10 Forced Induction 6

Some of the worst engines ever made fall into the six-cylinder category, because of which even great ones are still shunned in favor of V8s.

The humble V6 has provided the auto industry with the finest tuning potential. Primarily shunned by most for a V8, the six-cylinder engine doesn't mind playing ugly duckling in a world full of performance engine blocks.

While some reliable six-cylinder engines outperform their larger siblings, many can't carry the same note as a "screaming V8" or "wailing V10" seriously, have you ever heard an adjective for the V6? be that as it may, the six-cylinder combustion format has been the test bed for many successes when it comes to emissions and safety standards, leading to multiple breakthroughs. So let us get cynical and look at ten of the worst six-cylinder engines ever created!

Designed by Pierangelo Andreani, Maserati developed the first Biturbo production vehicle! Powered via a twin-turbocharged V6, the Biturbo produced just 222 hp in its most significant displacement, a 2.8-liter variant of the V6. However, low power was the least of Biturbo's problems.

The AM452-90 engine block was a pig, known as a reasonably solid block in previous iterations such as the Citroën commissioned Marek. Maserati, however, failed to provide intercoolers for the Biturbo setup and continued with a single Weber carburetor leading to a host of issues. In addition, the trailblazing engine couldn't handle its twin Garrett turbochargers leading to a poorly executed engine block that was immensely expensive to repair.

RELATED: Here's What The 1980s Maserati Biturbo Is Worth Today

The N57 BMW straight-six, this turbocharged diesel block, was found across the BMW range between 2010-2015. However, issues with the engine became so catastrophic, BMW was forced to replace it in favor of the B57 after just five years, The B57 made its debut on the G11 730d.

BMW's N57 block suffered from a multitude of issues, let's begin with the injectors, which failed prematurely when introduced to low-quality fuels. As a result, the fuel pump was also prone to failure, leading to a lack of fuel reaching the engine. However, an even more significant issue lurks within; the poor seals between the piston and the cylinder wall caused the N57 to pour oil into its combustion chambers, leading to catastrophic failure. As a result, the police in the United Kingdom refused to operate their fleet of BMW vehicles All down to the failings of the N57 engine.

Not to be confused with the British Essex engine of the '80s, this Canadian Ford Essex V6 lasted between 1981 and 2007. Bowing out on the 2008 Ford F-150, this mid-size block was a reliable little hunk of metal throughout its years, never really pushing the boat out. Unfortunately, it spent its teenage years mated to a troublemaker—the underwhelming 1989 Ford Thunderbird Supercoupe.

This supercharged variant of the V6 produced 230 hp alongside 330 lb-ft of torque. Sadly for our V6, Ford's 1989 Thunderbird SC weighed a porky 3,500 lbs, and many noted the sluggish performance of the once-great Thunderbird name. Our Essex V6 also hampered the Cougar RX7 in 1989 but was swiftly switched for a V8 block by 1991. Ford's Essex was not a bad engine, just better suited to breathing easy in a family carrier rather than trying to compete.

The VG33ER power plant Appeared for a few years on the Nissan Frontier and Xterra supercharged models. A variant of the 1983 VG engine family, which held the title of 'Japan's first mass-produced V6 engine'. Quite the legacy.

The 3.3-liter diesel lasted between 1996-2004. Nissans wily old block sported a dated single overhead camshaft setup. The supercharged variant (VG33E 'R') pumped out a measly 210hp and 246lb-ft of torque, leaving it highly underpowered. The dated arrangement also suffered from oil leaks, fuel pump issues, and fuel delivery problems. Another issue was the 16mpg, subjecting the Japanese manufacturer to safety and emissions standards at the turn of the millennium, it's no wonder Nissan sent this old pig out to pasture by 2005. The VG series was replaced by the 4-liter VQ in 2005, featuring on the Xterra also.

The Corvair had many issues with its groundbreaking air-cooled inline-six. This American classic from General Motors saw a turbocharged variant so catastrophic the USA would shun the force-induction technology for decades to come.

The 1962 Corvair arrived with a variant named the 'Super-Charged Spyder Engine'. Unfortunately, a turbocharged setup on an already air-cooled engine took the disastrous Corvair to further depths. The machine couldn't maintain operating temperatures making America's second turbocharged production vehicle a failure. GM had launched the Oldsmobile F-85 Jetfire a month before the Corvair, making the Jetfire America's first production vehicle armed with a turbocharger.

Toyotas 1MZ-FE appeared on vehicles such as the Camry, Solara, and Sienna. This standard block was armed with a supercharger if owners opted for the TRD kit on the above models during 1994 and 2000, taking power figures up to 242hp! A reliable little Japanese block with a now, controversial past.

Toyota settled a class action lawsuit in 2007 concerning the 3.0-liter V6. Costly head gasket failures and cracked cylinder heads were all common issues being reported, but worst of all was the dreaded sludge. The 1MZ regularly built up sludge within the block as the oil aged, affecting between 2-5 million Toyota and Lexus models. Toyota has staunchly maintained this was due to poor maintenance on the owner's behalf. Sadly for the former textiles' manufacturer, the jury was out on the 1MZ.

The legendary 1JZ predecessor was the 7M-GTE found in the Supra A70 and Soarer Z20, a legend in its own right featuring in Toyotas M-class of combustion engines; M-class blocks were considered a prestigious feat in the manufacturers' lineup. The GTE was capable of 267hp, producing 264lb-ft of torques between 1986 and 1992. Tuners of its era loved the Supra A70's engine.

Sadly, the Toyota 7M suffered from head gasket issues, significantly denting its reputation. It's worth noting Toyota had to redesign the head gasket on the 30-year-old power plant due to the use of asbestos being prohibited at the time. Bearing issues were also common, leading to rod knock, as are oil/coolant leaks. The leaky old 7M gave way to the much more reliable and tuneable JZ series of engines that inspired a generation.

RELATED: Why You Should Consider Swapping Toyota's 1JZ Engine Over The Hyped-up 2JZ

Making its debut on the 1997 Audi S4 (B5), this troublesome brute lasted six years in the German manufacturers' lineup featuring in the RS4, A4, A6, and following B6 A4 models. The unit was legendary for performance producing anywhere between 227 hp to 380 hp on the RS4 models! So why was it canned after a lowly six years?

At the height of its issues was a poor camshaft seal, leading to oil flooding the combustion chambers in the event of failure. In addition, a regularly failing CV boot and water pump collapse were standard features, leading to catastrophic results on a performance vehicle. These issues killed the engine, and Audi moved past it within six years of release.

RELATED: This Is How Much A 2000 Audi S4 Costs Today

Based on General Motors Ellesmere V6, the quirky Swedish Saab modified the 3.0-liter GML81 straight-six in their usual weird way. They began by strapping a Garrett GT15 turbocharger to the unit operating with an unpopular asymmetrical setup. Saab achieved a low 200 hp on their 9-5 model using their B308E branded motor. It is worth noting the same engine suffered recalls on the Cadillac Catera after timing belt issues began destroying the block between 1997-2001!

Pitiful performance figures from this engine were standard alongside Saab integrating their engine management system, the Trioinic T7. However, electrical gremlins followed, haunting the now-defunct manufacturer.

The PRV V6 was built by three manufacturers, Volvo, Peugeot, and Renault. A powerplant that went on to feature on multiple vehicles saw turbocharged variants on the Renault 25 Turbo and the Renault Alpine. The engine saw production over 24 years between 1974 and 1998.

The PRV engine began life as a V8 and butchered down to a V6 before being stuffed into anything and everything French! Being an old engine, the PRV has suffered many issues, but the most common reports are its inability to hold oil. Leaks are common, alongside difficulty working on the unit. Many forums indicate the hilarious nickname, 'chocolate block' for the PRV V6.

Sources: Consumer Affairs, Eastern Daily Press

An automotive writer based in the UK, suffering with an unhealthy obsession for cars and Formula One.​​​Providing commanding content that attracts attention and entertains all at the same time is key.At the weekends, you can find him Driving past Williams Racing making high pitch V10 noises with his mouth.... daring to dream...