Cloyes S250 Engine Timing Crankshaft Sprocket - Outer

Cloyes S250 Timing Crankshaft Sprocket

The Cloyes S250 is a steel engine timing crankshaft sprocket built for specific-fit applications that require accurate chain engagement and stable timing operation. It features a helical tooth form for quieter running and a precision-machined bore for a true fit in the engine timing system.

Compatible with 1955-1958 Ford Thunderbird, outer, and 1959-1962 Mercury Colony Park, outer, this sprocket is a direct replacement choice for timing service on classic Ford and Mercury engines. The S250 part number is also referenced as B8A6306B for the same application.

Key Features

• Steel construction for engine timing durability
• 21-tooth design with a 1-row chain layout
• Helical tooth form for quieter operation
• Precision-machined 1.25 in. bore for accurate fit
• Specific-fit design with keyway notch
• Gray finish
• Outside diameter: 2.52 in.; thickness: 0.77 in.

Product Details

Cloyes S250 is an engine timing crankshaft sprocket used in the valve train timing system, where it works with the timing chain, tensioner, and guides to maintain proper cam and crank synchronization. Cloyes designs and manufactures timing components using CAD-based engineering and advanced materials, then tests each part for function and durability. For rebuilds and routine timing replacement, the S250 provides a direct-fit solution for 1955-1958 Ford Thunderbird outer and 1959-1962 Mercury Colony Park outer applications that require a silent type chain.

Common Uses

• Replacing a worn or damaged crankshaft timing sprocket
• Restoring proper timing chain engagement in classic Ford and Mercury engines
• Addressing timing noise caused by worn sprocket teeth
• Correcting timing wear during engine rebuilds
• Servicing outer timing positions on silent type chain applications

Installation Notes

Before installation, verify the engine uses the correct silent type chain and confirm the outer position application. Cloyes recommends replacing the chain tensioner(s), sprocket(s), and guide(s) when the timing chain is replaced, since these parts work together to keep the chain tight and properly supported. Always confirm fitment by year, make, model, and position before assembly.

Quality Assurance

Cloyes timing sprockets are CAD designed, manufactured with advanced materials, and individually tested for function and durability. The S250 is built to deliver dependable timing performance for engine rebuilds and replacement service.