{"product_id":"piston-ring-set-for-mercury-mariner-75-125-hp-3-4-cyl-3-500-std-bore-replaces-39-822321a12-sierra-18-3982","title":"Sierra 18-3982 Piston Ring Set, 3.500 Standard Bore, for Mercury 140-200 HP XR6\/MAG III V-6 Outboards","description":"\u003cp\u003eThe Sierra 18-3982 Piston Ring Set is a set of two piston rings sized for a 3.500 inch standard bore, built for Mercury 140-200 HP XR6\/MAG III V-6 outboard engines. It is manufactured as a direct equivalent to Mercury Marine 39-822321A12, giving boat owners and marine technicians a reliable replacement option when rebuilding or servicing the powerhead on these two-ring inline piston applications. Each ring is finished with a brushed exterior surface for proper seating and wear characteristics during break-in.\u003c\/p\u003e\u003cp\u003ePiston rings seal the combustion chamber, control oil consumption, and transfer heat from the piston to the cylinder wall, so correct bore sizing is critical to a good rebuild. This set is specified for the 3.500 inch standard bore listed for the 140-200 HP XR6\/MAG III V-6 application, matching the piston (18-4635 port \/ 18-4636 starboard) used in that engine family. Sierra manufactures its parts to meet or exceed the specifications of the original equipment part it replaces, making the 18-3982 a straightforward drop-in for engine rebuilds, top-end overhauls, or piston ring replacement jobs on the applicable Mercury outboards.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-3982\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Mercury Outboard 2 Ring Inline Pistons\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBore Size:\u003c\/strong\u003e 3.500 inches \/ Standard\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRings per Set:\u003c\/strong\u003e 2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.07 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Dimensions:\u003c\/strong\u003e 0.39 x 0.39 x 0.39 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Brushed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282124809\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eMercury 140-200 HP, XR6\/MAG III V-6 outboards, 3.500 inch standard bore (port and starboard piston applications)\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e39-822321A12\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-3982 piston ring set fit?\u003c\/strong\u003e It fits Mercury 140-200 HP XR6\/MAG III V-6 outboards with a 3.500 inch standard bore, matching both the port and starboard piston applications for that engine family.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many rings come in the 18-3982 set?\u003c\/strong\u003e The set includes two piston rings, matching the two-ring inline piston design used on the applicable Mercury 140-200 HP XR6\/MAG III V-6 outboards.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does the Sierra 18-3982 replace?\u003c\/strong\u003e Sierra 18-3982 is a direct equivalent to Mercury Marine part number 39-822321A12.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this ring set for a standard bore or an oversize bore?\u003c\/strong\u003e The 18-3982 set is sized for a 3.500 inch standard bore, not an oversize (.015 or.030) bore.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3982 piston ring set weigh?\u003c\/strong\u003e It weighs 0.07 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of the individual piston ring?\u003c\/strong\u003e Each ring in the 18-3982 set measures 0.39 x 0.39 x 0.39 inches.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs Sierra 18-3982 genuine Mercury or an aftermarket part?\u003c\/strong\u003e The 18-3982 is a Sierra-branded aftermarket ring set manufactured to meet or exceed the specifications of the Mercury Marine 39-822321A12 part it replaces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3982 set work with both the port and starboard pistons?\u003c\/strong\u003e Yes, the same 18-3982 ring part number is used with both the port piston (18-4635) and starboard piston (18-4636) on the 140-200 HP XR6\/MAG III V-6 application.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat finish do the Sierra 18-3982 piston rings have?\u003c\/strong\u003e The rings have a brushed exterior finish.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the UPC for the Sierra 18-3982 piston ring set?\u003c\/strong\u003e The UPC for the Sierra 18-3982 Piston Ring Set is 808282124809.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988170780891,"sku":"SIE-18-3982","price":40.42,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/18-3982__52369.1722490177.500.750.jpg?v=1785188340","url":"https:\/\/www.goodvibesmarina.com\/products\/piston-ring-set-for-mercury-mariner-75-125-hp-3-4-cyl-3-500-std-bore-replaces-39-822321a12-sierra-18-3982","provider":"Good Vibes Marina","version":"1.0","type":"link"}