What are the disadvantages of a horizontally opposed engine?
4 Answers
The horizontally opposed structure is relatively complex, and there are issues such as oil lubrication that are difficult to resolve. Due to gravity, the horizontally positioned cylinders cause oil to flow to the bottom, leaving one side of the cylinders inadequately lubricated. The high-precision manufacturing requirements also lead to higher maintenance costs. Additionally, the wider engine body makes it less favorable for layout. Introduction to automotive engines: 1. The automotive engine is the device that provides power to the vehicle, serving as the heart of the car and determining its power, fuel efficiency, stability, and environmental friendliness. 2. Depending on the power source, automotive engines can be categorized into diesel engines, gasoline engines, electric vehicle motors, and hybrid engines, among others.
I've been driving a car with a horizontally opposed engine for over five years, and the most frustrating part is the hassle of maintenance. Last time I had the spark plugs replaced, the mechanic said half the engine bay had to be dismantled, and the labor alone cost over 800 yuan. What's more, this engine is particularly prone to burning oil—I have to check the dipstick every month, or the warning light pops up in no time. The low ground clearance is another issue; I'm always afraid of hitting the oil pan when driving over rough roads. As for parts, waiting for an imported piston ring can take half a month, and the repair costs are significantly higher than those for regular cars. After long-term use, I've noticed uneven cylinder wear, and specific oil must be used during maintenance. It's truly expensive and exhausting.
Having worked on cars for over a decade, horizontally opposed engines are the most challenging. With cylinders laid out sideways, just removing the valve cover requires lifting the transmission, doubling the labor time. Subaru models are particularly troublesome—replacing spark plugs means disassembling the intake piping, and the bolt placements are extremely awkward. The oil lubrication system is another flaw: while the piston bottoms sit submerged in oil, the tops suffer from insufficient lubrication, leading to uneven cylinder wall wear. Our shop frequently sees these engines returned for cylinder scoring repairs. What's worse, the specialized tools are expensive, and the repair manuals are overly complex—only seasoned mechanics dare tackle these engines.
From a structural design perspective, horizontally opposed engines have inherent flaws. The low center of gravity is an advantage, but the horizontal arrangement of the two cylinder banks leads to unbalanced piston inertial forces, resulting in greater vibrations at low speeds. Oil lubrication is also problematic—gravity causes oil to accumulate at the bottom of the cylinders, leaving the upper piston rings inadequately lubricated, which can lead to oval deformation of the cylinder liners over long-term operation. Cooling is another challenge, as the lower cylinders are farther from the coolant, increasing the risk of localized overheating. These structural issues directly contribute to soaring maintenance costs in the long run, with repair expenses being 30% higher than those for conventional engines.
