{"title":"Engine Breather Filters","description":"\u003cp\u003eEngine breather filters are vented filtration caps and inline filter assemblies that allow crankcase pressure to vent safely to atmosphere without releasing raw oil vapor, reducing the internal pressure buildup that can push past valve cover seals, rear main seals, and PCV grommets in high-output and modified engines. Unlike a standard PCV system that routes crankcase gases back into the intake manifold, an open breather filter vents directly to air, making it the preferred choice on dedicated track cars, drag builds, and any engine running so much blowby that the factory PCV system cannot handle the volume without saturating the intake with oil mist. Performance engines that produce significantly more blowby than stock through increased displacement, high-lift camshafts, or forced induction benefit most from breather filter upgrades that vent excess crankcase pressure without contaminating the intake charge. Proper crankcase ventilation reduces oil consumption, keeps the intake tract cleaner, and extends oil change intervals on high-mileage performance applications.\u003c\/p\u003e\u003ch4\u003ePopular Upgrades\u003c\/h4\u003e\u003cp\u003ePopular engine breather filter products include K\u0026amp;N breather caps in both push-in and threaded configurations that fit standard 1-inch, 1.25-inch, and 1.5-inch valve cover bung diameters, Moroso breather filter setups for oval track and drag applications that include a remote overflow canister to capture liquid oil before it exits the breather, and Earl's and Vibrant Performance inline crankcase breather filters for custom fabricated ventilation setups on turbocharged and supercharged engines. Oil catch can systems from Billet Technology and MightyMouse that incorporate a breather filter at the vent outlet are a popular combined solution for Hellcat, Trackhawk, and LS-based boosted builds where both PCV routing and crankcase venting require management.\u003c\/p\u003e\u003ch4\u003ePerformance and Handling\u003c\/h4\u003e\u003cp\u003eA well-designed engine breather filter system prevents the vacuum and pressure cycles in the crankcase from forcing oil past gaskets and seals, which is the primary cause of the oil consumption issues that appear on modified engines shortly after performance upgrades increase blowby beyond the factory PCV system's design capacity. On turbocharged engines, positive crankcase pressure that is not managed by adequate venting can also pressurize the oil return line from the turbocharger, causing oil to pool in the center housing and be pulled into the compressor side on boost. Matching breather filter flow capacity to the actual blowby volume of the engine, rather than using the smallest available unit, is the most important sizing decision for any crankcase ventilation upgrade.\u003c\/p\u003e\u003ch4\u003eWhat size breather filter do I need?\u003c\/h4\u003e\u003cp\u003eBreather filter sizing depends on the valve cover bung diameter and the expected blowby volume, with most V8 street engines being adequately served by a K\u0026amp;N 62-1010 or equivalent 1.25-inch push-in breather cap on each valve cover. High-output engines above 600 horsepower, forced-induction builds, and engines with worn piston rings generating excessive blowby require larger flow-capacity filters or remote breather tank setups that can accommodate higher gas flow rates without pushing back-pressure into the crankcase. Measure the valve cover bung diameter before ordering to confirm whether a push-in or threaded breather is required.\u003c\/p\u003e\u003ch4\u003eCan I use a breather filter instead of a PCV valve?\u003c\/h4\u003e\u003cp\u003eOpen breather filters vent to atmosphere rather than routing crankcase gases back into the intake, which means they are not emissions-compliant replacements for a PCV system on street-registered vehicles in most states. For dedicated race cars and track builds that operate under competition-only regulations, an open breather setup is acceptable and often preferred for its simplicity and reduced risk of oil contaminating the intake. Street builds that want cleaner crankcase ventilation should use a catch can system that routes gases back into the intake after separating out the oil, maintaining emissions compliance while improving over the factory PCV routing.\u003c\/p\u003e\u003ch4\u003eWhy These Parts Fit Right\u003c\/h4\u003e\u003cp\u003eBreather filters in this collection are listed by bung diameter, thread pitch, and mounting type so you can confirm the correct fit for your valve cover or catch can outlet before ordering. Product pages include flow capacity data and application notes for common valve cover configurations on domestic V8, LS, HEMI, and import performance platforms. Fast shipping and expert support are available for any crankcase ventilation fitment question.\u003c\/p\u003e\u003cp\u003ePair your breather filter upgrade with a catch can from our \u003ca href=\"\/collections\/exhaust\"\u003eexhaust collection\u003c\/a\u003e, improve chassis stability with upgrades from our \u003ca href=\"\/collections\/suspension\"\u003esuspension catalog\u003c\/a\u003e, and maximize induction airflow with parts from our \u003ca href=\"\/collections\/air-intake-systems\"\u003eair intake systems collection\u003c\/a\u003e.\u003c\/p\u003e","products":[{"product_id":"spectre-breather-filter-10mm-flange-2in-od-1-3-4in-height-red","title":"Spectre Breather Filter 10mm Flange \/ 2in. OD \/ 1-3\/4in. Height - Red","description":"This Spectre breather filter, also known as a crankcase vent filter, has a flange with an inside diameter of 10mm. By using the included adjustable worm gear clamp, this air filter will fit tubes with outside diameters from 3\/8 inch to 1\/2 inch (8-12mm). Spectre breathers use pre-dyed synthetic media for lasting color, feature a triple chrome-plated steel top and base, and come factory pre-oiled and ready to use. Note: Legal in California only for racing vehicles which may never be used, registered, or licensed for use upon a highway. See spectreperformance.com for CARB status on each part for a specific vehicle.","brand":"Spectre","offers":[{"title":"Default Title","offer_id":40481197359183,"sku":"SPE3992","price":13.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/spectre-breather-filter-10mm-flange-2in_-od-1-34in_-height-red-engine-breather-filters-spectre.jpg?v=1699953153"},{"product_id":"spectre-breather-filter-10mm-flange-2in-od-1-3-4in-height-black","title":"Spectre Breather Filter 10mm Flange \/ 2in. OD \/ 1-3\/4in. Height - Black","description":"This Spectre breather filter, also known as a crankcase vent filter, has a flange with an inside diameter of 10mm. By using the included adjustable worm gear clamp, this air filter will fit tubes with outside diameters from 3\/8 inch to 1\/2 inch (8-12mm). Spectre breathers use pre-dyed synthetic media for lasting color, feature a triple chrome-plated steel top and base, and come factory pre-oiled and ready to use. Note: Legal in California only for racing vehicles which may never be used, registered, or licensed for use upon a highway. See spectreperformance.com for CARB status on each part for a specific vehicle.","brand":"Spectre","offers":[{"title":"Default Title","offer_id":40509805002831,"sku":"SPE3991","price":13.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/spectre-breather-filter-10mm-flange-2in_-od-1-34in_-height-black-engine-breather-filters-spectre-2.jpg?v=1700058374"},{"product_id":"bmc-universal-engine-breather-filter-12mm-inlet-40mm-filter-length","title":"BMC Universal Engine Breather Filter 12mm Inlet \/ 40mm Filter Length","description":"BMC Universal Engine Breather Filter 12mm Inlet \/ 40mm Filter Length","brand":"BMC","offers":[{"title":"Default Title","offer_id":40712650555471,"sku":"BMCFBSA12-40","price":36.3,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/bmc-universal-engine-breather-filter-12mm-inlet-40mm-filter-length-engine-breather-filters-bmc.jpg?v=1700370273"},{"product_id":"bmc-universal-engine-breather-filter-16mm-inlet-40mm-filter-length","title":"BMC Universal Engine Breather Filter 16mm Inlet \/ 40mm Filter Length","description":"BMC Universal Engine Breather Filter 16mm Inlet \/ 40mm Filter Length","brand":"BMC","offers":[{"title":"Default Title","offer_id":40712650588239,"sku":"BMCFBSA16-40","price":36.3,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/bmc-universal-engine-breather-filter-16mm-inlet-40mm-filter-length-engine-breather-filters-bmc.jpg?v=1700370277"},{"product_id":"bmc-universal-engine-breather-filter-20mm-inlet-40mm-filter-length","title":"BMC Universal Engine Breather Filter 20mm Inlet \/ 40mm Filter Length","description":"BMC Universal Engine Breather Filter 20mm Inlet \/ 40mm Filter Length","brand":"BMC","offers":[{"title":"Default Title","offer_id":40712650621007,"sku":"BMCFBSA20-40","price":37.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/bmc-universal-engine-breather-filter-20mm-inlet-40mm-filter-length-engine-breather-filters-bmc.jpg?v=1700370281"},{"product_id":"bmc-universal-engine-breather-filter-25mm-inlet-40mm-filter-length","title":"BMC Universal Engine Breather Filter 25mm Inlet \/ 40mm Filter Length","description":"BMC Universal Engine Breather Filter 25mm Inlet \/ 40mm Filter Length","brand":"BMC","offers":[{"title":"Default Title","offer_id":40712650653775,"sku":"BMCFBSA25-40","price":37.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/bmc-universal-engine-breather-filter-25mm-inlet-40mm-filter-length-engine-breather-filters-bmc.jpg?v=1700370285"},{"product_id":"bmc-universal-engine-breather-filter-30mm-inlet-40mm-filter-length","title":"BMC Universal Engine Breather Filter 30mm Inlet \/ 40mm Filter Length","description":"BMC Universal Engine Breather Filter 30mm Inlet \/ 40mm Filter Length","brand":"BMC","offers":[{"title":"Default Title","offer_id":40712650686543,"sku":"BMCFBSA30-40","price":37.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/bmc-universal-engine-breather-filter-30mm-inlet-40mm-filter-length-engine-breather-filters-bmc.jpg?v=1700370288"},{"product_id":"ford-racing-black-crinkle-finish-breather-cap-w-ford-mustang-logo","title":"Ford Racing Black Crinkle Finish 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Valve Cover Breather","description":"Granatelli -12AN Male Insert Billet Valve Cover Breather","brand":"Granatelli Motor Sports","offers":[{"title":"Default Title","offer_id":41127306559567,"sku":"GMS280112","price":50.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/products\/3bfc1f73d8e18b1fbccf956400b3733a.jpg?v=1706246776"},{"product_id":"granatelli-insert-valve-cover-breather-threaded-female-receptacle","title":"Granatelli Insert Valve Cover Breather Threaded Female Receptacle","description":"Granatelli Insert Valve Cover Breather Threaded Female Receptacle","brand":"Granatelli Motor Sports","offers":[{"title":"Default Title","offer_id":41127326416975,"sku":"GMS451000","price":50.69,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/products\/57e5d2ce9956d5b673d4a9fc4497ac4a.jpg?v=1714153613"},{"product_id":"granatelli-pres-in-valve-cover-breather","title":"Granatelli 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Sports","offers":[{"title":"Default Title","offer_id":41127326548047,"sku":"GMS451003","price":15.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/products\/061ce8f23edc3ea03b25b6efc33d38a6.jpg?v=1714156913"},{"product_id":"granatelli-push-in-pcv-breather","title":"Granatelli Push-In PCV Breather","description":"Granatelli Push-In PCV Breather","brand":"Granatelli Motor Sports","offers":[{"title":"Default Title","offer_id":41127327006799,"sku":"GMS451004","price":15.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/products\/b97f52617218ae7c90f41d4801d447cf.jpg?v=1714156924"},{"product_id":"spectre-extraflow-push-in-breather-filter-blue","title":"Spectre ExtraFlow Push-In Breather Filter - Blue","description":"Spectre's High Performance Push-In Breather was designed for valve covers with a 1-1\/4 inch breather hole. With a triple chrome-plated steel top and base and an overall height of 2-3\/4 inches, this breather features a 2 inch tall Extraflow filter element made from our blue synthetic fiber filter media. Manufactured using high quality materials and designed for a universal fit. Note: Legal in California only for racing vehicles which may never be used, registered, or licensed for use upon a highway. See spectreperformance.com for CARB status on each part for a specific vehicle.","brand":"Spectre","offers":[{"title":"Default Title","offer_id":42602324983887,"sku":"SPE42876","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/b9695a7aedb8562b814a4104dcdb1bb3.jpg?v=1740444550"},{"product_id":"spectre-oil-breather-cap-3-4in-push-in","title":"Spectre Oil Breather Cap 3\/4in. (Push-In)","description":"\u003cdiv\u003e\n\u003cstrong\u003eSKU:\u003c\/strong\u003e \u003cspan itemprop=\"sku\"\u003e4300\u003c\/span\u003e   |   \u003cstrong\u003eUPC:\u003c\/strong\u003e 089601430003\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch4\u003e\u003cstrong\u003eSpectre Oil Breather Cap 3\/4in. (Push-In)\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003eThe Spectre Oil Breather Cap 3\/4in. (Push-In) stands as the essential valve cover accessory for classic and performance engines. It features a chrome-plated steel housing with an internal baffle that prevents oil splash while delivering superior crankcase ventilation that outperforms basic grommet caps or twist-on breathers by maintaining consistent airflow without leaks or oil misting during high-RPM operation. Designed for universal fitment on valve covers with 3\/4-inch to 1-1\/4-inch breather holes, this push-in cap integrates seamlessly with stock or aftermarket setups to reduce pressure buildup and extend engine life. This ensures builders and daily drivers experience cleaner engine bays and reliable performance compared to exposed PCV valves or undersized filters. Crafted from durable triple-chrome plated steel for corrosion resistance and easy cleaning, it provides a polished look that complements show cars or hot rods better than plastic alternatives. It also supports emissions compliance where applicable for a straightforward upgrade that enhances overall engine breathing across street, strip, or track conditions.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eChrome-Plated Steel Housing – Triple-plated for rust resistance and high-shine finish\u003c\/li\u003e\n\u003cli\u003eInternal Baffle Design – Blocks oil splash while allowing unrestricted air flow\u003c\/li\u003e\n\u003cli\u003ePush-In Installation – Fits 3\/4-inch to 1-1\/4-inch holes without tools\u003c\/li\u003e\n\u003cli\u003eSuperior Ventilation – Reduces crankcase pressure for better ring seal and power\u003c\/li\u003e\n\u003cli\u003eUniversal Compatibility – Works with small-block Chevy, Ford, Mopar, and imports\u003c\/li\u003e\n\u003cli\u003eEasy Maintenance – Removable foam filter for cleaning or replacement\u003c\/li\u003e\n\u003cli\u003eUSA-Made Durability – Built to last with precision stamping\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eProduct Notes\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eUniversal fit for valve covers with 3\/4-inch to 1-1\/4-inch breather holes\u003c\/li\u003e\n\u003cli\u003eRecommend grommet kit 5333 or 5339 for 1-1\/4-inch holes\u003c\/li\u003e\n\u003cli\u003eCalifornia legal for racing vehicles only, check CARB status\u003c\/li\u003e\n\u003cli\u003eReplaceable foam filter available as 5331\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eWarranty\u003c\/strong\u003e – Spectre limited lifetime warranty against defects\u003cbr\u003e\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eClean breather hole on valve cover, insert cap by hand\u003c\/li\u003e\n\u003cli\u003eFor larger holes, use included or optional grommet\u003c\/li\u003e\n\u003cli\u003eSecure by pushing firmly until flush, no tools needed\u003c\/li\u003e\n\u003cli\u003eTest for leaks at idle, adjust if necessary\u003c\/li\u003e\n\u003cli\u003eTools required – None, est. time: 2-5 min\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eThis Part Fits\u003c\/h4\u003e\n\u003ctable border=\"1\" cellpadding=\"6\" cellspacing=\"0\" style=\"width: 100%; max-width: 800px;\"\u003e\n\u003cthead style=\"background: #f4f4f4;\"\u003e\n\u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eExamples\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eValve Covers\u003c\/td\u003e\n\u003ctd\u003eSmall Block Chevy, Ford Windsor, Mopar LA\u003c\/td\u003e\n\u003ctd\u003e3\/4-inch to 1-1\/4-inch holes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImports\u003c\/td\u003e\n\u003ctd\u003eHonda B\/D Series, Nissan SR20\u003c\/td\u003e\n\u003ctd\u003eUniversal breather fit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCustom Builds\u003c\/td\u003e\n\u003ctd\u003eAny Engine\u003c\/td\u003e\n\u003ctd\u003eAftermarket valve covers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch4\u003eWhat's Included in the Purchase\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e1 x Chrome Push-In Oil Breather Cap 3\/4in.\u003c\/li\u003e\n\u003cli\u003eFoam Filter Insert\u003c\/li\u003e\n\u003cli\u003eInstallation Guide (PDF)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePart Weight:\u003c\/strong\u003e 0.3 lbs | \u003cstrong\u003eShipping Box Dimensions:\u003c\/strong\u003e 6 in × 4 in × 2 in\u003c\/p\u003e\n\u003ch4\u003eWhy Choose Spectre Oil Breather Cap?\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered for universal valve cover use with proven splash control\u003c\/li\u003e\n\u003cli\u003eTriple-chrome finish for show-quality appearance\u003c\/li\u003e\n\u003cli\u003eUSA-made with reliable ventilation for performance engines\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eFrequently Asked Questions\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eQ: Does it fit 1-1\/4-inch holes?\u003cbr\u003eA: Yes with grommet kit 5333 or 5339\u003c\/li\u003e\n\u003cli\u003eQ: Is it CARB legal?\u003cbr\u003eA: For racing only in California, check spectreperformance.com\u003c\/li\u003e\n\u003cli\u003eQ: Replaceable filter?\u003cbr\u003eA: Yes, foam insert SKU 5331 available\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eShipping \u0026amp; Handling\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eMethod – Ground shipping, expedited available\u003c\/li\u003e\n\u003cli\u003eAvailability – In stock, ships within 1-2 business days\u003c\/li\u003e\n\u003cli\u003ePackaging – Protective polybag to prevent scratches\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Spectre","offers":[{"title":"Default Title","offer_id":43831250321487,"sku":"SPE4300","price":17.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/spectre-4300-breather-cap_01.jpg?v=1764014626"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/collections\/engine-breather-filters.jpg?v=1782252197","url":"https:\/\/www.blackopsautoworks.com\/collections\/engine-breather-filters.oembed","provider":"Black Ops Auto Works","version":"1.0","type":"link"}