A Guide to Replacing Spark Plugs on Your 1947 Oldsmobile E-47
Keep your classic Oldsmobile's engine running smoothly with the right set of new spark plugs.
- Champion brand copper spark plugs are a historically appropriate and reliable choice for your 1947 Oldsmobile's ignition system.
- Properly gapping new spark plugs to between .030 and .040 inches before installation is critical for engine performance.
- Key symptoms of failure include engine misfires, a rough idle, and difficulty starting the engine.
- Replacing spark plugs is a simple, low-cost DIY task that can be done with basic hand tools in under an hour.
Symptoms of Failing Spark Plugs
When spark plugs wear out, they can cause several noticeable problems. Because they are simple wear items, they require replacement as part of regular maintenance. If you experience any of these symptoms, it might be time for a new set of plugs.
- Engine Misfires: You may feel a stumble or hesitation from the engine, especially when you accelerate.
- Rough Idle: The engine might shake or run unevenly when the car is stopped.
- Hard Starting: The engine may take longer than usual to start, or it might crank without firing up.
- Reduced Fuel Economy: Worn plugs can lead to inefficient fuel combustion, causing you to use more gasoline.
Choosing the Right Aftermarket Spark Plug
For a vintage vehicle like the 1947 Oldsmobile E-47, you do not need to search for rare "New Old Stock" (NOS) or original equipment parts. Modern aftermarket spark plugs from a reputable manufacturer will provide excellent performance. Champion is a historically appropriate and dependable brand for this era of American automobile, known for its reliability.
Focus on the Basics
Your 1947 Oldsmobile does not require expensive platinum or iridium plugs. A standard copper plug, like the Champion Copper Plus, is the correct type for your vehicle's ignition system. These plugs offer excellent conductivity and heat control, which is ideal for vintage engines. The Champion J11C or RJ12C are common, suitable options.
Known Issues and Recalls
There are no active recalls or modern Technical Service Bulletins (TSBs) from the National Highway Traffic Safety Administration (NHTSA) for a 1947 vehicle. Any service information was published during the original manufacturing period and is not tracked by modern systems. Common issues of the era, such as plug fouling from rich carburetor settings or leaded fuel, are well-understood. Using a modern, quality spark plug and ensuring it is gapped correctly will prevent most problems.
Cost of New Aftermarket Spark Plugs (1947 Oldsmobile E-47)
| Part Type | Price Range (Per Plug) |
|---|---|
| Aftermarket Champion Spark Plug | $3.70 - $4.69 |
Frequently Asked Questions (FAQ)
What is the correct spark plug gap for a 1947 Oldsmobile E-47?
The recommended spark plug gap is typically between .030 and .040 inches for these engines. However, always consult a service manual for your specific engine if possible. It is critical to check and set the gap on new plugs with a gap tool before installation, as they may not be pre-gapped correctly for your vehicle.
How often should I change the spark plugs?
For a classic car with a standard ignition system, a good interval for spark plug inspection and replacement is every 10,00t0 to 15,000 miles or every two years. Since these vehicles are often driven less, time can degrade electrodes as much as mileage.
Do I need special tools to change the spark plugs?
You will need a standard ratchet, a spark plug socket (which has a rubber insert to protect the plug's porcelain), and an extension. You will also need a spark plug gap tool to ensure the gap is correct before installation. These are all common and inexpensive tools.
What does a fouled spark plug mean?
A fouled plug is one that has become coated with a substance like oil, fuel, or carbon. This coating can prevent the plug from sparking correctly. Sometimes, a non-fouler adapter can be used on engines that burn oil to help prevent the plug from becoming fouled.
Technical Specifications
Thread Size: 14mm; Reach: 0.375 inches; Hex Size: 13/16 inch or 0.813 inches. A standard copper core plug is recommended. The most critical specification is the gap, which should be set manually before installation.
We Have This Part in Stock
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.