Sierra 18-5431 Distributor Rotor Assembly for MerCruiser V8 Thunderbolt Ignition

The Sierra 18-5431 is a premium replacement distributor rotor assembly designed for GM V-8 marine engines equipped with Thunderbolt IV and V ignition systems. This rotor and trigger wheel assembly is a critical component of the electronic ignition distributor, ensuring reliable spark timing and optimal engine performance.

Key Features:

• Precision-engineered rotor and trigger wheel assembly for electronic ignition systems
• Fits GM V-8 engines including 5.0L, 5.7L, and 7.4L displacements
• Designed to meet or exceed OEM specifications for reliable performance
• Direct replacement for MerCruiser Thunderbolt IV and V ignition distributors
• High-quality construction ensures durability in harsh marine environments

Replaces OEM Part Numbers:

• MerCruiser: 13524A1, 13524A3, 13524A5, 13524T1, 19405A3, 90576A2
• Mallory: 9-29200
• GLM: 71080

Sierra Marine is known for producing premium aftermarket marine engine components engineered to deliver reliable performance and long service life. This rotor assembly is an essential replacement part for maintaining proper ignition function on MerCruiser stern drive applications.