This tool is required on engines where the flywheel and crankshaft must be held at the correct timing position after attaching the flywheel locking plate the toothed profile is adjusted and locked after being fully engaged in the flywheel ring gear covers most engines in the ford range pre 2007 including both petrol and diesel and the zetec engine this tool is required on engines where the flywheel and crankshaft must be held at the correct timing position after attaching the flywheel loc