vincen47

Next up, I’ll add the frame-mounted primary fuel filter, a common sight on these Cats. I took a fuel filter from a Italeri Series 60, with a scratch built frame mount and fuel lines.

Just to the right of the cab mount, I added a Bendix AD-SP Air Dryer and associated connections and hoses. I started with an air dryer from CTM, and modified it a bit to better represent the Bendix model, and used decals from Modeltruckin for both the fuel filter and air dryer.

To connect the charge air cooler to the turbo and engine block, I used rubber air to air connectors from Moluminum along with Plastruct elbows and aluminum tubing, cut to fit and painted with Molotow chrome. 

The rubber air connectors came in blue and orange, and though that’s common in real life, (orange on the hot side, blue on the cool side) I opted to paint them rubber black to better match the overall look. You can find black silicone connectors on 1:1 trucks as well.I also added the chrome rings around the connectors by using brass zip ties from CTM, painted chrome. That was one of the most tedious things I’ve done on this build, but the only option that seemed to work. Painting the recesses chrome was a failure, so CTM to the rescue.

For the exhaust exiting the turbo, I needed a flex tube, just like the real thing, in order to make the awkward curvature needed to fit between the engine block and frame. Once I had the plastic tubing bent to fit, I wrapped it in wire, and added putty between to get the look. Painted in aluminum, it works well.

I finished with adding the tubing clamps where the connections are with chrome bands made from strips of furnace tape.

Now onto the rear axles, suspension, hubs and brakes. The main chassis color is Tamiya Semi Gloss Black. There’s a couple other shades of black, and also Tamiya Rubber Black (a very realistic color) used on the air bags.

The rear axles needed a sleeve of wider tubing to fit the wheel hubs. Those beautiful real aluminum hubs are from M&R Wheels. Highly recommended, they make excellent products.

I got the M&R hubs to go with the Keystone Aluminum Peterbilt Alcoa wheels, which are fantastic, but didn’t come with hubs with a socket for the axle stubs. I probably could have figured out a way to make the Keystone hubs work, but M&R provided a much simpler option. More about the wheels in a later post.

I added resin Bendix Air Disc Brake assemblies from Moluminum. Drilled them out to fit over the hub axle mounts.

I included air lines to the brake chambers, and ran the lines up to the frame rails. I didn’t bother running lines further than that, because, well, none of this area of the chassis will be seen on the completed model unless you turn it upside down. Not planning on that. The frame rails are mostly devoid of bolt detail for the same reason.

In fact, on the rear axles, all you’ll see is the outside wheels and tires. But, I guess when the build is finished, I’ll know the brakes and lines are there and that’s what matters. But, I sometimes have to ask myself “does it matter when you won’t see it?”

After all, this project has been about striking a balance between the sane and crazy, right? 

The front axle has disc brakes, too. I painted and decaled the shocks to represent Bilstein commercial truck and coach shocks.

The front brake assemblies were also run with lines, along with the air bags. Air Bag Levelers were added using bits from the parts box. These details make more sense because they will be seen when you tilt the hood.

The air lines to the bags are braided line from Detail master with their fittings connecting to the mounts and to the frame rails. The resin air bags are brush painted in Tamiya rubber black. I opted to go with solid bags rather than rubber ones because of the potential amount of weight they’ll need to support.

The hubs are fixed in place, not enabling the model to roll, though the front axle steering is functional. I like rolling models, but the vast majority of the time I glue the wheels in place because they can usually be positioned better (plumb and square) that way and they won’t roll off a shelf.

Next up is the chassis. Factoring in the length of a scale 45’ rig, I wanted a strong frame, even though the RV body itself will provide a source of support having it’s own framework, but I didn’t want to risk it. Since I’d have to stretch a factory frame so much anyway, I figured a fully scratchbuilt, one-piece frame would be easier to make in the long run - and stronger, too.

I scratchbuilt the frame rails with styrene strip/sheet and added brass angle to the inside corners. No flex.

The frame rail material is thicker than the stock Italeri 378 frame rails, so I had to modify the ends of the Italeri crossmembers to fit inside the new rails.

I then began work on the front axle and suspension. I wanted to model an air ride front axle with a 16k capacity. Here’s a photo of a 1:1 Pete 379 upfitted with an aftermarket air ride front axle.

Like the photo above, the build represents a retired Pete 379 that’s been retrofitted with a heavier axle and aftermarket suspension during the conversion to an RV.

I used 3/16” brass strip for the single leaf spring, auslowe resin air bags and components from the parts box, along with parts from a glue bomb Italeri 378 - old parts getting a new lease on life, just like the real thing. 

In the photo above, you see the shocks in a slightly different position than I ultimately decided on. I later changed the angle to match the 1:1 inspiration photo in this post.

Spring hangers are from the Italeri kit. On the theme of a sturdy frame, I added a metal front axle from Auslowe.

For the Italeri rear axles, I cut off the ends and I carved out the inside a little to be able to insert metal tubing to make them stronger.

Here the tubing is way too long, but I later cut the tubing to match the width of the original kit parts.

I added some bolt head detail to the front area, but most of the frame rails are smooth with no added detail as they will be pretty much hidden when the body is added.

Imagine taking a retired truck and building your dream RV from it?

This build will be mostly custom work, just like the real thing. These rigs don’t roll out of the ‘ol Winnebago factory…and you find models like this in a kit, either.

I will use Italeri’s 378 for some parts, along with Bill Drennan’s 379 hood. Lots of scratcbuilding and a host of aftermarket parts.
Inspiration for this project came from rigs like this, (though the one above is a 389) where a used or factory-fresh commercial class 8 chassis is stretched and a coach body is added, creating the ultimate RV.

The ultimate RV starts with the ultimate engine. Some may argue differently, but I think Cat’s 3406e from the late 1990’s is the finest example of diesel power, especially when it’s been decked out in aftermarket chrome and ceramic performance parts.

I started with a resin Cat 3406E from Jamie at Moluminum. I detailed it using Ken Smith’s Car Modeller article on Fotki. I used 3d printed elbows from modelbuildermatt on Shapeways and metal fittings from Detail Master.

Several engine components were scratch-built. The 18 speed Eaton Auto-shift transmission came from Moebius, with a lot of detail parts added using reference photos. 

Jamie’s casting didn’t include the 3 dimensional “CAT” logo on the chrome timing cover, but I added one using a casting of a Cat lapel pin I found on EBay that was the perfect size. I’m not a pro resin caster by any means, but I’ve found casting small, very simple parts, to be useful in this project.

It took me several attempts, maybe a half-dozen, to get the valve covers looking good. I finally found putting Molotow down first, then adding the black in the recessed areas via a Molotow black pen was best. Careful painting of the red stripe and a triangle-cut of a yellow decal finished the iconic look of the Caterpillar 3406e’s valve covers.I put together a simple engine stand using square styrene tube. I currenty use it for other engines that are waiting to be installed in the next chassis. It’s a handy tool.

That’s the basic engine so far, more about the other engine components when we get to the chassis installation. Ask questions, I’m sure there’s explanations I missed.

Next, let’s get the frame rails laid down…