What is the torque specification for the cylinder head bolts of the EA888 engine?
2 Answers
90N is the approximate torque value for the cylinder head bolts of the EA888 engine. The EA888 engine is a design by Volkswagen, integrating advanced technologies such as direct fuel injection, turbocharging, and variable valve timing, achieving a balance between power, economy, and environmental friendliness. It is installed in various models under the Volkswagen brand, including the Magotan, CC, Tiguan, Passat, and the Audi Q5. Cylinder head with valve lift switching function: The EA888 engine features a newly developed cylinder head that integrates the exhaust manifold into the cylinder head. This allows for exhaust gas recirculation cooling to occur within the cylinder head, with the exhaust gases flowing inside it. The intake and exhaust camshafts have variable valve timing functionality. The exhaust camshaft also has a valve lift switching function, enabling the valves to open and close on two different cam profiles. The EA888 series engines include two displacements: 1.8L and 2.0L. The 1.8TSI has a maximum power output of 118kW (160PS) at 5000-6200rpm and a maximum torque of 250Nm at 1500-4500rpm. The 2.0TSI can achieve a maximum power of 147kW (200PS) at 5100-6000rpm and a maximum torque of 280Nm at 1700-5000rpm. The mechanical structures of these two displacement engines are fundamentally the same, with the main differences being the length of the connecting rods between the crankshaft and pistons. The 2.0TSI has shorter connecting rods than the 1.8TSI, with an increased crankshaft radius to enhance displacement. Additionally, the piston top structures differ slightly, primarily to adjust the working volume of the combustion chamber, ensuring a consistent compression ratio and achieving the same combustion effect.
I've disassembled quite a few EA888 engines, especially in Volkswagen models. The torque value for the cylinder head bolts isn't a single figure but involves a multi-stage process. The standard procedure generally starts with pre-tightening to 30 Nm using a torque wrench to ensure even force distribution across all bolts. Then, following the manual's specified sequence, you need to rotate them an additional 90 degrees, which effectively increases the torque incrementally. Some versions require a second 90-degree turn to enhance preload force. Throughout this process, bolt sequence is critical to prevent cylinder head deformation that could lead to oil leaks or knocking. I always remind people to check official service documentation before starting, as the EA888 has gone through several generations with possible torque value adjustments. Using incorrect torque can easily damage the aluminum cylinder head, making repairs both troublesome and expensive. It's best to replace with new bolts since stretched old ones can't guarantee proper sealing. Opt for a torque wrench with angle markings for higher precision. During routine engine inspections, always check bolt conditions to prevent unexpected failures.
