Urgent technical note: Fiat/Lancia TC cast-iron Flywheels
Posted: April 1st, 2009, 9:28 am
With immediate effect a new regime is in place at GCRE (that you would be wise to copy) and that is the non-destructive (NDT) crack testing of OE flywheels in every case. Part of the reason for an abnormal incidence of cracks around the central region on items I have examined lately is age, the material is just 'weaker' than it used to be.
Primary reasons for cracking:
1. Severe imbalance of fw or assy
2. Embedding of fw bolts into fw and subsequent loss of preload
3. Incorrect torque setting (over/under) on fw bolts - easily upset by incorrect lubrication regime.
4. 'Swashing' of fw friction face. This can be balanced out - but it puts an fluctuating and very adverse axial load across the radius of the fw every time the clutch is engaged. It can be caused by a poor quality regrind of the item or bent crank/flange out of true.
5. Cracks inherent in fw - precision grind and crack test is advisable on each rebuild.
Cracks in the friction face are not uncommon and usually disappear after grinding.
GC
Primary reasons for cracking:
1. Severe imbalance of fw or assy
2. Embedding of fw bolts into fw and subsequent loss of preload
3. Incorrect torque setting (over/under) on fw bolts - easily upset by incorrect lubrication regime.
4. 'Swashing' of fw friction face. This can be balanced out - but it puts an fluctuating and very adverse axial load across the radius of the fw every time the clutch is engaged. It can be caused by a poor quality regrind of the item or bent crank/flange out of true.
5. Cracks inherent in fw - precision grind and crack test is advisable on each rebuild.
Cracks in the friction face are not uncommon and usually disappear after grinding.
GC