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QB93Z · 12-20-2012

Here are some additional pictures of the broken clutch fork from a 1994 ZR-1 with greater than 130,000 miles.

The goal of our analysis was to determine if the failure could have been predicted by visual inspection prior to the failure.

The fork failure occurred during a routine shift from second to first gear while Yun was entering the parking space in the parking garage at his condo.

There were no prior indications of clutch operational degradation.

Here are some close up pictures of the fracture:

It looks like the fork suffered fatigue failure under tensile stress during clutch opeartion. There is no indication of deformation (twisting or bending) occurring prior to the failure.

There is no indication of mechanical damage (strikes, marks, or scrapes) to the fork prior to the failure.

The failure crack probably started in the edges of the rivit hole and spread outward to the edges of the fork.

I suggest visual inspection of any clutch fork that is to be reinstalled. Examine the area around the rivit, looking for cracks.

I would be intersted in any other comments.

Jim

12-20-2012	#1
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	Clutch Fork Failure Analysis Prediction? Here are some additional pictures of the broken clutch fork from a 1994 ZR-1 with greater than 130,000 miles. The goal of our analysis was to determine if the failure could have been predicted by visual inspection prior to the failure. The fork failure occurred during a routine shift from second to first gear while Yun was entering the parking space in the parking garage at his condo. There were no prior indications of clutch operational degradation. Here are some close up pictures of the fracture: It looks like the fork suffered fatigue failure under tensile stress during clutch opeartion. There is no indication of deformation (twisting or bending) occurring prior to the failure. There is no indication of mechanical damage (strikes, marks, or scrapes) to the fork prior to the failure. The failure crack probably started in the edges of the rivit hole and spread outward to the edges of the fork. I suggest visual inspection of any clutch fork that is to be reinstalled. Examine the area around the rivit, looking for cracks. I would be intersted in any other comments. Jim