Piston Rings by Bore & Ring Pack

Piston rings are bought on measurements, not applications: your finished bore size and the three groove widths in your pistons decide the set, and everything else is a detail. This page pulls together the ring sets we currently have in stock organized the way builders actually order them - by bore and ring pack: 24 ring sets from Hastings Piston Rings, Sealed Power, Perfect Circle, JE Pistons, Speed Pro, Mahle Motorsport, NPR, Total Seal, Clevite and Diamond Racing Products, from $39.99 to $381.57, covering bores from 4.000 to 4.500 in and packs from the classic 5/64 street pack through 1/16 and metric 1.5 mm packs down to thin .043 in and 1.0 mm race packs. Every set listed is in stock and ready to ship, and every order over $200 ships free.

OUR PISTON RING PICKS

Ring set	Pack / style	Key spec (from the product listing)	Price	Why it is here
Piston Ring Set 4.030 5/64 5/64 3/16	5/64 x 5/64 x 3/16 in, drop-in	4.030 in bore, steel, plasma moly, standard tension	$50.99	The street value hero: Hastings’ plasma-moly drop-in set in the classic 5/64 street pack, for a 4.030 in bore.
Piston Ring Set 4.000 Bore 1.5 1.5 3.0mm	1.5 x 1.5 x 3.0 mm, drop-in	4.000 in bore, steel, plasma moly, standard tension	$63.99	The metric-pack pick: the same Hastings plasma-moly, drop-in formula in the thinner 1.5 mm pack modern pistons use.
Piston Ring Set 4.030 Bore 1/16 1/16 3/16	1/16 x 1/16 x 3/16 in	4.030 in bore	$118.05	The 1/16-pack step up from Mahle Motorsport, for pistons grooved for the thinner 1/16 in compression rings.
Piston Ring Set 4.030 Classic 1/16 1/16 3/16	1/16 x 1/16 x 3/16 in, file-fit	4.030 in bore, ductile iron, plasma moly, Classic Race	$164.63	The file-fit race pick: Total Seal’s Classic Race set - you file the end gaps to your build instead of taking a drop-in gap.
Piston Ring Set 4.030 Gapls Top 1/16 1/16 3/16	1/16 x 1/16 x 3/16 in, file-fit, gapless top	4.030 in bore, ductile iron, Maxseal gapless top ring	$381.57	The top of this page’s ladder: Total Seal’s Maxseal set with a gapless top ring, file-fit, for a 4.030 in bore.

READ THE THREE NUMBERS BEFORE YOU ORDER ANYTHING

Every set on this page is named the same way: bore first, then the ring pack as three numbers - the top ring thickness, the second ring thickness, and the oil ring thickness. A 4.030 set in a 5/64 x 5/64 x 3/16 pack and a 4.030 set in a 1/16 x 1/16 x 3/16 pack fit the same bore but completely different pistons, because the pack has to match the groove widths machined into your pistons. The packs on this page span the range builders run into: 5/64 in (the classic street pack), 1/16 in, metric 1.5 mm and 1.2 mm packs, and the thin race packs - .043 in and Total Seal's 1.0 x 1.0 x 2.0 mm TFX sets. Oil rings vary the same way (3/16 in, 3.0 mm, 4.0 mm, 2.5 mm and 2.0 mm listings all appear here), so read all three numbers, not just the first two. And the bore number is your finished bore: a standard 4.000 in bore machined .030 over takes the 4.030 sets, not the 4.000 ones.

DROP-IN OR FILE-FIT - THE LISTING TELLS YOU

The product listings on this page state the style plainly, and it changes the job. Drop-in sets (the Hastings 2M-series, Sealed Power's moly sets, NPR's nitride V8 sets and the Clevite Cummins set among them) are sized for the stated bore with the end gap set by the maker. File-fit sets (JE Pistons' Sportsman series, Total Seal's Classic Race, Classic Steel and Gold sets, and Diamond's Pro Select) are supplied so the builder files each ring's end gap by hand - a file-fit set named for your bore is not a different bore size, the extra material is the filing allowance. File-fitting is not a defect or an upgrade by itself - it is how a builder sets the exact gap a given build needs. Either way, follow the ring maker's instructions that come with the set for gap and installation: the right gap depends on the build, and no listing page can set it for you.

MATERIALS, AS LISTED

Face material is the other line to read in each listing. Most of the street and street/strip sets here are plasma moly on steel (Hastings' 2M sets) or moly (Sealed Power, Perfect Circle and JE's plasma-moly ductile iron Sportsman sets). NPR's performance V8 sets are listed as steel, nitride; Total Seal's TFX sets as stainless steel; and the diesel end of the page is different again - Clevite's Cummins set is listed as ceramic chrome on ductile iron. Where a listing does not state a material, this page does not guess one - the Mahle Motorsport sets, for example, are listed by bore and pack only, and that is exactly how they are presented in the table above.

GAPLESS AND THIN-PACK SETS

The top of the ladder is Total Seal territory, and the listings name the styles: Gapless Top sets (including the Maxseal hero above and a gapless set listed for the Dodge Cummins), Gapless 2nd styles elsewhere in the wider range, thin .043 in file-fit sets (including a low-tension Classic Race Gold set), and the CS Classic Steel file-fit sets. These are specialist sets for builders who have already chosen that direction - if you are not sure whether a gapless or low-tension set suits your build, that is a conversation to have before ordering, not after the engine is together.

QUESTIONS BUILDERS ASK US

How do I know which bore size to order? Order for the finished, honed bore your block will actually run - not the bore it started at. If the block was machined .030 over a 4.000 in standard bore, you need the 4.030 sets. If you do not know the finished size, measure (or have your machinist measure) before ordering; a ring set cannot be stretched or shrunk to a different bore.

Can I run a 1/16 pack ring in a 5/64 groove piston, or the other way round? No. The ring pack must match the groove widths in your pistons - all three grooves. That is why this page is organized by pack as well as bore, and why the same 4.030 bore appears here in 5/64, 1/16, 1.5 mm and .043 packs. Check your piston paperwork or measure the grooves.

Do I need to file-fit a drop-in set? Drop-in sets are listed as drop-in because the maker sized them for the stated bore. File-fit sets are the opposite: filing is part of the job, and the listing says so. Whichever style you buy, check every ring's end gap in its own bore before final assembly and follow the maker's instructions in the box.

Are there sets here for LS and diesel builds? Yes - Sealed Power lists a moly set specifically for the LS 6.2L at a 4.065 in bore (1.5 x 1.5 x 2.5 mm pack), and the diesel end has Clevite's chrome Cummins 5.9L set and Total Seal's gapless Cummins set, both at a 4.016 in bore. Those listings name their applications; everything else on this page is sold on bore and pack measurements, so match the numbers. If you are stuck between two sets, call us at 213-549-4279 (Mon-Fri, 9am-5pm PT) with your bore and groove widths and we will match the set with you.

Shopping the wider range? Browse the full Pistons and Piston Rings collection, read our guides on the News & Builds blog, or see the page that came before this one: Quick Release Steering Wheel Kits.

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