Technical Service Bulletin - Flywheel Inspection


Mar 5, 2003
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NUMBER 08 - 1

Date: 28 March 2008

Subject: Inspection of Viper Competition Coupe World Challenge/GT3 Tilton Flywheels.

During the 2007 season, some competitors experienced flywheel failures during races; two in Europe, one in the U.S. These failures were associated with Tilton steel flywheels used with the triple plate bronze clutch. Analysis indicates the failures start with cracks propagating from the edges of the radii of the timing windows or the lightening holes in the flywheel located closest to the O.D. of the clutch face.

It is most strongly recommended that all flywheels of this type currently in service be NDT, i.e. magnetic particle (Magnaflux®) or X-ray inspected for cracks at the start of the season and every ten hours of subsequent service by a certified testing laboratory. In addition, flywheels in service for three full seasons or more should be replaced in order to prevent general fatigue failures.

Between the periodic lab inspections the area of the flywheel between the clutch face and the roots of the ring gear teeth can be checked with a commercial dye penetrant system such as Magnaflux Spotcheck ® or equivalent. If any suspicious indications are found the flywheel should be removed and sent out to have a more thorough inspection performed.

Any flywheel indicating cracks anywhere on the surface should be immediately removed from service and replaced. Failure to do so can lead to a flywheel failure which can severely damage the engine and transmission.

On a final note, if a competitor does experience a flywheel failure, the engine should be shut off IMMEDIATELY to minimize damage to engine, transmission or the vehicle.

I. K. Zwicker
Dodge Motorsports


Viper Specialty

Viper Owner
Feb 14, 2002
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Cape Coral, FL
For anyone curious, that would be one of these:

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FYI#1; If anyone out there with a CC does end up needing one, I have a couple laying around, 1 new and 1 used.

FYI#2; This issue DOES NOT affect the Heavyweight Flywheel version that we offer for Tilton Clutches, we have removed all lightweights from service already due to other reasons.