What does 'file fit' mean for piston rings?

File fit rings are designed to be custom-gapped by the installer. You use a specialized file to reduce the end gap of the ring to the precise measurement required for your engine's cylinder bore. This allows for a more accurate seal compared to pre-gapped rings.

What is the advantage of +.005in oversize rings?

These rings are slightly larger than standard bore size. This is useful if your cylinder bore has been honed out to a +.005 inch over size, or if you need to achieve a specific ring gap by starting with a slightly larger ring.

Why are these rings not CARB approved?

Some engine components, particularly those that can affect emissions, require specific certifications for use in certain regions. These Mahle rings do not meet the California Air Resources Board (CARB) standards, meaning they cannot be legally sold or installed on vehicles registered in California.

Mahle Piston Ring Set 4325MS-15 - File Fit

Name: Mahle MS 4.320in+ .005in 1.5 1.5 3.0 mm File Fit Rings
Brand: Mahle
SKU: mahle-mahle-ms-4-320in-005in-1-5-1-5-3-0-mm-file-fit-rings-t14-29806
Price: 179.36 USD
Availability: BackOrder

Mahle MS 4.320in+ .005in 1.5 1.5 3.0 mm File Fit Rings

$179.36

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, 4325MS-15. Standard tension, 1.5mm, 1.5mm, 3.0mm sizes. +.005in. Not CARB approved.

Key Features

Fits Universal applications.
Standard tension ring set.
Top and second rings are 1.5mm.
Oil ring is 3.0mm.
Rings are +.005 inch oversize.
File fit design allows for custom ring gap setting.

⚠️ 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

Secure CheckoutFast Shipping631-982-0042

Product Details

This is a Mahle file fit piston ring set, part number 4325MS-15. These rings are designed for engine rebuilding where precise gap setting is needed. The set includes standard tension rings with dimensions of 1.5mm for the top and second rings, and 3.0mm for the oil ring. They are sized at +.005 inches, meaning they are slightly larger than standard bore size and require filing to achieve the correct piston ring gap for your specific cylinder bore.

Mahle is a well-known name in engine components, and these file fit rings are a solid option when you need to ensure the correct ring seal for optimal compression and oil control. The file fit design allows mechanics to custom-fit the ring gap to the exact cylinder bore, which is crucial for performance and longevity, especially in performance or heavily used engines. This method ensures a tighter seal, reducing blow-by and improving overall engine efficiency.

Because these rings require custom gapping by filing, they are best suited for experienced engine builders or professional mechanics. Please note that these rings are not CARB approved and cannot be shipped to California. Always refer to your vehicle's specific service manual for correct installation procedures and ring gap specifications.