The Porsche 911 SC, produced from 1978 to 1983, is a beloved classic that combines performance with relative mechanical simplicity. One of the key systems that keep this flat-six running smoothly is the ignition system, which relies on several components inside the distributor. If you're searching for "Porsche 911 SC distributor pick up coil advance auto parts," you're likely dealing with ignition issues or planning a preventative replacement. This article explains what these parts are, how they work together, common failure symptoms, and what to look for when buying replacements.
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Formula Auto Parts PUC9 Distributor Pick-Up Coil, black
Understanding the Distributor Pick Up Coil
The distributor pick up coil (also called a pulse generator or magnetic pickup) is a small electromagnetic device mounted inside the distributor. Its job is to sense the position of the crankshaft (via the distributor rotor) and send a signal to the ignition control unit. In the 911 SC, this signal triggers the ignition module to fire the coil, which then sends high voltage to the spark plugs. Without a functioning pick up coil, the engine won't start or will run poorly.
How the Pick Up Coil Works with the Advance Mechanism
The "advance" in your keyword refers to the ignition advance mechanism, which adjusts the timing of the spark based on engine RPM and load. On the 911 SC, this is handled by both mechanical (centrifugal) advance and vacuum advance. The mechanical advance uses weights and springs inside the distributor to rotate the base plate that the pick up coil is mounted on, advancing the timing as RPM increases. The vacuum advance adjusts timing based on manifold vacuum for better fuel economy and driveability. When the pick up coil or its related components fail, the entire ignition timing can be thrown off.
Why These Parts Are Critical for Your 911 SC
The Porsche 911 SC uses a breakerless (electronic) ignition system from the factory. This means there are no points to replace—the pick up coil and the ignition control unit replace the old mechanical contact breaker set. The system is more reliable than points, but components still wear out over time, especially the pick up coil, which can degrade due to heat and vibration. A failing pick up coil can cause symptoms like:
- Intermittent stalling or no-start conditions
- Misfires at various RPMs
- Rough idle
- Poor acceleration
- Backfiring through the intake or exhaust
- Check engine light (on later models) - though 911 SCs only have a basic diagnostic connector
If you experience any of these, the distributor pick up coil and advance mechanism should be high on your diagnostic list.
Choosing the Right Distributor Pick Up Coil and Advance Parts
When searching for "Porsche 911 SC distributor pick up coil advance auto parts," you have a few options. Original equipment (OE) parts are discontinued, but aftermarket manufacturers like Bosch, Beru, and OEM suppliers such as Porsche Classic offer replacements. Here's what to consider:
Original Equipment vs. Aftermarket
- OE/OEM parts: These are identical to the factory parts. For the 911 SC, the original Bosch system uses a specific pick up coil (Bosch part number 0 231 100 020 or similar). These are still available from Porsche Classic or specialty retailers.
- Aftermarket parts: Many brands produce direct replacements. They may be more affordable but vary in quality. Look for reputable ignition brands with proven track records in air-cooled Porsches.
What to Check When Buying
- Fitment: Ensure the pick up coil matches your 911 SC model year. Changes between early and late SC models are minimal, but confirm.
- Air gap: The gap between the pick up coil and the reluctor (the spoked metal wheel on the distributor shaft) should be set to factory specifications—typically around 0.3mm (0.012 inches). Some replacement coils come with a spacer to help adjust.
- Wiring harness condition: Often the wires leading from the pick up coil to the ignition module become brittle. Consider replacing the entire ignition harness if needed.
- Ignition control unit: The pick up coil works hand-in-hand with the ignition control module. If you're replacing the coil, consider testing the module or replacing it if the symptoms suggest both could be failing.
- Distributor cap and rotor: While you're in there, replace the cap, rotor, and spark plug wires as well. This ensures the entire ignition system is refreshed.
Advance Mechanism Parts
The advance mechanism is also part of the distributor kit. If your timing is not advancing properly, you may need new centrifugal weights, springs, or vacuum advance diaphragm. These are often sold as part of a distributor rebuild kit. A common upgrade is to install a vacuum advance unit with adjustable stops (like those from 123ignition or aftermarket sources) to fine-tune the advance curve.
Step-by-Step Inspection and Replacement Tips
If you're comfortable working on your 911 SC, here's a general procedure. Always consult your factory workshop manual for exact specs.
Testing the Pick Up Coil
- Disconnect the wires from the pick up coil to the ignition module.
- Set a multimeter to measure resistance (ohms).
- Measure across the two terminals of the pick up coil. The resistance should be between 600 and 1200 ohms (check your manual for exact value). If open or shorted, replace.
- Check for shorts to ground: one lead to a coil terminal, the other to a good ground. Should show infinite resistance. If not, the wire or coil is shorted.
Inspecting the Advance Mechanism
- Remove the distributor cap and rotor.
- Grab the rotor and try to rotate it against spring tension. It should return to a stop when released.
- Look for any stuck or broken springs inside the distributor. Clean any dirt or corrosion.
- For vacuum advance, apply vacuum to the diaphragm canister. The base plate should move and hold vacuum. Leaks mean replacement.
Replacement Process (Overview)
- Mark distributor position and remove the distributor if desired (or work in place).
- Remove the rotor, then the small screws holding the pick up coil.
- Disconnect wires and remove the old coil.
- Install the new coil, ensuring proper air gap. Tighten screws firmly but not overtight.
- Reinstall rotor and cap, set timing to factory specs (typically 25-28 degrees BTDC at idle with vacuum hose disconnected).
- Test drive and verify no pinging and smooth idle.
Common Pitfalls to Avoid
- Not checking the ignition control module: A failing module can mimic a bad pick up coil. If the coil tests good but problems persist, the module may be at fault.
- Using generic parts: Some universal pick up coils do not fit correctly or produce the wrong signal. Stick to parts specifically for 911 SC.
- Ignoring the air gap: Too large a gap leads to weak signal, too small can rub and fail prematurely.
- Overlooking wiring: The wires from the distributor to the module are known to become brittle and break internally. Replace them if any doubt.
Recommendations
For most 911 SC owners, the best approach is to replace the distributor pick up coil with an OEM-quality unit from Bosch or Porsche Classic. These parts are proven to last another 30+ years. If you also need advance components, consider a distributor rebuild kit that includes the advance springs, weights, and vacuum can. Brands like 123ignition offer modern electronic distributors that replace the entire assembly, but they require careful setup and may alter the car's character.
If you are chasing an ignition fault, always start with the simplest checks: spark plugs, wires, cap and rotor, then move to the pick up coil and ignition module. Keep the air gap specification and timing spec hand-printed on a card in your glovebox.
Ultimately, investing in a quality pick up coil and advance parts for your Porsche 911 SC ensures reliable performance and preserves the driveability that makes these cars so enjoyable. Whether you're restoring a garage queen or daily-driving a survivor, these components are essential to keeping the flat-six firing correctly for miles to come.