A Guide to the Distributor Cap for the 1987 Chevrolet V20
Keep your classic Chevy V20's ignition system firing on all cylinders with the right replacement distributor cap.
- A failing distributor cap will cause misfires, hard starting, stalling, and poor engine performance.
- For best results, choose an aftermarket cap with brass terminals from a quality brand like MSD, Delphi, or Standard Ignition.
- Always replace the distributor rotor at the same time as the cap.
- Replacement is an easy DIY job, but be careful not to break the mounting screws, which can seize in the distributor housing.
Symptoms of a Failing Distributor Cap on a 1987 V20
A distributor cap is a wear item, meaning it needs to be replaced as part of regular tune-ups. When it starts to fail, the flow of electricity to the spark plugs is interrupted. You will likely notice one or more of these signs:
- Engine Misfires or Rough Idle: The engine may shake, sputter, or run unevenly, especially when idling. This happens when a cylinder doesn't fire correctly.
- Hard Starting: The truck may take longer than usual to start, or it might crank but not fire up at all. This can be caused by cracks or moisture inside the cap preventing a strong spark.
- Stalling: The engine may stall unexpectedly, either while driving or when stopped at a light.
- Hesitation or Lack of Power: When you press the gas pedal, the truck might hesitate or feel sluggish. This is a sign of inconsistent spark delivery.
- Check Engine Light: On a 1987 V20 with its early diagnostic system, a severe and consistent misfire can trigger the Check Engine Light.
Watch for Carbon Tracking
When you inspect your old cap, look for thin black lines that look like pencil marks on the inside. This is called carbon tracking, and it creates a short circuit for the spark to follow, preventing it from reaching the spark plug. If you see this, the cap must be replaced.
Choosing the Right Aftermarket Distributor Cap
For a 1987 Chevrolet V20, you have several good aftermarket options. The original GM and AC-Delco parts set the standard, but modern aftermarket brands offer comparable or even superior performance. The biggest difference often comes down to the material used for the metal contacts inside the cap.
Brass vs. Aluminum Contacts: Higher-quality caps use brass or copper terminals. These materials are excellent conductors and resist corrosion much better than the aluminum terminals found in many budget-friendly caps. For the reliability of your V20, choosing a cap with brass contacts is a worthwhile investment.
Brand Quality Tiers
- High-Performance (MSD): MSD is a top name in performance ignitions. Their caps are made from very strong, high-dielectric materials like Rynite and feature high-quality brass terminals. An MSD cap is an excellent upgrade, especially if you have other performance parts like a high-output coil.
- OEM-Quality (Delphi, Standard Ignition): Delphi was a major original equipment (OE) supplier for GM and their parts are built to meet or exceed factory specifications. Standard Motor Products (SMP) is another well-respected brand that produces reliable, quality replacement parts, often with options for brass terminals. These brands are a safe bet for daily-driver reliability.
- Standard Replacement (Walker Products): Walker offers parts that are designed to be a direct fit and restore original performance. They are a solid choice for owners looking for a functional, value-oriented replacement that meets OE standards.
Always Replace the Rotor
The distributor rotor spins inside the cap and is exposed to the same heat and high voltage. It wears out at the same rate as the cap. For a complete and lasting repair, always replace the rotor when you replace the cap. Most quality caps are sold in a kit with a new rotor.
Known Issues for the 1987 Chevrolet V20
Searches for official recalls or Technical Service Bulletins (TSBs) from Chevrolet for the distributor cap on the 1987 V20 did not find any specific issues. However, owner forums highlight a common problem during replacement: the two hold-down screws can seize in the aluminum distributor housing and break off. Be sure to spray them with penetrating oil and turn them carefully to avoid a much more difficult repair.
Cost of Replacing a Distributor Cap on a 1987 V20
| Part or Service | Estimated Cost |
|---|---|
| New Aftermarket Distributor Cap & Rotor Kit | $19 - $41 |
| New OEM (AC-Delco) Distributor Cap & Rotor Kit | $40 - $60 |
| Shop Labor | $75 - $150 |
Frequently Asked Questions (FAQ)
How often should I replace the distributor cap and rotor?
For a 1987 V20, it's good practice to inspect the cap and rotor during every major tune-up or every 30,000 miles. If you see any cracks, corrosion on the terminals, or carbon tracking, it should be replaced.
Is this a difficult job to do myself?
No, replacing the distributor cap and rotor is a very DIY-friendly job. It requires basic hand tools and about 30-60 minutes. The most important step is to transfer the spark plug wires from the old cap to the new one in the exact same order to maintain the correct engine firing order.
What is the firing order for a 1987 Chevy V20 with a 350 V8?
The firing order for the standard small-block Chevy V8 is 1-8-4-3-6-5-7-2. The #1 terminal on the distributor cap is usually marked, and the cylinders are numbered with odd numbers on the driver's side (1-3-5-7) and even numbers on the passenger's side (2-4-6-8).
Do I need to adjust the ignition timing after replacing the cap?
No. As long as you only replace the cap and rotor and do not loosen and turn the distributor housing itself, the ignition timing will not be affected.
Technical Specifications
OEM Part Numbers: 10477599 10493663 D329A
HEI Style, Male Terminals, 8-Cylinder + Coil Tower
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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.
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- Symptoms of a Failing Distributor Cap on a 1987 V20
- Watch for Carbon Tracking
- Choosing the Right Aftermarket Distributor Cap
- Brand Quality Tiers
- Always Replace the Rotor
- Known Issues for the 1987 Chevrolet V20
- Cost of Replacing a Distributor Cap on a 1987 V20
- Frequently Asked Questions (FAQ)
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