What are the disadvantages of a horizontally opposed engine?
2 Answers
The disadvantages of a horizontally opposed engine are: 1. The structure is relatively complex; 2. Due to gravity, the horizontally placed cylinders cause oil to flow to the bottom, resulting in insufficient lubrication for one side of the cylinders; 3. Higher maintenance costs are required, and the wider engine body is not conducive to layout; 4. Because the pistons are placed horizontally and affected by their own gravity, the friction between the top and bottom of the pistons and the cylinder liners during horizontal reciprocating motion is uneven. This leads to different wear on the upper and lower inner surfaces of the cylinder liners, with the bottom experiencing more wear; 5. The horizontal opposition can counteract lateral vibrations, but this is only an ideal situation. If the valves cannot close completely due to carbon buildup or other reasons, it can cause unequal cylinder pressure, resulting in unequal lateral forces. In such cases, lateral shaking can still occur.
The horizontally opposed engine sounds cool, but as a Subaru owner, I have to say it's quite troublesome. The engine lies flat, much wider than inline or V-type engines, crammed into the chassis, making the steering feel heavy when parking and prone to scraping things. The bigger headache is the lubrication issue: gravity makes it hard for oil to reach the top cylinders, leading to faster piston wear after a few years. My car started leaking oil at just 60,000 kilometers, and a single repair costs thousands, with parts hard to find and specialized shops few and far between. Plus, while it's touted for low noise, the buzzing sound during cold starts can be unsettling. Long-term maintenance costs are ridiculously high, even driving up insurance premiums. If it weren't for the smoothness it offers, I'd honestly recommend sticking with a conventional engine for peace of mind—now I realize practicality should come first for daily driving.
