What is the compression ratio with these Mahle pistons?

These Mahle pistons feature a -40.6cc dish volume, which results in a 16.0:1 compression ratio when installed in the GM 6.6L L5P Duramax engine. This ratio is optimized for diesel combustion.

What is the benefit of the thermal barrier coating?

The thermal barrier coating on the piston crown helps to reflect heat away from the combustion chamber. This can contribute to improved combustion efficiency and increased durability, especially under heavy loads or high operating temperatures.

Are these pistons suitable for all 6.6L Duramax engines?

These pistons are specifically designed for the GM 6.6L Duramax L5P engine. It is important to verify fitment for your specific engine model and year before purchasing, as other Duramax variants may have different requirements.

Mahle GM 6.6L L5P Piston Set 197987855T

Name: Mahle MS GM 6.6L L5P 4.055in Bore 3.898in Stk 6.417in Rod -40.6cc 16.0 CR w/Thermal Barrier Set of 8
Brand: Mahle
SKU: mahle-mahle-ms-gm-6-6l-l5p-4-055in-bore-3-898in-stk-6-417in-rod-40-6cc-16-0-cr-w-t14-848314
Price: 2049.20 USD
Availability: BackOrder

Mahle MS GM 6.6L L5P 4.055in Bore 3.898in Stk 6.417in Rod -40.6cc 16.0 CR w/Thermal Barrier Set of 8

$2049.20

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 16.0:1 compression ratio for improved performance.

Key Features

Fits GM 6.6L Duramax L5P diesel engines.
Set includes 8 cast performance pistons.
Designed for a 4.055 inch bore and 3.898 inch stroke.
Features a -40.6cc dish volume for a 16.0:1 compression ratio.
Includes a thermal barrier coating on the piston crown.
Piston pin diameter is 1.417 inches.

These pistons are designed for GM 6.6L Duramax 403 cu in. diesel engines. They are 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 MS pistons specifically made for the GM 6.6L Duramax L5P diesel engine. These pistons are designed for a 4.055-inch bore and feature a 3.898-inch stroke with a 6.417-inch rod length. They come with a -40.6cc dish volume, resulting in a 16.0:1 compression ratio, and include a thermal barrier coating on the crown.

Mahle builds these pistons with a cast performance design, suitable for the 403 cubic inch displacement of the L5P Duramax. The thermal barrier coating on the piston crown helps to reflect heat away from the combustion chamber, which can lead to improved efficiency and durability under demanding conditions. The 16.0:1 compression ratio is optimized for diesel combustion, working with the specific combustion chamber design of the L5P engine. Each piston weighs approximately 925 grams and uses a 1.417-inch pin.

This set includes eight pistons, enough to rebuild a complete engine. Please note that these pistons are not CARB approved and cannot be shipped to California. It's always a good idea to consult with your engine builder or a qualified mechanic to ensure these pistons are the right choice for your specific build and to discuss any other components you might need for your engine overhaul.