{"product_id":"castair-4-7-5-hp-two-stage-inline-2-cylinder-air-compressor-bare-pump-with-16-875-2b-flywheel-od-2-qt-oil-capacity-c1","title":"Castair, 4-7.5 HP Two Stage, Inline 2 Cylinder Air Compressor Bare Pump, with 16.875 - 2B Flywheel OD, 2 Qt. Oil Capacity C1","description":"\u003cp\u003eThe Castair C1 is a two-stage, inline 2-cylinder air compressor bare pump rated for use with 4 to 7.5HP motors. This is a replacement pump — it ships without a motor, tank, or base. You supply the motor and mount it to your existing or new compressor frame. The C1 is the right choice when you're rebuilding a worn-out compressor that's in an otherwise serviceable frame, or when you're doing a ground-up build with a specific motor and tank combination.\u003c\/p\u003e\n\n\u003cp\u003eKey specifications from the product listing: 16.875\" flywheel OD with a 2-groove B-section (2B) pulley configuration, and a 2-quart oil capacity. The two-stage inline cylinder arrangement means the air is compressed twice — first stage brings it to an intermediate pressure, second stage takes it to full system pressure — which is why two-stage pumps deliver better efficiency and lower discharge temperatures than single-stage designs at the same pressure.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo-Stage Compression:\u003c\/strong\u003e Two-stage design delivers better thermal efficiency and lower discharge air temps compared to single-stage at equivalent pressures\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInline 2-Cylinder Configuration:\u003c\/strong\u003e Compact inline layout — both cylinders in a straight line rather than a V arrangement\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e16.875\" Flywheel OD, 2B Groove:\u003c\/strong\u003e 2-groove B-section pulley accepts standard B-section V-belts for motor connection\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4-7.5HP Motor Range:\u003c\/strong\u003e Wide HP compatibility gives you flexibility in motor selection for a rebuild or new build\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2 Quart Oil Capacity:\u003c\/strong\u003e Splash-lubricated cast iron pump — change oil per manufacturer intervals for long service life\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCast Iron Construction:\u003c\/strong\u003e Cast iron cylinders and components resist wear and maintain sealing surfaces over long service periods\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBare Pump (No Motor):\u003c\/strong\u003e You choose and supply the motor — select the HP and voltage that matches your application\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e C1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump Type:\u003c\/strong\u003e Two-stage, inline 2-cylinder reciprocating\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor Compatibility:\u003c\/strong\u003e 4 to 7.5HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlywheel OD:\u003c\/strong\u003e 16.875\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePulley\/Flywheel Grooves:\u003c\/strong\u003e 2B (2-groove, B-section V-belt)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil Capacity:\u003c\/strong\u003e 2 quarts\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLubrication:\u003c\/strong\u003e Splash-lubricated\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder Material:\u003c\/strong\u003e Cast iron\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air\u003c\/li\u003e\n\u003cli\u003e\u003cem\u003eCFM output, maximum working pressure, RPM range — contact us for complete specifications.\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen to Choose the C1\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump Replacement:\u003c\/strong\u003e Your existing compressor has a seized or worn pump, but the motor, tank, and frame are in good shape — replace just the pump\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNew Build, 4-7.5HP Range:\u003c\/strong\u003e Building a custom compressor with a specific motor and tank configuration — the C1 gives you the pump head to pair with your own components\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUpgrade Path:\u003c\/strong\u003e Replacing a single-stage pump with this two-stage unit for better efficiency on a high-duty-cycle application\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCommercial Shop Air:\u003c\/strong\u003e Suitable for auto shops, body shops, fleet maintenance, and light industrial applications in the 4-7.5HP motor range\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTwo-Stage vs. Single-Stage\u003c\/h2\u003e\n\u003cp\u003eSingle-stage pumps compress air once and send it directly to the tank. Two-stage pumps like the C1 compress the air in two steps with intercooling between stages. The result is lower discharge temperatures, less moisture in the compressed air, and better volumetric efficiency at higher pressures. If you're running tools that need sustained 100-175 PSI or running a high duty cycle, two-stage is the right design. For lighter-duty use at lower pressures, single-stage is simpler and less expensive. The C1 is the two-stage option in this HP range.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Buy From OEM Diagnostic Tools?\u003c\/h3\u003e\n\u003cp\u003eWe stock Cast Air compressor pumps and components for commercial and industrial applications. Specialist supplier since 2016. Free shipping on qualifying orders. Call us for pricing, availability, and help identifying the right pump for your motor and application — this is the kind of purchase where a 5-minute conversation saves you from ordering the wrong unit.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for pricing, availability, and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342526603477,"sku":"C1","price":2272.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/CastAirTwoStageAirCompressorPump.png?v=1772652601","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-4-7-5-hp-two-stage-inline-2-cylinder-air-compressor-bare-pump-with-16-875-2b-flywheel-od-2-qt-oil-capacity-c1","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}