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Clutch Ring Gear
- Porsche 911 1978-1989 3.3L Turbo (930)
Teeth: 135 / Diameter: 225mm

Fits:
Porsche 911 Turbo (930) 3.3L 1978-89
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011623003
The product you are viewing cross references to these numbers
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1975-1977 3.0L Turbo (930)
Flywheel Ring Gear
Restore dependable engine starting performance with this OE
Match Flywheel Ring Gear, designed for Porsche 911 models produced between 1970 and 1986. The flywheel
ring gear is a critical component of the engine starting system, providing the
engagement surface for the starter motor and allowing the engine to crank
reliably every time the ignition is activated.
Fits:
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1975-1977 3.0L Turbo (930)
Manufactured to OE specifications, this replacement ring gear delivers the correct tooth profile, fitment and durability required for classic air-cooled Porsche applications. Whether you're rebuilding an engine, replacing a worn flywheel component or restoring a classic 911, fitting a new flywheel ring gear helps ensure smooth starter operation and long-term reliability.
What Does the Flywheel Ring Gear Do?
The flywheel ring gear is a hardened steel gear mounted around the outer circumference of the flywheel. Its primary purpose is to engage with the starter motor pinion gear during engine start-up.
When the ignition key is turned, the starter motor extends its pinion gear into the teeth of the flywheel ring gear. The starter then rotates the flywheel, turning the engine over until combustion begins and the engine starts.
The flywheel ring gear plays a vital role by:
- Providing a durable engagement surface for the starter motor.
- Allowing the engine to crank during start-up.
- Ensuring smooth and reliable starter operation.
- Transferring rotational force from the starter motor to the crankshaft.
- Supporting consistent engine starting performance.
Without a properly functioning ring gear, starter engagement can become unreliable or impossible.
Why Do Flywheel Ring Gears Fail?
Although manufactured from hardened steel, flywheel ring gears experience repeated mechanical loading every time the vehicle is started. Over decades of service, wear and damage can occur.
Common causes of failure include:
- Tooth wear caused by repeated starter engagement.
- Damaged or chipped gear teeth.
- Starter motor misalignment.
- Worn starter pinion gears damaging the ring gear.
- Excessive heat generated during clutch or flywheel issues.
- Corrosion caused by moisture contamination.
- General wear associated with high mileage and age.
On classic Porsche 911 models, decades of repeated engine starts can eventually lead to worn sections of the ring gear, particularly in the areas where the engine most commonly stops after shutdown.
When Should the Flywheel Ring Gear Be Replaced?
The flywheel ring gear should be inspected whenever the
engine, clutch or flywheel assembly is removed. Replacement is recommended if
you observe:
Chipped,
broken or heavily worn teeth.
Replacing a worn ring gear while the transmission or engine is already removed can prevent future starting problems and reduce labour costs.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91111623904
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)
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.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011623003
The product you are viewing cross references to these numbers
- Porsche 911 1987-1989 3.2L G50
- Porsche 964 (911) C4 1989-93
The OE Match Ring Gear is a high-quality replacement drivetrain component designed to work as part of the engine starting system. Manufactured to OE specifications for fit, strength and durability, the ring gear is mounted to the flywheel or flexplate and provides the engagement surface for the starter motor pinion gear during engine start-up.
Fits:
- Porsche 911 1987-1989 3.2L G50
- Porsche 964 (911) C4 1989-93
Precision-machined from hardened steel, the ring gear is engineered to withstand repeated engagement loads and high torque forces generated during engine cranking. Accurate tooth geometry ensures smooth starter engagement, reliable engine starting and long service life under demanding operating conditions.
What This Product Does:
- Provides the engagement surface for the starter motor pinion gear.
- Transfers rotational force from the starter motor to the engine.
- Enables reliable engine cranking and starting.
- Works in conjunction with the flywheel or flexplate assembly.
- Ensures smooth engagement during start-up.
- Supports consistent operation of the starting system.
- Contributes to dependable vehicle reliability.
Symptoms Of Wear Or Failure:
- Grinding noises during engine starting.
- Starter motor spinning without turning the engine.
- Intermittent starting problems.
- Clicking noises during starter engagement.
- Starter motor slipping during cranking.
- Visible chipped, worn or missing teeth on inspection.
- Engine only starting when stopped in certain positions.
- Premature wear of the starter motor pinion gear.
Why Replacement Matters:
- The ring gear is subjected to repeated high-torque engagement every time the engine is started. Over time, the teeth can become worn, chipped, rounded or damaged, particularly in vehicles with high mileage or faulty starter motors. Excessive wear can prevent the starter pinion from engaging correctly, resulting in unreliable starting performance.
- A damaged ring gear can place additional strain on the starter motor, accelerating wear of both components and potentially leading to complete starting system failure. If left unresolved, the vehicle may become difficult or impossible to start, resulting in inconvenience and costly repairs.
- Replacing a worn ring gear restores proper starter engagement, improves starting reliability and helps protect the starter motor from unnecessary wear. An OE Match replacement provides factory-style fitment, precision machining and long-term durability, ensuring dependable starting performance and preserving the reliability of your Porsche.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
95011614305
The product you are viewing cross references to these numbers
- Porsche 911 1975-1977 3.0L Turbo (930)

Fits:
Porsche 930 3.0L Turbo 1975-77
Click 'Zoom in' for large parts diagram.
Fits to nr 3 on diagram.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011623004
The product you are viewing cross references to these numbers
- Porsche 911 1975-1977 3.0L Turbo (930)

Fits:
Porsche 930 3.0L Turbo 1975-77
Click 'Zoom in' for large parts diagram.
Fits to nr 3 on diagram.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011623004
The product you are viewing cross references to these numbers
Porsche Ring Gears | Precision-Engineered for Reliable Engine Starts
The ring gear is a crucial component of your Porsche’s flywheel assembly. It provides the toothed surface that engages with the starter motor pinion to crank the engine during startup. A precisely machined and properly fitted ring gear ensures smooth, reliable engine starts and efficient power transfer between the starter and flywheel.
At Design911, we supply high-quality ring gears designed to meet or exceed the original design standards. Manufactured from hardened steel and heat-treated for superior durability, each ring gear is engineered for perfect alignment, smooth engagement, and long-lasting performance under the most demanding conditions.
Whether you’re replacing a worn or damaged gear or rebuilding a flywheel assembly, our Porsche ring gears guarantee accuracy, reliability, and consistent performance across all Porsche models.
What Do Ring Gears Do?
The ring gear forms an integral part of the flywheel or flexplate and works directly with the starter motor to initiate engine rotation.
Core Functions:
- Provides a precision-toothed surface for the starter motor pinion.
- Enables smooth and consistent engine cranking.
- Maintains correct rotational balance in the flywheel assembly.
- Ensures long-term reliability of the starting system.
Without a properly functioning ring gear, the starter motor may struggle to engage, producing grinding noises or failing to turn the engine over — leading to hard starting or complete failure to start.
Why Do Ring Gears Fail or Wear
Out?
Ring gears operate under high rotational speeds and repeated
impact stress from the starter motor, making them prone to wear and fatigue
over time.
Common Causes of Failure Include:
- Worn or chipped teeth from repeated starter engagement.
- Misalignment between the starter pinion and ring gear.
- Heat damage or warping caused by excessive friction.
- Corrosion from oil leaks or moisture exposure.
- Manufacturing stress or improper installation leading to cracks.
Once the teeth become worn or damaged, the starter motor can no longer engage properly — resulting in grinding noises, intermittent starting, or complete engine start failure.
Why Replace Your Porsche Ring Gear?
Replacing a damaged or worn ring gear ensures smooth, reliable engine starts and prevents costly damage to the starter motor and flywheel. A new, precision-machined ring gear restores proper alignment and engagement, guaranteeing dependable performance with every start.
Key Benefits:
- Restores reliable engine starting and power transfer.
- Prevents starter motor slippage or grinding noise.
- Reduces vibration and wear on the flywheel assembly.
- Engineered from hardened, heat-treated steel for longevity.
- Ensures perfect fitment and balance for Porsche engines.
- Suitable for standard maintenance or performance rebuilds.
It’s strongly recommended to replace the ring gear during clutch or flywheel servicing to ensure full compatibility and long-term reliability.
Highlights
- Precision-engineered Porsche ring gears for reliable starting.
- Manufactured from high-strength, heat-treated steel.
- Designed for exact fitment and rotational balance.
- Ideal for Porsche 911, Cayman, Boxster, and classic models.
- Prevents starter motor damage and engagement issues.
- Suitable for restoration, maintenance, and performance rebuilds.