Porsche 944 Spark Plug Guide (1983-1991): Choosing the Right Aftermarket Plugs
Get the right spark and avoid common issues with this guide to aftermarket spark plugs for your 1983-1991 Porsche 944.
- Bosch and NGK copper spark plugs are the most recommended and cost-effective choices for the 944.
- Always check and adjust the spark plug gap before installation; a common setting is 0.028 inches (0.7mm).
- While modern platinum and iridium plugs last longer, they may not offer any performance advantage in the 944's engine and are not worth the extra cost for most owners.
- Changing spark plugs is an easy DIY job on a 944 that can be done in under an hour with basic tools.
Symptoms of Failing Spark Plugs
Worn or faulty spark plugs can cause a range of noticeable problems in your Porsche 944. Because the ignition system is sensitive, even small issues with plugs can have a big impact.
- Rough Idle: The engine may shake or run unevenly when stopped. 🎬 See how to diagnose a rough idle and other engine issues.
- Engine Misfires: You might feel a hesitation or stumble during acceleration. This can be more noticeable under load, like going uphill.
- Reduced Power: The car may feel sluggish and less responsive than usual.
- Poor Fuel Economy: Failing plugs lead to inefficient combustion, meaning you'll use more gas.
- Hard Starting: The engine may crank longer than usual before it starts, or it might not start at all.
- Check Engine Light: A modern diagnostic tool might pick up misfire codes (e.g., P0300, P0301-P0304), though many 944s pre-date universal OBD-II standards.
Known Issues & Recalls
While there are no specific recalls or Technical Service Bulletins (TSBs) for spark plugs on the 1983-1991 Porsche 944, there have been recalls for related fuel system components that could create a fire risk near the plugs. For example, recall 90V061000 addressed a high-pressure fuel line hose that could harden and leak fuel, a dangerous situation in the engine bay. Always ensure your fuel lines are in good condition when servicing spark plugs.
🎬 Learn how to test and replace your spark plug cables too.Choosing the Right Aftermarket Spark Plug
For the Porsche 944, sticking to proven technology is often the best approach. While modern iridium and platinum plugs are available, many owners and specialists find that traditional copper plugs offer excellent performance, provided they are changed more frequently. Bosch was the original equipment (OEM) supplier for these cars.
Brand Tiers & Quality
Tier 1: OEM & Proven Performers
- Bosch: As the original supplier, Bosch copper plugs (like the WR7DC or WR8DC, depending on the specific year/model) are a safe and reliable choice. They are designed for the 944's ignition system and are highly recommended by many owners.
- NGK: NGK is another top choice, with many owners preferring them for their reliability and performance. Standard copper plugs like the BPR6ES are a popular, affordable, and effective option. Some owners report good results with NGK Iridium plugs, noting they last longer, but others feel they are an unnecessary expense for this engine.
Tier 2: Reputable Alternatives
- Denso: Denso plugs are well-regarded in the automotive world. Some 944 owners have had positive experiences, finding they perform well. They are a solid choice if Bosch or NGK are not available.
Tier 3: Budget Options
- Autolite / Champion: While these brands are major players in the spark plug market, they are less commonly discussed and recommended in Porsche 944 communities. They can work, but for a classic German engine, most owners stick with the German (Bosch) or Japanese (NGK, Denso) brands that have a proven track record with these vehicles.
A Note on Plug Materials
The main debate for the 944 is between traditional copper plugs and modern platinum or iridium plugs.
- Copper: Excellent conductivity, provides a strong spark. They are very affordable but have a shorter lifespan. Given how easy it is to change plugs on a 944, many owners prefer to use fresh copper plugs and change them often (every 15,000 miles or so).
- Platinum/Iridium: These are designed for longevity, often lasting 60,000 miles or more. However, some owners report that these expensive plugs offer no noticeable performance benefit in the 944's 1980s-era engine and ignition system. Some even report issues with platinum plugs causing problems. For most owners, standard copper plugs are the most cost-effective and reliable choice.
Cost Comparison
| Part Type | Price Range (Set of 4) | Notes |
|---|---|---|
| New Aftermarket (Copper) | $12 - $25 | Most common and recommended choice (Bosch, NGK). |
| New Aftermarket (Platinum/Iridium) | $35 - $70 | Longer life, but may not offer performance benefits for this car. |
| New OEM (Porsche Branded) | $50 - $95 | Essentially a rebranded Bosch or NGK plug at a higher price. |
Frequently Asked Questions (FAQ)
What spark plug gap is correct for a Porsche 944?
The correct spark plug gap can vary slightly by year and model (Base, S, S2, Turbo). However, a common specification is 0.028 inches (0.7mm). Some manuals allow for a tolerance up to 0.032 inches (0.8mm). Always check the factory recommendation for your specific model. Do not rely on the pre-gap from the box; always verify the gap with a feeler gauge before installation.
Is it hard to change the spark plugs on a 944?
No, it is a relatively easy job. The spark plugs are located on the top of the engine and are easily accessible between the intake runners on most models. It is a straightforward DIY task that requires basic tools like a spark plug socket and a ratchet.
🎬 Watch this step-by-step spark plug replacement walkthrough for the 944.Should I use anti-seize on the plug threads?
This is a topic of debate. Traditionally, a small amount of anti-seize was recommended for plugs going into an aluminum cylinder head like the 944's. However, modern plugs from brands like NGK often have a special plating that provides anti-seize properties, and they recommend against using additional lubricant. If you use anti-seize, be sure to reduce the tightening torque by about 15-20% to avoid over-tightening and damaging the cylinder head threads.
How often should I change the spark plugs?
Porsche's original recommendation was around every 30,000 miles. However, if you use standard copper plugs, many enthusiasts recommend changing them more frequently, such as every 15,000 miles or every two years, to keep the engine running at its best. It's an inexpensive way to ensure optimal performance.
Helpful Videos
Technical Specifications
OEM Part Numbers: 99917006290 99917015690
Thread Size: 14mm Hex Size: 13/16" (21mm) Seat Type: Gasket Common Gap: 0.028" (0.7mm) Recommended Plug Types: Bosch WR7DC/WR8DC, NGK BPR6ES
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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