All About the Legendary 2JZ-GE Valve Cover - Upgrades and Maintenance

Understanding the 2JZ-GE Valve Cover

The 2JZ-GE is a legendary 3.0L inline 6-cylinder gasoline engine produced by Toyota for use in luxury performance vehicles like the Lexus IS300. This robust powerplant is revered in tuning circles for its immense power potential, thanks in part to its strong internals and excellent turbocharged configurations. One key component of the 2JZ-GE valvetrain is the valve cover, which plays an important role in engine operation and maintenance.

Valve Cover Function

The valve cover is a removable metal or plastic cover that sits on top of the cylinder head. Its main functions are:

• Protecting the valve train components like the rocker arms, valve springs, camshaft, etc. from dirt and debris.
• Containing engine oil spatter and splashing from within the valvetrain.
• Allowing proper ventilation within the cylinder head.
• Providing an access point for valve adjustments.

On the 2JZ-GE, the valve cover contains oil splash guards which prevent excessive oil from impacting valve train operation. It also has molded gaskets which form a seal, preventing oil leaks. Breather hoses route harmful blow-by gases out of the valve area as well.

2JZ-GE Valve Cover Variants

There were a few different Toyota OEM valve covers used on the 2JZ-GE over its production run:

• Cast aluminum silver valve cover - This is the most common original 2JZ-GE valve cover, used on early model engines. It has Toyota lettering embossed on top.
• Cast aluminum black wrinkle finish valve cover - A later design valve cover also carrying the Toyota name on top. The wrinkle coat finish helps retain oil better.
• Plastic black valve cover - The most modern cost-reduced valve cover Toyota used lacks the embossed lettering. A removable oil cap is installed.

There are also many aftermarket valve covers available with different finishes and designs to customize the 2JZ's appearance.

Removing the 2JZ-GE Valve Cover

The valve cover must be removed to access the valve train for inspection, adjustments, repairs, or upgrades. The procedure is:

1. Disconnect negative battery terminal.
2. Remove any hoses or wiring connected to the valve cover.
3. Remove the oil fill cap if non-OEM cover is installed.
4. Loosen and remove the bolts securing the cover perimeter.
5. Carefully pry off the cover starting at the camshaft end. Watch for any stuck gaskets.
6. Clean the sealing surfaces thoroughly.

Be very gentle when removing the valve cover to avoid damaging the gasket surfaces or any internal components. The goal is to get the cover off smoothly and reseal it properly during reinstallation.

Reinstalling the Valve Cover

When reinstalling the OEM or aftermarket valve cover, be sure to:

• Replace the valve cover gasket with a new Toyota gasket or OEM equivalent.
• Apply a light film of gasket sealant if recommended by the maker.
• Torque the valve cover bolts to factory specifications in the proper sequence.
• Reconnect all hoses and electrical connectors properly.
• Refill the engine oil to proper level.
• Check for leak after running engine.

Taking the time to reseal the valve cover correctly will prevent messy oil leaks and ensure optimum engine performance.

Maintaining the 2JZ-GE Valve Cover

Like any engine component, the 2JZ-GE valve cover requires periodic inspection and maintenance for maximum longevity. Here are some tips:

Watch for Leaks

Frequently check around the valve cover gasket for any signs of oil seepage or dripping. Replace the gasket promptly if leaks are found to prevent extra engine damage.

Check the PCV System

Make sure the PCV (positive crankcase ventilation) breather hoses are in good condition, ensuring blowby vapors vent properly. Clogged PCV lines can increase pressure and blow out the valve cover gasket.

Listen for Noise

Strange valve train noise like tapping or rattling can indicate an issue with a valvetrain component. Remove the cover and inspect the rockers, cam, valves, etc. for anything loose or damaged.

Adjust the Valves

If valve lash has shifted, performance will suffer. Periodically check and adjust valve clearances to factory specs for maximum power.

Inspect the Gasket Surface

When removing the valve cover, check the sealing surface for warpage or damage. Refinish or replace the cover if the surface is compromised and won't seal.

By proactively maintaining the 2JZ valve cover, you can avoid many annoying engine issues down the road.

2JZ-GE Valve Cover Upgrades

Here are some popular valve cover upgrades to improve the performance or aesthetics of the 2JZ-GE:

Aftermarket Valve Covers

Many companies like HKS, JUN, and TRUST offer billet aluminum valve covers for the 2JZ to replace the OEM cover. Benefits include better oil retention, aluminum construction, and a polished or painted finish for a custom look.

Vacuum-Actuated Valve Covers

An upgrade for high boost 2JZ builds, these valve covers have vacuum-actuated vents that help regulate crankcase pressure for optimized performance.

Valve Cover Spacers

Small spacers are installed between the valve cover and cylinder head to provide extra valve train clearance. This allows running more aggressive camshaft profiles.

Breather Tank Installation

Adding a catch can or breather tank to the PCV system provides extra oil vapor volume to handle blowby at high power levels without pressurizing the crankcase.

Ventilation Modifications

Drilling or adding ports to the OEM valve cover can alter crankcase airflow dynamics. This is an economical way to experiment with ventilation without replacing the valve cover.

With some smart upgrades and proper maintenance, the 2JZ-GE valve cover will provide many miles of reliable high performance service.

FAQs

What is the valve cover gasket material on a 2JZ-GE?

The OEM 2JZ-GE valve cover gasket is typically made from multilayer steel or sometimes silicone/rubber materials. Aftermarket gaskets may use advanced multilayer steel, or Viton rubber for maximum durability.

How often should I replace the 2JZ valve cover gasket?

Inspect the valve cover gasket every 60k miles or so. It's good practice to replace it whenever the valve cover is removed for service. Use a fresh gasket to ensure a leak-free seal.

What torque spec should I use for 2JZ valve cover bolts?

The factory torque spec for the Toyota 2JZ-GE valve cover bolts is: 8mm bolts: 14 ft-lbs 10mm bolts: 18 ft-lbs Always torque bolts in the proper OEM sequence for even clamping force.

Will an aftermarket 2JZ valve cover fit my Supra?

Many aftermarket valve covers are direct bolt-on replacements for the OEM 2JZ-GE covers. However, some tuning focused covers may not be compatible with non-Supra engine swaps so check fitment before buying.

What causes valve cover oil leaks on a 2JZ-GE?

The most common causes are worn valve cover gasket, warped sealing surface, clogged PCV system leading to excessive blowby pressure, or incorrect valve cover bolt torque procedure.