1946 GMC EF350 Ignition Contact Set: A Complete Guide
Keep your classic GMC running strong by understanding how to diagnose and replace your ignition points.
- The Ignition Contact Set, or 'points', is a critical mechanical wear item in your 1946 GMC's distributor.
- Symptoms of failure include no-start, rough running, misfiring, and loss of power.
- New aftermarket parts from brands like Standard Ignition are the most practical replacement option.
- It is highly recommended to replace the condenser at the same time as the points.
What are Ignition Points?
On a vintage truck like your 1946 GMC EF350, the ignition system is simpler than on modern cars. Instead of computers, it uses a mechanical switch called the ignition contact set, or "points," located inside the distributor. These points are a wear-and-tear item designed to be replaced as part of regular maintenance. They consist of two small electrical contacts that are opened by a cam on the distributor shaft and closed by a small spring. This constant opening and closing eventually causes the contacts to wear down, pit, or burn, requiring replacement.
Symptoms of a Failing Ignition Contact Set
When your ignition points start to fail, the symptoms are usually very noticeable. You might find that your truck is hard to start or won't start at all. This is the most common sign of bad points. If the engine does run, it may run rough, misfire, or hesitate during acceleration. You might also notice a significant loss of power, as the weak or inconsistent spark can't burn the fuel mixture efficiently. Stalling at idle is another key indicator that your points need attention.
Don't Ignore the Signs
A failing ignition contact set will not fix itself and will eventually leave you stranded. Because the part is inexpensive and critical to engine operation, it's best to address the symptoms as soon as they appear.
Choosing the Right Aftermarket Part
For a 1946 GMC EF350, finding original "new" parts from GMC is not possible. You have two main options: New Old Stock (NOS) or new aftermarket parts.
- New Old Stock (NOS): These are original parts that were never sold and have been sitting on a shelf for decades. They are rare, can be very expensive, and are not always in perfect condition due to age.
- New Aftermarket: This is the most common and practical choice. Companies produce new parts designed to meet or exceed the original specifications. For your GMC, Standard Ignition is a widely available and long-standing brand known for producing reliable ignition components for American vehicles. Given the limited options for this vintage truck, a new contact set from a reputable brand like Standard Ignition is a solid choice.
Pro Tip: Replace the Condenser Too
The condenser is a small capacitor that works with the points to prevent them from arcing and burning out too quickly. It is highly recommended to replace the condenser whenever you replace the ignition contact set. They are often sold together as a kit.
Estimated Replacement Costs
The cost to replace the ignition contact set is very reasonable, especially if you do the work yourself. The part itself is inexpensive, and the job is straightforward for those with basic mechanical skills.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Ignition Contact Set | $21.44 |
| Shop Labor | $100 - $200 |
| Total Estimated Cost (Shop) | $121 - $221 |
| Total Estimated Cost (DIY) | $21.44 |
Frequently Asked Questions
How often do ignition points need to be replaced?
Ignition points are a maintenance item. They should be inspected at every major tune-up and typically need replacement every 10,000 to 20,000 miles, depending on use. The rubbing block can wear down, and the contact surfaces can become pitted or burned.
What tools are needed to replace ignition points?
You will need basic hand tools like a screwdriver and wrenches to remove the distributor cap. The most important special tool is a feeler gauge to set the gap between the points correctly. Some people prefer using a dwell meter for a more precise adjustment.
What is the "gap" on ignition points?
The gap is the maximum distance the points open. Setting this gap correctly is critical for proper ignition timing and coil saturation. An incorrect gap will cause poor engine performance. The correct specification for your vehicle should be followed using a feeler gauge.
Can I upgrade my 1946 GMC to electronic ignition?
Yes, electronic ignition conversion kits are available for many classic vehicles. These kits replace the points and condenser with a solid-state module that fits inside the distributor. The main benefits are increased reliability and the elimination of the need for periodic point adjustment and replacement. However, some owners prefer to keep the original points system for authenticity.
Technical Specifications
Mechanical contact switch located inside the distributor.
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.