13257-40F06 Rocker Arm Set – Model-Matched for Nissan KA24E

Verified Cross-References — Every 13257-40F06 variant mapped against engine serial ranges to eliminate fitment guesswork before you commit to a bulk order.

Technical Specifications

Application Suitability

Why the Same Part Number Ships in Four Variants

The suffix tells you which engine serial range it actually fits.

I have seen too many KA24E teardowns where the mechanic held a rocker arm stamped 13257-40F06, the cross-reference table said it swaps with 13257-40F07, and the shaft bore was off by just enough to cause valvetrain chatter within the first hundred kilometers. Nissan revised this Rocker Arm Set for Nissan KA24E across production years, and each suffix variant reflects a change in pivot geometry, shaft diameter, or tip radius that a simple parts catalog will not show. Sellers copy cross-reference tables from one another, and the errors compound until nobody remembers which suffix fits which engine serial [NEED_CITE: Nissan KA24E valvetrain revision history across model years]. The result is a part that looks correct on paper but refuses to seat properly on the shaft.

Mapping Engine Serial to the Correct Suffix

A 13257-40F06 cross reference fitment check starts with the engine serial number, not the vehicle model year alone. The KA24E SOHC 12V was produced across nearly a decade, and Nissan introduced incremental changes to the rocker shaft diameter and the rocker arm pivot bore tolerance during that run. We verify each variant — 13257-40F06, 13257-40F07, 13257-40F16, and 13257-40F17 — against your specific engine build record before confirming the order.

Interface Dimensions That Separate a Fit from a Failure

The pivot bore tolerance, tip radius, and overall runout are the three dimensions that determine whether this Rocker Arm Set for Nissan KA24E will operate quietly and survive beyond the break-in period. A pivot bore that is even marginally oversized allows the arm to wobble on the shaft, accelerating wear on both surfaces. Tip radius must match the valve stem cap geometry to distribute load evenly [NEED_CITE: rocker arm tip radius and valve stem wear correlation in SOHC engines]. We measure these interfaces against the worn originals before shipping the replacement set.

Reading the Metallurgy for the Operating Environment

The forged SAE 1045 carbon steel body with phosphate coating is selected for the heat cycles and contamination levels typical in light commercial and agricultural service. Phosphate treatment provides a break-in surface that retains oil film during the first critical minutes of operation, reducing scuffing risk on the shaft contact face. The hardness range specified for these arms is intended to balance wear resistance against the need for the arm to wear preferentially rather than the cam lobe or valve stem, a deliberate design choice in Nissan's valvetrain architecture.

What Happens When the Variant Is Wrong

A rocker arm that technically bolts on but carries the wrong pivot bore or tip radius will announce itself within the first few hundred kilometers — not with catastrophic failure, but with a persistent tick that grows louder as the mismatch wears both mating surfaces. By the time the noise becomes unacceptable, the shaft is scored, the valve stem cap is dished, and the repair scope has expanded from a simple arm swap to a full top-end refresh [NEED_CITE: valvetrain noise diagnosis and progressive wear patterns in KA-series engines]. Shops that skip the serial-level verification absorb this cost repeatedly.

Why Fitment Verification Belongs Before the Purchase Order

Our process for this 13257-40F06 rocker arm begins with your engine serial or a clear photograph of the existing rocker assembly on the head. We cross-check the pivot bore dimension, tip radius, and shaft interface against the production variant that matches your engine build. When the cross-reference path involves a superseded number, we document the substitution so your maintenance records stay traceable. Single-piece samples are available for physical fitment confirmation before you release a fleet quantity, because the cost of a sample is always less than the cost of a return shipment from a job site.

Documentation & Verification

• Commercial invoice listing each rocker arm variant and engine serial it was verified against
• Cross-reference sheet mapping 13257-40F06 to superseded numbers, marked reference only
• Dimensional inspection record covering pivot bore, tip radius, and runout per unit
• Warranty terms specifying coverage period and manufacturing defect scope
• Packing photographs showing set completeness before crate closure
• HS code and customs classification support for cross-border shipment

Fitment Check Before Installation

• Compare pivot bore diameter of the new Rocker Arm Set for Nissan KA24E against the removed original using a bore gauge
• Verify tip radius matches the valve stem cap profile; mismatch causes concentrated edge loading
• Confirm rocker shaft surface is within specification; a worn shaft will destroy a new arm rapidly
• Install one arm first and check for free rotation without lateral play before assembling the full set
• If any dimension disagrees with the original, halt installation and contact us with photographs for variant re-check

Send Us the Details That Lock In the Right Variant

Provide your engine serial number, the vehicle VIN, or a clear photograph of the nameplate and one of the existing rocker arms. If the nameplate is illegible, a photo of the casting marks on the original arm or the cylinder head casting number gives us enough to narrow the variant. We will return a confirmed part number with the cross-reference path documented, and we can ship a single sample for your bench verification before you authorize the full set.

Frequently Asked Questions

Q: How do I confirm this rocker arm set fits my specific Nissan model and year? A: Model year alone is not sufficient because Nissan revised the KA24E valvetrain across production runs. We need the engine serial number or a photograph of the nameplate to match your engine to the correct variant among 13257-40F06, -40F07, -40F16, or -40F17. Our technical team typically returns a confirmed fitment answer within two hours of receiving your engine details.

Q: Can 13257-40F06 and 13257-40F07 be used interchangeably? A: Not in every case. Although these numbers share a common base part, the suffix reflects changes in pivot bore tolerance and tip radius that Nissan introduced at specific engine serial breakpoints. Installing the wrong variant may result in valvetrain noise and accelerated shaft wear. We verify interchangeability against your engine serial before confirming any substitution.

Q: The nameplate is worn off and I only have the machine model. Can you still identify the right part? A: Yes. Send us a photograph of the cylinder head casting number, the existing rocker arm casting marks, or the engine block stamping. Combined with the vehicle model and approximate production year, these details allow us to narrow the correct variant. We can also send a sample for physical comparison against your original components.

Q: Why does the same base part number appear with several different suffixes? A: Each suffix corresponds to a production revision where Nissan altered one or more critical dimensions — typically the pivot bore diameter, tip radius, or shaft contact geometry — to address wear patterns or accommodate changes in adjacent valvetrain components. The correct suffix depends on your engine's production date and serial range, not just the vehicle model.

Q: Can I order one sample to confirm fitment before placing a bulk order? A: Yes. Our minimum order is one piece, and we encourage first-time buyers to order a single Rocker Arm Set for Nissan KA24E for bench fitment and clearance verification. Once you confirm the variant matches your engine, we release the remaining quantity from the same production batch to maintain dimensional consistency across your order.