5 Of The Best Mini Engine Kits You Can Build Yourself

It's almost time to send your kids back to school, and if your child has an interest in mechanical engineering or model building, there are several model engine kits to help them get started with wrenching. Each will teach them basic concepts of how engines work, as well as lessons in how to follow complex instruction sets and solve problems. These kits range from simple engines that demonstrate how thermodynamics work, to fully functioning replicas of automotive engines, to a pump that resembles an oil drilling rig and a variety of steam-powered engines.

Let's take a look at some of the available mini engine kits and evaluate which are best suited for curious young minds, and which might be more appropriate for an adult's workbench. Nearly all of these kits have small pieces, and some of them use potentially dangerous materials like fuel or open flames; none of them are intended for very young children, and an adult should supervise any building and experimentation. All of these kits are available for purchase at EngineDIY.com.

One of the simplest and least expensive engine kits that comes with some invaluable science lessons is the $29.99 all-metal desktop Stirling engine kit. A Stirling engine uses a gas or fluid that is moved back and forth from a cold chamber to a hot chamber. Stirling engines rely on the expansion and compression that come with changes in temperature to provide power, and are remarkably efficient. 

This kit contains small parts and uses an open-flame alcohol burner, and is recommended for ages 14 and up. Assembly time is about 15 minutes, although some reviewers recommended having tweezers on hand for assembly, particularly when it comes time to placing the tiny bushings. 

Others suggested not operating the engine on a wooden desk, as the flame can scorch some surfaces. When the wick is lit beneath the combustion chamber and the engine's wheel is spun by hand, the expansion and compression of the ethanol gas push on a piston, further spinning the wheel vigorously and giving a demonstration of the principles of thermodynamics.

Another simple and inexpensive kit that works well as a team project is the Exploring Kid Steam Engine Kit, which also retails for $29.99. This mostly plastic kit, when assembled, includes a boiler and tube leading to a piston. 

The boiler is filled 2/3 of the way with water, and the alcohol burner is filled and lit: the heat generated boils the water, and the steam generated moves the plastic piston. Because of the open flame and numerous small parts, this kit is also recommended for ages 14 and up, although some reviewers noted that they used it with children as young as six under close supervision, and their children were able to enjoy the kit. 

Assembly time was not specified, although the kit is relatively simple with just 43 pieces, and the assembly instruction video is less than five minutes long. No glue is needed for assembly, and a screwdriver is included in the kit.

If you're looking for a kit more representative of something you might find in the real world, the 270-piece metal and plastic V8 engine kit should fit the bill. This kit features most of the components found in a real automotive V8 engine like pistons, a timing belt, cranks, and a valve system. 

The battery-operated engine sells for $89.99 and is functional when assembled, giving you and your children a chance to see how a real car engine's components work together. The model is advertised as being suitable for ages 12 and up, but one reviewer said his eight and 10-year-old children were able to successfully assemble it on their own.

Assembling this kit is not a quick project, however. One reviewer said it took them approximately six hours to assemble with their 11-year old child, and another said it was an overnight project for three adults. More than one reviewer commented that it was difficult to separate the two different sizes of tiny screws, which added to the assembly time.

For a step up in realism and complexity, try the Teching inline-4 cylinder 1:10 diesel engine. This all-metal kit sells for $349.99, contains more than 300 pieces, and takes at least four hours to assemble. The engine's battery is powered by a USB cable, and reviewers were near unanimous in their praise for the quality of the components and their overall satisfaction with the model once assembled. 

Because of the complexity of this kit, it is not particularly suitable for most children, but parents of teenagers who are interested in automotive engineering will definitely want to consider it as an advanced lesson in engine functionality. 

Victoria McIlrath passed on a testimonial from her father, who said "My career started in a diesel engine factory 60 years ago and I have been directly involved with diesels ever since. So, it is with some authority that I can honestly state that this is an excellent model and the best that I have seen."

Another very realistic and complex model suitable for teenagers and adults is Teching's 1:3 scale all-metal V8 engine kit. This kit contains more than 500 pieces and sells for $699.99. It takes about five hours to assemble, and is recommended for ages 12 and up. 

The 3.7V 500mAh battery will run the motor for about an hour after two hours of charge time, and 46 out of 50 reviewers gave the kit a full five stars. John Elegant of Portland wrote, "I so enjoyed building this engine! Everything goes together excellently. I used this build as part of self-training for my building my 2023 LT6's engine myself at the Corvette factory. When it was done, I flipped the switch and watched the pistons and valves go up and down, the crank and the camshafts all go around exactly at they should. Putting this model together was a treat!"