Product NO.

Product Information Cylinder Head

Factory part numbers for the Z24 SOHC 2.4L head include  11041‑13F00, 11041‑22G00, 11041‑20G13 for the standard 4-spark (one plug/cylinder) head, and 11041‑20G18 for the dual-spark (two plugs per cylinder) NAPS‑Z version. These numbers appear in Nissan parts catalogs and aftermarket listings. For clarity, common OEM part numbers are summarized below (source references in captions):

Material and Construction

The Z24’s cylinder head is a cast aluminum alloy forging. Like other Nissan Z-series heads, it features iron/steel valve seat inserts to withstand wear. Aftermarket suppliers note that Z24 heads use “steel rings inserted onto exhaust seats (3-angle)”, implying that exhaust ports are hardened with nickel-alloy seats. In summary, the stock head is an aluminum cast head with pressed-in hardened valve seats.

Valve Train Configuration

The Z24 head is SOHC, 8‑valve (2 intake, 2 exhaust per cylinder). All Z-series engines share this single-overhead-cam, 8-valve layout. U.S. NAPS‑Z (anti‑pollution) versions of the Z24 have dual spark plugs per cylinder (total of 8 plugs). Valve clearance (measured cold/hot as specified) is 0.012 inch on both intake and exhaust. (In practice, adjustment is done with the engine hot per the shop manual.)

Vehicle Applications (Models & Years)

The Z24 head was used in mid-1980s Nissan/Datsun trucks, SUVs, and industrial engines. Key applications include:

Table: Selected Nissan models using the Z24 2.4L engine head.

Common Failure Points and Issues

    • Blown head gaskets: Z24 heads are notorious for head-gasket failures. Many owners report gaskets blowing between cylinders (often #2–3) after overheating or high mileage.

    • Overheating/warpage: Thermal stress can warp or crack the head deck. Forum reports note that even one serious overheat can warp the Z24 head and lead to leaks. (However, some experts argue the real issue is loss of clamp force in the bolt threads.)

    • Valve guide wear: Overheating or lean running can cause abnormal valve-stem/guide wear in high-hour Z24 heads. Excessive guide clearance will cause smoking and loss of compression.

    • Intake manifold gasket leaks: Especially on high-hour engines, the intake (and exhaust) manifold gaskets are prone to leaking oil or coolant. These are often discovered when servicing the head or during engine rebuild.

    • Block/head casting defects: Some sources suggest early Z24 engines had poor block metallurgy or thin head decks, exacerbating gasket failure. In practice, always inspect the head and block for cracks or distortion when doing head service.

Maintenance Recommendations

    • Head bolt retorque: Nissan’s service procedure calls for periodic retorquing of head bolts (e.g. at every major tune-up). In other words, after initial assembly the bolts should be loosened and retightened by the book to maintain clamp load. This prevents gradual loosening and gasket failure.

    • New head gasket and bolts: Always install a new multi-layer steel (MLS) head gasket and new head bolts (if one-time torque bolts) whenever removing the head. Clean and flatten both the head and block decks before assembly.

    • Valve clearance: Check/adjust the valve lash at scheduled intervals. Nissan specifies 0.012 in (0.30 mm) intake and 0.012 in exhaust (engine hot). Proper clearance prolongs valve-train life.

    • Cooling system care: Keep the cooling system in top condition – use the correct thermostat and coolant mixture. Notably, avoid GM-type “Dexcool” or other OAT coolants; users report that those formulations can corrode head gaskets on these engines. A quality ethylene-glycol coolant (traditional blue/green) is recommended.

    • Installation tips: Lubricate all head-bolt threads, heads and washers with clean engine oil before torquing. Also lock or block the timing-chain tensioner when removing/installing the head to prevent it from dropping out. Ensure all coolant and oil passages are clean. Re-install the head at Top-Dead-Center #1 cylinder to ease timing re-assembly.

Torque Specifications and Installation

Proper torque sequence and values are critical. Nissan (and remanufacturer) procedures typically use a multi-stage pattern. For example, one documented sequence is:

    • Step 1: Tighten all 10 head bolts to 29 N·m (≈21 ft‑lb).

    • Step 2: Tighten all bolts to 78 N·m (≈58 ft‑lb).

    • Step 3: Loosen all bolts completely (releasing clamping stress).

    • Step 4: Retighten all bolts to 29 N·m again.

    • Step 5: Final torque, turn all bolts an additional 90° (one-quarter turn).

This yields a final clamp equivalent to roughly 80–90 ft‑lb per bolt. The exact bolt order must be followed (typically center-outward in a criss-cross 10-bolt pattern). In all cases, use a calibrated torque wrench and follow manufacturer or remanufacturer instructions. All torque values above are supported by industry remanufacturer documentation.

Aftermarket and Replacement Head Options

Apart from OEM/Nissan parts, several aftermarket heads and reconditioning services exist:

    • Remanufactured OEM heads: Suppliers like Powertrain Products offer fully remanufactured Z24 heads built to factory specs (model for 11/82–4/93 Z24 engines). These are often brand-new castings refurbished with new valves/springs.

    • New aftermarket heads: Vendors (e.g. EnginePartStore) sell new “crate” Z24 heads. These are castings claimed stronger than stock (reinforced ribs, thicker seats, nickel-alloy coatings). Such heads come bare (no valves) and are advertised to meet or exceed OEM durability.

    • Performance heads: ProMaxx Performance offers a bolt-on high-flow Z24 head machined from the OE casting. It retains OEM mounting but is ported for better airflow. (No factory DOHC Z24 head exists; KA24DE 16‑valve heads can be retrofitted but require custom manifolds/timing.)

    • Salvage or OEM parts: Used Nissan Z24 heads from salvage yards are also reconditioned by machine shops. Rebuilding a stock head (resurfacing, new guides/seats, valve job) is common.

    • Fasteners: High-strength head-stud kits (ARP or OEM studs) can be substituted for the stock bolts. Some builders use KA24E head studs, which fit with minimal modification, to improve clamp reliability.

Note: Whenever fitting an aftermarket or reconditioned head, follow the same installation and torque procedures. Use matching valves, springs, and seals per spec. Verify gasket match (4‑plug vs 8‑plug versions) and port alignment before assembly.