How to replace the timing belt on a 1970 Plymouth Hemi 'Cuda?

Replacing the timing belt on a 1970 Plymouth Hemi 'Cuda is a critical task to ensure the engine runs smoothly. A worn or broken timing belt can lead to serious engine damage, as it synchronizes the camshaft and crankshaft, allowing the engine's valves to open and close at the correct times during the intake and exhaust strokes. If you notice signs like rough running, ticking noises from the engine, or difficulty starting the car, it may indicate that the timing belt needs replacement. To resolve this, follow these steps carefully.

Step 1: Gather Necessary Tools and Parts
Before starting, ensure you have all the necessary tools and parts:

• A new timing belt compatible with the 1970 Plymouth Hemi 'Cuda
• Socket and wrench set
• Screwdrivers
• Torque wrench
• Jack and jack stands
• Timing light
• Harmonic balancer puller

Step 2: Prepare the Vehicle

1. Park your car on a flat surface and engage the parking brake.
2. Using a jack, lift the front of the vehicle and secure it with jack stands for safety.
3. Disconnect the negative battery terminal to avoid any electrical hazards.

Step 3: Access the Timing Belt

1. Remove the necessary components that obstruct access to the timing belt. This includes the fan shroud, radiator, and belts. Locate the fan shroud in the engine bay, around the front of the engine, and unscrew it.
2. Drain the coolant by locating the drain plug at the bottom of the radiator and letting the fluid flow into a container.
3. Remove the cooling fan and radiator. The cooling fan is mounted in front of the engine, usually attached with bolts that need to be unscrewed.

Step 4: Remove Engine Covers

1. Locate and remove the timing belt cover. It is positioned at the front of the engine and is usually held in place by several bolts around its perimeter.
2. Once the cover is removed, you will have a clear view of the timing belt and pulleys.

Step 5: Align Timing Marks

1. Rotate the crankshaft using a wrench until the timing marks on the camshaft and crankshaft pulleys align with the marks on the engine block. These marks ensure the engine is at Top Dead Center (TDC) of the compression stroke.
2. You can find the timing marks near where the pulleys meet the block, often marked as lines or dots.

Step 6: Remove the Old Timing Belt

1. After ensuring the timing marks are aligned, loosen the tensioner that holds the timing belt in place. The tensioner looks like a small pulley mounted on a bracket near the timing belt.
2. Slide the old timing belt off the pulleys carefully, so you don't disturb the alignment.

Step 7: Install the New Timing Belt

1. Carefully position the new timing belt onto the pulleys, ensuring the teeth of the belt align properly with the teeth on the pulleys.
2. Adjust the tensioner to apply the correct tension to the new belt. The tension should be firm but not overly tight; you should be able to twist the belt slightly with your fingers.

Step 8: Reassemble Engine Components

1. Replace the timing belt cover, securing it with the bolts you previously removed.
2. Reattach the radiator, cooling fan, and any other components that were removed.
3. Refill the radiator with coolant, using the fill neck at the top of the radiator.

Step 9: Final Checks and Testing

1. Reconnect the negative battery terminal.
2. Start the engine and observe its operation, using a timing light if necessary to ensure the timing is perfect.
3. Check for any leaks or unusual sounds and rectify them as needed.

Following these steps meticulously will ensure that your 1970 Plymouth Hemi 'Cuda's engine runs smoothly with a new timing belt. Proper maintenance and timely replacement of the timing belt are key to preserving the performance and longevity of your classic car.