Timing belts will often last much longer than the recommended replacement interval, but they won’t last forever. Today, it ranges from 100,000 to 120,000 miles thanks to belts constructed of stronger and more durable materials. On older applications (1990s vintage and earlier), the recommended replacement interval for OHC timing belts was typically 60,000 miles. But belt life is limited by the material the belt is made from. The tensile cords inside a timing belt prevent it from stretching, which allows a belt to maintain accurate valve timing for a longer period of time than a chain typically would. Timing belts may be made of synthetic rubber such as neoprene, Highly Saturated Nitrile (HSN) or EPDM, and reinforced with tough fiber cords (often Kevlar). Timing belts are quiet, and they generate less friction than a timing chain or gear drive, which reduces parasitic horsepower losses inside the engine and improves fuel economy and power. Timing belts have been used on a wide variety of OHC cam engines over the years. Chain rattle can also occur in OHC engines as a result of stretching, but is often caused by worn or damaged chain guides or a bad chain tensioner. Chain rattle is a common complaint in high mileage pushrod engines when the chain has stretched and is rubbing against the timing cover. Chain stretch is not good because it creates slop, noise and retards valve timing and ignition timing. Their downside is that they stretch, which typically occurs after many miles of service but can happen fairly early in the chain’s life in a high-performance engine with high valve spring pressures. A chain is usually quieter than a straight cut gear set but not as quiet as a belt.Ĭhains are usually less expensive than gears but more expensive than belts. Timing chains are reliable and can be used in pushrod engines or overhead cam engines. Any type of cam drive is capable of doing the job, but there are advantages and disadvantages with each type. The cam drive may be a chain and sprockets, a belt and sprockets, a gear drive, or a combination of any of these such as Chevy’s 3.4L DOHC V6 that uses a timing belt to drive the cams and a chain to drive the intermediate sprocket that drives the belt. Note: Modifications may be required to some timing covers / blocks when fitting double row timing chain sets.Camshafts rotate at half the speed of the crankshaft in four-stroke engines, so there is always a two-to-one gear ratio between the timing components that connect the crank and cam. The Number 4 gear is a single-bolt 4X gear for 58x Gen IV 6.0L & 6.2L engines. This kit suits factory single bolt cams and aftermarket camshafts that use a single bolt gear. We carry the Rollmaster red series timing chain sets. This kit suits factory 3 bolt cams and most aftermarket camshafts that use a 3 bolt gear. We carry the Rollmaster red series timing chain sets. The Number 3 gear is a three-bolt, later LS2 6.0L & LS3 6.2L 4X trigger required for 58x reluctor Gen IV engines. We carry the Rollmaster red series timing chain sets. The LS2 cam position sensor is at the front on the timing cover. The Number 2 is an LS2 Gen III 6.0L 1x trigger for 24x Reluctor engines with three attaching bolts suits Holden Commodore VZ LS2 6.0L V8. The LS1 cam position sensor is at the rear (closest to firewall). The Number 1 gear is an early Gen III LS1 LS6 5.7L with three attaching bolts suits Holden Commodore VT VU VX VY VZ LS1 5.7L V8. This photo reveals the four different Gen III/IV cam gears. The timing chain sets are one of these parts that can sometimes confuse the buyer as there are a few different cam gear options. The LS Platform can be confusing sometimes when it comes to getting replacement or performance parts. Concept Performance ~ LSR Engine Blocks.Boundary Racing Oil Pumps & Billet Gears.
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