BMW Valvetronic Repair in Seattle
BMW is known for using unique technology and design. In the early 2000s BMW engineers implemented an uncommon system known as Valvetronic. You may have heard of this system, but likely do not understand the importance it holds.
What is the BMW Valvetronic System?
At their most fundamental level, gasoline internal combustion engines (ICE) need three things to run. Air, fuel, and a spark to ignite the air-fuel mixture. Most production consumer focused ICEs are intended to burn air and fuel in a carefully calculated ratio to optimize power and efficiency. Air and fuel is mixed in a ratio of 14.7 parts air to 1 part fuel. This is known as the stoichiometric ratio, and ensures all fuel is completely burnt off. Not enough air or too much fuel is referred to as a “rich” mixture, and leads to wasted fuel and other fuel related contamination. Too much air or not enough fuel is referred to as a “lean” mixture and is dangerous since it will become very hot and can severely damage engine internals. The Valvetronic system is paramount in regulating the air aspect of this equation. Valvetronic is BMW’s name for their proprietary variable valve lift technology. This regulates the lift and the duration of the intake valves, thus precisely controlling the air intake into the combustion chamber. This system essentially functions as a traditional throttle would, but allows further fine tuning which benefits the efficiency and power of the engine. It is worth noting that many BMW engines that use Valvetronic also include a traditional throttle body. This serves its primary function as a redundancy should the Valvetronic system fail, and should remain completely open under normal operation.
How does the BMW Valvetronic System work?
BMW Valvetronic works by adding a complex mechanism to the valvetrain. It utilizes a toothed shaft, referred to as the eccentric shaft, that is controlled by a motor with a worm gear known as the Valvetronic motor. This motor can rotate the shaft precisely through its approximately 225 degree sweep. The eccentric shaft interacts with an ovular profiled lever called the intermediate arm which in turn interfaces with the valve rocker arm. This ovular profile changes the distance the valve opens based on its point of contact with the valve rocker arm. What this boils down to is many more moving parts, and thus points of failure. But also great fuel savings when operating properly.
What happens when the BMW Valvetronic System Fails?
As mentioned, the increase in the number of moving parts leads to many potential points of failure. Most commonly being the interface between the eccentric shaft, and the Valvetronic motor. Wear between the spiral gear of the motor, and teeth of the eccentric shaft is commonly seen due to higher mileage, and causes the system to lose its precise control. This may present itself as a rough idle, lack of acceleration, difficulty starting, and many other symptoms. Simply put, your BMW will not behave as it should with a malfunctioning Valvetronic system.
While BMW was arguably the pioneer of this technology in consumer automobiles, other manufactures implement some form of variable valve life due to its fuel saving benefit. Volkwagen implements a similar concept on many of their engines, but executed in a different manner. Instead of using 225 degrees of adjustability, VWAG’s engines use two distinct intake camshaft profiles, offering two modes of valve lift, high and low. This is controlled by one solenoid per valve. The benefit of BMW’s system is clear, a much finer control of valve lift allows for the redundancy of the throttle body, and greater fuel savings. However, VW’s system only adds about nine additional moving parts, whereas BMW’s adds, in some cases, over a hundred.
Precision Motorworks Specializes in BMW Valvetronic Systems
Since the Valvetronic system holds so much importance in the way your engine runs, it is important to trust a repair and service center who holds intimate knowledge of its workings. Trying to take on Valvetronic issue without the proper tooling and knowledge is a recipe for disaster. You can trust Precision Motorworks to be your Seattle area BMW Valvetronic expert.
