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New LuK flywheel /DMF axial rock / tilt 1.8 tdci


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Hi guys,

I purchased clutch/flywheel kit from LuK to replace it on my 2007 1.8 tdci focus. The first kit I purchased from autodoc and it came with damage on the clutch plate due to poor handling during shipping but the flywheel came very soild with not much rock and in good condition. Due to damaged clutch I had to return everything. Since the return proceudre takes so long I got a friend to purchase it locally for me at almost the same price as form autodoc, it was purchased form a reputable company. The new kit is in good conditon the rotational play of the flywheel is the same as on the first kit but I am worried about the axial rock /tilt. I measured the depth of the hole as seen on the picutre below when one side of the dmf is pressed down and than again when the oposite side is pressed down. The difference is around 2-2,5 mm. The spec on LuK site for the specific dmf (LuK 415 0647 10) is up to 2,9 mm of rock after that it must be replaced for a new unit. I dont know if they use the same measuring technique but in this Valeo document TSB-VSUK-CL268 20 Dual Mass Flywheel 836316 Tolerances.pdf the measuring technique looks similar. I also filmed a video so you can have better understanding how much rock there really is and how it sounds in some positions. Does any of you guys have any experience how much rock should there be with a new 1.8 tdci LuK DMF and would you try to repalce it for another one in my case?






Thank you so much for the help!

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Official response I got from LuK, it was written in Croatian and is translated with google translate so there may be some mistakes and weird sentences:


Regarding the flywheel of the divided mass of catalog number 415 0647 10 and your questions about the value of the magnitude of the axial deflection of the secondary mass, or the appearance of sounds when rocking the secondary mass relative to the primary mass, answer as follows:


Assuming that the measurement of the new flywheel in question was performed in accordance with standardized Schaeffler / LuK split mass flywheel measurement procedures, for the purpose of checking the condition and assessing functionality in workshop conditions (using the so-called "on-car" or "off-car" special tool), the specified axial deflection value of 2.0 mm indicates the fully functional condition of the part (tolerance ≤ 2.9 mm allowed). Since the minimum size of the axial deflection as such is not prescribed, it cannot be too large, nor can it be considered a relevant indication for premature failure of the part function in the future.


It is important to note that in the case of all Schaeffler products, all individual components are subjected to multiple, very strict quality controls during each step of the production process, directly on the production lines. Strict production standards, harmonized with all relevant industry standards, ensure a very high level of quality of each new product and eliminate the possibility of manufacturing errors almost completely.


Regarding the detail about the appearance of sounds, let us clarify a few technical details in this part of the answer:

In the case of split-mass automotive flywheels, for proper operation and radial guidance of the secondary mass, the design of the bearing at the junction of the two masses implies a certain size of the bearing clearance. Due to the described method of execution, in the unmounted condition of the flywheel, an increased clearance of the secondary mass can be noticed, in the form of its deflection or oscillation in relation to the central axis of the primary mass (shown in the figure below). This design feature is called axial deflection, and is defined as the measurable magnitude of the difference between the positive and negative inclinations of the central axis of the secondary mass relative to the central axis of the primary mass. The magnitude of the axial deflection is expressed in millimeters and is measured at a precisely defined distance from the central axis of the part (exact measure defined in the technical drawing of the part).




Another characteristic design feature of a split mass flywheel involves the size of the free travel of the drive flange wing relative to the coil arc springs, when rotating the secondary relative to the primary mass. It is observed as a certain degree of angle of free rotation of the secondary mass - without the appearance of resistance due to compression of the coil arc springs inside the assembly (shown in the figure below). This design feature is called the freewheeling angle and is defined as the measurable magnitude of the degrees of free-rotation angle of the secondary mass relative to the primary mass in the unladen state, in any direction, to the point of contact of the flange wing and arc springs inside the flywheel assembly. arc springs in any direction).




With the part not installed, both the described features (and the oscillation of the secondary mass relative to the primary mass, as well as the rotation of the secondary mass flange until contact is made between the flange wing and the arc springs, before the arc springs begin to sag inside the flywheel) metallic sounds from inside the part - which as a rule do not represent any malfunction or damage, but belong to the normal technical characteristics of the flywheel of divided mass!


In the case of split-mass flywheels of part number 415 0647 10 for FORD vehicles, equipped with 1.8-liter, diesel TDCi units, it should be noted that this flywheel is equipped with an additional damping mechanism in the form of a control friction plate (shown in the figure below). The function of this mechanism is additional damping of vibrations and loads at large angles of rotation of the secondary mass flange (eg change from load to unloading or vice versa). In the case of checking the condition and functionality of the non-installed part, a characteristic feature of the flywheels equipped with a control friction plate is the feeling of sticking to the obstacle with the appearance of a dull metallic sound (which can be interpreted as a blow), when turning the secondary mass in one or both the exact position at which the control friction plate is stopped. All the described constructions are of a technical nature, are considered normal and do not affect the functionality of the part in any way.



Overview of factory tolerances ZPM 415 0647 10:



ADDITIONAL NOTES to flywheel 415 0647 10:

In the case of the divided flywheel in question for FORD vehicles, equipped with 1.8-liter, diesel TDCi units, for the proper function and longevity of the new flywheel it is mandatory to take into account the condition and correctness:

all mechanical components of the engine and transmission (crankshaft, main and axial bearings, etc.), fuel supply and injection system, starter (starter), positive and negative lines (cables), vehicle batteries, etc .. !!


Namely, there have been cases in which, soon after the installation of a new part, malfunctions, vibrations and similar symptoms occur that can be associated with the flywheel of the divided mass. In most of the analyzed cases, the melting of the polymer ring of the control friction plate inside the flywheel was recognized as the main drawback that leads to the appearance of the problem. The main cause, ie one of the basic preconditions for melting the control friction plate material, is the occurrence of very high temperature and consequent overheating of the components, which occurs due to excessive friction between the flywheel elements in contact with each other. Such problems occur as a result of flywheel operation in operating conditions outside the design limits, with very frequent and very large angles of rotation of the secondary mass (change from load to unloading and vice versa), and consequent frequent activation of the control friction plate. The described shortcomings in the subject engines are most often associated with improper operation or unfavorable / problematic preparation and combustion of the fuel mixture.


We hope we have answered all your questions with the above.


In case of ambiguity or further questions, we are at your disposal.


Like I expected, they say the rock/ tilt is normal but only time will tell how good it really is. I would still appreciate any input from you guys. 🙂

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