Choosing the Right Engine Timing Set for Your 1979-1987 GMC C2500 Suburban
Keep your classic Suburban's engine running strong by selecting the correct timing set for your V8 or Diesel engine.
- You must correctly identify your engine (e.g., 5.7L V8, 7.4L V8, 6.2L Diesel) before ordering, as timing sets are not interchangeable.
- Any aftermarket timing set with all-metal gears is a significant upgrade over the original nylon-toothed gear.
- For heavy towing or modified engines, a double-roller timing set from a performance brand is a worthwhile investment in durability.
- If you hear a rattling noise from the front of your engine, stop driving and have the timing set inspected to prevent further damage.
Is Your Timing Set Failing?
For 1979-1987 GMC C2500 Suburbans, the original timing sets, especially on the gasoline V8 engines, had a known weak point: a camshaft gear with nylon-coated teeth. Over decades of use, this nylon becomes brittle, cracks, and breaks apart. This causes the timing chain to become loose, a condition known as "chain stretch" or "slop."
Common Symptoms of a Bad Timing Set
- Rattling Noise: A distinct rattling or clattering sound coming from the front of the engine, especially noticeable at idle or on a cold start. This is the sound of the loose chain slapping against the inside of the timing cover.
- Poor Engine Performance: A stretched chain can cause ignition timing to become retarded, leading to a loss of power, hesitation, engine stutter, and difficulty starting.
- Engine Misfires: As the chain loses its precision, it can skip a gear tooth, throwing the cam and crank out of sync and causing the engine to misfire.
- Metal Shavings in Oil: When the nylon gear fails, or if the chain is making contact with other metal parts, small metal or plastic bits can end up in the engine oil and oil pan.
Choosing the Right Aftermarket Timing Set
For a vehicle of this age, original OEM parts are generally unavailable. The aftermarket, however, offers excellent options that are often significant upgrades over the factory parts.
Stock Replacement vs. Performance
The most important upgrade is moving from the original nylon-toothed gear to a full-steel timing set. Virtually all aftermarket replacements offer this. The next choice is between a standard "silent" chain and a double-roller chain.
- Standard Sets: These are perfect for a daily driver or stock restoration. They use a design similar to the original but with all-metal components for much greater durability. Brands like Melling and Cloyes are well-known providers of quality OE-style replacements. Based on user feedback, Melling sets are often preferred for their tight tolerances out of the box.
- Performance Sets: For engines that are modified, used for heavy towing, or if you simply want maximum durability, a performance set is a wise investment. Brands like Edelbrock and Melling Select Performance offer "double roller" timing sets. These use two rows of chain rollers, making them incredibly strong and precise, reducing the chance of chain stretch over the engine's life.
Installation and Cost
Replacing the timing set is a moderately difficult job that requires draining the coolant and removing the fan, belts, water pump, harmonic balancer, and timing cover. While it's a straightforward job for a professional mechanic, it can be a challenging weekend project for a DIYer.
| Item | Estimated Cost |
|---|---|
| Aftermarket Part (Standard) | $25 - $80 |
| Aftermarket Part (Performance Double Roller) | $80 - $215 |
| Shop Labor | $450 - $700 |
Frequently Asked Questions
Do I have to replace my timing set?
If your engine has over 100,000 miles and still has the original timing set with the nylon gear, replacement is highly recommended as a preventative measure. If you are experiencing any of the symptoms like engine rattle, it should be inspected and replaced immediately to avoid engine damage.
How do I know which engine my Suburban has?
The 1979-1987 C2500 Suburbans came with several engine options, most commonly the 5.7L (350) V8, 7.4L (454) V8, or the 6.2L Diesel V8. The timing set is specific to each engine. Check the emissions label under the hood or decode your vehicle's VIN to be certain which engine you have before ordering a part.
Is an aftermarket timing set better than the original?
Yes. For the gasoline V8 engines, almost any aftermarket timing set is an upgrade because it replaces the failure-prone original nylon cam gear with a durable all-steel gear. This is one of the most common and important reliability upgrades for these classic GM engines.
What is the difference between a timing chain and a timing belt?
Your GMC Suburban's engine uses a timing chain, which is a metal chain that runs inside the engine and is lubricated by engine oil. Timing belts are typically made of rubber and are located outside the engine. Chains are designed to last much longer than belts.
Technical Specifications
Vehicle and engine specific. Key types include standard replacement (all-metal gears) and performance double-roller chains. The most common engines for this vehicle are the 5.7L (350ci) V8, 7.4L (454ci) V8, and 6.2L Diesel V8.
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.