Cummins 6BT Overhaul Kits – Rebuild Kits by CPL and Compression Ratio

For marine and industrial engine rebuilds, the Cummins 6BT stands out as one of the most reliable and widely used 5.9L diesel engines. When it’s time to restore performance, rebuild efficiency, or address internal wear, a professionally matched overhaul kit is the most efficient way to return your engine to OEM-level operation.

At Diesel Pro Power, we carry CPL-specific Cummins 6BT rebuild kits with correct piston sizes, liner types, gasket configurations, and compression ratios. Whether you're overhauling a marine generator, auxiliary drive, or a propulsion system, we provide engine rebuild kits tailored to your specific CPL and combustion requirements.

With over 40,000 satisfied customers globally, we’ve built our reputation on fast shipping, excellent technical support, and rebuild kits that match your Cummins 6BT exactly — the first time.

Engine Specifications & Applications for Cummins 6BT

The Cummins 6BT (also referred to as the 6BT5.9) is a turbocharged, inline 6-cylinder diesel engine used widely in marine and stationary industrial applications. Though similar to the naturally aspirated 6B, the 6BT features forced induction and higher compression variants designed for heavier duty cycles and greater torque output.

Key Engine Specifications:

• Configuration: Inline-6, 4-stroke diesel

• Displacement: 5.9 liters (359 cubic inches)

• Bore x Stroke: 102 mm x 120 mm

• Fuel System: Direct injection with rotary or inline mechanical pumps

• Aspiration: Turbocharged

• Common Compression Ratios: 15.3:1, 16.5:1, 17.3:1, 17.5:1

• Cooling: Liquid-cooled

• Applications:

  • Marine propulsion systems

  • Marine generators and auxiliary drives

  • Stationary industrial power units

  • Hydraulic pump drives and irrigation engines

CPL-Matched Overhaul Kits for Cummins 6BT

Each CPL (Control Parts List) number represents a specific combination of pistons, injectors, camshaft, and timing. Diesel Pro Power supplies CPL-specific kits so you avoid costly mismatches in compression height or valve timing.

Overhaul Kit for Cummins 6BT – 17.5:1 Compression Ratio

Compatible CPL Numbers: 597, 692, 712, 716, 729, 761, 804, 807, 856, 938, 943, 947, 948, 949, 950, 970, 971, 994, 1160, 1163, 1168, 1189, 1207, 1245, 1246, 1266, 1279, 1288, 1289, 1440, 1554, 1601, 1627, 1685, 2049, 2413

This 17.5:1 ratio is standard for many mid-range turbocharged 6BT engines. It balances cold start reliability with fuel efficiency and combustion pressure.

Overhaul Kit for Cummins 6BT – 17.5:1 Compression Ratio

Compatible CPL Numbers: 953, 970, 1165, 1247, 1313, 1322, 1408, 1570, 1613, 1638, 1928

Same high-efficiency piston dome profile as the kit above, but with different liner and bearing setups to match this CPL group.

Overhaul Kit for Cummins 6BT – 17.3:1 Compression Ratio

Compatible CPL Numbers: 596, 691, 714, 791, 802, 845, 960, 999, 1320, 1403, 1433, 1608

This slightly lower ratio improves durability under higher boost conditions and is used in 6BT applications with sustained heavy-duty load cycles.

Overhaul Kit for Cummins 6BT – 16.5:1 Compression Ratio

Compatible CPL Numbers: 599, 600, 698, 713, 715, 742, 792, 834, 912, 940, 961, 962, 983, 998, 1174, 1209, 1518, 1523, 1524, 1581, 2050, 2530, 2891, 8206

Lower compression is designed for engines operating in hotter climates or under longer power-up cycles. Helps reduce peak cylinder pressures for improved longevity.

Overhaul Kit for Cummins 6BT – 15.3:1 Compression Ratio

Compatible CPL Numbers: 1975, 2205, 2208, 2956, 8457

This is the lowest compression ratio in the 6BT lineup, engineered for high-boost turbo setups or extremely hot ambient environments. Reduces stress on internal components while still maintaining power under load.

Overhaul Kit for Cummins 6BT – Standard Compression Ratio

Compatible CPL Numbers: 1071, 1902, 1948, 1961, 1962, 2014, 2015, 2016, 2071, 2122, 2125, 2242, 2292, 2296, 2372, 2373, 2417, 2551, 2868, 3868, 8444

This group includes some of the most common CPLs and is often used in marine generators or auxiliary drives where consistent low-RPM operation is critical.

What Compression Ratio Means for Your Cummins 6BT

Compression ratio is the ratio of the volume inside the cylinder at bottom dead center compared to top dead center. In diesel engines, a higher compression ratio typically improves combustion efficiency, cold start ability, and fuel economy. However, it also raises peak cylinder pressure.

Lower compression ratios, such as 15.3:1 or 16.5:1, are used to extend engine life under high turbo boost or heavy-duty usage. These are common in marine or power generation applications where reliability and cooling system stability are essential.

Always match the compression ratio of your overhaul kit to your CPL. Using a piston with the wrong compression height can lead to valve interference, poor combustion, or excessive blow-by.

Related Components for Cummins 6BT Engine Rebuilds

In addition to overhaul kits, Diesel Pro Power offers all essential parts to support a full 6BT rebuild:

Salvage Sleeves and Liner Repair

Our standard salvage sleeves are precision-fit and allow you to repair blocks worn beyond normal liner spec. Perfect for overhauls where cylinder bores are out-of-round or scored.

Piston Cooling Nozzles

Cummins 6BT engines with turbochargers often include piston cooling jets. These nozzles spray oil under the pistons to control temperature and prevent thermal failure. Replace one per cylinder during overhaul.

Expansion Plug Kits

Essential for resealing water jackets and oil galleries. Our kits include all core plugs needed to reseal your 6BT engine block after machine work.

Crankshaft Seal Kits

Available for both front and rear seals. Includes dust shield, seal, and installation guidance for leak-free operation after crankshaft inspection.

Maintenance Components and Filters

A proper rebuild should always include replacement of basic service parts:

• Fuel Filters and Water Separators: Protects new injectors and pumps from contamination.

• Oil Filters: Spin-on filters matched to 6BT threads and diameter.

• Gaskets and Seals: Our full gasket sets include cylinder head gaskets, valve stem seals, intake and exhaust gaskets, front and rear main seals, and more.

Tools Recommended for a 6BT Rebuild

To complete your overhaul efficiently and safely, Diesel Pro Power carries the following tools compatible with Cummins 6BT:

• Feeler Gauge (.002"–.025"): For setting valve lash post-assembly.

• Piston Ring Installation Tool: Prevents ring damage during piston installation.

• Oil Filter Wrench: Required to torque filters to spec during final service.

• Fuel Filter Wrench: Speeds removal and installation of filters without damaging housings.

• Radiator Cleaner: Removes scale and deposits during coolant system flushing.

• Temperature Switches and Sensors: Replace old switches that may not trigger at correct temperatures, especially in marine cooling loops.

• Mechanical and Electric Gauges: Available in 12V and 24V configurations for oil pressure, temperature, and RPM.