What does 'file fit' mean for piston rings?

File fit rings mean you need to manually adjust the end gap of the top and second rings to match your engine's cylinder bore size and expected operating temperature. This allows for a more precise fit compared to pre-gapped rings.

What is the significance of the 0.005in+ size?

The '+0.005in' indicates that these rings are slightly larger than standard and are intended for a cylinder bore that has been honed or bored out by 0.005 inches. This is common when rebuilding an engine to ensure a proper fit.

Why can't these rings ship to California?

These piston rings are not CARB (California Air Resources Board) approved. This means they do not meet California's emissions standards and therefore cannot be legally sold or shipped into the state.

Mahle Piston Rings 3903MS-15 - File Fit

Name: Mahle MS 3.989in+.005in 1.5 1.5 3.0 mm File Fit Rings
Brand: Mahle
SKU: mahle-mahle-ms-3-989in-005in-1-5-1-5-3-0-mm-file-fit-rings-t14-29822
Price: 158.86 USD
Availability: BackOrder

Mahle MS 3.989in+.005in 1.5 1.5 3.0 mm File Fit Rings

$158.86

On Backorder

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

Mahle file fit piston ring set for 3.989in bore. Features 1.5mm/1.5mm/3.0mm ring sizes.

Key Features

This is a Mahle file fit piston ring set.
Designed for a 3.989-inch bore with a 0.005-inch oversize.
Features 1.5mm top and second rings, and a 3.0mm oil ring.
File fit design allows for precise ring gap setting.
Not CARB approved; cannot ship 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 Mahle file fit piston ring set, designed for a 3.989-inch bore with a 0.005-inch oversize. The ring dimensions are 1.5mm for the top and second rings, and 3.0mm for the oil ring. File fit rings give you the flexibility to precisely set the ring gap for your specific engine build, which is crucial for optimal performance and sealing, especially in performance or rebuilt engines.

Mahle is a well-known name in engine components, and this set is built to meet the demands of engine rebuilding. The file fit design means you'll need to carefully measure and file the ends of the top and second rings to achieve the correct gap before installation. This process ensures the rings expand properly within the cylinder bore under heat and pressure, preventing them from butting up and causing damage. This set is a solid option for mechanics and DIYers looking for precise control over their engine's internal sealing.

Please note that this ring set is not CARB approved and cannot be shipped to California. Always refer to your engine's specific service manual for correct ring gap specifications and installation procedures.