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- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 993 (911) RS 1994-97
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
Flywheel Ring Gear – Hardened Steel (OEM 964.114.143.31). This precision-machined hardened steel ring gear features starter-pinion teeth pressed onto the outer edge of a single-mass “RS” or lightweight flywheel. It’s the critical interface between the starter motor and the engine — the starter’s small pinion engages these teeth to crank the engine during start-up.
Technical Summary
- Function: Transfers starter motor rotation to the flywheel for engine cranking.
- Location: Pressed or shrink-fitted onto the outer diameter of the flywheel.
- Construction: Heat-treated, hardened steel with precision-machined teeth for maximum strength and wear resistance.
- OEM Part Number: 964.114.143.31 (also listed as 96411414331).
- Applications: Designed for RS, single-mass, or lightweight flywheels used in various Porsche 964 and 993 models, and select 996/997 GT3 and GT2 variants. Not compatible with dual-mass flywheels.
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 993 (911) RS 1994-97
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 GT3 2007-09
Why You Should Replace Your Ring Gear
1. Damaged or Missing Teeth
Grinding, rough engagement, or failed starts often result from chipped, flattened, or missing teeth on the ring gear. When the teeth are damaged, the starter pinion can’t engage properly, leading to grinding or slipping during start-up.
2. Wear, Pitting, or Corrosion
Over time, surface wear, rust, or pitting can develop due to age or moisture exposure. These issues reduce engagement quality and increase wear on both the starter and ring gear.
3. Loose or Shifted Ring Gear
Although ring gears are press-fitted, heat cycles or improper installation can cause them to loosen or shift. A loose ring gear creates noise, accelerates wear, and poses a potential safety hazard.
4. During Flywheel or Clutch Service
Whenever the flywheel is removed for clutch replacement or resurfacing, it’s best practice to inspect the ring gear closely. Replace it if you find any damage or wear—it’s far cheaper than removing the transmission again later.
5. Starter or Pinion Replacement or Upgrades
If you’re installing a new or upgraded starter—or have had a starter failure that damaged the pinion—inspect and replace the ring gear at the same time to ensure proper engagement and reliable operation.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96411414331
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 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