Cam/VCT Bolt failure
It’s always fun to share results from the dynamometer or track with the new Ford 7.3L Godzilla, but to keep with our goals of full transparency I want to share a problem we had with a customer engine at Willis Performance in October of 20221. After completing multiple dynamometer runs the customer installed the engine in their vehicle started it, then it shut off. Further investigation found the cam fastener/VCT flow valve failed. Looking at the failure I, nor several of my engineering friends, could be certain of the exact cause of failure. It could have been engine builder error of over/under torqueing the fastener, material defect, or the camshaft position trigger/synchronization yielding and loosening the clamp load. This was frustrating as we had multiple other engines, including our supercharged engine that had gone over 8000 RPM with no fastener issues. This being said we cannot risk this happening again. So, our fix is to eliminate all probable failure modes. We have a revised check procedure for fastener torque, eliminated the stock VCT fastener and designed a new fastener which will not allow VCT to function (all VCT’s will be locked out), and revised the camshaft synchronization wheel so the clamp load does not transfer through it. We are at our first iteration of the revised fastening method. Below are photo's of the revised parts. We are working on some additional changes as well for future incorporation.