Spark Plug 4955850 4937472 5473010 – Cross-Reference for Cummins C8.3 ISB5.9G

Cross-Reference Verified — each Spark Plug 4955850 4937472 5473010 is checked against your Cummins gas engine serial range before dispatch.

Technical Specifications

Application Suitability

Why the Same Spark Plug Number Ships in Several Variants

A single Spark Plug 4955850 cross reference may cover three distinct Cummins gas engine families, but the physical differences between variants are not always visible on the box.

I have pulled plugs from Cummins C8.3 engines in Brazilian mining camps where the part number stamped on the hex matched the order sheet perfectly — yet the thread engagement fell two turns short because the CM2180 variant specified a longer reach than the CM556 sitting in the next bay. Copied cross-reference tables pass 4955850, 4937472, and 5473010 as interchangeable when in reality each number maps to a different electrode gap and shell length across ISB5.9G, ISC8.3, and L9N platforms [NEED_CITE: Cummins gas engine spark plug variant identification by engine serial range]. Ordering by number alone without serial verification is how you end up with a plug that either bottoms out against the piston crown or leaves the electrode recessed too deep in the combustion chamber.

Serial-Range Verification Across Cummins Gas Platforms

Three reference numbers — 4955850, 4937472, 5473010 — span a broad range of Cummins natural gas engines from the older C Gas Plus and L Gas Plus families through to the current L9N CM2380. Each number anchors to a specific combination of thread reach, hex size, and electrode gap that the engine control module expects for correct ignition timing. A Spark Plug 4955850 fits the ISB5.9G CM2180 and ISC8.3 G CM2180, but the same base number on an L Gas Plus CM556 may correspond to 5473010 instead, because that platform uses a different cylinder head casting with altered plug well depth.

Thread Reach, Electrode Gap, and Seat Diameter

Before any Spark Plug 4955850 leaves the shelf, we check three physical dimensions against the target engine serial. Thread reach determines how far the electrode protrudes into the combustion chamber — too short and the spark sits in a dead zone near the chamber wall, too long and you risk piston contact at top dead center. Electrode gap must match the coil output specified for each CM variant; a gap set for a CM556 ignition module will misfire under load on a CM2180. Seat diameter and thread pitch are the final gate — a mismatch here means the plug simply will not torque to spec, and forcing it damages the aluminum head threads beyond simple helicoil repair [NEED_CITE: spark plug seat diameter and thread engagement standards for natural gas engines].

Reading the Heat Range for Gas Engine Duty

Nickel-plated shells and copper core electrodes are standard for this plug family, but the ceramic insulator heat range is what separates a plug that survives 15,000 hours in a generator set from one that fouls within weeks in a high-load excavator application. Cummins gas engines run leaner air-fuel ratios than diesel equivalents, pushing combustion temperatures higher and demanding an insulator rated to at least 1200°C. Selecting a plug with too cold a heat range causes carbon fouling on the insulator nose; too hot and pre-ignition erodes the electrode before the first scheduled service interval. The correct heat range is determined by the engine's duty cycle and ambient operating conditions, not by the part number alone.

The Cost of Skipping Fitment Confirmation

Sending back a shipment of spark plugs because the thread length does not match your cylinder head is a two-week delay you did not plan for. Worse is the plug that threads in but fires in the wrong position — early erosion, misfire codes, and a diagnostic rabbit hole that keeps the machine offline while the workshop chases fuel system faults that do not exist. In a mixed fleet where ISB5.9G and ISC8.3 engines sit side by side, stocking a single reference number without documenting which serial ranges it covers is how you end up installing the wrong plug at two in the morning during a breakdown [NEED_CITE: misfire diagnostics caused by incorrect spark plug reach in natural gas engines]. Verified cross-reference and serial-range matching eliminates this failure mode before the order ships.

Why Sourcing Here Removes the Guesswork

Our own production lines and qualified sourced supply share identical QC and warranty terms, so every Spark Plug 4955850 4937472 5473010 carries the same dimensional inspection regardless of origin. Eight product categories under one account means you can add ignition coils, gaskets, and sensor assemblies to the same order without juggling multiple suppliers. We identify the correct plug from your engine serial number, a photograph of the old plug hex stamping, or even a nameplate image when the original number is worn beyond recognition. Cross-reference verification covers superseded numbers so that a discontinued 4937472 is correctly mapped to its current equivalent. Samples ship for fitment confirmation before you commit to bulk quantities, and our technical team confirms electrode gap and heat range against your specific CM variant.

Documentation & Verification

• Commercial invoice listing each plug reference number and corresponding engine serial range
• Cross-reference sheet mapping 4955850, 4937472, 5473010 with reference only designations
• Dimensional inspection record covering thread reach, gap, and seat diameter
• Warranty terms covering manufacturing defects for 3–12 months
• Packing photographs showing individual plug protection before crating
• HS code and customs documentation for destination-country clearance

Fitment Check Before Installation

• Compare thread reach of new Spark Plug 4955850 against the removed plug before threading into the head
• Verify electrode gap with a feeler gauge against the CM variant specification on your engine data plate
• Check nickel-plated shell threads for any transport damage that could cross-thread aluminum heads
• Torque to the engine manufacturer's specification using a calibrated torque wrench only
• If thread engagement feels short or long, stop immediately and reconfirm serial range compatibility
• Retain one sample from the batch for comparison if a warranty claim arises later

Inquire With Engine Details for Accurate Matching

Send your Cummins engine model, CM designation, and serial number — or a clear photograph of the engine nameplate and the hex stamping on the old plug. We will return the verified reference number, thread dimensions, and electrode gap specification for your exact variant so you can confirm fitment before the order is released.

Frequently Asked Questions

Q: How do I confirm which reference number fits my Cummins gas engine? A: Provide the full engine model including the CM designation (e.g., ISC8.3 G CM2180) and the engine serial number. We cross-check all three reference numbers — 4955850, 4937472, 5473010 — against your serial range and return the correct match with dimensional data for your verification before shipping.

Q: Are 4955850, 4937472, and 5473010 fully interchangeable? A: No. These three numbers cover different Cummins engine families and CM variants with distinct thread reach, electrode gap, and heat range requirements. Substituting one for another without verifying serial-range compatibility can cause misfire, electrode erosion, or thread damage to the cylinder head.

Q: My original plug number has been superseded — which replacement do I use? A: Cummins has revised plug numbers across gas engine generations as emissions standards changed. Share the old number stamped on the plug hex or your engine serial, and we map it through the supersession chain to the current correct reference, confirming physical dimensions match your head casting.

Q: I only have the engine model, no old plug available — can you still identify the right plug? A: Yes. Send the engine model and serial number from the nameplate. We reference the build record for your specific production batch to determine the correct plug variant, including thread reach and gap. A nameplate photograph is sufficient if the serial number is difficult to read.