Pair New Ford/Mazda 4.0 OHV Cylinder Heads for Ranger, B4000, Explorer (1990-1995) W/ Head Gasket Set & Bolts, Water Pump & Timing Set

New Ford & Mazda 4.0L OHV Cylinder Heads Pair (1990–1995) – Includes Gasket Set, Bolts, Water Pump & Timing Kit

Complete Premium Cylinder Head Rebuild Kit with Professional-Grade Components

For the Ford and Mazda 4.0L OHV engines, “hammered” valve seats are a notorious failure point that leads to costly loss of compression and persistent misfires. Because these iron heads often run lean and hot, the repetitive impact of the valve eventually recedes the seat into the head casting—a process known as valve seat recession.

Here is a paragraph you can use to explain why your new castings are the definitive fix for this specific technical issue:

The Solution to 4.0L Valve Seat Recession

One of the primary failure modes for the Ford 4.0L OHV is the development of “hammered” or recessed valve seats, which occurs as the factory iron softens over thousands of heat cycles. This recession prevents the valves from sealing correctly, leading to a loss of cylinder pressure and “dead misses” that a simple tune-up won’t fix. Our new cast iron cylinder heads are engineered with reinforced seat areas designed to withstand the high thermal loads of the 4.0L combustion chamber. By replacing your worn castings with these precision-machined units, you eliminate the root cause of seat failure, restoring the airtight seal required for peak volumetric efficiency and consistent idle quality.

🛠️ In-House Machining Process

• Debris-Free Preparation: Every new casting is chemically cleaned and blown out to remove all residual machining oils, metal shavings, and manufacturing debris. This ensures your oiling system remains uncontaminated from the first start-up.

• In-House Precision Machining: Unlike “shelf-stock” heads, we perform all final machine work in-house. This includes final guide sizing and precision valve seat cutting to ensure perfect geometry and clearances before the head reaches the assembly bench.

• Pressure & Integrity Testing: To go beyond the factory standard, we pressure-test every head to 60 PSI. This verifies that the casting is free of porosity leaks or internal defects that could compromise the cooling or oiling systems.

• Dimensional Inspection: Our technicians perform a multi-point inspection of the gasket-sealing surface and bore alignment. This ensures the head is perfectly flat and meets tight OEM tolerances for a flawless fit.

• Professional Assembly & Setup: Valvetrain components are installed and verified in a clean-room environment. We check spring heights and seal seating to ensure the assembly is balanced and ready for high-performance use.

• Vacuum-Seal Verification: Every intake and exhaust port is Vacuum Tested. This guarantees a 100% airtight seal between the valves and seats, ensuring maximum compression and peak performance right out of the box.

📊 Technical Specifications

• Engine Size: 4.0L OHV
• Condition: Brand New
• Quantity: Sold as a Pair (2 Cylinder Heads)
• Assembly: Fully Assembled with Valves, Springs, and Seals
• Installation Note: Rocker arm torque specification is 30 ft-lbs
• Core Return Required
• Each Cylinder Head Includes: Valves and Springs Installed
• Additional Hardware: Head Gasket Set and Bolts, Water Pump and Timing Set

🚛 Fitment Data

Common Applications:

• Ford Aerostar: 1990–1994 Ford Aerostar 6-245 (4.0L)
• Ford Explorer: 1991–1994 Ford Explorer (4.0L)
• Mazda B4000: 1994 Mazda B4000 (4.0L)
• Mazda Navajo: 1991–1994 Mazda Navajo (4.0L)
• Ford Ranger: 1990–1994 Ford Ranger 6-245 (4.0L OHV)