Flywheel ring gear. Porsche 930 1978-89  ❭  93011623003

Flywheel Ring Gear 

Restore dependable starting performance to your classic Porsche 911 Turbo with this OE Match Flywheel Ring Gear. Designed for Porsche 911 turbo (930) models produced between 1978 and 1989, this precision-engineered ring gear provides the critical interface between the starter motor and flywheel, ensuring reliable engine cranking and smooth engagement during every start-up.

Fits:

• Porsche 911 1978-1989 3.3L Turbo (930)       

Manufactured to OE specifications, this replacement ring gear is engineered to deliver exceptional durability and precise fitment for the demanding requirements of the turbocharged air-cooled flat-six engine. Whether you're rebuilding a transmission, replacing a worn flywheel component or carrying out a full engine restoration, this OE Match ring gear helps maintain reliable starting performance and long-term drivetrain integrity.

Technical Specifications

• Number of Teeth: 135
• Internal Diameter: 230mm
• External Diameter: 280mm

Quality Precision Machined Gear Teeth for Correct Starter Engagement

What Does the Flywheel Ring Gear Do?

The flywheel ring gear is mounted around the outer edge of the flywheel and serves as the engagement point for the starter motor pinion gear.

When the ignition is activated, the starter motor extends its pinion gear into the teeth of the flywheel ring gear. The starter then rotates the flywheel, which in turn rotates the crankshaft and starts the engine.

The flywheel ring gear performs several essential functions:

• Transfers rotational force from the starter motor to the engine.
• Allows the engine to crank during start-up.
• Provides precise engagement with the starter pinion gear.
• Supports smooth and reliable engine starting.
• Helps prevent starter slippage and gear damage.

On the turbocharged Porsche 930, where higher compression and engine loads place greater demands on the starting system, proper ring gear condition is especially important.

Why Do Flywheel Ring Gears Fail?

Although manufactured from hardened steel, flywheel ring gears endure repeated mechanical stress throughout their service life. Every engine start places load on the gear teeth, eventually leading to wear and damage.

Common causes of flywheel ring gear failure include:

• Tooth wear from repeated starter engagement.
• Chipped, cracked or broken gear teeth.
• Worn starter motor pinion gears.
• Starter motor misalignment.
• Corrosion caused by moisture exposure.
• Excessive heat from clutch or flywheel issues.
• High mileage and decades of use.

Many Porsche 930 models have now accumulated decades of service, making flywheel and starter system inspections increasingly important during restoration and maintenance work.

When Should the Flywheel Ring Gear Be Replaced?

The ring gear should be inspected whenever the clutch, transmission or engine assembly is removed. Replacement is recommended if any of the following are found:

• Worn or rounded gear teeth.
• Broken or chipped teeth.
• Starter grinding noises.
• Intermittent starter engagement.
• Difficulty cranking the engine.
• Visible corrosion or physical damage.
• Excessive wear concentrated in specific areas of the gear.

Because replacement requires flywheel removal, many specialists recommend fitting a new ring gear during clutch replacement or major drivetrain refurbishment when access is readily available.

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93011623003

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