How to adjust valve clearance on a 1968 Ford Mustang GT Fastback (Bullitt)?

When maintaining a classic car like the 1968 Ford Mustang GT Fastback (Bullitt), valve clearance is one of the critical aspects to ensure the engine runs smoothly and efficiently. Improper valve clearance can lead to poor engine performance, excessive noise, and even potential damage. Whether you've noticed a ticking noise under the hood or just performing routine upkeep, adjusting the valve clearance is essential. Here is how to solve this issue:

Step 1: Gather Your Tools and Materials
Before starting, ensure you have the following tools:

• Feeler gauges
• Wrench set
• Screwdriver
• Socket set
• Torque wrench
• Shop manual for the specific clearance specifications

Step 2: Prepare the Engine
First, ensure the engine is cool to the touch. Working on a hot engine can result in inaccurate measurements and potential burns.

Step 3: Locate the Valve Cover
The valve cover is typically situated on the top of the engine. In the 1968 Ford Mustang GT Fastback, you'll find it directly above the cylinder head. The cover is an elongated, rectangular metal piece held down by several bolts.

Step 4: Remove the Valve Cover
Using the appropriate socket from your socket set, remove the bolts securing the valve cover. Carefully lift off the cover, and be mindful of any gaskets; they need to be in good condition for reassembly.

Step 5: Identify the Rocker Arms
Once the valve cover is off, you'll be able to see the rocker arms. These are the components that directly interact with the valves. The rocker arms will be mounted on the top side of the pushrods.

Step 6: Position the Engine
Using a wrench, turn the crankshaft pulley to bring the number one cylinder to the top dead center (TDC) on the compression stroke. This position means both the intake and exhaust valves for cylinder one should be closed.

Step 7: Measure the Clearance
Insert the appropriate feeler gauge between the rocker arm and the valve stem. The gauge should fit snugly, moving with slight resistance. Refer to your shop manual for the correct clearance specification.

Step 8: Adjust the Clearance
If the clearance is incorrect, you'll need to adjust it. Loosen the lock nut on the rocker arm using a wrench. Then, using a screwdriver, turn the adjusting screw to achieve the correct clearance. Tighten the lock nut while holding the screw in place.

Step 9: Rotate and Repeat
Turn the crankshaft to bring the next cylinder to TDC and repeat the measurement and adjustment process. Continue this for all the cylinders.

Step 10: Reassemble the Engine
Once all valve clearances have been adjusted, replace the valve cover. Ensure the gasket is properly seated and secure the cover with its bolts. Tighten them to the specified torque mentioned in the shop manual.

Step 11: Test the Engine
Start the engine and listen for any unusual noises. If the valve clearance is properly adjusted, the engine should run smoothly with minimal valve noise.

Adjusting the valve clearance might seem daunting, but with patience and accurate measurements, you'll keep your iconic Mustang running in top form.