What is the compression ratio for these pistons?

These Mahle pistons are designed for a 16.0:1 compression ratio. This is an updated ratio optimized for performance in the GM 6.6L Duramax L5P engine.

What is the purpose of the thermal barrier coating?

The thermal barrier coating on the piston crown helps to reflect heat away from the combustion chamber. This reduces piston temperatures, protecting the component from extreme thermal stress and improving overall engine efficiency.

Are these pistons suitable for stock engines?

These are performance cast pistons designed for the GM 6.6L Duramax L5P engine. While they can be used in a stock rebuild, they are built to handle higher stresses often found in modified or performance applications. Always ensure proper installation and compatibility with your specific engine build.

Mahle GM 6.6L L5P Piston Set 197987995T

Name: Mahle MS GM 6.6L L5P 4.095in Bore 3.898in Stk 6.417in Rod -41.2cc 16.0 CR w/Thermal Barrier Set of 8
Brand: Mahle
SKU: mahle-mahle-ms-gm-6-6l-l5p-4-095in-bore-3-898in-stk-6-417in-rod-41-2cc-16-0-cr-w-t14-848319
Price: 2248.12 USD
Availability: BackOrder

Mahle MS GM 6.6L L5P 4.095in Bore 3.898in Stk 6.417in Rod -41.2cc 16.0 CR w/Thermal Barrier Set of 8

$2248.12

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Mahle GM 6.6L L5P diesel engine piston set. Features thermal barrier coating and 16.0 CR.

Key Features

Set of 8 Mahle cast performance pistons for GM 6.6L Duramax L5P diesel engines.
4.095 inch bore size.
Designed for a 3.898 inch stroke and 6.417 inch connecting rod.
Features -41.2cc valve reliefs for proper valve clearance.
Optimized for a 16.0:1 compression ratio.
Includes a thermal barrier coating (TBC) on the piston crown to reduce heat.

This piston set is designed for GM 6.6L Duramax 411 cu in. diesel engines. It is not CARB approved and cannot be shipped to California.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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Product Details

This is a set of Mahle performance cast pistons specifically for the GM 6.6L Duramax L5P diesel engine. These pistons are built to handle the demands of a performance diesel application, featuring a 4.095-inch bore and designed to work with a 3.898-inch stroke and a 6.417-inch connecting rod. The -41.2cc valve reliefs are precisely machined to accommodate the L5P's valve train geometry, and the 16.0:1 compression ratio is optimized for performance and efficiency in this engine platform.

Mahle has included a thermal barrier coating (TBC) on the piston crown. This advanced coating helps to reflect heat away from the combustion chamber, reducing overall temperatures and protecting the piston from extreme thermal stress. This is particularly important in high-performance diesel engines where combustion temperatures can get very high. The pistons are cast from a durable alloy and weigh approximately 956 grams each, ensuring a solid build that's ready for serious work. The 1.417-inch wrist pin diameter is standard for many performance diesel applications.

This set includes all eight pistons needed to rebuild your L5P engine. Please note that this part is not CARB approved and cannot be shipped to California. Always refer to the manufacturer's installation instructions for proper fitment and assembly procedures.