If you’ve spent any time around the current BMW lineup within the last decade, you’re likely aware of the technologically-advanced but also challenged N63 V8 engine. The first to market with a hot-vee layout featuring the exhaust manifolds and turbochargers mounted between the cylinder banks as opposed to outside, the N63 and M derivative S63 have been substantially refined and revised over the years, but the initial version of the N63 has earned a reputation for poor reliability thanks to a variety of potential problems. Such teething troubles aren’t exactly unheard-of when it comes to the first few model years years of a new engine, especially one as radical as the N63 was when it arrived, but the number of potential faults and their propensity to occur appear to have been worse with the first mass-produced hot-vee V8 engine, which was subsequently followed by similar designs from Audi, Mercedes-AMG, and Cadillac.
Some of the potential problems with early N63 engines include oil consumption due to valve train wear which has been attributed to the heat associated with the inboard turbochargers and exhaust manifolds. Timing mechanism failure has also been documented as occurring thanks to guides and tensioners that can’t seem to stand up to repeated heat cycles over the long term. Fuel injectors present another point of contention, as the N63 features direct-injection, but the units have been revised over the years, and fuel injection problems aren’t isolated to the N63 specifically (see the N54). To cope with the excess heat inherent with the design, some N63 engine software has also been documented as continuing to run the fans and even the water pump after the engine has been shut off, which, in combination with Efficient Dynamics, that only charges the electrical system during coasting, causes premature battery failure.
So, which problem befell the N63 V8 in question? Through the course of nearly 40 minutes, Eric of the I Do Cars YouTube channel takes the engine from a complete long block with a full wiring harness down a bare block with removal of the pistons and crankshaft. The sped-up process is fascinating to watch, as the video allows for an in-depth look at the systems and components which make the N63 the complex piece of technology and machinery that it is. These include the direct fuel injectors, the turbochargers, the variable valvetrain, and their associated peripherals, all of which are disassembled before your eyes, allowing for a view only engineers and service technicians are typically accustomed to.
You’ll have to watch the full video to appreciate all of the details, but in the end, it seems like the subject N63—which is an early example based on the lack of twin-scroll turbochargers and Valvetronic—suffered from a variety of problems, with evidence of prior service found within the cylinder heads, along with shattered timing chain guides.—Alex Tock
[Photo courtesy BMW AG. Video courtesy I Do Cars on YouTube.]