Ignition System - Dis; Renew Spark Plugs - Ford LRG 425 Operator's Handbook Manual

Ignition System - DIS

The Distributorless Ignition System (DIS) used on this engine does not have a
distributor or vacuum advance mechanism. Ignition timing is set by design and
cannot be readily changed. In the event that the engine is converted to alternative
fuels, the timing can be re-set by trained technicians. Please contact a Ford
Distributor listed at the back of this manual.

Renew Spark Plugs

WARNING: THE DIS IGNITION SYSTEM COMMONLY CARRIES VOLTAGES
IN EXCESS OF 60,000 VOLTS. PLEASE USE CAUTION.
1. Remove the lead from each spark plug by grasping, twisting and then pulling
the molded boot on the end of the lead.
CAUTION: Do not pull directly on the lead as this could cause the wire con-
nection inside the boot to become separated.
2. After loosening each spark plug one or two turns with a proper spark plug
spanner, clean the area around each spark plug port with compressed air then
remove the spark plugs.
WARNING: PROTECTIVE GOGGLES MUST BE WORN TO PROTECT THE
EYES WHEN USING COMPRESSED AIR.
3. Check the gaps of the new spark plugs
with a feeler gauge, and, where
necessary, bend the outer ground
extension to achieve the specified gap.
4. Use a proper spark plug spanner to avoid
damaging the insulators, screw the new
spark plugs into the cylinder head and
tighten them to the specified torque --
Refer to "SPECIFICATIONS" on page 42.
CAUTION: Do not over tighten spark
plugs as the gap may change consider-
ably due to the distortion of the plug outer
shell.
5. Coat the inside of each spark plug boot with Motorcraft Silicone Brake Caliper
Grease and Dielectric Compound XG-3 or equivalent, using a small screwdriver
blade.
6. Re-connect each high tension lead to the correct spark plug.
NOTE: The plug numbers are printed on the leads to aid correct re-assembly.
NOTE: Be sure each lead is fully pressed onto each plug and that the molded boot
is firmly in place.
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