Apparently, several companies have made their fair share of mistakes while building naturally aspirated 4-cylinder engines.

Although we all love a big burly V8 or a tuned turbocharged V6, the automotive industry is quite literally built upon the naturally aspirated inline-4.

It is the configuration that has traditionally found the best balance for fuel economy, usable power, and manufacturing costs. Also, it's still to this day the staple, especially in developing countries where the high maintenance costs of running a small turbo-petrol engine are off-putting to most customers.

As you might expect, this is a powertrain that has received big chunks of developmental budgets, and companies like Mazda and Toyota have pretty much perfected it. Along the way, every company has made their fair share of mistakes though, and these are 10 of them.

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With a cast iron head in a time when other manufacturers were already using aluminum alloy blocks, this was outdated before it even made its debut in the '80s.

It is incredibly heavy for a transverse mounted engine, which does nothing for handling or performance. Ford somehow repurposed it and continued to shove it into the Taurus way into the '90s.

In truth, these engines were ahead of their time, and it was technically the carb that destroyed them.

At a certain rpm, the fuel would froth, causing a list of different, often terminal issues. Over the years, these engines have proven to be fairly reliable with more modern carburetion, but in most cases, the damage has already been done.

Another engine with an iron head and block. This was obviously durable, but it was also incredibly underpowered and hopelessly inefficient.

GM also had the cheek to put it into the Camaro, which is quite simply one of the most ridiculous things any manufacturer has ever done. Today, it makes for a useful boat anchor, and that is about it really.

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Of all the Japanese manufacturers, Mazda is the only one really willing to push the envelope when it comes to innovative engineering. Proof of that lies in their rotary obsession, but the FS-DE engine was also pretty advanced for its time.

It is a well engineered engine that has proven to be pretty reliable. Unfortunately, Mazda could never make it very efficient for whatever reason. Getting the same mileage as other V6 models at around 20 MPG. It will leave you frustrated if you thought you were buying an economy car.

We all love to hate British engineering. The truth is that a lot of their actual engineering were excellent, they were just let down by inconsistent and often below industry standard production.

One of the many victims of their poor work ethic was this BMC line of engines. By the '70s, these engines were already out of step with the industry in terms of technology and had no place in the MGB GT. It was unreliable, underpowered, and just disappointing.

Although there was precious little to get excited about any K-car (aside from maybe the Dodge Daytona pictured), Chrysler devised a way to make them even more boring.

Considering how underpowered these engines were, it is pretty incredible that they made it all the way into the '90s with EFI the only real “advancement.”

If you are unfamiliar with the Tritec engine, count yourself lucky. This was the lump of sadness the first generation (R50/53) Mini Coopers came out with in the early 2000s. Although the supercharged version made good power, the naturally aspirated version was far less inspiring.

BMW themselves were unhappy with it and considered it “outdated” as well as underpowered. We would love to say BMW rectified the issue in the next generation, but their engines were also pretty woeful in terms of reliability.

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In an effort to improve performance, economy, and emissions, Fiat came up with the bright idea of adding a spark plug to every cylinder. Spoiler alert; it didn’t work.

It proved to be an improvement on their previous engines, but other manufacturers were able to deliver better power, economy, reliability, and efficiency without adding cost and complexity to the design. All they did was add an extra failure point to an already failure-prone brand.

Arguably one of the worst modern engines still in production. The issues with the FSI engine are wide-ranging and there are no easy fixes for it either. Firstly, the biggest problem is the cam chain tensioner (made of plastic) fails.

It is an interference engine, so when this happens, it will result in a full top-end rebuild or a replacement head. These engines are pretty efficient but like most direct injection cars, it suffers from carbon buildup. Unlike other direct injection models, its carbon buildup is excessive and can actually result in serious problems if left unchecked.

Hyundai and Kia have been in the headlines for all the wrong reasons lately. Most of this negative publicity is down to these Nu engines they put in a host of different models across their lineup. With their piston rings not getting the correct heat treatment, they fail, which has resulted in some cars catching fire. It has also come to light that the big-end bearings will fail, which is equally concerning because that is no easy fix.

What is unfathomable though is why they still consume so much oil even after getting fixed, something that customers should take into account post recall. Both brands enjoy one of the highest reliability ratings, and are going to great lengths to paper over this issue, but this kind of engine is something consumers need to be more aware of.

Sources: Car Complaints, Consumer Reports

Luke Zietsman is an all out automotive enthusiast based in The Philippines. If it has two or four wheels he has either owned it, researched about it or dreamed about it.