Cloyes S1021 Engine Timing Crankshaft Sprocket - Outer

Cloyes S1021 Engine Timing Crankshaft Sprocket

The Cloyes S1021 is a steel engine timing crankshaft sprocket built for precise chain engagement and quiet operation. It is a direct-fit timing component for select Mazda applications, including Mazda 3, Mazda CX-7, and Mazda 6 outer positions.

Key Features

• Steel construction for timing system durability
• 20-tooth design for accurate chain indexing
• Precision-machined bore for true fit
• Helical tooth form for quieter operation
• Single-row chain design
• Includes one timing mark for alignment reference

Product Details

Cloyes S1021 is an engine timing crankshaft sprocket engineered for rebuilds and routine timing service where accurate chain drive performance matters. The sprocket uses a precision-machined 1.04-inch bore, a 2.06-inch outside diameter, and a 0.43-inch width, with a 0.169-inch tooth width. Its steel construction and helical tooth profile support consistent chain tracking in the timing system. This part cross-references Monroe Shocks & Struts (e.g., L3K9-11-316-A) for the same application.

Compatible With 2007-2013 Mazda 3, outer; 2007-2012 Mazda CX-7, outer; and 2006-2007 Mazda 6, outer. The Cloyes S1021 is a practical choice when replacing timing system wear components on these Mazda engines.

Common Reasons for Replacement

• Worn or noisy timing sprocket teeth
• Timing chain service on a Mazda 3, Mazda CX-7, or Mazda 6
• Chain indexing concerns during engine rebuild work
• Visible wear on the crankshaft sprocket surface or bore
• Timing system refresh after extended mileage

Installation Notes and Tips

Replace the timing chain tensioner, sprockets, and guides together when servicing the chain, since these parts work together to maintain chain tension and alignment. Verify application details by year, model, and outer position before installation. Follow the vehicle service procedure for timing mark alignment and proper chain routing.

Quality Assurance

Cloyes designs this sprocket using CAD-based engineering and advanced materials, then tests each part for function and durability to support dependable engine service. The S1021 is built for consistent performance in timing system repair and replacement work.