{"product_id":"cummins-isx-qsx-crankshaft-damper-bolt-kit","title":"Cummins ISX QSX X15 Crankshaft Damper Bolt Kit","description":"\u003ch1\u003eCummins Crank Shaft Damper Hexagon Flange Head Cap Screw Kit\u003c\/h1\u003e\n\u003cp\u003eThis OEM \u003cstrong\u003eCummins Hexagon Flange Head Cap Screw\u003c\/strong\u003e is a genuine OEM fastener designed for use in heavy-duty Cummins diesel engines in the On-Road, Off Road and Marine applications. Engineered to Cummins manufacturing standards, this cap screw provides reliable clamping force, excellent vibration resistance, and long service life in demanding engine applications.\u003c\/p\u003e\n\u003ch2\u003eProduct Overview\u003c\/h2\u003e\n\u003cp\u003eThis Cummins OEM cap screw set features The 12 required OEM fasteners with an integrated \u003cstrong\u003ehexagon flange head\u003c\/strong\u003e, which helps evenly distribute load across the mounting surface and reduces the need for separate washers. The flange head design improves joint stability and helps prevent loosening in high-vibration environments commonly found in heavy-duty diesel engines.\u003c\/p\u003e\n\u003cp\u003eThe Cummins 3680750 cap screw set is used primarily on\u003cstrong\u003e the 15-liter ISX, QSX, and X15 series engines\u003c\/strong\u003e and is intended as a direct replacement for the original factory hardware.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eGenuine Cummins OEM fastener\u003c\/li\u003e\n\u003cli\u003eHexagon flange head for improved load distribution\u003c\/li\u003e\n\u003cli\u003eDesigned for high-vibration diesel engine environments\u003c\/li\u003e\n\u003cli\u003eDirect-fit replacement with no modification required\u003c\/li\u003e\n\u003cli\u003eManufactured to Cummins quality and durability standards\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eApplications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCummins ISX 15L engines\u003c\/li\u003e\n\u003cli\u003eCummins QSX 15L engines\u003c\/li\u003e\n\u003cli\u003eCummins X15 engines\u003c\/li\u003e\n\u003cli\u003eEngine and component assemblies requiring OEM Cummins fasteners\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFitment Note:\u003c\/strong\u003e Always verify compatibility using your engine serial number (ESN) before ordering. If you have any questions about the application of this product please \u003ca href=\"https:\/\/klmperformance.com\/pages\/contact-us\" title=\"KLM Contact  Us\"\u003eContact Us \u003c\/a\u003ewith your ESN prior to placing and order for this Non Returnable OEM Cummins Part. \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003eReplacing the \u003cb\u003eOEM crankshaft damper bolts\u003c\/b\u003e on a Cummins ISX, QSX or X15 when you install a new viscous crankshaft damper is essential because the bolts are \u003cb\u003etorque‑to‑yield fasteners\u003c\/b\u003e that lose their engineered clamping force once used. A fresh, high‑performance damper can only work correctly if the hardware securing it can maintain full, reliable clamp load.\u003c\/p\u003e\n\u003ch3 class=\"MsoNormal\"\u003eWhy Cummins ISX QSX X15 Crankshaft Damper Bolts Must Be Replaced\u003c\/h3\u003e\n\u003cp class=\"MsoNormal\"\u003eThese OEM Cummins crankshaft damper bolts are engineered to \u003cb\u003estretch\u003c\/b\u003e when torqued. That stretch is what creates the precise clamping force needed to keep the damper locked to the crankshaft.\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003eOnce stretched, they \u003cb\u003ecannot return to their original length\u003c\/b\u003e, meaning:\u003c\/p\u003e\n\u003cul type=\"disc\" style=\"margin-top: 0in;\"\u003e\n\u003cli style=\"mso-list: l0 level1 lfo1; tab-stops: list .5in;\" class=\"MsoNormal\"\u003eThey cannot achieve full clamp load a second time.\u003c\/li\u003e\n\u003cli style=\"mso-list: l0 level1 lfo1; tab-stops: list .5in;\" class=\"MsoNormal\"\u003eReusing them risks loosening under vibration.\u003c\/li\u003e\n\u003cli style=\"mso-list: l0 level1 lfo1; tab-stops: list .5in;\" class=\"MsoNormal\"\u003eAny loss of clamp load allows micro‑movement between the damper and crank snout.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003eThis is the single biggest reason Cummins and professional engine builders treat them as \u003cb\u003esingle‑use hardware\u003c\/b\u003e.\u003c\/p\u003e\n\u003ch3 class=\"MsoNormal\"\u003eMechanical Risks of Reusing Old Bolts\u003c\/h3\u003e\n\u003cul type=\"disc\" style=\"margin-top: 0in;\"\u003e\n\u003cli style=\"mso-list: l1 level1 lfo2; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eDamper walk\u003c\/b\u003e — the damper slowly shifts on the crankshaft, throwing off balance.\u003c\/li\u003e\n\u003cli style=\"mso-list: l1 level1 lfo2; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eFretting damage\u003c\/b\u003e — microscopic movement chews into the crank snout and damper hub.\u003c\/li\u003e\n\u003cli style=\"mso-list: l1 level1 lfo2; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003ePremature damper failure\u003c\/b\u003e — even a premium viscous damper can fail if not clamped correctly.\u003c\/li\u003e\n\u003cli style=\"mso-list: l1 level1 lfo2; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eCrankshaft damage\u003c\/b\u003e — severe fretting can require crankshaft replacement.\u003c\/li\u003e\n\u003cli style=\"mso-list: l1 level1 lfo2; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eWarranty exposure\u003c\/b\u003e — any damper‑related failure will be blamed on the damper, not the reused bolts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003eA complete set replacement bolts protects a $600–$1,000 damper and a $20,000+ engine.\u003c\/p\u003e\n\u003ch3 class=\"MsoNormal\"\u003eWhy It Matters Even More With High‑Performance Viscous Dampers\u003c\/h3\u003e\n\u003cp class=\"MsoNormal\"\u003eHigh‑performance viscous dampers (PDI, Vibratech, Fluidampr, Pittsburgh Power, etc.) are heavier and absorb more torsional energy than stock units. That means:\u003c\/p\u003e\n\u003cul type=\"disc\" style=\"margin-top: 0in;\"\u003e\n\u003cli style=\"mso-list: l3 level1 lfo3; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\u003cb\u003eHigher inertia loads\u003c\/b\u003e\u003c\/li\u003e\n\u003cli style=\"mso-list: l3 level1 lfo3; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\u003cb\u003eMore torsional resistance\u003c\/b\u003e\u003c\/li\u003e\n\u003cli style=\"mso-list: l3 level1 lfo3; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\u003cb\u003eGreater demand on the clamping hardware\u003c\/b\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003eOld bolts simply cannot maintain the required preload to keep a performance damper stable under these loads.\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003ePractical and Customer‑Facing Benefits\u003c\/p\u003e\n\u003cul type=\"disc\" style=\"margin-top: 0in;\"\u003e\n\u003cli style=\"mso-list: l2 level1 lfo4; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eProfessional best practice\u003c\/b\u003e — every reputable Cummins builder replaces these bolts.\u003c\/li\u003e\n\u003cli style=\"mso-list: l2 level1 lfo4; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eCleaner installation\u003c\/b\u003e — no guessing about bolt history or stretch.\u003c\/li\u003e\n\u003cli style=\"mso-list: l2 level1 lfo4; tab-stops: list .5in;\" class=\"MsoNormal\"\u003e\n\u003cb\u003eReduced comebacks\u003c\/b\u003e — eliminates one of the most common causes of damper‑related failures.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 class=\"MsoNormal\"\u003eSummary of the Cummins Crankshaft Damper Bolt Kit\u003c\/h3\u003e\n\u003cp class=\"MsoNormal\"\u003eYou replace the bolts because they are \u003cb\u003esingle‑use, torque‑to‑yield fasteners\u003c\/b\u003e, and reusing them risks damper loosening, crankshaft damage, and premature failure of even the best viscous damper. Fresh bolts ensure full clamp load, proper damper function, and long‑term engine protection.\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 123680750\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Cummins Genuine OEM Part\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFastener Type:\u003c\/strong\u003e Hexagon Flange Head Cap Screw\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Compatibility:\u003c\/strong\u003e  ISX | QSX | 15L\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApproximate Weight:\u003c\/strong\u003e 0.21 lb\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhy Choose Genuine Cummins Hardware?\u003c\/h2\u003e\n\u003cp\u003eUsing genuine Cummins fasteners ensures proper fit, correct clamping force, and long-term reliability. Non-OEM hardware may not meet Cummins engineering standards and can lead to improper torque retention, premature wear, or component failure. The 3680750 cap screw is designed to perform as part of the complete Cummins engine system.\u003c\/p\u003e\n\u003ch2\u003eInstallation \u0026amp; Service Notes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSold as a complete set of 12 Cap Screws. \u003c\/li\u003e\n\u003cli\u003eTorque specifications vary by application\u003c\/li\u003e\n\u003cli\u003eRefer to Cummins service documentation for proper installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eNOTE:\u003c\/strong\u003e If you have any questions regarding the application or purchase of this bolt kit please \u003ca title=\"KLM performance Contact Us\" href=\"https:\/\/klmperformance.com\/pages\/contact-us\"\u003eContact Us\u003c\/a\u003e prior to making a purchase. We at KLM Performance want to ensure you obtain the correct replacement mounting hardware prior to installation of your crankshaft damper! \u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine\u003c\/strong\u003e: Cummins ISX 15L | Cummins QSX 15L | Cummins X15 \u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eItem Number\u003c\/strong\u003e: Cummins-ISX-QSX-X15-Crankshaft-Damper-Bolt-Kit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMake\u003c\/strong\u003e: Cummins\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel\u003c\/strong\u003e: Diesel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYear \u003c\/strong\u003e:  2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part No\u003c\/strong\u003e: \u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Application\u003c\/strong\u003e: Early Cummins ISX, Cummins X15, ISX15, ISX12, ISX12G, ISX, and Signature 600 Engine Series produced from 2001 to 2025.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeight \u003c\/strong\u003e: 3\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 17\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: Vibratech\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFAQ\u003c\/strong\u003e: What happens if I choose not to change the damper on my 2001 to 2025 Cummins ISX, ISX15, and X15 Engine? If you choose not to replace your Viscous Crankshaft Damper, the destructive torsional vibrations may lead to a cracked or broken crankshaft, valve train problems, and premature bearing wear.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number\u003c\/strong\u003e: Cummins-ISX-QSX-X15-Crankshaft-Damper-Bolt-Kit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer\u003c\/strong\u003e: Cummins\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Note\u003c\/strong\u003e: The Torsional Vibration Damper on your Cummins ISX, QSX or X15 engine is a wear item that requires replacement at the 500,000-mile mark.  The installation of a new Damper is strongly recommended in an effort to eliminate harmful torsional crankshaft vibration and ensure trouble-free operation. The replacement of the engine crankshaft damper is often overlooked during the In-Frame overhaul process due to costs. We at KLM Performance come across two different types of customers: the ones who choose to purchase a replacement viscous crankshaft damper and the ones who wish they had. The second customer is the one now dealing with a damaged crankshaft and other serious engine failures.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Cummins","offers":[{"title":"Default Title","offer_id":51704218681624,"sku":"Cummins-ISX-QSX-X15-Crankshaft-Damper-Bolt-Kit","price":107.75,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0061\/8918\/7156\/files\/Cummins_ISX_QSX_X15_Crankshaft_Damper_Bolt_Kit.png?v=1772059052","url":"https:\/\/klmperformance.com\/products\/cummins-isx-qsx-crankshaft-damper-bolt-kit","provider":"KLM Performance","version":"1.0","type":"link"}