Faq Answers Your Frequently Asked Questions Q: What is Center Distance? ANSWER: Center Distance or (CD) is the measurement from the center of the camshaft to the center of the crankshaft. Accurately matching your timing set to the center distance of your engine will determine the performance and longevity of your timing set. CC = MOS - (CRANK DIA./2 + CAM DIA./2) Q: What is HAND MATCHING? ANSWER: Each and every Cloyes Premium Race set (Hex-A-Just®, Quick Adjust®, Race Billet, and Original Race True®) is matched at the Cloyes facility by trained technicians. This process starts with a detailed component fitment and critical feature analysis. Each set is then measured on a pneumatic matching fixture, allowing rotation of the timing set under a detail that sets Cloyes apart from all competitors. Accurate and consistent valve timing is a key component to maximizing engine performance. The illustrations below show a typical mass-produced OE timing set versus a hand-matched Cloyes True® Roller set. OE Set Center Distance measure 0.010” too long causing chain deflection, resulting in: Timing Variation: The cam sprocket is allowed to rotate a certain number of degrees (relative to amount of deflection) without taking lead from the crank sprocket. This prevents the engine from attaining optimum performance. Chain Whip: This will lead to shortened chain fatigue life and can cause ultimate failure. Cloyes Hand-Matched Set Center Distance measures to exact engine specification: Exact and Consistent Timing = Optimum engine performance Smooth Chain Operation = Increased chain life Q: Does Cloyes have undersize sets for aligned bored/honed engines? ANSWER: Yes, in minus 0.005” and minus 0.010” increments. First, the Center Distance as a result of the main bearing alignment needs to be measured. With this measurement, the closest increment that is longer than the measurement can be selected. To order, start with the Cloyes premium timing set number (Race/Adjustable) you have selected for your application and add the respective increment to the end of the number. Example: 9-3100A-5 Q: Why would I want to advance or retard my valve timing? ANSWER: Adjusting your valve timing gives you the ability to customize your torque and power curves to optimize your desired engine output for your specific application needs. ADVANCED TIMING = MAXIMUM TORQUE AT LOW RPM Recommended for towing, performance street driving, and drag racing with automatic transmissions. Retarded Timing = Maximum torque at high RPM Recommended for circle track, drag racing with manual transmissions and other all-out racing applications. Q: How do I advance or retard my valve timing? ANSWER: Cloyes offers several different options to adjust your valve timing: HEX-A-JUST® With the simple turn of an allen wrench or fuel pump eccentric, our patented Hex-A-Just® systems allow you to infinitely adjust valve timing within a window of +/- 6 degrees. QUICK ADJUST® Another Cloyes patented and innovating way to adjust your valve timing. By simply loosening the six fasteners and using the supplied tool you can infinitely adjust valve timing within a window of +/- 6 degrees. MULTIPLE KEYWAYS Use our three or nine keyway crank sprockets for incremental adjustments.