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Belts / Tensioners / Rollers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- 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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 1969-73
Porsche 911SC 1974-83
Porsche 911 Turbo 1975-77
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90019202750
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- 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 1975-1977 3.0L Turbo (930)

Fits:
Porsche 911 1969-73
Porsche 911SC 1974-83
Porsche 911 Turbo 1975-77
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90019202750
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- 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 1975-1977 3.0L Turbo (930)

Fits:
Porsche 911 Turbo 1984-89
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919225550
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 Turbo 1984-89
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919225550
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 Turbo 1978-83
Porsche 928 1978-89 *
*Cars upto 1989
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919230550
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92

Fits:
Porsche 911 Turbo 1978-83
Porsche 928 1978-89 *
*Cars upto 1989
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919230550
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92

Fits:
Porsche 911 Turbo 1978-83
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919217350
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 Turbo 1978-83
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919217350
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)
Fits:
Porsche 911 Turbo 1978-83
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919217350
The product you are viewing cross references to these numbers
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 Carrera 1984-1989
Click 'Zoom in' for large parts diagram.
Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919225450
The product you are viewing cross references to these numbers
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50

Fits:
Porsche 911 Carrera 1984-1989
Click 'Zoom in' for large parts diagram.
Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919225450
The product you are viewing cross references to these numbers
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50

Fits:
Porsche 911 3.2L 1978-89
Click 'Zoom in' for large parts diagram.
Diagram Ref No 35.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90019200550
The product you are viewing cross references to these numbers
- 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 1987-1989 3.2L G50

Fits:
Porsche 911 3.2L 1978-89
Click 'Zoom in' for large parts diagram.
Diagram Ref No 35.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90019200550
The product you are viewing cross references to these numbers
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
Belt size: 10 x 710

Fits:
Porsche 911 1965-73
Porsche 911 Turbo 1976 >>
Porsche 911 SC 1974-79 (Check Size of your Belt)
Porsche 911 SC 1980-83
Porsche 911 3.2L 1984-89
Porsche 914 1970-76
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9991921765A
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- 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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
The Genuine Porsche 99919209750 alternator belt is an OE V-belt for selected Porsche 911 1974–1979 models. It drives the alternator and cooling fan, helping maintain battery charging and essential air-cooled engine cooling. Ideal for routine servicing or replacing a cracked, slipping, noisy or worn original belt.
Fits:
Porsche 911 Turbo/SC 1974 - 1979 (Please choose by size)
Diagram ref no 12
This belt is used on selected classic Porsche 911 models and fits the alternator / cooling fan pulley system.
What This Part Does / Functions
• Drives the alternator from the engine pulley system
• Helps keep the battery charged while the engine is running
• Drives the engine cooling fan on air-cooled Porsche 911 models
• Supports correct engine cooling airflow
• Helps maintain stable electrical system performance
• Provides correct OE Porsche belt fitment for the listed pulley setup
• Replaces a worn, cracked, stretched, glazed or noisy belt
• Helps prevent belt slip, squeal and charging/cooling issues.
Why Replace This Part?
The alternator belt is a critical service item on air-cooled Porsche 911 models because it drives both the alternator and the cooling fan. Over time, the belt can crack, glaze, stretch, fray or lose grip on the pulleys. A worn or slipping belt can cause charging problems and may reduce cooling fan speed, which can lead to engine temperature concerns. Replacing the belt with a Genuine Porsche OE alternator belt helps restore correct belt drive, reliable battery charging and proper cooling fan operation.
When to Replace This Part
• If the belt is cracked, glazed, frayed or visibly worn
• If the belt squeals or slips during engine operation
• If the battery or charging warning light appears
• If the belt tension can no longer be set correctly
• During scheduled service or preventative maintenance
• When replacing alternator, fan pulley, shims or related belt-drive hardware
• If the belt has been contaminated by oil, fuel or debris
• When recommissioning a stored classic Porsche 911.
Where It Fits on the Car
This belt fits on the rear engine alternator / cooling fan pulley system. It runs between the crankshaft pulley and the fan/alternator pulley assembly, driving the alternator and cooling fan.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919209750
The product you are viewing cross references to these numbers
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
This OE Match alternator belt is a replacement engine drive belt for Porsche 911 models from 1974 to 1979. It is designed to match the original-style fitment and function. This replacement drive belt helps power the alternator and cooling fan assembly, supporting reliable battery charging and engine cooling system operation.
Fits:
Porsche 911 Turbo/SC 1974 - 1979 (Please choose by size)
Diagram ref no 12
The alternator belt transfers rotational drive from the engine pulley to the alternator and fan assembly. This allows the alternator to generate electrical power for the vehicle while also helping drive the engine cooling fan. A correctly fitted and tensioned belt is essential for reliable charging, cooling airflow, and overall engine operation.
Functions
• Replaces the alternator drive belt
• Drives the alternator and cooling fan assembly
• Supports correct battery charging
• Helps maintain air-cooled engine cooling airflow
• Replaces cracked, glazed, stretched, frayed, noisy, or slipping belts
• Suitable for routine servicing and preventative maintenance
• OE Match replacement for classic Porsche 911 engine service.
Why Replace This Part?
Alternator belts wear over time due to heat, engine vibration, pulley contact, age, and tension changes. A worn belt can crack, glaze, stretch, fray, squeal, slip, or fail completely. If the belt fails, the alternator may stop charging and the cooling fan may stop operating correctly, which can lead to warning lights, battery issues, overheating risk, or vehicle breakdown. Replacing the belt helps maintain dependable charging and cooling system performance.
When to Replace This Part
• The alternator belt is cracked, glazed, frayed, loose, or worn
• Belt squeal or chirping is heard during start-up or acceleration
• The battery warning light appears
• Charging system output is low or inconsistent
• Cooling fan drive is being inspected or serviced
• Alternator, fan, pulleys, or related hardware are being repaired
• Preventative belt replacement is being carried out during scheduled maintenance.
Where it fits on the car
This belt fits on the alternator and cooling fan drive system on Porsche 911 models from 1974 to 1979. It runs between the relevant engine pulley and alternator / fan pulley according to the factory belt routing.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99919209750
The product you are viewing cross references to these numbers
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
-
air cooling 911 1978-83 105-00
-
air injection 911 SC 1978-83 108-00
-
air cooling 911 1970-73 105-00
-
YORK compressor mounting and driving mechanism 911 1978-83 813-30
-
NIPPONDENSO compressor mounting and driving mechanism 911 TURBO 1978-83 813-35
-
air cooling 911 1987-89 105-00
-
air injection 911 CARRERA 930.26 1987-89 108-00
-
accessories 911 1978-83 001-00
-
air cooling 911 1984-86 105-00
-
Air injection 911 CARRERA 930.26 (AUS) (CH) (S) 1984-86 108-00
-
compressor mounting driving mechanism 911 1987-89 813-20
-
Tool, jack, stickers 911 1984-86 001-00
-
tool, jack 911 1987-89 001-00
-
Compressor mounting and driving mechanism 911 1984-86 813-20
-
Air conditioner mount for compressor not for (USA) 911 1970-73 813-60
-
Air Cooling 911 1974-77 105-00
-
Air conditioner, compressor driving mechanism mounting 911 1974-77 813-45
-
air cooling 911 1965-69 105-00
-
mount compressor 911 E/S/T 1969 onwards 813-85
-
air cooling 911 TURBO 1975-77 105-00
-
air conditioner, compressor, driving mechanism, mounting 911 TURBO 1975-77 813-45
Engine Rebuild Belts, Tensioners & Rollers – Precision Timing for Reliable Porsche Performance
Engine rebuild belts, tensioners, and rollers are essential components in maintaining your Porsche’s precise engine timing and smooth operation. These parts work together to synchronise the camshaft and crankshaft, ensuring valves open and close at exactly the right time for optimal combustion. Over time, these components can wear or deteriorate, especially under high performance or extended use, making replacement vital during an engine rebuild or major service.
At Design911, we supply a full range of genuine and high-quality belts, tensioners, and rollers for various Porsche models including, 911, Boxster, Cayman, Cayenne, Macan, and Panamera models. Each component is designed for strength, accuracy, and long-lasting reliability — ensuring your rebuilt Porsche engine performs flawlessly mile after mile.
What Do Engine Belts, Tensioners & Rollers Do?
These components form the heart of the engine’s timing and
auxiliary systems. They:
- Drive
key engine components, including the camshaft, alternator, and water
pump.
- Maintain
accurate timing for optimal combustion and efficiency.
- Reduce
friction and noise through smooth roller and tensioner operation.
- Ensure consistent belt tension to prevent slippage or premature wear.
Together, they guarantee your Porsche’s engine runs smoothly, efficiently, and reliably — whether cruising or driving at peak performance.
Why Do Belts, Tensioners & Rollers Fail?
Exposure to high temperatures, vibration, and constant
motion causes natural wear over time. Common causes of failure include:
- Aging
rubber belts becoming brittle or cracked.
- Worn
bearings in rollers or tensioners leading to noise or vibration.
- Loss
of tension causing belt slippage or timing misalignment.
- Contamination
from oil or coolant degrading materials.
- Extended maintenance intervals leading to unexpected failure.
Symptoms of failing components include squealing noises, poor engine performance, rough idle, or even timing belt failure, which can cause severe engine damage if ignored.
Why Replace Belts, Tensioners & Rollers During an Engine Rebuild?
Replacing these components during an engine rebuild ensures long-term reliability and eliminates the risk of future timing-related failures. A fresh set of belts, rollers, and tensioners restores precision, efficiency, and performance — protecting your investment.
Benefits of replacement include:
- Restored precise timing and smooth operation.
- Reduced risk of catastrophic engine failure.
- Enhanced reliability and longevity of the rebuild.
- Quieter, more efficient engine performance.
All components available from Design911 are made using premium-grade materials, precision bearings, and advanced heat-resistant compounds, ensuring maximum durability and performance in high-stress Porsche engines.