 4x4's) and 450 pounds for plywood inside and out. I've since pared down the plywood thicknesses, but haven't done more recent analyses. If I ever lay the truck on its side or find myself in a colder weather than I reckoned on, I'll be glad for having overbuilt the box. Since I can, I am. Round roofs look much better (from here)... ...but don't work as well for cargo on the roof, and I want to keep the frontal area as small as the dimensions allow. Thanks for the links, that's a good bit of reading to do. I've read through the Super Camper blog and gleaned a few ideas from it regarding construction. Not so much design, though - I call my project a "motor home", but it's a size class below the smallest vehicles that are typically called that, commercial and DIY builds alike. That's a good point about the axles. My VIN plate says: vehicle rating is 4550, but the axle ratings of 2630 and 3000 add up to half a ton more . The manual says the payload on top of the ~200 bed is 1100, which point is about when it starts riding on the bumpstops, but there's inconsistencies with that number too. If the axle somehow turns out to not suffice, keeps eating wheelbearings or whatnot, there are plenty of stronger axles that either bolt right up or won't take much work to. Haven't decided on a diesel, just compiled a lot of data and come to some preferences. Still doing homework regarding: Isuzu 4JB1T, Volkswagen 1Z or AHU (probably converted to mechanical control), Toyota 2L-2T, 1KZ.

Assuming a cab-rear bumper length of 4 meters, that's about 3.6 times the volume and 2.7 times the surface area of my box. Thanks! That car took 9 months to move on its own power and another 3 before I started living in it. That experience is the only reason I feel remotely confident in my ability to build a camper truck. Here's more of the BMW.

Tongue weight is dependent on bumper/hitch construction more than anything else. The relationship between net payload, GAWR, and tongue weight isn't a simple one, unfortunately, as it involves knowing the wheelbase, distance from the rear axle to the trailer hitch, and is further complicated by a motorhome being on top of the rear axle. The fact that your wheels are 6-lug has absolutely nothing to do with the tongue weight your vehicle in its present configuration can support. What kind of motorhome is this, what springs are in the back, what's the trailer attachment style (receiver hitch, bumper, bungee cords...), and how much extra cargo is already over the rear axle?

Derek, you appear to be from Canada... whereabouts, and how adequate have you found the insulation of whatever MH you've got? I drove up to Inuvik, NT in my wagon summer '10, but that was in late June and mostly t-shirt weather. I used to live in southern Manitoba and want to build something adequate for its winters, or Yukon which is apparently not any colder (-30C). I don't expect to go up to the tundra in the winter, but who knows... no practical purpose, but then neither was the arctic expedition in the first place, and I'd get a real big kick out of comfortably sipping tea in a homemade box with a -50 polar night outside... Dolphinite, what kind and how thick insulation did your boats have? I'm not settled on a woodstove design, choosing between a conventional castiron airtight and a DIY "rocket stove". The latter are typically designed with a sort of vertical feed tube, which burns the bottom of the sticks that you, er, stick in it, burning them in a horizontal burn tunnel, such that the fuel feeds itself steadily as its bottom combusts. I'm not sure how big a Dolphin is, but the dimensions I'm working with are 125cm height x 140cm width x 240cm length excluding the cab (all interior dimensions). 89mm (3.5") rigid foam everywhere except the cab, including full-thickness door and window shutters, and maybe more for the roof. Cab gets whatever I can fit on the floor, firewall, inside doors, and temporarily over the glass. Spray foam in whatever nooks and crannies remain. With how tiny the space is, versus how cold I expect it to survive in, I really have no idea what to expect from the insulation, whether it's overkill or merely adequate, or not enough...? Maineah, I'm being very cautious about weight, though the project plans include a wheelbase stretch courtesy of uprated Ford springs, which will also increase my GVW rating, and a diesel engine swap to replace the 20R. I'm shooting for a loaded weight of about 4000-4500lb. The truck weighs a bit over 3000 with the bed. Sound realistic? The wheelbase stretch gives me 28cm, almost a foot more room in front of the wheels, enough to fit a 50cm side door and a small stove between the cab and one wheel well. I'm going to move the box back the same distance, so as not to decrease departure angle (this is a 4x4 after all). I'm having some trouble reading what you say about R-values...