Shim washer for alternator belt pulley 0.5mm. Porsche 911  ❭  9301065640Y

Shim washer for alternator belt pulley 0.5mm for Porsche 911 models, used to fine-tune alternator belt alignment and tension across classic 911 applications from 1965–1989.

What This Product Does
This 0.5mm shim washer sits between the alternator belt pulley halves to adjust pulley spacing, helping to achieve correct belt tension and alignment. Using the appropriate number of shims supports smooth belt operation and reduces the risk of premature belt wear.

Functions

• Spaces the alternator pulley halves to achieve correct belt tension
• Helps align the alternator belt with adjacent pulleys
• Allows fine tolerance adjustment in 0.5mm steps
• Contributes to stable alternator and cooling fan drive

Symptoms of Fault

• Squealing or chirping from the alternator belt area on start-up or under load
• Visible belt slack or difficulty setting correct belt tension
• Uneven belt wear or fraying at the pulley edges
• Traces of belt dust around the alternator and pulley
• Intermittent charging issues linked to belt slip
• Overheating risk on engines where the belt also drives the cooling fan

Why Replacement Matters
Alternator and fan belt systems on classic Porsche 911 models rely on a stack of correctly sized shims to set belt tension within specified tolerances. Missing, damaged, or incorrect shims can make precise adjustment difficult, leading to belt slip, noise, and accelerated wear. Replacing worn or lost shim washers when servicing the belt or pulleys helps restore proper alignment and tension control, supporting reliable charging and cooling operation on older 911 engines.

Fits

• Porsche 911 & 912 (1965–1989)
• Porsche 911 1974–1977 2.7L / 1976–1977 3.0 Carrera
• Porsche 911 1975–1977 3.0L Turbo (930)
• Porsche 911 1978–1983 3.0L SC
• Porsche 911 1984–1986 3.2L
• Porsche 911 1987–1989 3.2L G50

FAQs

• Q: How many shims should be used?
  A: Follow the Porsche workshop manual for your specific model. The total number of shims is usually fixed, with the split between in-use and parked shims determining belt tension.
• Q: Where are the spare shims stored?
  A: Typically, unused shims are kept under the pulley nut or outer pulley half so they remain available for future adjustment.
• Q: When should shims be renewed?
  A: Replace shims that are bent, corroded, damaged, or missing when changing the alternator belt or pulley components, to ensure accurate tolerance adjustment.

Support & Advice
Ensure you use the correct combination of shims to bring the belt tension within the recommended tolerances for your engine. Always confirm fitment against your vehicle details (model, year, engine) before installation.