A Comprehensive Guide to the 1956-1957 Lincoln Mark II Spark Plug Wire Set
Keep your classic Mark II's 368 V8 running strong by understanding how to choose the right new spark plug wires.
- All new wire sets are aftermarket; focus on quality brands like Standard Motor Products for reliability or reproduction sets for a period-correct look.
- Replacing wires one at a time is the most critical step to avoid mixing up the engine's firing order.
- Symptoms like rough idle, misfiring, and difficulty starting are strong indicators that your wires need replacement.
- This is a simple and effective DIY tune-up job that requires no special tools and can be completed in about an hour.
Symptoms of a Failing Spark Plug Wire Set
Old or damaged spark plug wires can cause noticeable problems with your Lincoln's performance. Because the original wires are now over 60 years old, replacement is a common maintenance item. If you experience any of these symptoms, your spark plug wires are a likely culprit.
- Rough Idle: The engine may shake or run unevenly when the car is stopped.
- Engine Misfires: You might feel a stumble or hesitation from the engine, especially when accelerating.
- Difficulty Starting: A weak spark from old wires can make the engine harder to turn over, particularly in cold or damp weather.
- Reduced Power and Poor Acceleration: Your Mark II may feel sluggish and less responsive than it should.
- Radio Static: Old, unsuppressed wires can create electrical interference, causing static or a whining noise through your AM radio.
Choosing the Right Aftermarket Wire Set
For a classic vehicle like the Mark II, you won't find new OEM parts from Lincoln. All available new wire sets are aftermarket, but they come in different styles and quality levels.
OEM-Style vs. Modern Wires
OEM-Style Reproduction Wires: For owners seeking a factory-correct look, reproduction wires are available. These are often made to look like the original Packard wires, sometimes with correct lettering. They typically use a 7mm diameter wire. While perfect for show cars, their core technology might be older. A high-quality reproduction set can cost $150 or more.
Modern Replacement Wires: Most aftermarket sets are modern, universal-fit, or direct-fit replacements. Brands like Standard Motor Products offer reliable, quality wire sets that are a good choice for most drivers. These wires often feature a modern spiral or carbon core for excellent radio frequency interference (RFI) suppression and a durable silicone jacket that resists heat and oil better than original materials. They may come in 7mm or slightly larger 8mm diameters, both of which work well.
Aftermarket Brand & Cost Comparison
| Brand Tier | Example Brands | Price Range | Best For |
|---|---|---|---|
| Standard Replacement | Standard Motor Products | $33.50 - $65.00 | Daily drivers and general use. Offers reliable performance and good value. |
| OEM-Style / Restoration | Lectric Limited, various restoration suppliers | $90.00 - $155.00+ | Show cars and owners wanting a period-correct engine bay appearance. |
| Performance | ACCEL, Mallory, MSD | $70.00 - $120.00 | Modified engines or owners wanting higher-performance materials like spiral cores and thicker jackets. |
Known Issues, Recalls, or TSBs
There are no active recalls or Technical Service Bulletins (TSBs) from the NHTSA related to the spark plug wires for the 1956-1957 Lincoln Mark II. Any issues today are related to the age and wear of the components, not a manufacturing defect. The most common problem reported by owners is misfiring due to arcing from old, cracked wire insulation.
Frequently Asked Questions (FAQ)
Do I need special tools to replace the spark plug wires?
No special tools are required. A good set of pliers for gripping the boots can be helpful, but often you can remove and install them by hand. It's important to twist the boot to break the seal before pulling it off the spark plug or distributor cap. Applying a small amount of dielectric grease inside the new boots can make installation easier and prevent them from getting stuck in the future.
Should I replace the wires one at a time?
Yes. This is the most important tip for a successful DIY replacement. Replace one wire at a time, matching the length of the old wire to a new one from the set. This prevents mixing up the firing order, which would cause the engine to run poorly or not at all.
What is the difference between 7mm and 8mm wires?
The measurement refers to the diameter of the wire's outer jacket. Both 7mm and 8mm wires will work on a Mark II. An 8mm wire has slightly thicker insulation, which can offer a little more protection against heat and electrical arcing, but a quality 7mm wire is perfectly adequate for a stock engine.
What are "suppression" wires and do I need them?
Suppression wires are designed to reduce Radio Frequency Interference (RFI). This interference can cause static or buzzing in your radio. Modern wires from brands like Standard Motor Products use a carbon or spiral core that provides this suppression. If you enjoy listening to the radio, a modern suppression wire set is a good choice.
Technical Specifications
OEM Part Numbers: FDU-12259-A
Engine: 368 cu in (6.0L) V8. Wire Diameter: 7mm (original) or 8mm/8.5mm (modern replacements). Core Type: Modern sets typically use a carbon or spiral core for RFI suppression. Boot Type: Straight boots for both spark plug and distributor ends.
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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.