Metal valve covers may last longer, but modern cars use plastic: here’s why – Jalopnik

A valve cover, located directly above the cylinder head, is a critical component that prevents oil from escaping through the top of an engine. Oil keeps temperatures low and reduces friction between moving metal parts. That’s why any damage to your valve cover – which can lead to oil leaking – can cause serious problems under the hood. Given its importance, you might wonder why automakers have largely moved away from relying on metal. In some cases, a car’s engine compartment has become a plastic mess these days, and that’s because plastic is cheaper and lighter than traditional materials.

Since the 1970s, when the Energy Policy and Conservation Act required automakers to easily display fuel economy figures on window stickers, brands have been looking for ways to improve efficiency. During the same period, corporate standards for average fuel economy were also introduced, essentially setting the bar for what automakers had to deliver in terms of miles per gallon to avoid fines. According to a report published on SpringerFor every 10% reduction in weight of a car, fuel consumption improves by up to 8%. Replacing heavier metal parts with plastic helps vehicles shed pounds, improving gas mileage.

While the automotive industry has eagerly entered the world of plastics as a replacement for metal, it is not the only industry making this change. Overall, switching from metal to plastic could result in potential cost savings of up to 50%, the researchers said KAYSUN. This is because there are not as many stages involved in manufacturing plastic parts as there are in manufacturing metal parts, which essentially means that more parts can be made faster.

While it’s clear why automakers have switched to plastic, some argue that those covers diminish the appearance of an engine. When lifting the hood (especially on a vehicle with a more robust engine), the greeting with large plastic covers does not provide enthusiasts with the same experience as vintage models with metal parts. Just look at some of the best production motorcycles ever made; While there are some exceptions, most do not feature large plastic pieces instead of metal. Granted, you can always follow the guides on how to paint your valve cover to give it a nicer look, regardless of the material.