Adjusting the valves on a 1968 Ford 302 engine with hydraulic lifters is a crucial procedure that can greatly impact engine performance and longevity. Hydraulic lifters are designed to maintain zero valve lash, allowing for quiet and efficient operation. However, for this system to function correctly, it needs to be set up properly, which involves adjusting the valves. Here’s a step-by-step guide on how to go about this task.
- Engine State: Ensure the engine is cold. This is crucial for accurate adjustment.
- Safety Measures: Disconnect the battery to ensure safety during the procedure.
- Workspace: Work in a well-ventilated area with good lighting conditions.
- Tools Required: You’ll need a basic set of hand tools like wrenches, a socket set, a feeler gauge, and a flat-head screwdriver.
Removing Valve Covers:
- Begin by removing the valve covers to expose the rocker arms and valves. Use an appropriate socket or wrench to loosen and remove the valve cover bolts.
Finding Top Dead Center (TDC):
- It’s crucial to set the valve adjustment when the piston is at Top Dead Center (TDC) on the compression stroke. Remove the spark plug from the #1 cylinder (the cylinder closest to the radiator) and rotate the crankshaft manually until the piston reaches TDC. You can confirm this by using a screwdriver in the spark plug hole; the piston will push it upwards.
- Eliminate Lash: Start with the #1 cylinder and adjust one valve at a time. Loosen the rocker arm nut so that you can easily spin the pushrod with your fingers. Slowly tighten down the rocker arm nut until there is zero lash. Zero lash is the point at which you can just barely not spin the pushrod.
- Setting Preload: After reaching zero lash, tighten the rocker arm nut an additional one-half to three-quarters of a full turn to set the lifter preload. This will ensure the hydraulic lifter is properly seated and can compensate for the expansion and contraction that happens during engine operation.
- Double-Check: Confirm that you’ve properly set the preload and that the valve closes completely. Inaccurate adjustment could cause issues like burnt valves or excessive wear.
- Other Cylinders: Repeat the process for each valve in the engine, working in a sequence as specified by the engine’s firing order.
- Once all the valves have been adjusted, reinstall the valve covers using new gaskets. Tighten the valve cover bolts to the manufacturer’s torque specifications.
Start the Engine:
- Reconnect the battery and start the engine. Pay attention to any abnormal noises. If you hear anything unusual, shut off the engine immediately to investigate.
Adjusting the valves on a 1968 Ford 302 engine with hydraulic lifters is a meticulous task but highly rewarding. Done correctly, this process can extend the lifespan of your engine and improve its performance. Always adhere to manufacturer guidelines, and if you’re ever unsure about any step, consult a professional. This is a vintage engine, and treating it with the care it deserves can keep it running smoothly for many more years.