Ignition Contact Set Guide for the 1938 GMC T15
Keep your classic 1938 GMC T15 running reliably by understanding its mechanical ignition points.
- The ignition contact set (points) is a normal wear item on a 1938 GMC T15 that requires periodic replacement, typically with the condenser.
- Common symptoms of failure include hard starting, rough running, engine misfires, and loss of power.
- Standard Ignition is a well-regarded aftermarket brand for vintage ignition components.
- Proper installation requires setting the point gap with a feeler gauge to ensure correct engine timing.
Understanding the Ignition System in Your Vintage Truck
Unlike modern vehicles, the ignition in your 1938 GMC T15 is a mechanical system. At its heart are the ignition contact set and condenser. The points are a set of electrical contacts that are opened and closed by a cam on the distributor shaft. Over thousands of miles, the rubbing block that rides on this cam wears down, and the electrical contacts can become pitted or burned. This wear changes the timing and quality of the spark, leading to poor engine performance. Because they are a wear item, points require periodic maintenance and replacement.
Symptoms of a Failing Ignition Contact Set
When the points in your T15 begin to fail, you'll notice several signs that your engine isn't running correctly. These symptoms often start subtly but will worsen over time, potentially leaving you stranded.
- Hard Starting or No Start: Worn, pitted, or misaligned points can't deliver the clean electrical break needed to produce a strong spark, making the engine difficult or impossible to start.
- Engine Misfires and Rough Running: As the points wear, the spark becomes inconsistent, causing the engine to misfire, run roughly, and feel shaky, especially at idle.
- Stalling: An engine may stall, particularly at low speeds or when stopping, if the points are not making consistent contact.
- Reduced Power: Inefficient combustion from a weak or poorly timed spark will cause a noticeable loss of power and sluggish acceleration.
Pro Tip: Always Replace the Condenser
It is highly recommended to replace the ignition condenser every time you replace the contact set. The condenser absorbs excess voltage to prevent the points from arcing and burning out prematurely. A failing condenser will cause a new set of points to fail very quickly. Quality aftermarket kits typically include a new condenser with the points.
Choosing the Right Aftermarket Ignition Contact Set
For a vintage vehicle like the 1938 GMC T15, new original equipment (OEM) parts are no longer manufactured. The market consists entirely of aftermarket parts. Fortunately, companies like Standard Ignition have been making quality ignition components for many decades. Standard Ignition and its premium line, Blue Streak, are often considered reliable choices for classic vehicles. Given the simplicity and importance of the part, choosing a reputable brand known for quality materials is a wise investment in your truck's reliability.
Cost to Replace the Ignition Contact Set on a 1938 GMC T15
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Ignition Contact Set | $26 - $28 |
| Shop Labor | $100 - $150 |
| Total Estimated Cost | $126 - $178 |
Cost estimates are for reference only and may vary based on location and the specific repair shop.
Frequently Asked Questions (FAQ)
How often do ignition points need to be replaced?
Ignition points are a maintenance item and typically require replacement every 6,000 to 10,000 miles, depending on use. The rubbing block wears and the contacts pit over time, which changes the engine's timing.
What is the difference between points and a condenser?
The points are the mechanical switch that triggers the spark. The condenser is a capacitor connected to the points that absorbs voltage to prevent the points from arcing and burning out too quickly. They should always be replaced together.
Is replacing ignition points a DIY job?
Yes, for a mechanically inclined owner. The process involves removing the distributor cap and rotor, unscrewing the old points and condenser, and installing the new set. The most critical step is setting the correct point gap using a feeler gauge, as this determines the engine's dwell and timing.
Are there any recalls for the 1938 GMC T15 ignition system?
No. There are no active recalls or Technical Service Bulletins (TSBs) from the NHTSA for the ignition system on a 1938 vehicle. Recalls for modern issues do not apply to this classic truck.
Technical Specifications
A mechanical switch with tungsten contacts and a rubbing block, designed for the original distributor. The set typically includes a matching condenser to prevent arcing.
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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.