Porsche 356 Generator Parts: A Complete Guide to Sourcing and Rebuilding

The Porsche 356’s electrical system relies on a generator, not an alternator. While reliable when new, these generators eventually need attention. Whether you’re restoring a 356 or keeping one running, understanding the specific generator parts available today is essential. This guide covers the main components, common upgrade paths, and how to choose parts that match your driving style and restoration goals.

Original Generator vs. Alternator Conversion

One of the first decisions you’ll face is whether to stick with a stock generator or convert to an internally regulated alternator. Each approach has trade-offs.

Benefits of Keeping the Original Generator

• Authenticity: Shows, concours, and purists prefer the original 6-volt or 12-volt generator.
• Simplicity: Fewer wiring changes needed if you stay with the stock voltage.
• Availability of NOS parts: You can still find NOS (New Old Stock) armatures, field coils, and voltage regulators.

Why Consider an Alternator Conversion

• Better charging at idle: Alternators produce more current at low RPM.
• Higher output: Supports modern accessories like electric fans, stereos, or better lighting.
• Internal regulator: Eliminates the problematic external voltage regulator. Conversion kits are available from several specialty suppliers. Most retain the original generator housing so the exterior looks stock, but the internals are replaced with a modern alternator rotor and stator. If you drive your car often, this is a practical upgrade.

Key Generator Parts and What to Look For

When rebuilding or buying a generator, you’ll encounter these main components:

Armature

• The rotating core that windings wrap around.
• Look for pitted commutator bars or worn bearings. NOS armatures are available but verify correct part numbers for your year (Pre-A, A, B, or C).
• 6-volt and 12-volt armatures are different; 12-volt windings are finer and more numerous.

Field Coils

• Stationary electromagnets that create the magnetic field.
• Can be rewound or replaced. Binding and shorted windings are common after 60+ years.
• Replacement field coils are sold as sets; ensure polarity matches your grounding (positive or negative).

Voltage Regulator

• External electromechanical unit on the generator housing.
• Early 356s used a two-brush setup; later models used three brushes.
• Solid-state replacements are available that fit inside the original regulator case for a stock look but better reliability.
• Avoid cheap generic regulators; they often have incorrect cut-in voltages.

Bearings and Bushings

• The generator has two bearings: a bushing at the rear and a ball bearing at the front (under the fan).
• Upgrade to high-quality sealed bearings for longer life.
• Replace the felt oil wick if you stick with the original bushing.

Brushes and Springs

• Wear items that should be replaced during any rebuild.
• Use original-spec carbon brushes (not copper). Proper spring tension ensures consistent contact.

Fan and Pulley

• The fan is specific to the generator. If you convert to an alternator, you may need a different fan or adapter.
• Pulley ratios affect charging RPM. Stock pulleys are fine for normal use.

Sourcing Quality Parts

Where you buy matters because low-quality parts can cause electrical fires or premature failure.

Specialty Porsche Parts Suppliers

• Companies like Stoddard, Pelican Parts, and 356 Performance offer NOS or reproduction parts.
• Many suppliers have been in business for decades and know the nuances between 356 years.
• Ask whether the part is made in Germany or elsewhere – German-made parts often fit better.

Rebuilt Generators

• Some rebuilders take your core and return a fully rebuilt unit with upgraded bearings and modern insulation.
• This is often the best route if you want original looks with improved reliability.
• Expect a lead time of 2-4 weeks because they are bench built.

Swap Meets and Online Forums

• The 356 Registry classifieds, early 911S Registry, and Porsche-specific Facebook groups can yield NOS parts.
• Be cautious: seller reputation matters. Ask for photos of armature commutator condition and resistance readings.

Step-by-Step Rebuilding Tips

If you plan to rebuild your own generator, follow these practical steps:

1. Disassemble carefully: Take photos or mark the housing orientation. The fan nut is left-hand thread.
2. Test field coils: Use a multimeter for resistance and insulation to ground. Anything below 0.5 megohm indicates shorted coils.
3. Turn the commutator: If grooved, lightly turn it on a lathe (0.005-0.010 inch removal) and undercut the mica. Use a hacksaw blade ground to width.
4. Replace bearings: Knock out old ones with a drift. Press in new bearings (do not hammer directly).
5. Adjust voltage regulator: For 6-volt systems, target 7.2-7.5 volts at 2000 RPM. For 12-volt, 14.0-14.5 volts.

Final Recommendation

For a show car or occasional driver that stays stock, rebuild your original generator with NOS or reproduction parts from a trusted Porsche specialist. Use a solid-state voltage regulator hidden inside the stock case for reliability. For a driver that sees daily use or long trips, a quality alternator conversion kit (like those from 356 Performance) is the smarter choice. It keeps the stock appearance externally while providing modern charging performance. Whichever path you take, avoid cheap generic parts – the 356 electrical system is finicky, and a few extra dollars for quality components saves headaches later.

Invest time in proper setup: verify polarity, check belt tension, and test output before reinstalling. With the right parts and careful work, your 356’s generator will provide trouble-free service for many more miles.