Essential Information on the 1.6 Miata Valve Cover - Design, Maintenance & Repairs

Overview of the 1.6 Miata Valve Cover

The Mazda MX-5 Miata has been one of the most popular affordable sports cars since its introduction in 1989. The first generation Miata, known as the NA, was produced from 1989 to 1997 and featured a 1.6 liter dual overhead cam inline 4-cylinder engine.

One of the key components of this engine is the valve cover, which performs a few important functions. On the 1.6 liter Miata engine, the valve cover is made from aluminum and located at the top of the cylinder head.

Purpose of the Valve Cover

The valve cover serves several purposes on the 1.6 liter Miata engine:

• It protects the timing belt, camshafts, rocker arms, valve springs and other valve train components from dirt and debris.
• It contains splashes of oil from the valve train and prevents oil leaking externally.
• It provides an attachment point for the camshaft position sensor and breather hoses.
• Its shape helps promote proper airflow through the cylinder head.

Without the valve cover, the delicate valve train components would be exposed to contaminants and the engine would quickly wear out.

Valve Cover Design

The stock 1.6 Miata valve cover has a distinctive shape designed to fit around the dual overhead cams. Key features include:

• Made from cast aluminum for light weight and durability.
• Machined gasket surface to seal against the cylinder head.
• Reinforced cam cap areas prevent flexing.
• Ventilation holes allow blow-by gases to escape.
• Coil pack brackets position ignition coils.
• Swirl oiling holes feed oil to the camshafts.

These design elements all contribute to the proper functioning of the 1.6 liter Miata cylinder head.

Removing the Valve Cover

There are a few reasons why you may need to remove the 1.6 Miata valve cover:

• To access the camshafts, rockers or valves for servicing.
• To check for sludge buildup inside the engine.
• To replace the valve cover gasket if oil is leaking.
• To install aftermarket upgrades like camshafts.

The procedure for removing the valve cover involves:

1. Disconnecting the negative battery cable.
2. Removing engine covers and intake components for access.
3. Labeling and disconnecting any hoses or wiring.
4. Removing the coil packs by unbolting from the valve cover.
5. Unbolting and carefully lifting the valve cover off.

When re-installing, make sure to replace the valve cover gasket and tighten the bolts to the proper torque specifications.

Common Valve Cover Problems

Some common issues that can occur with the 1.6 Miata valve cover include:

• Cracked or warped valve cover - can cause oil leaks.
• Failed valve cover gasket - also leads to oil leaks.
• Excessive sludge buildup - clogs oiling passages.
• Faulty PCV valve or breather hoses.
• Stripped or broken coil pack brackets.

Typical symptoms of valve cover problems include oil leaks, rough engine operation, Check Engine lights for misfire or lean codes.

Aftermarket Valve Covers

There are a number of aftermarket valve cover options available for the 1.6 liter Miata:

• Lightweight covers - made from materials like carbon fiber to reduce weight.
• Polished or painted covers - for custom appearance.
• Coil relocation kits - moves coils off valve cover for Headers.
• Vented covers - improved ventilation for forced induction.

When installing an aftermarket valve cover, it’s critical to check for proper clearance with no binding and to use a quality gasket for a leak-free seal.

Maintenance and Repairs of the 1.6 Miata Valve Cover

To keep your 1.6 liter Miata engine running smoothly, it’s important to perform proper maintenance and repairs on the valve cover when needed.

Inspecting the Valve Cover

You should periodically inspect the valve cover for any signs of problems including:

• Oil leaks - inspect gasket for drying or damage.
• Sludge buildup - clean and improve oil quality to prevent.
• Damaged or stripped bolts - replace to maintain proper torque.
• Warped surface - resurface or replace cover.

Cleaning the Valve Cover

Over time, varnish and sludge can build up inside the valve cover, negatively affecting oil flow. Methods for cleaning include:

• Removing cover and spraying with gasket remover and degreaser.
• Using a soft wire brush to loosen stubborn deposits.
• Wiping surfaces clean with lint-free rags.
• Blowing out passages and holes with compressed air.

Avoid using abrasive pads or brushes that could damage the sealing surface.

Replacing the Valve Cover Gasket

If you have an oil leak from the valve cover, replacing the gasket can fix the issue. Steps include:

1. Cleaning mating surfaces of old gasket material.
2. Applying a small bead of RTV sealant to block mating surfaces.
3. Installing the new valve cover gasket.
4. Torquing cover bolts to OEM specifications.

Using a quality gasket and proper torque is critical to prevent leaks.

Upgrading the Valve Cover

As mentioned earlier, the 1.6 Miata valve cover can be upgraded for appearance, weight savings or performance:

• A polished or painted cover can really dress up an engine bay.
• Lightweight covers help rev faster and squeeze out every last HP.
• Coil relocation kits allow running long tube headers.
• Vented covers help reduce heat for forced induction setups.

Just make sure any upgraded valve cover properly fits your Miata’s cylinder head.

Conclusion

The valve cover on the 1.6 liter Miata engine plays an important role in protecting the valvetrain, controlling oil splash and supporting engine tuning upgrades. Keeping it properly maintained with gasket replacements as needed, cleaning sludge buildup, and installing upgrades like lightweight or vented covers can help keep your NA Miata's engine running strong for years to come.

FAQs

What is the valve cover on a 1.6 Miata?

The valve cover is an aluminum casting that bolts to the top of the cylinder head. It protects the camshafts, rockers, valves and other valve train components while also controlling oil splashing and providing attachment points for sensors and hoses.

Why does my Miata have an oil leak from the valve cover?

The most common cause of valve cover oil leaks is a failed or damaged valve cover gasket. The gasket seals the mating surfaces between the cover and cylinder head. Over time, the gasket can become brittle and leak.

How do I remove the 1.6 Miata valve cover?

Start by disconnecting the battery and removing engine covers/intake components for access. Label and remove any hoses or wiring attached to the cover. Unbolt the coil packs and carefully lift the valve cover off the cylinder head.

What are some upgrades available for the valve cover?

Some popular 1.6 Miata valve cover upgrades include lightweight carbon fiber or aluminum covers, custom polished/painted covers, coil relocation kits, and vented covers for forced induction engines.

How can I clean sludge buildup from inside the valve cover?

Use gasket remover, degreaser and a soft wire brush to loosen deposits inside the valve cover. Wipe clean with lint-free rags and blow out passages with compressed air. Avoid abrasive pads that could damage the surface.