What materials are used for the intake and exhaust valves?

The intake valves are made from NK-844 material, which offers high tensile strength at elevated temperatures. The exhaust valves are constructed from XH-428 material, known for its exceptional strength and heat resistance.

What kind of testing have these valves undergone?

These Severe Duty valves have been subjected to rigorous fatigue testing. In tests at 40,000 psi and 1400°F, the exhaust valves endured up to 100 million cycles, demonstrating significant durability.

Are these valves suitable for all engine types?

These valves are specifically designed for high-temperature gasoline engines. Their advanced materials and construction are intended to handle the stresses and heat associated with performance gasoline applications.

Specifications

Brand: Manley Performance
Part #: 11232-8
UPC: 807298048031

Manley Chevy Small Block Severe Duty Valves 2.020in. Head Dia. / 5.010in. OA L (Set of 8)

Name: Manley Chevy Small Block Severe Duty Valves 2.020in. Head Dia. / 5.010in. OA L (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-small-block-severe-duty-valves-2-020in-head-dia--t14-426955
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Chevy Small Block Severe Duty Valves. Set of 8, 2.020in head dia. / 5.010in OA L. Built for high-temp gasoline engines.

Key Features

This product is a set of 8 Manley Severe Duty valves.
Intake valves are made from NK-844 material, and exhaust valves are made from XH-428 material.
Valves feature chrome stems and hard tips for enhanced durability.
Under head areas are swirl polished and combustion faces are fully machined for improved airflow.
Designed for high-temperature gasoline engines.
Exhaust valves tested at 40,000 psi and 1400°F endured up to 100 million cycles in fatigue tests.

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About this part

Product Details

This set includes eight Manley Severe Duty valves, designed for Chevy small block engines. You get intake valves made from NK-844 material and exhaust valves crafted from XH-428 material. These valves are built to handle the demands of high-temperature gasoline engines, featuring chrome stems and hard tips for improved durability and a longer lifespan. The under-head areas are swirl polished, and the combustion faces are fully machined to help optimize airflow and combustion efficiency.

Manley's Severe Duty valves are put through rigorous fatigue testing. While normal valve stress is around 20,000 to 25,000 lbs, and bouncing on the seat can push that to 40,000 to 60,000 lbs, these exhaust valves have been tested at 40,000 psi and 1400°F, enduring up to 100 million cycles. This is a notable improvement over competitor valves that often fail after just 100,000 cycles. The XH-428 exhaust valve material offers nearly double the ultimate tensile strength at 1500°F compared to common EV-8 materials, and the NK-844 intake material shows over four times the ultimate tensile strength of other leading intake valve materials at 1000°F.