Ignition Contact Set Guide for the 1945-1947 GMC EC101
Keep your classic GMC running strong by understanding how to spot and replace a failing ignition contact set.
- Failing ignition points are a common cause of starting and running problems in the 1945-1947 GMC EC101, including no-starts, misfires, and stalling.
- As a regular maintenance item, points should be inspected often and replaced along with the condenser.
- Standard Ignition is a reliable aftermarket brand for this part, as new OEM parts are no longer produced.
- Proper installation requires setting the correct point gap with a feeler gauge, a critical step for engine performance.
Understanding the Ignition Contact Set in Your Classic Truck
For owners of a vintage 1945-1947 GMC EC101, the ignition contact set, or points, is a basic but essential part of the ignition system. Unlike modern vehicles with electronic ignition, this system is purely mechanical and electrical, requiring regular maintenance. The points wear down over time from the constant friction of opening and closing and the small electrical arc that occurs each time. Worn, dirty, or improperly adjusted points can cause a variety of engine performance issues.
Symptoms of a Failing Ignition Contact Set
When the ignition points begin to fail, your truck will give you clear signs. Because there is no "Check Engine Light" on a vehicle from this era, you must rely on noticing changes in how the engine runs. 🎬 Watch this guide on identifying classic car ignition symptoms. Symptoms often get worse as the points continue to wear.
- Difficulty Starting or No-Start: This is the most common symptom. If the points are too worn or burnt to make good electrical contact, the ignition coil won't receive the signal to create a spark, and the engine will crank but not start.
- Engine Misfires and Rough Running: Dirty or pitted points can cause an inconsistent spark, leading to a shaky idle, hesitation during acceleration, and a general lack of smoothness.
- Stalling: At low engine speeds, like at a stoplight, weak spark from failing points can cause the engine to stall unexpectedly.
- Reduced Power and Poor Fuel Economy: An inefficient spark leads to incomplete fuel combustion. This robs your engine of power and forces it to use more fuel.
Choosing the Right Aftermarket Part
For a vehicle as old as the EC101, new original equipment (OEM) parts are no longer manufactured. The only option is to use aftermarket parts. Fortunately, reputable brands have been making quality ignition components for decades.
Standard Ignition (Standard Motor Products): This is a well-known and long-standing brand in the aftermarket world. For American-built vehicles, their parts are generally considered to be of good quality and a reliable choice for tune-up components like ignition points. The Standard Ignition points available for the EC101 are designed to meet or exceed original specifications.
Aftermarket Brand Assessment
| Brand | Tier | Our Assessment |
|---|---|---|
| Standard Ignition | Standard Aftermarket | A reliable and widely available option for vintage American trucks. Standard has a long history of producing quality ignition components. |
Pro Tip: Replace the Condenser Too
The ignition condenser is a small capacitor that works with the points. Its job is to absorb excess voltage when the points open, preventing them from arcing and burning out prematurely. It is highly recommended to replace the condenser any time you replace the points. They are inexpensive and are often sold together. A failing condenser will cause the new points to burn up quickly.
Frequently Asked Questions (FAQ)
What are ignition points?
Ignition points, also called an ignition contact set, are a mechanical switch inside the distributor that triggers the ignition coil to fire the spark plugs. This system was used in most vehicles before the widespread adoption of electronic ignition.
How often should I replace the ignition points?
For a vehicle that is driven regularly, ignition points are a standard tune-up item that should be inspected and likely replaced every 10,000 to 20,000 miles. Since these are mechanical parts, they wear out with use and require periodic adjustment and replacement.
Is replacing ignition points a difficult job?
For a DIY mechanic with some experience, this is a relatively simple job. However, it requires specific tools, including a feeler gauge to set the point gap and ideally a dwell meter to fine-tune the adjustment. Incorrectly gapped points will cause poor engine performance.
🎬 See how to properly install and adjust breaker points.Can I convert my truck to electronic ignition?
Yes, many owners of classic trucks choose to replace the points and condenser system with an electronic ignition conversion kit. These kits eliminate the need for regular point adjustment and can provide a more consistent spark. However, a properly maintained points system is very reliable.
🎬 Learn how to replace your points with electronic ignition.Helpful Videos
Technical Specifications
The most critical specification is the point gap, which must be set with a feeler gauge during installation. Refer to a service manual for the exact specification for your truck's 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.