Ford Bronco Engine Timing Set Guide for 1966-1971 Models
Keep your classic Bronco's engine in sync by choosing the right timing set.
- Original V8 engines often had failure-prone nylon cam gears; always replace them with an all-metal set.
- Symptoms of a bad timing set include rattling noises, rough running, and loss of power.
- Standard replacement brands like Cloyes and Melling are great for stock engines.
- While replacing the timing set, it's a good idea to also replace the front crank seal and water pump.
Signs of a Failing Timing Set in Your Bronco
When a timing set starts to wear out, it gives you warnings. The most common sign in these classic Broncos is a rattling or chain-slapping noise coming from the front of the engine. You might hear it most when you first start the engine. Other symptoms include a rough idle, engine misfires, and a noticeable loss of power. If the chain has stretched significantly, the ignition timing can become unsteady, making the engine hard to tune. In a worst-case scenario, the chain can jump a tooth or break, which will cause the engine to stop running and could lead to major internal damage.
The Original Nylon Gear Problem
Many original Ford V8 engines from this era, including the 289 and 302, used a camshaft sprocket with nylon-coated teeth. Ford did this to make the engine run quieter. After decades of heat and age, this nylon becomes brittle and can break off. The broken plastic pieces fall into the oil pan, where they can clog the oil pump's pickup screen, starving the engine of oil. If you have the timing cover off, it is highly recommended to replace any nylon-toothed gear with an all-metal set, even if it looks okay.
Choosing the Right Aftermarket Timing Set
When shopping for a new timing set, you have a few good options. The key is to choose an all-metal set to avoid the problems of the original nylon gears. Many owners also choose to upgrade from the standard silent-type chain to a more durable double-roller chain.
Standard Replacement Brands
For a daily driver or a stock restoration, brands like Cloyes and Melling are excellent choices. They are well-known in the industry and offer quality that meets or exceeds original factory specifications. Both brands offer durable, all-metal sprockets and high-quality chains. Forum members have used both brands for years with good results.
Performance Upgrade Brands
If you are building your Bronco's engine for more power, consider a performance-oriented set from Edelbrock or Melling Select Performance. These kits often feature stronger billet steel gears and true double-roller chains that reduce stretch and maintain more accurate timing under high RPMs. Some performance sets also offer multiple keyways on the crankshaft sprocket, allowing for advanced or retarded cam timing to shift the engine's power band. These are ideal for modified engines but are not necessary for a stock rebuild.
Cost of a New Timing Set (1966-1971 Bronco)
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (Standard) | $35 - $75 |
| New Aftermarket (Performance) | $80 - $155 |
| Shop Labor for Installation | $350 - $600 |
Cost estimates are approximate and can vary by location and supplier.
While You're In There...
Replacing the timing set requires removing the water pump, harmonic balancer, and timing cover. This is the perfect time to also replace the timing cover gasket, the front crankshaft seal, and inspect or replace the water pump. Addressing these items at the same time can save you from having to do the same job twice later on.
Frequently Asked Questions
Do I need a double-roller timing chain?
For a stock engine, a standard all-metal replacement set is perfectly fine. A double-roller chain is a durable upgrade that reduces chain stretch over time and is highly recommended for performance builds or if you want extra peace of mind.
Are there any recalls for the 1966-1971 Bronco timing set?
No, there are no official recalls or Technical Service Bulletins (TSBs) from the NHTSA for the timing set on 1966-1971 Ford Broncos. Any recall information you may see is for modern Bronco models and does not apply to these classic vehicles.
Can I replace a timing set myself?
Yes, this is a job that a knowledgeable DIY mechanic can do. It requires some specialized tools like a harmonic balancer puller and careful attention to detail to align the timing marks correctly. If you are not comfortable with this level of engine work, it is best to have a professional mechanic do it.
What are timing marks and why are they important?
Timing marks are dots or other indicators on the camshaft and crankshaft sprockets. To set the engine's timing correctly, these marks must be aligned in a specific way (usually with the cam mark at 6 o'clock and the crank mark at 12 o'clock) when the #1 piston is at Top Dead Center. Incorrect alignment will cause the engine to run poorly or not at all.
Technical Specifications
OEM Part Numbers: C0DZ-6268-A
The 1966-1971 Bronco uses a timing chain and sprocket set. Engines available were the 170ci inline-6, 289ci V8, and 302ci V8. Aftermarket upgrades often include double-roller chains and all-steel sprockets instead of the original silent chain and nylon-toothed cam gear.
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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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- Signs of a Failing Timing Set in Your Bronco
- The Original Nylon Gear Problem
- Choosing the Right Aftermarket Timing Set
- Standard Replacement Brands
- Performance Upgrade Brands
- Cost of a New Timing Set (1966-1971 Bronco)
- While You're In There...
- Frequently Asked Questions
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