Understanding and Replacing the Iconic 2JZ Valve Cover

Understanding the 2JZ Valve Cover

The 2JZ valve cover is an iconic piece in Toyota's popular 2JZ engine family. This twin-turbo inline 6 cylinder motor first debuted in 1991 and is still sought after by enthusiasts today for its immense tuning potential. But like any high-performance engine, the 2JZ requires proper maintenance and care to keep it running in top shape.

What Does the Valve Cover Do?

The valve cover, sometimes called the rocker cover, is a key component that performs several important functions:

• It encapsulates and protects the valve train - the valves, springs, retainers, keepers, and camshaft rides beneath it
• It controls oil splash and prevents excess oil from dripping into the combustion chambers
• It maintains proper ventilation within the valve train area

On the 2JZ engine, the factory valve cover is cast from aluminum alloy for light weight and durability. It features a distinctive red Toyota lettering across the top that has become signature to the 2JZ.

When to Replace the 2JZ Valve Cover

The 2JZ valve cover is generally very durable, but may need replacement over time under certain conditions, such as:

• Cracked, warped, or leaking valve cover - can cause oil burning issues or valve train damage
• Aftermarket upgrades - a new valve cover is sometimes required to accommodate performance modifications
• Preventative maintenance - some replace the cover as cheap insurance against problems

One weak point on the stock 2JZ valve cover is around the spark plug tube seals, which tend to become brittle and leak over time. Catching a leaky valve cover early and replacing it can prevent more expensive repairs down the road.

Choosing a Replacement 2JZ Valve Cover

When selecting a replacement 2JZ valve cover, you have a few options depending on your goals and budget:

• OEM Toyota valve cover - Most reliable option to restore it back to factory condition
• Upgraded billet aluminum cover - For maximum durability especially at high boost
• Machined OEM-style cover - Cost-effective upgrade over stock
• Custom valve covers - For show cars; polished, painted, etc.

Be sure to properly install the new valve cover with fresh gaskets, seals, and hardware. Also confirm that the PCV system is working correctly to prevent oil leaks or pressure issues.

Installing a New 2JZ Valve Cover

Replacing the aging factory 2JZ valve cover with a brand new OEM or high-performance aftermarket unit is a straightforward job any experienced DIY mechanic can tackle at home. Here are step-by-step instructions for the valve cover installation procedure:

Parts & Tools Needed

Gather the following items before getting started:

• New valve cover
• Valve cover gasket set
• RTV sealant
• Spark plug tube seals
• Engine oil
• Basic hand tools - sockets, ratchet, torque wrench, gaskets scrapers, rags, etc.

Step 1 - Disable Ignition and Remove Spark Plugs

First disconnect the negative battery cable to disable ignition. Then remove the coil packs and spark plug wires, labeling everything carefully for proper reinstallation. Finally, use a spark plug socket to remove all 6 spark plugs and set them aside.

Step 2 - Drain Oil and Remove Accessories

Drain out the old engine oil and remove any hoses, wiring, brackets, or accessories that impede access to the valve cover. The breather and PCV lines must also be detached.

Step 3 - Unbolt and Remove Old Cover

Use a 10mm socket or wrench to loosen and remove the 10 perimeter bolts holding the factory 2JZ valve cover in place. Carefully pry off and remove the old cover. Scrape any stubborn gasket material with a gasket scraper and clean the sealing surface thoroughly.

Step 4 - Install New Gaskets & Seals

Lay the new valve cover gasket into position on the cylinder head, pressing down firmly to adhere it. Install the small individual spark plug tube seals as well. Apply a thin layer of RTV sealant to the 4 corner areas of the gasket for bulletproof sealing.

Step 5 - Install New Valve Cover

Place the fresh 2JZ valve cover onto the engine, aligning it properly over the gasket. Insert the 10 bolts with washers and snug them down progressively in a criss-cross sequence. Then torque the bolts to 89 in-lbs to complete installation.

Step 6 - Reinstall Components and Refill Oil

Reconnect all hoses, wires, and accessories that were detached earlier around the valve cover area. Reinstall the spark plugs and ignition coils. Add fresh engine oil to replace what was lost during the job. Start up the engine and check for any leaks or issues.

With proper care taken during installation along with high-quality parts, your new 2JZ valve cover should provide years of reliable service!