(GTS 113R) Built for the (85-91) Toyota Corolla... When changing your timing belt, often times it may be tempting to skimp on what seems to be a part you can just replace with a generic one from your local parts store.Depending on your application, the timing belt can be one of the most critical and overlooked parts of an engine build. If a timing belt fails, it can potentially cause catastrophic engine damage.Once a timing belt breaks and the engine is still running, the vales are no longer moving in sync (or at all for that matter) with the pistons. The valves that get stuck open will then come into contact with the piston which is still moving. Depending on the duration that the engine still rotates without a timing belt, the valves will almost certainly get bent and the pistons could be damaged beyond use.Beyond providing insurance for your engine, the HKS Fine Tune Timing Belts will keep your engines timing precise.