If you’re into automotive hacks and don’t watch [Robot Cantina], you are missing out. This hack has [Jimbo] taking a break from automotive hacking to butcher a poor, innocent Tecumseh lawnmower to run diesel fuel (or anything else) by converting the motor into a hot bulb engine. (Video embedded below.)
The secret is a long stack of anti-fouling adapters, which are essentially extension tubes that move the spark plug out of the combustion chamber to keep it from getting crudded up in an engine that’s burning too much oil. In this case, burning is what’s happening inside the anti-fouling adapters: by stacking seven of them, [Robot Cantina] is able to create a hot-bulb– volume that stays hot enough between strokes to induce spontaneous combustion of the fuel-air mix.
Hot-bulb engines were popular for certain tractors (the Lanz Bulldog being the most famous) and stationary engines from the late 19th century until Rudolf Diesel’s eponymous invention drove them out of their niche completely sometime after WWII.
A working DIY two-stroke in all of its glory, with the flywheel removed. (Credit: Camden Bowen)
How hard could it to be to build a two-stroke internal combustion engine (ICE) from scratch? This is a challenge that [Camden Bowen] gladly set for himself, while foregoing such obvious wastes of time like first doing an in-depth literature study on the topic. That said, he did do some research and made the design in OnShape CAD before making his way over to the hardware store to make some purchases.
As it turns out, you can indeed build a two-stroke engine from scratch, using little more than some metal piping and other parts from the hardware store. You also need a welder and a lathe, with [Camden] using a Vevor mini-lathe that totally puts the ‘precision’ in ‘chatter’. As building an ICE requires a number of relatively basic parts that have to move with very little friction and with tight tolerances, this posed some challenges, but nothing that some DIY spirit can’t fix.
In the case of the very flexible boring bar on the lathe, improvising with some sturdy metal stock welded to a short boring bar resolved that, and precision was achieved. Together with an angle grinder, [Camden] was then able to manufacture the crank case, the cylinder and crank shaft and all the other pieces that make up an ICE. For the carburetor he used a unit off Amazon, which turned out to have the wrong throat size at 19 mm, but a 13 mm version worked. Ultimately, the first ICE constructed this way got destroyed mostly by running it dry and having the starter fluid acting as a solvent, but a full rebuild fixed all the issues.
This second attempt actually ran just fine the first time around, with oil in the crank case so that the poor engine wasn’t running dry any more. With a 40:1 fuel/oil mixture the little engine idles and runs as well as a two-stroke can, belching blue smoke and making a ruckus. This answers the question of whether you can build a two-stroke ICE with basic machining skills and tools, but of course the question that’s now on everyone’s lips is whether a four-stroke one would be nearly as ‘easy’. We wait with bated breath.
There’s no doubt the venerable internal combustion engine is under fire. A recent patent filing from Ford claims it can dramatically reduce emissions and, if true, the technology might give classic engines a few more years of service life, according to [CarBuzz].
The patent in question centers on improving the evaporative emission system’s performance. The usual evaporative emission system stores fuel fumes in a carbon-filled canister. The canister absorbs fuel vapor when under high pressure. When the engine idles and pressure in the cylinder drops, the canister releases fumes, which are combusted with ordinary fuel/air mixture.
We gotta love hacker Dads and Moms for being so awesome. Sooner or later, their kids get to play with some amazing toy that every other kid on the block is jealous of. [Meanwhile in the Garage aka MWiG] is one of those super hacker Dads who built a frickin’ Tank for his son (video, embedded below.). But it’s so much fun driving that beast around that we suspect Dad is going to be piloting it a lot more than the kid. The tank features metal tracks, differential steering, a rotating turret, periscopes and a functional paintball gun with camera targeting.
Building a tank, even if it’s a mini replica, needs an engine with a decent amount of torque. [MWiG] first tried reviving an old ATV engine, but it did nothing more than sputter and die. It went to the scrap heap after donating its rear transmission and axle. [MWiG] managed to get an old Piaggio scooter with a 250cc / 22 hp engine. The scooter gave up its engine, electricals and the instrument cluster before being scrapped. Looking at the final build, and the amount of metal used, we are left wondering how the puny 22 hp engine manages to drive the tank. We guess it’s the right amount of gearing for the win.
What’s this? News about robot dogs comes out, and there’s no video of the bots busting a move on the dance floor? Nope — it looks like quadruped robots are finally going to work for real as “ground drones” are being deployed to patrol Cape Canaveral. Rather than the familiar and friendly Boston Dynamics “Big Dog” robot, the US Space Force went with Ghost Robotics Vision 60 Q-UGVs, or “quadruped unmanned ground vehicles.” The bots share the same basic layout as Big Dog but have a decidedly more robust appearance, and are somehow more sinister. The dogs are IP67-rated for all-weather use, and will be deployed for “damage assessments and patrols,” whatever that means. Although since this is the same dog that has had a gun mounted to it, we’d be careful not to stray too far from the tours at Kennedy Space Center.
It is no secret that we like simulating circuits before we build something and there are plenty of great tools for that. But what about those of us who work on cars? Well, you might try engine-sim which is a real-time internal combustion engine simulation. Honestly, the program freely admits that it isn’t accurate enough to do engineering or engine tuning. But on the plus side, it has audio output and is at least good as an educational tool to show an engine running and how different parameters might affect it. You can see a video of the tool below.
[Ange-Yaghi] mentions that the code was primarily to power the YoutTube demo. However, the Readme hints that it might be better — or at least different — and collaboration to make it better is welcome.
When we think of tracked vehicles, we normally think of tanks, or perhaps heavy construction machinery. Meanwhile the average member of the public is left out of the fun. [Bob] of [Making Stuff] won’t be one of them, however, having put together a ride-on tracked vehicle for his own enjoyment.
The machine is welded together from plenty of steel, making it more than tough enough to soak up the punishment of off-road duty. The design features four suspended buggy wheels on either side running inside rubber tracks, with a cogged drive wheel at the front. Propulsion is thanks to a 440 cc DuroMax engine good for a full 18 horsepower and 26 ft-lbs of torque, driving the tracks through a differential mounted up front.
The design has one major issue at the moment. The heavy engine is mounted ahead of the front wheel inside the tracks, which means the vehicle wants to nosedive at the slightest provocation. Such an event would be highly uncomfortable for the rider, so mods are needed, either by scooching the engine back a little or pushing the wheels forward.
We look forward to seeing [Bob] fix the issues and get the machine driving soon. We’ve seen other tracked builds before, too – often on the smaller scale. Video after the break.
