A Guide to the Distributor Cap for the 1968 International 1100C
Keep your classic International truck running smoothly by understanding how to choose the right distributor cap.
- Always replace the distributor rotor when you replace the cap to ensure a complete ignition tune-up.
- Transfer spark plug wires one at a time from the old cap to the new one to maintain the correct firing order.
- Before ordering, check if your cap is held by clips or screws to ensure you buy the correct replacement.
- Remember that International V8s use cylinder #8 for timing, a unique trait for this family of engines.
Signs of a Failing Distributor Cap
The distributor cap on a vintage truck like the 1968 International 1100C is a wear item. Over time, the high voltage creates carbon buildup on the metal contacts and can even cause small cracks in the cap itself. When the cap starts to fail, your truck will let you know.
- Engine Misfires: The engine may sputter or hesitate, especially when you're accelerating. This happens when a spark fails to reach a cylinder correctly.
- Rough Idle: Your truck might shake or vibrate more than usual when it's stopped and running.
- Trouble Starting: A bad cap can make it hard to start the engine, or it might crank but not start at all.
- Visible Damage: If you look under the cap, you might see white buildup (corrosion), black carbon tracks, or small cracks. Any of these are signs it's time for a replacement.
Check for Moisture
Moisture can get trapped under the cap and cause corrosion or allow the spark to ground out. After washing the engine or driving in heavy rain, a quick check for moisture can prevent future problems.
Choosing the Right Aftermarket Cap
For a 1968 vehicle, finding original "New Old Stock" (NOS) parts from International Harvester is very rare and often expensive. The most practical and reliable option is a new aftermarket part. The quality of modern aftermarket ignition components is generally very good, sometimes using better materials than were available in the 1960s.
Two brands you will find are Standard Ignition and Walker Products.
- Standard Ignition (Standard Motor Products): Often considered a top-tier aftermarket brand, SMP has been making ignition parts for decades. Their products are known for meeting or exceeding original specifications and are a trusted choice in the restoration community.
- Walker Products: Another established aftermarket manufacturer, Walker also produces a range of engine management components and offers a reliable alternative.
Know Your Distributor!
International used distributors from different manufacturers over the years. Before ordering a new cap, it's a good idea to look at your current distributor for any brand names or markings. Also, note whether the cap is held on by clips or screws and the style of the spark plug wire terminals (male vs. female posts) to ensure you get an exact match.
Typical Replacement Costs
The distributor cap is an affordable part. The main cost difference comes from the brand and the materials used. Below is a general price estimate.
| Part Type | Price Range |
|---|---|
| New Aftermarket Distributor Cap | $24.44 - $51.85 |
| Shop Labor | $50 - $100 |
Frequently Asked Questions
Should I replace the rotor at the same time?
Yes, absolutely. The rotor is the spinning part inside the cap that directs the spark. It wears out just like the cap does. Replacing both at the same time is a standard part of a tune-up and ensures the whole system is fresh.
Is it hard to replace the distributor cap myself?
No, this is a great DIY job for beginners. The key is to transfer the spark plug wires from the old cap to the new cap one at a time to avoid mixing up the firing order. The cap is typically held on by two clips or screws.
What's the most common mistake when replacing an IH distributor cap?
Forgetting that International V8 engines use cylinder #8 as the primary timing reference, not cylinder #1 like many other manufacturers (e.g., Chevrolet). While you don't need to reset timing to just change a cap, it's a critical piece of information for any deeper ignition work. Always move wires one by one to prevent errors.
How often should I inspect the distributor cap?
A good practice is to inspect the cap and rotor during every oil change or at least once a year. Look for cracks, carbon tracking, and corrosion on the terminals. For a classic truck that may not be driven daily, regular inspection is more important than mileage-based replacement.
Technical Specifications
Varies by installed distributor. Check for clip-on vs. screw-down style, and male (HEI-style) vs. female (socket-style) terminals.
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.