Go-Parts
Cart 0
Your cart is empty
Add an item to see it appear here.
Wrenchy
Go-Parts Garage
Expert guides for diagnosing, troubleshooting, and replacing auto parts Expert guides for diagnosing and replacing auto parts
Browse All →
🎬 Helpful Videos 🛍️ Shop This Part

Spark Plug Guide for the 1949 Nash 600 Super Special

Keep your classic Nash running strong with the right set of new spark plugs.

3 minutes to read 1949-1949 Nash 600 Super Special
Difficulty
1/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$50-$100
⚠️ Drivable, but... — You can drive with failing plugs, but you will experience poor performance and could cause unburned fuel to enter the exhaust.
Key Takeaways
  • Only use standard copper-core spark plugs from a brand like Champion for your Nash 600.
  • Do not use modern platinum or iridium plugs, as they are not compatible with the vintage ignition system.
  • Always check and set the spark plug gap (around 0.025 inches) before installation.
  • Replacing spark plugs is a simple and very affordable DIY task that can greatly improve engine performance.
The spark plug is a key part of your Nash 600's ignition system. It takes high-voltage electricity from the ignition coil and creates a perfectly timed spark inside each engine cylinder. This spark ignites the air and fuel mixture, creating a small explosion that pushes the piston down. This process repeats across all six cylinders, turning the crankshaft and making your car move. For the L-head engine in your 1949 Nash, having clean plugs with the correct gap is critical for easy starting and smooth performance.

Signs of Failing Spark Plugs

When spark plugs get old and worn, they can't create a strong spark. This leads to problems that are easy to spot in a vintage car like the Nash 600. Because the ignition system is simple, it depends on the plugs being in good shape.

  • Rough Idle: The engine may shake or sound uneven when the car is stopped. You might feel more vibration than usual.
  • Engine Misfires: You may feel the engine hesitate or jerk, especially when you press the gas pedal. A misfire means a cylinder isn't firing correctly.
  • Poor Acceleration: If your Nash feels sluggish or slow to respond, a weak spark could be the reason.
  • Reduced Fuel Economy: A sudden drop in gas mileage can be a sign that your plugs are not burning fuel efficiently.
  • Difficulty Starting: Worn-out plugs make it harder for the engine to fire up, especially in cold weather.

Choosing the Right Aftermarket Spark Plug

For a classic vehicle like the 1949 Nash 600, choosing a spark plug is simple. The original L-head engine was designed for standard copper-core spark plugs. Brands like Champion were common original equipment for cars of this era and continue to be an excellent, reliable choice today.

Avoid Modern Plug Types

Do not use expensive platinum or iridium spark plugs in your Nash. These are designed for modern, high-energy electronic ignition systems. They may not perform well or could even cause issues in your car's original-style ignition. Stick with the standard copper plugs the engine was designed for.

Brand & Quality Tiers

For the 1949 Nash 600 Super Special, the choice is straightforward. Aftermarket brands offer replacement parts that meet or exceed the quality of the original plugs from over 70 years ago.

  • Good: Standard copper-core spark plugs from a reputable brand like Champion are the best and most appropriate choice. They are designed to work perfectly with your vehicle's vintage ignition system, providing reliable performance and long life.

Aftermarket Spark Plug Cost for 1949 Nash 600 Super Special

The cost for new aftermarket spark plugs is very affordable. Your Nash 600 has a six-cylinder engine, so you will need to purchase six plugs.

Part Type Price Range (Single Plug) Price Range (Set of 6)
New Aftermarket (Champion) $3.70 - $4.69 $22.20 - $28.14

Pro Tip: Given the low cost, it's wise to replace all six spark plugs at the same time. This ensures even performance across all cylinders and prevents you from having to diagnose which single plug might be failing later on.

Frequently Asked Questions (FAQ)

How often should I change the spark plugs on my Nash 600?

For a classic car using standard copper plugs, it's a good practice to inspect them every year and replace them every 10,000 to 20,000 miles. If you don't drive the car often, replacing them every few years is good insurance for a healthy engine.

What is the correct spark plug gap for my 1949 Nash 600?

The correct spark plug gap for many vintage engines of this era is around 0.025 inches. However, it is critical to verify this with a service manual if possible. Always use a feeler gauge or gap tool to check and set the gap before installation, as new plugs are not always gapped correctly for your specific car.

Is it hard to change the spark plugs myself?

No, this is a very easy job for a DIY mechanic. The spark plugs on the Nash L-head engine are typically easy to access on the side of the engine block. The job requires only basic hand tools and can usually be done in under an hour.

🎬 Watch this step-by-step tutorial on how to replace spark plugs.
What do bad spark plugs look like?

A healthy plug will have a light tan or grayish deposit on the tip. A plug that is black and sooty may indicate the fuel mixture is too rich. If it's covered in oil, you may have an internal engine leak. A white or blistered appearance can mean the engine is running too hot or lean.

How to Replace Spark Plugs (Step-by-Step Tutorial)
How to Replace Spark Plugs (Step-by-Step Tutorial)

Technical Specifications

Engine Type: L-head Inline 6-cylinder Number of Plugs: 6 Recommended Plug Type: Standard Copper Core Recommended Brand: Champion Spark Plug Gap: Approximately 0.025 inches (verify with service manual)

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Jul 21, 2026

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.

Year Coverage
This article covers the Spark Plug for:
In this article
🎬 Helpful Videos
Jump to ▴

Email This Guide

We'll send you a link to this article so you can read it later or share it.

Added to cart · Part