{"product_id":"cometic-nissan-1991-1994-ka24de-top-end-gasket-kit-90mm-bore-051in-mls-cylinder-head-gasket","title":"Cometic StreetPro Top End Gasket Kit - 1991-1994 Nissan KA24DE | 90mm Bore, .051\" MLS Head Gasket (C4514-051)","description":"\u003ch3\u003eCometic StreetPro Top End Gasket Kit - 1991-1994 Nissan KA24DE | 90mm Bore, .051\" MLS Head Gasket (C4514-051)\u003c\/h3\u003e\n\u003cp\u003eRebuild your KA24DE's top end with confidence using the Cometic StreetPro top end gasket kit. Designed for the 1991-1994 Nissan KA24DE (S13 240SX), this complete kit includes all necessary gaskets and seals for a top end rebuild, centered around a .051\" Multi-Layer Steel (MLS) cylinder head gasket in a 90mm bore — ideal for stock bore or mildly overbored KA24DE builds.\u003c\/p\u003e\n\u003ch4\u003eKey Features:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eComplete top end gasket kit\u003c\/li\u003e\n\u003cli\u003e.051\" Multi-Layer Steel (MLS) cylinder head gasket\u003c\/li\u003e\n\u003cli\u003e90mm bore diameter\u003c\/li\u003e\n\u003cli\u003eCometic StreetPro quality materials throughout\u003c\/li\u003e\n\u003cli\u003eMLS, AFM, Aramid Fiber, and Armor Clad materials included\u003c\/li\u003e\n\u003cli\u003eAll gaskets and seals needed for top end rebuild\u003c\/li\u003e\n\u003cli\u003eFits 1991-1994 Nissan KA24DE (S13 240SX)\u003c\/li\u003e\n\u003cli\u003eCometic Gasket quality and engineering\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eKit Contents and Materials:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder Head Gasket:\u003c\/strong\u003e .051\" Multi-Layer Steel (MLS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdditional Gaskets:\u003c\/strong\u003e AFM (Advanced Fiber Material), Aramid Fiber, and Armor Clad materials as required\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeals:\u003c\/strong\u003e All top end seals included\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComplete Kit:\u003c\/strong\u003e Everything needed for a full top end rebuild\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eSpecifications:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Cometic Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e C4514-051\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKit Type:\u003c\/strong\u003e StreetPro Top End Gasket Kit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHead Gasket Thickness:\u003c\/strong\u003e .051\" (1.30mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHead Gasket Type:\u003c\/strong\u003e Multi-Layer Steel (MLS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBore Diameter:\u003c\/strong\u003e 90mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 2.4 lbs (complete kit)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarcode:\u003c\/strong\u003e 191070025311\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eFitment Information:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003e1991-1994 Nissan 240SX S13 (KA24DE)\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine:\u003c\/strong\u003e KA24DE 2.4L DOHC inline-4\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBore:\u003c\/strong\u003e 90mm (stock bore or up to 90mm overbore)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNote:\u003c\/strong\u003e Verify your engine's bore diameter is 90mm before ordering\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNote:\u003c\/strong\u003e Stock KA24DE bore is 89mm - this kit is for engines bored to 90mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNote:\u003c\/strong\u003e Head surface finish must meet MLS gasket requirements before installation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Professional engine building experience recommended\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eWhat's Included:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eCometic MLS cylinder head gasket (.051\" \/ 90mm bore)\u003c\/li\u003e\n\u003cli\u003eAll additional top end gaskets (intake, exhaust, valve cover, etc.)\u003c\/li\u003e\n\u003cli\u003eAll top end seals\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNote:\u003c\/strong\u003e Bottom end gaskets sold separately if needed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNote:\u003c\/strong\u003e Head bolts\/studs sold separately - replace at time of rebuild\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eInstallation Notes:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional engine building experience strongly recommended\u003c\/li\u003e\n\u003cli\u003eDeck surface must be properly prepared for MLS gasket - minimum Ra 60 microinch surface finish required\u003c\/li\u003e\n\u003cli\u003eClean all mating surfaces thoroughly before installation\u003c\/li\u003e\n\u003cli\u003eDo not use sealant on MLS head gasket\u003c\/li\u003e\n\u003cli\u003eReplace head bolts or upgrade to ARP head studs at time of rebuild\u003c\/li\u003e\n\u003cli\u003eTorque head fasteners to manufacturer specifications in correct sequence\u003c\/li\u003e\n\u003cli\u003eAllow engine to reach operating temperature and re-torque if using head bolts (not required with ARP studs)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCometic StreetPro Kit - What It Is:\u003c\/h4\u003e\n\u003cp\u003eThe Cometic StreetPro series is designed for the budget-conscious engine builder who needs a complete, quality top end gasket kit without the premium price of Cometic's top-tier offerings. StreetPro kits include all the gaskets and seals needed for a complete top end rebuild, using quality materials appropriate for street and mild performance applications. The kit uses a mix of Cometic's proven gasket materials — MLS for the critical head gasket, and AFM (Advanced Fiber Material), Aramid Fiber, and Armor Clad for the remaining gaskets — providing the right material for each application in the kit.\u003c\/p\u003e\n\u003ch4\u003eMulti-Layer Steel (MLS) Head Gasket:\u003c\/h4\u003e\n\u003cp\u003eThe .051\" MLS head gasket is the centerpiece of this kit. Multi-Layer Steel head gaskets use multiple layers of embossed stainless steel to create a reliable, high-performance seal between the cylinder head and engine block. MLS gaskets provide superior sealing compared to traditional composite gaskets, particularly under the elevated temperatures and pressures of modified engines. The embossed layers create a spring-like sealing effect that maintains consistent clamping force across the gasket surface, even as the engine thermally cycles. MLS gaskets are the industry standard for performance engine builds and are required for any KA24DE build running elevated boost or compression.\u003c\/p\u003e\n\u003ch4\u003e.051\" Thickness - Compression Ratio Considerations:\u003c\/h4\u003e\n\u003cp\u003eThe .051\" (1.30mm) head gasket thickness affects the engine's compression ratio. A thicker head gasket increases the combustion chamber volume, reducing compression ratio, while a thinner gasket reduces combustion chamber volume and increases compression. For a stock-displacement KA24DE, the .051\" thickness provides a moderate compression ratio suitable for street use with pump fuel. If you are building a high-compression naturally aspirated KA24DE, a thinner gasket may be appropriate. For turbocharged builds, the .051\" thickness helps manage compression ratio at elevated boost levels. Consult with your engine builder to determine the correct head gasket thickness for your specific build targets.\u003c\/p\u003e\n\u003ch4\u003e90mm Bore - Stock vs. Overbore:\u003c\/h4\u003e\n\u003cp\u003eThe stock KA24DE bore diameter is 89mm. This kit is designed for engines that have been bored to 90mm — a common overbore for KA24DE rebuilds that allows the use of oversized pistons to restore cylinder dimensions after wear, or to increase displacement slightly. If your KA24DE has not been bored, verify your bore diameter before ordering. Using a head gasket with an incorrect bore diameter can result in the gasket overhanging into the combustion chamber or leaving the cylinder bore partially unsealed, both of which are serious engine-damaging conditions. Always measure your bore diameter before selecting a head gasket.\u003c\/p\u003e\n\u003ch4\u003eMLS Gasket Surface Finish Requirements:\u003c\/h4\u003e\n\u003cp\u003eMLS head gaskets require a properly prepared cylinder head and block deck surface to seal correctly. The surface finish must be smooth enough for the MLS layers to conform and seal — a minimum Ra 60 microinch (1.5 micron) finish is typically required, with Ra 30-60 microinch being ideal. Rough or damaged deck surfaces will not seal properly with an MLS gasket and can result in coolant or combustion gas leaks. If your KA24DE has been previously rebuilt or has a damaged head surface, have the head and block decks resurfaced by a machine shop before installing the Cometic MLS gasket. Do not use gasket sealant with MLS gaskets — they are designed to seal without sealant.\u003c\/p\u003e\n\u003ch4\u003eComplete Top End Rebuild:\u003c\/h4\u003e\n\u003cp\u003eWhen performing a top end rebuild on a KA24DE, replace all gaskets and seals in the kit simultaneously. Reusing old gaskets when replacing the head gasket is a false economy — the labour to access the top end is already done, and old gaskets are likely near the end of their service life. The StreetPro kit provides everything needed for a complete top end refresh, ensuring all sealing surfaces are renewed at the same time. Additionally, replace the head bolts (or upgrade to ARP head studs) at the time of rebuild — head bolts are torque-to-yield fasteners that should not be reused.\u003c\/p\u003e\n\u003ch4\u003eWhy Cometic Gasket?\u003c\/h4\u003e\n\u003cp\u003eCometic Gasket is one of the most respected names in performance engine gaskets, trusted by professional engine builders, race teams, and enthusiasts worldwide. Their MLS head gaskets are used in championship-winning race engines and high-power street builds across all motorsport disciplines. Cometic's StreetPro kits bring their quality materials and engineering to budget-conscious builders, providing reliable sealing for street and mild performance applications. Cometic's extensive coverage of Nissan applications, including the KA24DE, ensures their gaskets are engineered to the correct specifications.\u003c\/p\u003e\n\u003ch4\u003ePerfect For:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e1991-1994 Nissan 240SX S13 KA24DE top end rebuilds (90mm bore)\u003c\/li\u003e\n\u003cli\u003eKA24DE builds requiring MLS head gasket for elevated boost or compression\u003c\/li\u003e\n\u003cli\u003e240SX engine rebuilds needing a complete top end gasket kit\u003c\/li\u003e\n\u003cli\u003eBudget-conscious KA24DE builders wanting Cometic quality\u003c\/li\u003e\n\u003cli\u003eAny KA24DE build bored to 90mm needing a complete top end gasket set\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePerfect For:\u003c\/strong\u003e 1991-1994 Nissan 240SX KA24DE engine builders seeking Cometic StreetPro top end gasket kit with .051\" MLS head gasket for a 90mm bore rebuild.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePro Tip:\u003c\/strong\u003e Upgrade to ARP head studs at the same time as the gasket kit — ARP studs provide more consistent clamping force than factory head bolts, don't need re-torquing after heat cycling, and are reusable for future rebuilds.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eComplete Top End Kit:\u003c\/strong\u003e .051\" MLS head gasket. 90mm bore. MLS, AFM, Aramid Fiber, and Armor Clad materials. Fits 1991-1994 KA24DE S13. Deck surface preparation required. Do not use sealant.\u003c\/p\u003e\n\u003cp\u003eRebuild your KA24DE's top end with Cometic StreetPro — .051\" MLS head gasket, 90mm bore, complete kit, proven Cometic quality for the 240SX platform.\u003c\/p\u003e","brand":"Cometic Gasket","offers":[{"title":"Default Title","offer_id":48416260423847,"sku":"CGSPRO2014T-051","price":224.08,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0555\/8344\/1063\/files\/c75c281bd97e3ff4818d9833c88ab3fd.jpg?v=1776213972","url":"https:\/\/www.straightsiximports.com\/products\/cometic-nissan-1991-1994-ka24de-top-end-gasket-kit-90mm-bore-051in-mls-cylinder-head-gasket","provider":"Straight Six Imports","version":"1.0","type":"link"}