Parts for Caterpillar 3412C – Crankshaft Section

The crankshaft system is the backbone of the Caterpillar 3412C engine, converting combustion energy into rotational power. Every part in this section—whether the crankshaft itself, bearings, seals, dowel pins, gears, or dampers—plays a crucial role in maintaining smooth operation. For operators working in marine propulsion, heavy-duty construction, mining, or power generation, ensuring the crankshaft assembly is maintained with precision-engineered components is essential for engine reliability.

Diesel Pro Power supplies premium aftermarket crankshaft components for the Caterpillar 3412C, trusted by more than 40,000 customers worldwide. Our catalog is carefully organized, providing the replacement parts needed for a complete rebuild or targeted maintenance.

Crankshafts for Caterpillar 3412C

The crankshaft is the core rotating component of the 3412C. Built from high-strength forged steel, the crankshaft must withstand the massive forces of combustion while maintaining balance and alignment across all twelve cylinders.

Wide Bearing Design Crankshaft

The wide bearing design provides increased load-bearing capacity, distributing stress across a larger surface area. This design is ideal for high-duty cycles where engines operate under continuous heavy loads, such as marine propulsion systems and mining haul trucks. The wider bearing journals reduce wear and extend service intervals.

Standard Replacement Crankshaft

A standard forged crankshaft option is also available for the 3412C, designed to meet or exceed Caterpillar’s original performance specifications. Operators rebuilding engines for industrial power generation or general equipment applications can rely on this option to restore OEM-level performance.

Both crankshaft options are precision-balanced to reduce vibration and ensure smooth rotation, preventing premature wear on connecting rods, bearings, and seals.

Crankshaft Gears for Caterpillar 3412C

Crankshaft gears synchronize the crankshaft with the camshaft, ensuring proper valve timing and injector operation. A worn or damaged crankshaft gear can throw off engine timing, leading to power loss or catastrophic engine damage.

• Standard Crankshaft Gear (99 Teeth): Designed for engines requiring high precision in gear engagement. This gear maintains consistent timing under heavy loads.

• Alternative Gear Options (80 Teeth Compatibility): Certain applications may require dowel pin compatibility with 80-tooth gear systems, depending on build specifications.

Both gear types are machined from durable alloy steel and heat-treated for longevity, ensuring proper alignment with the camshaft gear train.

Crankshaft Dowel Pins

Dowel pins are small but critical for proper alignment of the crankshaft gear to the crankshaft. Even a minor misalignment can lead to gear chatter, noise, and uneven wear.

• Dowel Pins for 80-Tooth Gear Configurations: Used in specific 3412 builds that employ this gear type.

• Dowel Pins for 99-Tooth Gear Configurations: Compatible with many Caterpillar 3406, 3408, and 3412 models, making them a versatile service part for mixed fleets.

Replacing dowel pins during a rebuild ensures precise gear seating and prevents future failures caused by vibration or slippage.

Main Bearings for Caterpillar 3412C

Main bearings support the crankshaft inside the block, maintaining oil clearance and preventing metal-to-metal contact. They are among the most critical wear components in any engine rebuild.

Standard Main Bearings

These bearings are manufactured to factory-clearance specifications. They restore original oil film thickness and are suitable for engines with minimal crankshaft wear.

Oversize Main Bearings

When a crankshaft has been ground undersize to remove scoring or out-of-round wear, oversize bearings are required. The Caterpillar 3400-series engine family, including the 3412C, accepts several oversize increments:

• .010” Oversize Bearings: Common for light to moderate crankshaft reconditioning.

• .025” Oversize Bearings: Used in cases of more significant journal wear.

• .050” Oversize Bearings: Designed for crankshafts that have undergone extensive machining.

By selecting the correct oversize, operators can restore precise oil clearances, extending crankshaft and block life.

Thrust Washers for Crankshaft Endplay

Thrust washers control axial movement of the crankshaft, preventing excessive endplay that can damage connecting rods, pistons, and gears.

• Dual Washer Setup: The Caterpillar 3412 requires two thrust washers per engine.

• Wear Resistance: Made from high-strength bronze and coated with anti-friction material to ensure long service life.

Replacing thrust washers during a rebuild helps protect the crankshaft from forward and backward motion, a common failure point in high-horsepower applications.

Vibration Dampers

The vibration damper is a vital safeguard against harmonic vibrations that occur during combustion cycles. Without a properly functioning damper, crankshaft torsional stress can lead to cracks or complete failure.

• Heavy-Duty Damper for Caterpillar 3412C: Designed to absorb and dissipate vibration forces, extending the crankshaft’s operational lifespan.

• Replacement Interval: Dampers should be inspected and replaced periodically, as rubber elements or internal components degrade over time.

This component is especially critical for marine engines and generator sets where engines run at constant RPM for long durations.

Crankshaft Seals

Crankshaft seals prevent oil leaks at the front and rear of the engine. Worn seals not only cause oil loss but can contaminate the clutch housing or timing gear compartment.

Front Crankshaft Seal

• Prevents oil leakage where the crankshaft exits the timing cover.

• Made from heat- and oil-resistant materials to withstand high temperatures.

Rear Crankshaft Seal

• Protects against oil leakage where the crankshaft passes through the flywheel housing.

• Reinforced lip design ensures a tight seal even under heavy load.

Regular inspection and replacement of seals helps maintain lubrication integrity, prevents downtime, and keeps the engine compartment clean.

Importance of Using Correct Crankshaft Components

Each component in the crankshaft system works together to deliver power efficiently. Using incorrect or worn parts can lead to catastrophic engine failure, costly downtime, and reduced lifespan of the 3412C engine. Key considerations include:

• Bearing Fit: Using the wrong bearing oversize can cause oil starvation or excessive clearance.

• Gear Compatibility: Mismatched gear and dowel configurations will throw off engine timing.

• Damper Health: Neglecting damper replacement can result in crankshaft fractures.

• Seal Integrity: Oil leaks from worn seals can result in bearing damage and loss of oil pressure.

Why Buy Caterpillar 3412C Crankshaft Parts from Diesel Pro Power

Trusted by 40,000+ Customers Worldwide

Operators in over 180 countries rely on Diesel Pro Power for Caterpillar replacement parts. From offshore drilling platforms to inland construction sites, our crankshaft components have been tested in the harshest environments.

Premium Aftermarket Quality

Every crankshaft, bearing, gear, seal, and washer is built to meet or exceed Caterpillar’s stringent specifications. Materials are tested for hardness, tolerance, and wear resistance, ensuring long service life.

Fast Worldwide Shipping

We understand that downtime costs money. That’s why Diesel Pro Power offers expedited global delivery, ensuring that Caterpillar 3412C crankshaft components arrive quickly—whether you’re rebuilding in a shipyard, mine, or industrial facility.

Dedicated Caterpillar 3412C Catalog

Our online catalog is organized by system, making it simple to locate the exact crankshaft-related component you need without sifting through unrelated parts.

Expert Technical Support

Choosing between wide or narrow bearing crankshaft designs, selecting the correct oversize bearings, or properly installing vibration dampers can be challenging. Diesel Pro Power’s technical support team provides step-by-step guidance to help avoid costly mistakes during rebuilds.