2 Of The Worst V12 Engines Ever Made (And 2 Of The Best)

111 years ago, American automaker Packard unveiled a new model called the Twin Six. At the time, they were in a heated back-and-forth battle with Cadillac, each marque vying for the number-one spot as America’s premier luxury automaker. Cadillac was riding the high of its first V8, but with the Twin Six, Packard introduced the world to the first production V12. 

Since its inception with Packard, the V12 has been lauded as the ultimate form of the combustion engine. Huge power output can be extracted from its high cylinder count; its firing order is inherently balanced, resulting in smooth power delivery and stability in the engine bay; and it’s known for its vocal cords, too. In short, the V12 is perfectly suited to both performance and luxury applications. This grants the V12 a prestige and reputation that is unmatched by any other engine—they’re only found in the world’s finest cars.

The V12 is the statement piece of any automaker’s portfolio, so when you build one, it better be good. Because the V12 holds so much gravity, no holds are barred during its development, and usually, the result is something spectacular. The silky smoothness of a Rolls-Royce V12, or the rabid screams of a Lamborghini V12, are equally distinct, yet successful takes on the engine layout that both perfectly embody their brands’ ethos. However, not every instance is a success story. Here are two of the worst V12 engines ever made, and two of the best.

Today, the Jaguar E-Type is regarded as one of the world’s finest sports cars. Even during its production, the world and Jaguar knew that the E-Type was something special, so when it came time to make a replacement, Jaguar knew they had a near-insurmountable task on their hands. That replacement came in the form of the Jaguar XJ-S, a stately coupe with modernized looks, a relatively cheap price tag, and a 5.3-liter V12. At first, this seemed like a perfectly acceptable successor. A 285 horsepower V12 with a Jaguar badge for just $19,200 felt like a steal, but the truth soon reared its ugly head.

The XJ-S’s V12 was obscenely complex, especially the electronics. One particular problem area was the Marelli ignition system, which functioned as two separate six-cylinder ignitor layouts rather than a holistic 12-cylinder version. The issue was that one half could shut down, leaving unlit fuel in the banks that the working half could ignite at any moment, leading to engine fires. U.S. spec models also had the catalytic converters mounted too close to the exhaust manifolds, which could lead to engine fires.

Beyond the fire problems, a Road & Track owner’s survey also reported issues with the brakes, alternator, cooling system, fuel pumps, instruments, and more. These engines required constant, expensive maintenance to prevent catastrophic damage, making this V12 a stain on Jaguar’s legacy and adding to their reputation for poor reliability.

Despite entering the market at the tail end of the Great Depression, Lincoln decided to introduce its new V12-powered car, the Zephyr, in 1936. Regardless of the V12’s status as a range-topping engine, the Zephyr was meant to help Lincoln expand their market and move away from the low-volume, coachbuilding model it had followed up until this point. From the outside, the Zephyr is a wonderful thing to look at. Although the looks were polarizing at the time, its streamlined lines and teardrop proportions gave it an undeniable Art Deco panache.

Under the hood, though, the engine couldn’t match the exterior’s confidence. The Zephyr’s V12 had many similarities to Ford’s flathead V8, including its L-head valvetrain layout and twin-water-pump cooling system, but it failed to match Ford’s reliability. Almost all of the issues were caused by, or stemmed from, overheating. Thin cylinder walls that poorly withheld combustion heat, along with an underpowered crankcase ventilation system, made these engines run extremely hot. The water-cooling pathways were too small, further exacerbating heat buildup, which cooked the engine oil into sludge that could damage the engine and sap power. Even in a well-functioning example, the small bore and displacement meant these engines produced only 110 horsepower, which, even for the day, was underwhelming for a V12.

The car was a perfect example of 20th-century American elegance, but its underwhelming, problematic engine held it back, and it faded into obscurity as one of the forgotten cars of the 1930s.

The V12 engine is steeped in the very essence of the Ferrari brand. Since the beginning of the prancing horse, the V12 has been the continuous masterpiece of Maranello, constantly evolving and improving. Each iteration improves upon the last, so it’s no surprise that its most recent version is the best the world has ever seen. Developed in 2002 for Ferrari’s fourth ultimate supercar, the Enzo, the 6-liter V12 was dubbed F140. The engine was pure Formula One, utilizing a 65-degree bank angle that allowed for a larger bore, more space for the intake manifolds, and a shorter engine height, resulting in a lower center of gravity and a compact package. In the Enzo, this naturally aspirated V12 produced 651 horsepower and an operatic shriek.

The F140’s involvement in the Enzo project alone makes it legendary, but that’s just the beginning. Ferrari upped displacement to 6.3 liters, and tossed the F140 in the F12. Later, in the Enzo’s successor, they bumped the power up to 800 horsepower and added an electric motor and a KERS system, introducing the LaFerrari as the brand’s first hybrid. Then, Ferrari updated the engine again for the 812, increasing displacement to 6.5 liters and boosting power to 819 horsepower. This most recent version powers all 812 variants, the Daytona SP3 and other Icona series cars, and the Purosangue, Ferrari’s first SUV. The F140 is the mascot of Italian, high-performance V12s, and it’s been blessing the hearts and ears of Ferrari fans since 2002.

The M120 was developed with similar vigor as the F140, but its goal was different from the beginning. In the late 1980s, Mercedes was due for a new S-Class. An S-Class has to be solid and silky, and that includes the engine; it has to be solid and effortless. This quest for a smooth and stable powerplant gave rise to the M120 V12, and Mercedes brought out all the stops in its development. The engineers wanted power but opted for a naturally aspirated configuration over forced induction, as they felt the linear power delivery of an NA engine was better suited to the S-Class’s task.

Mercedes wanted nothing to come in the way of the M120’s longevity, and meticulously engineered and tested each component until they could comfortably withstand more stress than would ever be placed on them in regular use. Its cooling and oil circulatory systems were simple and robust, as was the rest of the engine. Its 390 horsepower was doled out smoothly and predictably, with torque available across the rev range. In the S-Class, the M120 was like a Navy SEAL playing paintball. It was so capable that you never had to worry about it, and its performance potential was quickly realized, too. Mercedes used an AMG-tuned version of the M120 in the fabled CLK-GTR, as did Pagani in the Zonda. The M120 was solid as a bank vault door, and it conquered both the luxury and performance arenas of V12 greatness.

The V12 engine family is known for excelling as a powerplant for both luxury and performance cars. In luxury applications, their inherent balance between cylinder banks and firing orders lends itself well to smooth running and stability in the engine bay even at high revs. Their high cylinder count means combustion overlaps almost constantly, making the powerband linear and acceleration predictable and easy to control.

As for performance applications, this linear powerband is also beneficial, eliminating power jumps or drops that could disrupt a driver’s instincts. Their high cylinder count and displacement mean their horsepower ceiling is very high as well, without the need for forced induction. 

Engines on this list were chosen based on their adherence or lack thereof to these characteristics. Engines that exemplify the benefits and exceed the expectations of a V12’s capabilities were chosen as the best, while engines that fell short of said capabilities and expectations were chosen as the worst. Beyond V12-specific criteria, engines were also ranked based on general metrics like reliability and maintenance needs.