{"product_id":"sierra-18-3911-piston-ring-set-020-oversize-for-johnson-evinrude-25-35-hp-2-cyl-60-75-hp-3-cyl-outboards-replaces-omc-396378","title":"Sierra Piston Ring Set 18-3911,.020 Oversize 3.020 Inch Bore, Fits 25-35 HP 2-Cyl and 60-75 HP 3-Cyl Outboards, Replaces 396378","description":"\u003cp\u003eThe Sierra 18-3911 is a piston ring set engineered for outboard engines with a.020 inch overbore, giving the piston a 3.020 inch bore diameter once the cylinder has been rebored.020 inch over standard. It is designed for use on 25-35 HP 2-cylinder outboards and on 60-75 HP 3-cylinder outboards that share the same 3.020 inch bore specification, making it a common rebuild part for these Evinrude inline engine families. The set directly replaces OEM piston ring number 396378, so it can be installed as a like-for-like match during a piston and ring rebuild without altering the original engine specification.\u003c\/p\u003e\u003cp\u003ePiston rings seal the combustion chamber, control oil consumption, and transfer heat away from the piston to the cylinder wall, so fitting the correct oversize is critical to maintaining proper compression and preventing blow-by after a cylinder has been bored. Because 18-3911 is sized specifically for the.020 inch overbore, it should only be installed after the block has been machined to that dimension; a standard-bore engine requires the standard-size ring set instead. This part is sold under Sierra's own part numbering and is built to the compact dimensions and light weight typical of a small-engine ring set, making it easy to stock alongside the matching piston, wrist pin, and circlip parts used in the same rebuild.\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 18-3911\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Piston Ring Set\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999542762\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.06 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\u003eCylinder Bore Size:\u003c\/strong\u003e 3.020 inches (.020 inch oversize)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e 25-35 HP 2-cylinder outboard; 60-75 HP 3-cylinder outboard\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 396378\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Evinrude Outboard Inline Piston and Rings\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e25-35 HP, 2-cylinder outboard, 3.020 inch bore (.020 inch oversize)\u003c\/li\u003e\n\u003cli\u003e60-75 HP, 3-cylinder outboard, 3.020 inch bore (.020 inch oversize)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e396378\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM number does the Sierra 18-3911 piston ring set replace?\u003c\/strong\u003e It replaces OEM piston ring number 396378, so the Sierra 18-3911 is a direct cross-reference for engines calling for that OEM part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does part number 18-3911 fit?\u003c\/strong\u003e This piston ring set fits 25-35 HP 2-cylinder outboards and 60-75 HP 3-cylinder outboards that use a 3.020 inch cylinder bore.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-3911 ring set a standard bore size or an oversize?\u003c\/strong\u003e It is a.020 inch oversize set, sized for a 3.020 inch bore after the cylinder has been rebored.020 inch over standard.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I install 18-3911 in a standard-bore engine that has not been rebored?\u003c\/strong\u003e No. The 18-3911 piston ring set is machined for a 3.020 inch bore (.020 inch oversize) and is not intended for a standard-bore cylinder.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3911 piston ring set weigh?\u003c\/strong\u003e The 18-3911 piston ring set weighs 0.06 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the physical dimensions of the 18-3911 piston ring set?\u003c\/strong\u003e Sierra part 18-3911 measures 0.39 x 0.39 x 0.39 inches.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat wrist pin is used with the same.020 oversize engines as 18-3911?\u003c\/strong\u003e Engines using the 18-3911.020 oversize piston ring set use wrist pin OEM part number 320954.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat circlip is paired with the 18-3911 piston ring set application?\u003c\/strong\u003e The matching circlip for these.020 oversize applications is Sierra part 18-4290, which corresponds to OEM number 317831.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWho manufactures part number 18-3911?\u003c\/strong\u003e Part number 18-3911 is manufactured by Sierra.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs there a standard-bore or.030 oversize version of this piston ring for the same engines?\u003c\/strong\u003e Yes. The same 25-35 HP and 60-75 HP engine applications also use a standard-bore ring set (OEM 396377) and a.030 inch oversize ring set (OEM 396379), which are different Sierra part numbers than the.020 oversize 18-3911.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the UPC for the Sierra 18-3911 piston ring set?\u003c\/strong\u003e The UPC for Sierra 18-3911 is 030999542762.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988170092763,"sku":"SIE-18-3911","price":11.13,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/18-3911__99199.1737881865.500.750.jpg?v=1785188897","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3911-piston-ring-set-020-oversize-for-johnson-evinrude-25-35-hp-2-cyl-60-75-hp-3-cyl-outboards-replaces-omc-396378","provider":"Good Vibes Marina","version":"1.0","type":"link"}