Unleashing Power: The 6.4L HEMI V8 Engine Explained

Chrysler currently produces the largest OE gasoline V8 engine commercially available, and it stuffs it in a multitude of vehicles from Dodge Chargers to RAM trucks.

The 6.4L HEMI V8, known by the codename “Apache”, is a medium-duty 90-degree pushrod V8 with two large valves per cylinder, 16 spark plugs, 410 horsepower and 429ft-lbs of torque. Featuring all-forged internals, cross bolted main journals, a nodular cast-iron block and aluminum heads – Chrysler went all out on what would become one of the best V8s on the block in some time.

It is a gasoline V8 in a 3/4 ton truck though, right? So it has to be thirsty… or so you would think.

We are here to tell you that yes, absolutely – it is. But not as bad as you would think.

The vehicle of choice in this story is a 2017 RAM 2500 Power Wagon, which when stock had 285/70R17D Goodyear Wrangler Duratrac tires and a gear ratio of 4.11. Stock, the vehicle saw 12-13mpg returns in the city, and 16-17mpg on the highway.

In it’s current iteration, the Power Wagon is now rolling on 37×13.50R20E Falken Wildpeak MT’s and 20×9.5” Trail Ready Beadlock wheels, and returns roughly the same fuel economy numbers.

So yes, the Apache is thirsty – but its a thorn in your side you can live with.

FREQUENTLY ASKED QUESTIONS

How reliable is the 6.4L HEMI engine for long-term use?

The 6.4L HEMI engine is celebrated for its robust performance and reliability over the long haul. This V8 powerhouse is known for delivering impressive horsepower and torque, making it a favorite among enthusiasts who value both power and dependability.

Durability and Longevity

Owners report that this engine consistently performs well over extended periods, showcasing remarkable endurance under normal driving conditions. It’s designed with American pushrod technology, a testament to its sturdy construction, contributing to its long lifespan. With proper maintenance, the 6.4L HEMI can efficiently cover hundreds of thousands of miles.

Warranty and Assurance

To top it off, the engine typically comes with a substantial factory warranty, often around five years or 100,000 miles, providing additional peace of mind to users. This warranty is a strong indicator of the manufacturer’s confidence in the engine’s longevity and reliability.

Summary

Overall, the 6.4L HEMI engine stands out as a reliable option for those seeking a V8 that’s built to last. Its track record of durability, combined with robust warranty support, makes it a solid choice for long-term use.

What maintenance is recommended for the 6.4L HEMI engine to ensure its longevity?

To ensure the longevity of your 6.4L HEMI engine, it’s crucial to adhere to specific maintenance practices:

• Oil Selection and Change: This engine relies on high-quality, thin 0W-40 oil. Always use the recommended oil to ensure optimal performance. Regular oil changes are essential, so stick to the manufacturer’s schedule to keep the engine running smoothly.
• Cylinder Deactivation System Care: The 6.4L HEMI features a Cylinder Deactivation System that benefits significantly from using clean oil. Fresh oil helps maintain efficient engine operation, particularly with this system.
• Routine Inspections and Services: Regularly check all fluid levels, and inspect components like spark plugs, air filters, and belts. Address any wear and tear promptly to prevent long-term damage.
• Keep It Clean: Ensure that the engine bay remains free from debris. This helps components function properly and reduces the risk of overheating.

By following these maintenance tips, you can enjoy the powerful performance of your 6.4L HEMI engine for years to come.

Read More: Under the Hood Insight: What Oil Testing Can Tell You About Engine Health

What are the common problems associated with the 6.4L HEMI engine?

The 6.4L HEMI engine is renowned for its power and reliability, but like any machine, it’s not without its quirks. Here’s a closer look at some common issues you might encounter:

• Hemi Ticking Sound: A familiar trait among HEMI engines, this subtle ticking noise is linked to the engine’s Multiple Displacement System (MDS). While the noise might be unsettling, it’s typically harmless. Proper maintenance, including regular oil changes using 0W-40 weight oil, is crucial.
• Cylinder Deactivation Sensitivity: The engine’s MDS system requires clean, specific oil to function optimally. Skipping oil changes or using the wrong oil can lead to performance issues.
• Exhaust Manifold Issues: The stock exhaust manifold is prone to distortion from high temperatures, potentially causing the manifold to warp and the studs to fail. This could lead to exhaust leaks and might require replacement parts.
• Engine Bottom End Limitations: Designed for durability rather than extreme power boosts, the stock engine’s bottom end can struggle under added stress. Non-forged pistons can limit the engine’s ability to handle significant power increases without risk of damage.

In Conclusion

The 6.4L HEMI is generally a robust engine, especially when used within its intended parameters. Regular maintenance and using recommended materials can help prevent many common issues, ensuring longevity and performance.

Why is the 6.4L HEMI engine not suitable for high levels of boost or power modifications?

The 6.4L HEMI engine, while powerful in its stock form, presents some limitations when it comes to handling high levels of boost or significant power enhancements. Here’s why:

1. Piston Construction: The engine’s pistons are not forged, which is a key factor when considering modifications for higher power output. Forged pistons are typically more durable under increased pressure and heat, making them essential for high-boost applications. In the 6.4L HEMI, the pistons lack sufficient material between the ring lands and the top, making them vulnerable to damage under intense conditions.
2. Bottom-End Durability: The engine’s bottom end, which includes the crankshaft, connecting rods, and related components, isn’t designed to withstand the additional stress that comes with increased power. This foundational weakness means that the engine is more susceptible to failures if pushed beyond its intended performance limits.
3. Exhaust Manifold Concerns: Another challenge is the exhaust manifold. Under high heat and pressure, the manifold may warp. This distortion can lead to the failure of the fastening studs, potentially causing leaks or further mechanical issues.

Overall, while the 6.4L HEMI is a robust engine for standard applications, these structural components make it less ideal for heavy modifications aimed at significantly boosting power and performance.