B5.9G, B5.9LPG, B Gas Plus, B LPG Plus, and B Gas International Engines – 013-016   Spark Plugs (Non Shielded)

CAUTION  Spark plug life is largely dependent on cleanliness of the plug’s porcelain. Dirt, oil, and fingerprints reduce the seal strength between the spark plug boot and the porcelain causing reduced spark plug life. Do not touch the porcelain area on the spark plug. Use rubbing alcohol and a lint-free cloth to clean the spark plug porcelain and rubber boot before installing the spark plugs.

A convenient option is an alcohol prep pad that does not contain any moisturizers or other cleaners. Compliant alcohol prep pads are available at many department stores, drug stores, and industrial supply centers.

CAUTION  Damage to the electrodes due to improper use of a feeler gauge will shorten the life of the spark plug.

Clean the tool gauges prior to usage.

Use a wire spark plug gap-check tool to make sure the spark plug gap is within specification. If the gap is not within specification, the plug is not to be used and must be returned to Cummins Inc.

CAUTION  Only gap B5.9G-230 hp, B Gas International-230 hp, B Gas Plus-200 hp, B Gas Plus-230 hp, or C8.3G and CNGE Prime Power applications or loss of spark plug life will occur.

For B5.9G-230 hp, B Gas Plus-200 hp, B Gas Plus-230 hp, L10G Manual Transmission, and CNGE Prime Power, set the electrode gap with an appropriate spark plug gap tool to 0.508 mm [0.020 in].

Adjust the gap by bending the ground (side) electrode, with the slots on the gap tool. Align the center and ground electrodes. The ground electrode should be parallel and centered over the middle of the center electrode.

If the electrodes can not be aligned, discard the plug.

For C8.3G and C Gas Plus with straight harness connector coils:

Remove and discard the terminal nut from the spark plug.

Check the spark plug. The ground electrode must be parallel to the center electrode and must be aligned along the centerline of the plug.

WARNING  To reduce the possibility of personal injury, do not touch any ignition wires or components while the engine is operating, unless using suitably insulated tools.

For ISB5.9 G, B5.9G, B5.9LPG, B Gas Plus, B LPG Plus, B Gas International, ISB5.9 G, and L10G:

Remove the spark plug wire.

Refer to Procedure 013-014 in Section 5.

WARNING  To reduce the possibility of personal injury, do not touch any ignition wires or components while the engine is operating, unless using suitably insulated tools.

For C8.3G, C Gas Plus, L Gas Plus, and ISL G:

Disconnect the wiring harness.

Remove the capscrews from the coil bracket.

Remove the ignition coil. Refer to Procedure 013-012 in Section 6.

Blow out any dirt and debris from the spark plug cavity.

Loosen the spark plugs. Use a 5/8-inch magnetic spark plug socket, Part Number 3824876.

Do not use a spark plug socket with rubber insert.

Use a magnetic spark plug socket and continue to back out the spark plug until the threads are no longer engaged.

Lift the spark plug out with the socket, being careful not to drop the plug.

Mark or tag the spark plug with the cylinder number from which it was removed.

For L10G:

Any time the spark plugs are removed or coolant is found in the oil, the copper sleeves in the cylinder head must be checked for leaks. This inspection can be performed by viewing the top of the piston through the spark plug hole for indications of an extra clean combustion bowl on any of the pistons.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

CAUTION  Spark plug life is largely dependent on cleanliness of the plug’s porcelain. Dirt, oil, and fingerprints reduce the seal strength between the spark plug boot and the porcelain causing reduced spark plug life. Do not touch the porcelain area on the spark plug. Use rubbing alcohol and a lint-free cloth to clean the spark plug porcelain and rubber boot before installing the spark plugs.

CAUTION  Do not clean boots on C8.3G, C Gas Plus, L Gas Plus, or ISL G applications. These boots are pre-greased.

A convenient option is an alcohol prep pad that does not contain any moisturizers or other cleaners. Compliant alcohol prep pads are available at many department stores, drug stores, and industrial supply centers.

Use rubbing alcohol and a lint-free cloth to clean the spark plug porcelain and rubber boot.

Inspect the spark plugs for the following issues:

1. Insulator flashover
2. Electrode deposits or fouling
3. Missing electrode.

A worn electrode need not mean that the spark plug must be replaced.

Inspect the spark plugs for the following issues (continued):

1. Cracked insulator
2. Electrode misalignment

If a plug exhibits any of these issues, it must be replaced.

NOTE: Spark plugs should not be replaced due to corona staining (3). Corona staining does not affect spark plug or ignition system performance.

Inspect the piston for damage. Contact a Cummins® Authorized Repair Location.

NOTE: If a spark plug exhibits electrode beading, check the electrode gap before discarding the plug. Replace the plug only if the gap is less than the minimum gap shown in Table 1, in the Intial Check section above.

A damaged spark plug showing traces of aluminum can indicate piston damage.

Inspect the piston for damage. Contact a Cummins® Authorized Repair Location.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

CAUTION  Spark plug life is largely dependent on cleanliness of the plug’s porcelain. Dirt, oil, and fingerprints reduce the seal strength between the spark plug boot and the porcelain causing reduced spark plug life. Do not touch the porcelain area on the spark plug. Use rubbing alcohol and a lint-free cloth to clean the spark plug porcelain and rubber boot before installing the spark plugs.

A convenient option is an alcohol prep pad that does not contain any moisturizers or other cleaners. Compliant alcohol prep pads are available at many department stores, drug stores, and industrial supply centers.

Clean the magnetic spark plug socket and spark plug.

CAUTION  Mechanical overtightening can damage the spark plug and cylinder head or adapter.

CAUTION  Proper spark plug torque is required for heat transfer from the spark plug to the cylinder head. Improper torque will lead to spark plug failure, disconnected spark plug wires, and possible engine damage.

Inspect the cylinder head plug cavity for debris. Clean as required.

Install the spark plug. Use a magnetic spark plug socket, Part Number 3824876, and thread the plug in by hand to make sure that the threads are smooth and the plug is not cross-threaded. Tighten the spark plug.

Check the ignition coil.

Refer to Procedure 013-012 in Section 6.

WARNING  Do not remove the coil extension or engine damage could possibly result.

CAUTION  Do not clean boots on C8.3G, C Gas Plus, L Gas Plus, or ISL G applications. These boots are pre-greased.

For C8.3G, C Gas Plus, L Gas Plus, and ISL G:

Clean the spark plug, replace the boot, and install the coil.

NOTE: For an angled coil, clean/remove the grease deposits from the end of the coil spring at each plug change interval prior to installing a new plug boot onto the coil.

Install and tighten the capscrews. Refer to Procedure 013-012 in Section 5.

For L10G:

Clean, replace the boot, add dielectric grease, and install the spark plug wires.

Refer to Procedure 013-014 in Section 5.