Looking for a lightweight (single mass) flywheel?
You won't find any sold or recommended here for an M96/M97 or newer watercooled Porsche engine. Porsche designed the M96/M97 engine (and later engines) to utilize a dual-mass flywheel which serves the purpose of countering torsional and resonance vibrations from the crankshaft. Neil Harvey from Performance Developments has an excellent write up as to why harmonics are the "Silent Killer." Furthermore Porsche advises in Technical Information Bulletin 36/08 that replacing the dual mass flywheel with a single mass is not recommended.
Is my flywheel balanced?
Another issue documented by Flat 6 Innovations is that the lightweight flywheels being sold are not balanced. They will tell you they are made on a lathe and can't be out of balance, however the timing wheel is bolted on and when checked, they are off by the weight of the missing timing teeth. This imbalance will further stress the crankshaft and can cause failures. If you look at any factory flywheel, even a dual mass, you will find balance marks (yes, you can balance a dual mass flywheel). When flywheels are manufactured, they are zero balanced so that they are internally balanced - you will see drill marks where they have been machined to balance them. Same goes for the pressure plate. Furthermore, when rebuilding your engine, it's always good practice to dynamically balance the engine, ensuring all rotating components are balanced. An engine free of harmonics and imbalance will make more power, run smoother, and last longer.
How do I inspect the dual mass flywheel to determine if it needs to be replaced?
When you are replacing your IMS bearing, you need to pay close attention to the flywheel. Unlike a single mass flywheel, the factory dual mass flywheel cannot be resurfaced or reconditioned because of its dual mass. The dual mass provides critical dampening for harmonics and must be retained. A single mass flywheel is not recommended as it eliminates the dampening provided by the dual mass which is critical. Besides the clutch surface, spring back of the dual mass must be checked to ensure it is within factory specifications. In doubt, replace with a new Genuine Porsche or OEM LuK dual mass flywheel along with new flywheel bolts.
How do I replace the rear main seal?
When replacing your IMS bearing, the rear mail seal should always be replaced with a Genuine Porsche PTFE rear main seal (RMS). If the RMS is leaking, the RMS go-no-go tool should be used before fitting a new seal. Under no circumstances should any product claiming to add a rear main seal bearing or any seal other than a Genuine Porsche seal be used. A leaky rear main seal is not caused by the weight of the dual mass flywheel, but rather from mismachining from the factory or if the engine has not been previously fitted with a Genuine Porsche PTFE rear main seal.
Do I need to replace my flywheel bolts?
On older aircooled Porsche engines, the factory did not use torque to yield (TTY) fasteners, meaning they can be reused, however most choose to replace them with upgraded ARP fasteners. However, in the case with modern Porsche engines including the M96 engine and thereafter, TTY bolts were used and must be replaced when the flywheel is removed from the engine as required to replace the rear main seal (RMS) and intermediate shaft bearing (IMS).
SKU: 400 0080 10
SKU: 99611401205OEM Luk Dual Mass Flywheel Porsche 911 99-08 All 996 & 997 Models
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