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Cat 3412 Engine

CAT 3412 Engines For Sale

CAT3412 Engine

The 3412 Cat is a heavy-duty, V-12 diesel engine capable of making big horsepower–with a maximum output of 551 bkW (750 bhp). The 3412 is used to power a variety of off-highway applications such as bulldozers, scrapers, haul trucks, and dump trucks. These engines also enjoy a familiar home in industrial applications like mining, drilling, oilfield, agricultural, forestry and construction equipment. Reviews and statistics show that the CAT 3412 is one of the most highly demanded engines in the aforementioned industries. This is due to the engine’s track record for reliability, outstanding performance, and long-term dependability.

Engine Applications and Uses

  • Construction
  • Agricultural
  • Trucks
  • Oil & Gas
  • Forestry
  • Mining

Common CAT 3412 Engine Problems & Failures

After years of working with the Caterpillar 3412, we’ve noticed pattern problems in the used engines our customers are considering replacing. Because of that, we’ve compiled a list of common problems that are frequently reported by 3412 owners. Some of the failures listed below may mean your engine has run out of time. However, if caught soon enough some of the following problems may leave your original engine salvageable.

AERA Association Member

  • Camshaft Failure
  • Connecting Rod Failure
  • Cracked Cylinder Head(s)
  • Crankshaft Failure
  • Dropped Valves
  • Extreme Blow By
  • Lack Of Oil or Oil Pressure
  • Lifter/Roller Failure
  • Overfueling
  • Scored Pistons and Liners
  • Spun Crankshaft Bearings

Caterpillar 3412 Engine Replacement Options

When it comes to the health of an ailing engine, there could be a whole host of issues contributing to its poor performance. In a worst-case scenario, your only choice may be to replace the engine completely. Less severe issues, on the other hand, may only require you to replace some parts or components. Of course, many engines can continue to run “OK” for a number of years. These tired 3412’s are typically the best refresh candidates. In the end, cost, time, and availability will ultimately influence your decision most, which is exactly why we’ve spelled out the pros and cons of buying a new CAT 3412 from the dealer.

Remanufacturing Process

A remanufactured 3412 long block from Big Bear Engine is a great replacement option for the customer who’s experienced a catastrophic internal engine failure. Coincidentally, a reman long block is an especially beneficial option if the customer still has functional, reusable external components that can be salvaged from their old engine. And finally, long blocks are a great alternative to buying new when you’re trying to reduce some of the costs associated with replacing an engine.

We always strive to uphold a professional level of service here at Big Bear Engine Company, whatever the task may be. Our dedicated team of machinists and engine builders perform all work in-house—which includes a full core tear down, cleaning, inspection, and all machining of the engine—before it leaves our facility. This ensures excellence every time.

It is crucial to note that all of our 3412 Cat remanufactured long blocks are built with both reman and new parts. We do not just recondition or refurbish old parts. Instead, we fully rebuild your old Caterpillar 3412 engine back to original OEM specs.

Thorough Cleaning

Careful cleaning is an essential first step in the remanufacturing process. After taking delivery of your 3412 CAT, the block, head, rods, crankshaft, and camshaft are all carefully cleaned in a chemical jet wash or hot tank to remove any impurities.


Before our quality control division inspects the finished product, the crankshaft is precision machined to precise tolerances, gets polished, and is then magnafluxed.

Cylinder Head

The cylinder heads are resurfaced to guarantee a proper sealing surface with the block, and to achieve a finish that is compatible with modern gasket materials. Valve height is mic’d and every head is vacuum tested to guarantee correct valve seating.


All 3412 blocks are inspected for cracks, imperfections, and other damage using magnetic particle. The cylinders are then bored, honed, and inspected to the specific tolerances. Torque plate honing is performed on certain engines to reduce the chances of cylinder distortion once the head is installed and torqued to the block. This process removes the main source of engine blow-by. Block surfaces are then machined and inspected to ensure proper finish.


The camshaft is inspected and precisely machined to provide correct lift. Lobes are measured with a micrometer to ensure OEM tolerances are met.

Connecting Rods

In order to attain an even distribution of stress across the bearings, the connecting rods are cleaned, machined to OEM specs, and are then honed to their traditional diameter. New bushings are fitted and machined in all bushed rods. Each connecting rod is also inspected for bend and/or twist.

New Parts

All of our 3412 long blocks receive a standard set of new parts such as pistons and rings, bearings, gaskets and seals, and liners. These new parts assure optimal performance and reliability throughout the life of your engine. New parts are a combination of OEM and aftermarket, when available.

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Please fill out the form below with your information and request. A member of our staff will be with you shortly.

Remanufactured Engine Standards

We believe that to remanufacture is to make as close to new as possible. This means that all wearable parts are automatically replaced. All 3412 core materials are then carefully inspected and examined against the original equipment specifications for correct dimensional tolerances. Replacement parts are new or requalified. If new, parts are made using the same production procedures as original equipment. Testing on all of our 3412 Cat engines is also performed to manufacturer specifications and according to original production standards.

CAT 3412 Long Block Parts List:

  • Caterpillar 3412 Diesel EngineCamshaft
  • Complete Loaded Cylinder Heads
  • Block
  • Followers/Lifters
  • Intermediate Cover
  • Liners
  • Upper and Lower Gasket Set
  • Pistons
  • Timed Front Gear Group
  • Rings
  • Crankshaft
  • Connecting Rods
  • **1 Year Warranty

*Note: We can provide a new oil pump, oil cooler, water pump, turbo, injectors and fuel pump for additional cost(s) with the long block, but these components will not come assembled to the engine.

**1-Year Warranty: First 6 Months Parts & Labor, Second 6 Months Parts Replacement Only. Ask your sales representative for a full copy of our remanufactured long block warranty.

CAT 3412 Specs

Engine Data

Minimum Power476.0 bkW (647 bhp)
Maximum Power551.0 bkW (750 bhp)
Bore5.40-inch (137 mm)
Stroke6.00-inches (152 mm)
AspirationTurbocharged and Aftercooled
Weight Net (dry)2,730 kg (6,018 lbs)
Oil Change Interval250 hours
Rotation (from flywheel end)Counter-Clockwise
Flywheel and Flywheel HousingSAE No. 0
Flywheel Teeth151
Lube System – Refill139.0 liters
Cooling System – Refill58.0 liters
Length1,980 mm
Width1,300 mm
Height1,285 mm

Give us a call today at 844-340-4114 for immediate sales and support for the Cummins 4BT, Cummins 6BT, 6CT, ISC, 855, QSB 4.5 L or CAT 3306. If you have any questions, check out our FAQ Page. We are always ready to help or just listen to your crazy off-roading adventures!

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