Ignition Contact Set Guide for the 1938 GMC T145
Keep your classic GMC's ignition system reliable by understanding and maintaining its ignition points.
- The ignition contact set (points) is a regular maintenance item on a 1938 GMC T145 that requires periodic replacement.
- Symptoms of failure include hard starting, rough running, stalling, and loss of power.
- New OEM parts are not available; rely on quality aftermarket brands like Standard Ignition.
- Proper installation requires setting a specific gap with a feeler gauge, so a service manual is highly recommended.
Understanding the Ignition Contact Set in Your 1938 T145
The ignition contact set, or points, is a fundamental service item for the ignition system in your vintage 1938 GMC T145. Unlike modern electronic ignitions, this system relies on a mechanical switch to time the spark. Over time, the contacts can wear, burn, or become misaligned, leading to a range of engine performance issues. Regular inspection and replacement are key to keeping your classic truck running as it should.
Symptoms of a Failing Ignition Contact Set
A failing set of points will give you noticeable clues. Because they control the spark, any issues will directly impact how the engine runs.
- Hard Starting or No Start: If the points are burnt, pitted, or improperly gapped, they can't create the electrical signal needed to generate a spark. This can make the engine turn over without ever firing up.
- Engine Misfires and Rough Running: Worn or dirty points can cause a weak or inconsistent spark. This leads to incomplete combustion in the cylinders, resulting in a shaky idle, stuttering during acceleration, and an overall lack of smoothness.
- Reduced Power and Poor Acceleration: If the points are not opening and closing at the precise moment, ignition timing is affected. This robs the engine of power, making the truck feel sluggish, especially when trying to accelerate or climb hills.
- Engine Stalling: Stalling, especially at idle or when coming to a stop, is a critical symptom. It happens when worn points can't consistently deliver the spark needed to keep the engine running at low RPMs.
Choosing the Right Aftermarket Part
For a 1938 vehicle, new Original Equipment Manufacturer (OEM) parts from GMC are no longer produced. All available new ignition contact sets are aftermarket reproductions. The key is to choose a part from a reputable, long-standing brand.
Standard Ignition (Blue Streak): Standard Motor Products is a well-known name in the aftermarket ignition world and has been around for a very long time. Their "Blue Streak" line is often considered a premium quality option for vintage vehicles. For a component as critical and simple as ignition points, a quality part from a trusted brand like Standard Ignition is a reliable choice.
Ignition Contact Set Cost for 1938 GMC T145
| Part Type | Price Range | Notes |
|---|---|---|
| New OEM | Not Available | Original parts for this vehicle are no longer manufactured. |
| New Aftermarket | $26.77 - $27.65 | This is the typical price for a quality aftermarket part from a brand like Standard Ignition. |
| Used OEM | Not Recommended | This is a wear item. A used part will have a very limited lifespan. |
Frequently Asked Questions (FAQ)
How often should I replace the ignition points on my T145?
For a classic vehicle, it's good practice to inspect the points annually. Replacement is typically recommended every 10,000 to 12,000 miles, or if you notice any signs of wear like pitting or a worn rubbing block. Given the age of the vehicle, regular checks are more important than mileage alone.
Do I need special tools to replace the ignition contact set?
Yes. At a minimum, you will need a set of feeler gauges to set the correct "gap" when the points are open. For a more precise adjustment, a dwell meter is the ideal tool. Basic hand tools like screwdrivers will also be necessary.
What is the correct "gap" for the points?
The point gap is a critical adjustment that determines ignition timing. While a typical gap for engines of this era is between 0.015" and 0.025", you must verify the exact specification for your T145's distributor in a service manual. An incorrect gap will lead to poor engine performance.
Can I clean the points instead of replacing them?
If the points are only slightly oxidized, you can sometimes clean the contacts with a piece of emery paper or a business card to restore function temporarily. However, if the contacts are pitted, burned, or the rubbing block is worn, replacement is the only proper solution.
Technical Specifications
This is a mechanical contact set located inside the distributor. It is designed for the 3.8L L6 engine with a clockwise-rotating distributor. The critical specification is the point gap, which must be set using a feeler gauge according to the vehicle's service manual.
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.