The internal combustion engine has come a long way since it first started squishing and banging over 120 years ago. These days, internal combustion motors are controlled by computers and run fine tolerances, so making sure that the moving parts are up to spec is of the utmost importance. You'd think with over a century of practice we'd have this thing on lock, but it turns out that big names still mess things up: back in 2018, Toyota had to recall certain Camry Sedans for oversized pistons. Other manufacturers have been pushing the boundaries, such as Porsche, who have 3D printed pistons for its high-performance 911 GT2 RS. Metals and alloys are the preferred choice of material for pistons, but as it turns out, you can use plastic, up until a certain point.

In the above video, a team of workshop pros take a tired old inline-four engine out of a minivan, remove the original pistons and replace them with plastic units. The Garage 54 team decides to use Kaprolon, a type of nylon, which has a strength rating close to that of normal steel. The Kaprolon is placed on a lathe and machined to match the original set of pistons. We have to admit that they look pretty legit. The assembly process includes adding steel piston rings, re-attaching the connecting rods, and stamping the new pistons into the block. The oil is replaced and everything is set to go.

The car turns over for a few seconds and eventually starts. The car idles like nothing is wrong, but is misfiring badly, and it sounds as if one of the cylinders isn't firing. It turns out that the plug leads weren't connected in the right order. The engine is started once more, and this time sounds much healthier. After a minute or two, the smell of burnt plastic fills the air. The pistons expanded due to the heat and fully seized after a few minutes of cooling down. The next morning, they returned to normal size, and the car started once again but quickly failed. After opening up the engine, the pistons aren't completely destroyed but are thoroughly crisped. If you're in an emergency situation, this solution will get you a few miles down the road.