How to adjust the timing on a 1968 Ford Mustang GT Fastback (Bullitt)?

When dealing with a classic 1968 Ford Mustang GT Fastback, especially an iconic Bullitt model, timing issues can manifest as poor engine performance, misfiring, or rough idling. Ensuring the timing is correct is critical for optimal engine function and longevity. Here is how you can address and solve this timing issue.

Step 1: Gather Necessary Tools
Before starting, make sure you have the essential tools on hand: a timing light, a wrench set, a distributor wrench, a pulley mark reader (if needed), and a wrench for the distributor clamp. These tools are crucial for making precise adjustments.

Step 2: Locate the Timing Marks
Open the hood and locate the timing marks on the harmonic balancer at the front of the engine. The harmonic balancer is situated at the lower part of the engine, connected to the crankshaft pulley. You'll see engraved marks and numbers indicating degrees before and after top dead center (TDC). Clean these marks if they're dirty to ensure they’re visible when illuminated by the timing light.

Step 3: Connect the Timing Light
Attach the timing light’s inductive pickup to the number one spark plug wire, usually the front-most cylinder on the passenger side. Connect the light's power leads to the battery terminals, red to positive and black to negative. Position yourself so that you can both operate the timing light and see the harmonic balancer timing marks.

Step 4: Warm Up the Engine
Start the engine and let it reach its normal operating temperature. This is important because timing can change with temperature variations. Keep the vehicle in “Park” and engage the parking brake for safety.

Step 5: Check the Initial Timing
Shine the timing light at the harmonic balancer. You should see the timing marks on the balancer aligning with the timing pointer. Compare the timing mark against the factory specification for your 1968 Mustang GT Fastback, which is typically 6° before TDC. If the marks do not align as specified, the timing needs to be adjusted.

Step 6: Loosen the Distributor Clamp
Turn off the engine. Locate the distributor; it's near the center-back of the engine, a cylindrical component with spark plug wires radiating from its cap. Using a distributor wrench, slightly loosen the distributor clamp just enough so you can rotate the distributor but not too much that it moves freely.

Step 7: Adjust the Timing
Restart the engine. With the timing light in hand, slowly rotate the distributor. Turning it clockwise will retard the timing, and counterclockwise will advance the timing. Align the harmonic balancer mark with the correct degree on the timing pointer as illuminated by the timing light.

Step 8: Tighten the Distributor Clamp
Once the timing mark aligns correctly at the specified degree, carefully tighten the distributor clamp while keeping the distributor in place. Ensure it's secure to maintain the timing setting.

Step 9: Recheck the Timing
Turn off the engine and disconnect the timing light components. Start the engine again and recheck the timing with the light to ensure it hasn't shifted during tightening.

Step 10: Test Drive and Final Checks
Take the Mustang for a test drive to ensure it runs smoothly. Listen for any signs of pinging (detonation) or sluggish performance, which may indicate the need for further fine-tuning.

By following these steps carefully, you can ensure the timing on your 1968 Ford Mustang GT Fastback is set accurately, allowing for peak performance and smoother operation.