What is the Napier hook design on the top ring?

The Napier hook is a specific shape on the top piston ring that helps it seal more effectively against the cylinder wall. This design is particularly beneficial for maintaining a strong seal under demanding engine conditions.

What does the 4.135-inch measurement refer to?

This measurement indicates the bore diameter of the cylinder that these piston rings are designed to fit. It's crucial to match this size to your engine's cylinder bore for proper installation and sealing.

Are these rings suitable for all engine builds?

These are performance steel rings with a Napier hook design, making them well-suited for engine builds that require robust sealing and durability. However, they are not CARB approved and cannot be shipped to California.

Mahle Piston Rings 3021271B - Performance Steel Napier

Name: Mahle Rings Perf Steel Napier THM-13 4.135in x .1.5MM .150RW Bulk Plain Ring Set (48 Qty Bulk Pack)
Brand: Mahle OE
SKU: mahle-oe-mahle-rings-perf-steel-napier-thm-13-4-135in-x-1-5mm-150rw-bulk-plain-r-t14-47684
Price: 348.86 USD
Availability: BackOrder

Mahle Rings Perf Steel Napier THM-13 4.135in x .1.5MM .150RW Bulk Plain Ring Set (48 Qty Bulk Pack)

$348.86

On Backorder

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

Mahle OE Performance Steel Napier Piston Rings. Bulk pack of 48 rings for engine builds.

Key Features

This is a bulk pack containing 48 Mahle Performance Steel Napier piston rings.
The top ring features a Napier hook design for improved sealing.
Designed for a 4.135-inch cylinder bore.
Ring dimensions are 1.5mm for the top ring, 1.5mm for the second ring, and 0.150-inch for the oil ring.
Constructed from steel for good durability and wear resistance.
Not CARB approved and cannot be shipped to California.

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Product Details

These Mahle Performance Steel Napier piston rings are built with a Napier hook design, which is a unique shape that helps the top ring seal better against the cylinder wall, especially under high load conditions. This particular set is for a 4.135-inch bore and features a 1.5mm top ring, a 1.5mm second ring, and a 0.150-inch oil ring, all made from durable steel for long-lasting performance.

When you're rebuilding an engine, especially one that's going to see some serious work, the piston rings are critical for sealing the combustion chamber and controlling oil. The Napier hook on the top ring is a smart design choice that helps maintain a solid seal as the piston moves, reducing blow-by and improving efficiency. This bulk pack of 48 rings means you'll have plenty on hand for multiple engine builds or if you need spares.

Because these are steel rings, they offer good durability and wear resistance. They are designed to fit right into the corresponding piston grooves, making installation straightforward for a mechanic. Just remember, these rings are not CARB approved and cannot be shipped to California.