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

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.

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.

SOME reviewers have gotten this to work. But as other reviewers have stated... this model is "challenging." Especially when your son's hopes are so pumped up, he's so excited to get working on it. Then you realize the following problems:- There is no way an 8 or 9 year old is building this- screws are *extremely* difficult to install. I'd use a power tool, but I'm sure I'd just wreck the plastic- so many places for pieces to bind up- instructions are NOT clear in at least 2 places - installation of the cam shaft and the rockers. Make a mistake here and you'll be doing a partial engine-rebuild to flip things around.- gears are plastic - if anything inside binds up and keeps the works from turning, the motor will spin away and grind down the teeth on the gear.- one of the electrical ports on the battery pack was dead. there's no way to open this up to repair unless you're confident of your abilities to fabricate new plastic parts. so we can now either plug in the motor or the spark plug lights, not both.This kit is SO challenging my son lost interest within a few minutes - his participation was limited to placing the screws, finding the parts... and then this is completely destroyed when the motor doesn't work as expected.I estimated to my wife that this motor would run a week and then die due to failure of the plastic parts. But it didn't even make a full minute before things went south.This was Christmas present and so now almost 10 months later, I'm sure there's no way to get a refund - I'm not even interested in a replacement, I don't think my fingers can take the torture of screwing in anymore screws.Buyer beware!

The media could not be loaded. This is a wonderful model engine. I ordered this for my 8 year old son, hoping that we would build it together, but I did most of the assembly. I can understand- it's a process that young children might get bored with. It doesn't help that the instructions aren't clear at every step. However, I got it done and seeing my boy's face light up was the best! He loves his engine and is genuinely fascinated by all of the mechanisms, but had little patience to help put it together. Keep that in mind- otherwise, a great project!

For the price this is a great kit. Very attractive and well designed. I build exhibits for a living and my general thoughts are that even though this is just a consumer model kit, that it does have some details and color choices that present elements of both scientific and artistic merit. These are some of the details I look for in exhibit production in creative and scientific terms. I like that fact that even though this is a consumer model kit that it has the creative choices of a more expensive device. I think that the end result of assembly is attractive enough to give this substantial review. I frankly like it enough to place it for viewing on a shelf or table so I consider its merits to be both educational and artistically relevant.

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.

Christmas gift for 9 1/2 year old Grandson who is a hands on learner. He started the project at 10:00 am, stopped for a lunch break and finished it about 4:30 pm. Both parents working, 12 year old sister assisted when asked to help find a part. He thought the written instructions were confusing so went by the diagrams. He said that it was important to not over tighten screws and had no problem with parts breaking. I almost didn’t buy this because of some negative reviews but Grandson enjoyed the challenge of the project and ended up with a working engine and a sense of accomplishment. A great gift!

Was able to build this in an evening, and it does work BUT... there were a few problems with this kit. First, everything is fastened together with screws, but the screws have a flat tip, rather than a pointed, sharp tip. So you really have to use some muscle to get the parts to mate nicely. Next some of the critical parts are not designed with good tolerances. An example is the two halves that connect the piston rod to the crankshaft. The top part is a nice half circle, as it should be, but the bottom part is a semi circle until near the bottom where it becomes beveled (!). Result is if you tighten the screws too hard the crankshaft will bind against the beveled portion. I wound up loosely screwing the two halves together to make it work. Also, when untangling the led wires one of the wires came out from the bulb. Was not able to reconnect the wire because the bulb unit is a sealed assembly. So now only three of the four spark plugs are firing. Typical made in China quality.