Ford Spark plug Gapping And Testing
Before going through sparkplug details,its suggested to go through spark plug firing order and wiring diagram.Click here
Spark Plugs Inspection & Gapping
Sparkplug Inspecting:- Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug.
- Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable job of cleaning with a stiff brush.
- If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%.
Sparkplug Gapping:
- Check spark plug gap before installation. The ground electrode (the L-shaped one connected to the body of the plug) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag. NEVER adjust the gap on a used platinum type spark plug.
- Always check the gap on new plugs as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate.
- A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all.
- Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained.
- Absolutely never attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.
FIG : Inspect the spark plug to determine engine running conditions.
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Spark Plug Removal & Installation
WARNING
Do not pull on the ignition wire directly, as it may separate from the connector inside the boot.
- Disconnect the negative battery cable.
- Grasp the spark plug boot firmly and with a twisting-pulling motion remove the spark plug wires from the spark plug.NOTEIf an original spark plug is reused, install it in the same cylinder from which it was removed. New spark plugs can be used in any cylinder.NOTEUse compressed air to remove any foreign material from the spark plug well before removing the spark plugs.
- Remove the spark plugs.
- Inspect the spark plugs.
- Installation:
Install a new head gasket and the cylinder head. - Lubricate the cylinder head bolt threads.
- Torque the cylinder head bolts in the proper sequence as follows:
- Step 1: 30 ft. lbs. (40 Nm).
- Step 2: Additional 90 degrees.
- Step 3: Loosen the bolts one full turn.
- Step 4: 30 ft. lbs. (40 Nm).
- Step 5: Plus an additional 90 degrees.
- Step 6: Plus an additional 90 degrees.
- Install or connect the following:
- Fill the coolant to the proper level.
- Start the vehicle and check for leaks, repair if necessary.