I am on board with others who have reviewed this product. Let me start by saying that I am an engineer and I am mechanically inclined. me an my 8 year old son built this in about 3 hours. He sensed my frustration and did not truly enjoy the project.

1. The screw holes were not tapped completely causing stripped screw heads, stripped screw driver heads and stress fractures on the plastic parts.

2. The instructions were vague and in many cases inaccurate. I found a better set online after I had finished putting it together. The instructions for the Cam assembly were completely wrong.

3. The spark plugs do not have anything to hold them on the engine so they keep falling out.

4. The battery pack that runs the motor and the spark plug lights was defective. The power plug on one side was to big for either of the plugs so you can run the motor or the lights but not both at the same time.

My son is really into mechanics and cars and this did give me a chance to show him how the motor works so it was not a complete waste.

excellent model.. Eric the dude must not have ever built a car model. This was not hard at all and went together perfectly. As a kid I have built models that were much harder. Everything works perfectly. All th eparts fit perfectly. Use a good screwdriver and you will be fine. If anyone wants a vid of it in action email me. I do not recommend this for an 8 year old though. Much too hard to screw in the non tapped screws for a kid. HIGHLY recommended and the insctructions are not the best.. (just think I was gonna listen to others and cancel my order, glad I did not)

It was a hit. My nephew, and brother, loved it. Very educational about workings of an engine.

I agree with much that the previous reviewers say, but I'm very glad we went ahead and tried it. It was a fun mother/son project, and my 8-year-old got great practice in understanding directions and drawings and learning the names of parts. He was able to set and turn some of the (too large) screws, but I would have to finish them all. He did everything else that didn't involve screws, including putting the cams on the camshaft properly.

I used my own screwdrivers, carefully shaved the pistons and cylinder head and made sure they moved freely. I also added a shim to keep the timing belt pulley from moving and pulling the timing belt off. One intake valve snapped in two, but I crazy-glued it back together.

Finally, the engine did work as described, and my son was thrilled to see 8 hours of work, spread out over several days, pay off. Unlike a previous reviewer, in our case the cams did move the rocker arms, which did move the valves.

I purchased this model for my 8 yr old son for Xmas '06'. I built hundreds of models as a kid from small scale ships and tanks to large scale hot rods but never a working model. However, after reading the reviews on the problems with this model I put-off it's assembly until Father's Day '08' when my son said his biggest wish was to put it together. It took 4 hours to assemble. Heed the previous reviews, all that they say are true. You'll need your own screwdriver, the one provided wears out after about 20 screws. Most moving parts have to be shaved with a knife especially the pistons and cylinder head to get it to move freely (check this as you go because there is no going back unless you want to take the whole thing apart). Overall this model has a great potential to be educational, especially as you assemble it and explain, but it's frustrating, the screws should be tapered or holes predrilled and the directions could be more graphic. We did get it to work just FINE but if you're a novice at model building and don't want to embarrass yourself (DAD), For-Get-About-It.