When it comes time to replace your engine, you might wonder if it's cheaper to buy a crate engine or try to build one ...

The $29.99 all-metal desktop Stirling engine kit is one of the simplest. It can be assembled in 15 minutes and is recommended for ages 14 and up. Also for $29.99 is the Exploring Kid Steam Engine Kit.

Now $69, down 30 percent off its usual $100 sticker price, this miniature engine kit seems to suggest otherwise. Get It! Made ...

For those aspiring to make the move from car enthusiast to master mechanic, online retailers like Amazon are full of listings ...