Smithsonian Motor-Works Blue, 15.0x11.0x2.0

My daughter (7) was ABSOLUTELY absorbed with this engine! She worked for hrs excitedly completing it and then explained to me the working components. Such a great hands on activity for that mechanical/ engineering mind. I really appreciate the poster from the Smithsonian for added learning. Highly recommend.

No glue. Real screws hold it together. Parts are what you find in a real engine. It provided a great lesson to my grandsons on what goes on in a working engine.

I was afraid of this after reading all the negative reviews, but went for it anyway because it looked so cool. It is, indeed, extremely cool -- once you get it together -- but also slightly frustrating to build. In my case, all the parts were nearly perfect, and everything fit together extremely smoothly, so no complaints there. You'll need a set of nail clippers and a nail file to remove a bit of flashing here and there, but no big deal. It could have used a few extra screws as well as I lost a couple, but in all honesty, you don't need them all. Some parts with 6 screw holes work fine with 4.There are, however, two MAJOR problems, but they have really easy fixes:The first is, as many have complained, the drive-shaft end of the timing belt keeps slipping off the lower gear. An extremely easy fix solves this problem entirely. Simply trim the top of spring container (or any other piece of thin flat plastic that you happen to have laying around from, say, a food container) to fit into the timing belt cover, cut a hole in the middle to fit over the lower gear, and stick it in under the timing belt cover. Five minutes. No special tools. No parts to buy. No muss. No fuss. Done deal. Never lost the timing belt again.The second problem is that it's actually quite difficult to get the timing exactly right. If you follow the instructions (And, BTW, for a toy of this nature the instructions were unusually good!) very very carefully, you can do it, but it's extremely twitchy. My solution: Forget it. Does anyone who isn't a mechanic really care that the timing and firing order are actually right? I was working with a number of kids ranging from 5 to 18, and they were (variously) fascinated depending on age and step with the whole thing, and you can demo the concept completely without the timing being exactly right. (In fact, I ended up with the timing about 160deg off -- like almost BACKWARDS!But no one, including (esp!) me, cared; no one notcies whne its running. You explain what's going on, and they see the explanation, not so much the actual timing.And you know what, when you turn it on and it runs, it IS so cool!

Great learning project

I've built model engines as a kid. Thought I'd buy this one and build it together with my nephew, who is 11 years old. The instructions are abominable. They are poorly written and the images in the instructions do not match the instructions. My nephew got bored after a while because of the multiple delays imposed from the horrible instructions. We gave up about mid-way because the cam shaft instructions were impossible to match the picture. The parts of the cam shaft were ridiculously hard to read. Had to view the markings by using a local lamp and a magnifying glass. Even then, the part had to be positioned just so in the light to read it.Pay a few extra bucks to get some other kit. Trust me, you will pull your hair out with this one.

This is a great model for teaching how a four stroke engine works. It is great for showing the concepts of engine timing between the crankshaft and the camshaft, as well as how the ignition timing comes into play. I have built this model twice — once with my older son when he was young, and now again with my 12 year old son. It is a great model and is relatively easy to assemble. The only complaint I have is that the instructions & image for assembling the cam shaft could be improved, as the orientation of the cams is a little unclear in the image for a couple of the cams. Other than that minor difficulty, I recommend this to anyone who wants to gain a basic understanding of a simple internal combustion engine.

Recipients enjoyed putting it together and watching it run

Great gift, great instructions. A little funky when it comes to the camshaft. The camshaft lobes are not opening at their right time and 3 cylinders intake ports were open at once. Had to 3d print the cam lobes to get rid of that issue. Works to introduce new kids to building. However, not 100% when it comes to display the operation of the engine.