LEGO 8850 Update

After updating 8640, I wanted to update another set with a Technic Fig. There was only one option, 8850 Rally Support Truck.

Free instructions are available at

8850 Update Side

Every once and a while I return to an old LEGO set, and try to modify and improve what was offered by The Lego Group when the set was released. I like to harken back to some of these influential sets because it helps me take stock of all the improvements that have happened in parts and design in LEGO Technic. 8850 was one of the first sets to use the, then new, cylinder and piston parts that have been used ever since. The set also had a driver, steering, and a robust design. When I set to work on this MOD, I placed the following constraints: keep the size, keep the engine, keep the steering, add suspension, update the bodywork, and keep the driver. Make it yellow.

8850 Rally Support Truck Update

The chassis came together quickly, as it is not too complicated, and utilized features I have used before. The rear live axle is simple, and linked forward by two links, and laterally by a Panhard rod. I used the new differential to increase the final engine speed. The front suspension is another simple design; double A-arms with a rear steering link. The steering mechanism travels under the engine, through an idler gear, and moves upward towards the HOG gear on the top of the truck.

8850 Update Chassis

The body work was quick as well, though I needed to slow down to be conscientious to the original design. Liftarms replaced Technic bricks, and the lines were kept. I added some engine detail including a intake, and gave a new grill design. I removed the headlights on top of the A-pillar, because they look silly to my eyes. I played with some ideas for the front bumper including a bull-bar, and other colors, but this simple design ended up being the one I like the most. I gave a little tailgate on the rear with some color, and a little exhaust pipe. Finally, I gave a little OCTAN coloring to highlight the race focus of the truck.

In my effort to improve access to my builds, I have created this MOD in Bricklink Studio, and have made instructions that are a little more clear than the photo sequence instructions I have done in the past. You may find a partlist and download the instructions PDF at Send me a photo if you enjoy the build.

Sample of the Instructions

8850 is a tricky set to update, because it has some defining features that I find unattractive, such as the front bumper, the rear, and the upper A pillar headlights. With this in mind, I think I carried the themes through to this build well. The OCTAN livery while keeping the main yellow with white highlights worked very well for my eyes. Functionally, keeping what 8850 had, and adding suspension was a fun project. I am already thinking about how to convert this build into an overland version with 4×4 and more bodywork. Stay tuned…

Until then, Happy building.

Unimog U500 (405.201)

Every couple of years I build another Unimog; they tend to be a favorite subject.

Instructions may be found here.

Unimog U500 (405.201)

Right after the LEGO Batmobile 76139 was released, I saw the front tires, and immediately planned this Unimog. The tires were perfect for a U500. I stared working on a draft before I had acquired the tires. I wanted the build to be in the theme of my Unimog 437 in that it was about 1:18 in scale, and had modular cabins and bed options. But I wanted to take this idea to the next level so that front and rear attachments could be added, as well as trailers. Many of my builds as of late are more system focused, in that a main build supports lots of other attachments, trailers, and versions of the same build. With this one, standard attachment points on the front, rear, bed, cab, and hitches allow for a variety of versions and attachments to be added quickly. I’ll make more of these soon.

Rear Hitch, Attachment point, PTO, and PPTO

I quickly set up a front and rear suspension using what was learned on the 437. The MOC has front and rear live axle suspension, four wheel drive, and front steering. A I4 engine is placed under the cab, over the front axle. Unlike the 437, I added a front and rear PTO. The rear PTO has an on/off switch. A center PTO is present as well for attachments that go in place of the rear bed. Finally, I added a Pneumatic pump behind the cabin to run pneumatics on the front or rear of the truck. A value determines if the preasure goes to the front or rear.

U500 Chassis

I added a three way tipper bed on the rear of the chassis, and created a way for the cab to be tilted. Both can be released by pulling a couple of axles out to allow for the tipping. The cab has seating for three, and both doors open. Finally, I added a front winch that is released and wound up using the fake air tanks on the left of the truck.

In the coming months I will make some attachments and trailers for this truck and for a U400/430 version that use the chassis of the U500 with some adjustments.

2016 Unimog U430

The truck turned out how I wanted it too, and had the features work the way as intended. The suspension is a little hard, but that supports various attachments well. This tipper bed and winch are a little addictive to play with. I did not spend much time making attachments for this truck, but I hope to do so soon. Until the next build or Unimog, Happy Building.

Atmos Tractor

I guess I am on a little bit of a tractor kick lately.

Instructions for the tractor may be found here, which links to instructions for attachments, implements, and trailers.

Atmos Tractor

I had recently rebuilt my 9393 MOD, and as I took it apart, I wondered if I could make another tractor with the same implement attachments, improve the esthetics, and use different sized front and rear wheels. Then I thought maybe a pneumatic pump would be fun. My builds as of late have become much more dynamic, in that I like to be able to quickly change them or add a feature. Tractors work great for this, as adding a new trailer or implement can change the build dramatically. Additionally, I enjoy the challenge of making a system that supports lots of additions, while retaining the mechanics that my builds have always had.

Atmos Rear

The tractor came together very quickly for me. In 10 days I went from having a size draft of the tractor to a final MOC. I used the same driveline, albeit stretched, as the 9393 MOD so the mechanical parts were easy. Direct steering is used, and goes through a rear wheel drive system that connects to a two cylinder engine. A PTO is present at the rear of tractor, but not at the front. Adding a pneumatic pump required a stronger frame which was quickly modified, as well as a hose running to an attachment point at the rear.

The bodywork took the most time; about four days. I wanted to keep a simple hood, so I kept the design of 9393. I added some headlights to dress up the front, and the interior left some room for a steering wheel. Shaping the roof and the cabin was a little tricky due to all the half-stuff offsets of the front windshield. The fenders are simple, but match well. Just like that on day ten, the tractor was done. At the time of writing, the tractor can be built in orange, lime, white, and black.

Atmos with Mower

Part of what attracts me to building tractors is all the options one can present with a tractor: implements, trailers, plows, and on and on. The design of the tractor needed to support all of these possibilities. There is a hard point on the front, a hitch on the rear, and a three-point hitch on the rear.

Once these hard points were set, I began to spice it up. It’s no secret that set 8049 is one of my favorites, and since this tractor had a pneumatic pump, I thought a forestry trailer was needed. But then I wanted a snow plow, and a hooklift loader, and a dumper, and some farming equipment. So of course I built them all. You can find links to instructions for the tractor and most of the additions in my instructions tab.

Atmos Tractor with Trailers

The build was great little addition to my portfolio. The system supported a lot of different trailers and implements, some of which are still coming. The design language is consistent with my other builds, and the size is right in my sweet spot. I hope you enjoyed it too. Until the next build, happy building.

8081 SRT Tremor

Lego set 8081 is one of my favorites. It’s a cute little set, that has some mechanical diffenciencies, so I have made a number of MODs of the set. Here’s another one.

The full gallery may be found here.

It’s becoming a bit of a bad habit for me to start a new project while I am currently building something else. While I was building the 8081 110, I founds myself making another draft of a little pickup. I moved pretty quickly on the 8081 110, but this project stalled. The chassis came together quickly. The live axle rear suspension is a simple design with five links to keep non-vertical movement at bay. The front is a simple independent wishbone design just like the original 8081. Finally, I placed a V-8 right over the front suspension, and geared it to the rear wheels. I used the new differential in the rear axle, which drives the V-8 a little faster than in my previous designs.

The sport pickup is a silly I idea that was all the rage in the United States in the late ’90s and early ’00s. Pickups like the SVT Lightning, the Ram STR-10, and my personal favorite the Dodge Dakota RT, were prevalent. This MOC slowed while I was trying to get the styling in the vein of these notable pickups. I liked what I designed for the front and rear bumper, and the rear bed was sufficient. But all the designs I came up with for the hood and the front grill looked dull and basic. Each of the above pickups had bold grills, and a hood line that communicated more power than anyone would need.

At some point, I realized I was not making any changes to the design, and I was running out of creativity. So it was time to be done.

While this is not my favorite MOD of 8081, it is another one to add to my long lists of MODs. The MOD worked well in that each of the simple features functioned without any problems. But I do feel like I did not do justice to 8081 with this MOD, nor did I represent any of those sport pickups well with this MOD. Maybe I’ll need to build a replacement soon….

Happy building.

8081 110

I have made it clear on a number of occations that I love LEGO set 8081. To celebrate this little unloved set, I created another MOD of this set.

Full gallery may be found here.


A couple of years ago I did my first MOD of 8081, the 8081 4×4. It was the same bodywork of 8081, but I added 4 wheel drive, a front mounted V-8, and rear seats. It was a substantive change to the set. Likewise this MOD is so different from the first set, I am not sure if this is a MOD, or a MOC. I keep the design features of 8081, but not much from the original set still remains.

I took from front end of the 8081 4×4 which mounted the V-8, and the front bumper. Then I lengthened the chassis to accommodate a 4 stud longer wheelbase. The rear axle is the same, but the front axle needed to be modified to handle the increased weight of the truck. The center differential powers the V-8.


Both axles are live axles that are suspended with a hard spring at each corner. Each axle has two stabilizing links on the bottom, and a Panhard rod for each. Steering is on the front axle. Combined with the Fischertechnik tires, the truck has significant suspension articulation.


I added the bodywork last, but this did not take long as much of the design work followed themes determined by set 8081, though the pickup body style was planned from the beginning. The truck looked too big and black when I was done, so I added the roof rack/roll cage, the running boards, and a bull bar (though its little clunky).

The truck works well, and looks pretty tough. The suspension works much better than the first 8081 4×4. The new wheel hubs help the front a lot. Also the front suspension is better supported laterally than the first iteration. The Fischertechnik tires work great on this model, and while not LEGO parts, they are quickly becoming a favorite addition to my builds.

Throughout the whole project I kept asking myself, when is a build a MOD, and when is it a MOC. This project felt a lot like the later, but still connects to 8081.

Happy Building.

LEGO 42098 Car MOD

I do not buy many sets these days, mostly due to the fact that the space required for a gazillion new parts every year is not priority I am willing to resource. But some sets are a fun opportunities to MOD.


The little car from 42098 caught my eye. While the truck was neat, it was not what I was interest in, so after a query of my own part collection, and a quick order from LEGO, I got the parts I needed. Upon completion, there were a couple parts of the car that bothered me, and a couple of parts I thought I could improve. So I started taking apart the car to see what I could do.

First, I made a mock-up of the side of the car to see if opening doors could work without lengthening the car. Turns out by moving the curved panel forward one stud, it works easily.


Next, I was off to the rear axle. It was easy enough to design a simple live axle and connect it to the V-8. What become tricky was mounting the shocks. 42098 has low rear deck, and I do not like how the rear wheels are pushed down away from the wheel wells; it make the car look tilted forward. So finding an appropriate ride height to lower the rear while mounting the shocks in the limited space available took the rest of the time. Once this was in, I added the bodywork back on with a couple of changes to the 1950s rear and the side sills and the car was done.

The car worked well enough, though any live axle setup is a little silly when there is not suspension on the front. The engine still worked smoothly. The steering HOG on the back is still not optimal, but adding one on the roof would take away from the fantastic roof-line. Another round of edits may be needed to add back in the nominal opening hood. It is a pretty basic feature in the original car, but since opening doors were added in this MOD, the opening hood is missed. We’ll see what I end up MODing next time.

Happy building.

3T Sports Sedan

The sport sedan is my favorite kind of car. You can have your McLaren, if I can have four doors and a long hood. One with the proportions of a C-class, the suspension of the ATS, the engine of a Mazda 6, the suede interior of the M3, and the value of the G70. Don’t worry about me, I’ll be set. But there are few good sedans in LEGO, and even fewer smaller ones. Let’s change that.

Instructions may be downloaded here.


When I set out to make a sedan, I wanted it to be smaller. What were the features I could add in a smaller LEGO car? It had to have some style, suspension, a gutsy engine, steering, and a transmission. Finally, it had to be strong. So I got to work. The scale was set on a 3 Series that was a little wide, so I set the hardpoints and set off to work.

I first set the two axles and suspension. I have built a couple cars with a floating rear differential, and this setup has worked well in the past, so it would work well for this car. Each side had a dual arm independent setup with two shock absorbers. The front suspension used a dual A-arm setup and a wheel hub with only one hard shock absorber.  Before adding the steering, the driveline would need to be finalized.


I played around with a number of transmissions, but settled on a simple two speed design for a number of reasons. First, it was smallest as something else would take a lot of space from the interior. Second, something better would take away from the rigidity of the model. Sedans need a lot of support through the transmission tunnel as you lose a lot of rigidity near the doors. Finally, anything more complicated than 2 speeds would be tricky to manually operate (play with) in this scale. About half way through my work on this project, some fun new gears came out which improved the design.


Next, I moved on to the bodywork. This is the part that causes me the most problems in my car builds, and this car was no exception. I set the doors first as I wanted to use two panels for each side. Then I worked on the front and rear bumpers. The rear came together quickly, but the front took a little more time. I wanted something that was sporty, and with a simple grill. I think it worked out well. Finally was the roof and the rear quarter panels. This part took a long time, as I wanted something strong and stylish. The result is strong and has the C pillar split into a D pillar. It is not perfect, but it is stronger than all the panel ideas I tried.

After the bodywork was set I did something I have never done before, I rebuilt a second whole car. This time, I knew all the final features, and where all the body work would attach so I could focus on creating a strong frame that would best support the whole design. I am happy I did this, as it cleaned up the inside, found some new solutions, and made the whole car stronger. Building this way also helped me think through how clear instructions could be made.


In the end, I was pleased with the final design. It accomplished all the goals I wanted, and it is an accessible design for others to recreate. I love building in this scale, and cars are a lot of fun, so I will need to do another small car design again.

Until the next time, happy building.

Unimog 437

If my previous builds are any indication, I am a big fan of Unimogs. So it was just a matter of time before I built another one. Rather than building one this time, I built a modular system that allows for a number of different versions.

Full instructions can be found here.

This build started with a desired to make another small build with the great Fischertechnik tires I acquired. I wanted to build something small and playful like RM8s FJ or Sheepo’s Defender. As has been happening with many of my recent builds, I wanted to give the MOC some playable options and easy modifications. A Unimog was a perfect option, and who am I to turn down a Unimog? So I gave myself the following constraints: 4×4, I4 fake engine, steering, manual and PF drive options, removable cabs, removable bed, and two chassis. I set off to work.

The axles came together fairly quickly. I decided quickly not to do portal axles, because I wanted the complexity of the MOC to be elsewhere. Both axles have a differential, two soft springs, and are stabilized longitudinally via steering links and laterally via panhard links. All for shocks are mounted on crankshaft parts to get the ride height of the Unimog just right. There is about 1.5 studs of travel for each wheel, which provides adequate articulation.

The axles are connected to a fixed axle that powers a I4 fake motor. Since I wanted the MOC to be easily switched between manual control and PF, the driveline got a little over-complicated quickly. The steering axle and drive axles cross each other twice. This allows for the steering to go to the top for a HOG, and backwards so a PF servo motor can be added. A 16t gear is available at the top of the chassis to power a PTO, or add a PF XL motor to give the Unimog propulsion. The long Chassis can fit a full a full Power Functions pack. When the power pack is not installed lots of open space is available for other additions. I added a three way tipper lift mechanism for both the long and short wheelbase chassis.

Attachment points were added for the rear bed and for the cab. I created three cabs, and each can be added to both chassis (though the Doka looks best on the LWB). Two axles with stop can be pulled to free the cab. I created three beds and a power pack. Four axles with stop are required at each corner to secure the bed. A camper and a crane bed are not far behind on my building queue.

The Unimog turned out exactly as I wanted. The suspension and steering are light and smooth under manual operation, and work great with PF. I am excited about the ability to offer and develop multiple beds and cabs. Instructions are posted, so I look forward to seeing other options people develop to make their own Unimog.

CAT 914K

These days, some projects are taking longer than they have in the past. The little Wiggs in my house and a mirad of other reponsibilities are slowing my production. This loader was started a little over a year ago, and it was finally finished last week.

The full gallery can be seen here.


I was sitting on a train in Chicago, and saw a little CAT 914k out the window, and thought, “I should finally make a loader.” I got home and started to work. My collection recently added the Fischertechnik tires and the pneumatic parts from the LEGO 42053 Volvo, so I started calculating the scale. Once the scale was set I worked on the linkage for the bucket. I spent two full nights working on the linkage to take full advantage of the longer pneumatic rams. I used the longer ones on the lift, and a shorter one on the tilt.


After the bucket mechanism was set, I worked on the chassis. The size allowed for four wheel drive. The rear axle was set in a pendular setup, which allowed for some articulation over varied terrain. The rear differential linked to a small I4 motor that was placed in the rear. The pneumatic valves were placed over the motor. The light on the roof operated the steering.


While the project took a little too much time to complete, it was a fun project that turned out well. The linkage and bucket range worked well. It also held a load well. The stability of the loader could have been a little better when pumping the pneumatic pump, as the suspension took a lot of rigidity out of the rear. The design allowed for normal LEGO 81mm tires as well.

Happy Building.

The Toaster

When I was in high school, we had a little bus; we called it “The Toaster.” We had big buses for the large football team and various student “schlepping,” but the Toaster was the perfect size for a cross country or soccer team. But, boy was it hot; the short wheelbase and many windows fused shut allowed for virtually no air movement in travel, and it would spend all day baking in the hot Arizona desert. Hence the name.

When when the Eurobricks Technic Challenge 12-Wacky Racers was announced, I figured this subject would be a good basis for an entry.  Maybe I could visualize my fantasies of the ultimate racing bus. What would it be like to give the bus a stupid big engine, and some sport tires, and make it visually hot?

The contest required wheels or tracks and, steering. No problem. It also required a wacky feature to gain an advantage in a race. I’m not very violent, so I immediately thought of a bus that would toss out its seats to make it harder to follow in race. I built a chassis, added a V12 and I was off.

Very early, I had the idea of an attacking sill as well. I gave the bus a lowered look, and this gave a lot of internal space under the drivetrain. I created a side panel that would spring out to attach a racer to the left of the bus. You can see it work here. It was a fun addition to my plans. Then I started working on the seat toss feature. Five seats would be mounted on a 32l axle on both sides of the bus. The seats would slide out the back, driven by two chains with controls on the roof.

I added some visual excitement such as the exhaust pipes, the engine intakes, a stop sign (I know, I know, I need a sticker), and and internal roll cage. I built a simple working bus door, and closed up the body work. Visually, it could have used a little more excitement, but I liked how it turned out.

All the functions of the bus worked mostly well. Sometimes, some of the seats would get stuck as they were being thrown out the back. The attacking sill worked flawlessly each and everytime. It was a fun feature. I wish the bus has a little more creative styling. Next time.

Until then, happy building.