GM 12630431 Engine Crankshaft

( Brand: Gm ), ( Manufacturer Part Number: 12630431 ), ( Part Type: Engine Crankshaft ), ( Manufacturer Warranty: 1 Year ), ( Fitment Type: Direct Replacement ), ( Genuine Oem: Yes )

Review GM Genuine Engine Crankshaft

The **GM 12630431 Engine Crankshaft** is a precision-engineered component designed specifically for General Motors high-performance and durability-focused internal combustion engines, particularly those found in select models of the **LS-series** platform, including the **LS3, LS7, and LS9** engines. Crafted from **forged 4340 steel**, this crankshaft is built to withstand extreme loads, high RPMs, and prolonged use under demanding conditions, making it an ideal choice for both stock and modified applications. The crankshaft features a **five-main-bearing journal design**, providing exceptional stability and reducing vibration, which is critical for maintaining power delivery and longevity in high-output engines. Each journal is meticulously **ground and polished** to exacting tolerances, ensuring smooth operation and minimizing friction, while the **counterweights** are dynamically balanced to optimize rotational efficiency and reduce stress on the engine s support structure.

The **12630431 crankshaft** incorporates **full-floating pins** that are press-fit into the crankshaft journals, allowing for precise alignment and enhanced durability, especially in high-performance setups where additional stress is placed on the connecting rods. The **main bearing journals** are designed to accommodate **high-capacity bearings**, such as those from **Clevite, Fel-Pro, or Sealed Power**, ensuring reliable operation even under extreme torque loads. Additionally, the crankshaft s **fillet radii** are strategically reinforced to prevent fatigue failure, a common concern in forced-induction applications where cylinder pressures can reach extreme levels. This attention to detail extends to the **crankshaft s overall geometry**, which is optimized for **balanced power delivery** across the engine s powerband, whether in naturally aspirated or turbocharged configurations.

For applications requiring even greater strength, the **12630431 crankshaft** can be paired with **aftermarket upgrades**, such as **hardened rods, forged pistons, or high-flow oil pumps**, to further enhance reliability in high-performance builds. The part is fully compatible with **GM s LS-series engine blocks**, including those from the **Corvette, Cadillac CTS-V, Chevrolet Camaro SS, and other high-performance applications**, ensuring seamless integration with stock or modified engine components. Whether used in a **street rod, drag racing application, or high-revving supercharged setup**, this crankshaft delivers the structural integrity and performance required to handle the most demanding driving conditions. Built to **GM s stringent quality standards**, the **12630431 crankshaft** is a critical component for anyone seeking to maximize power, reliability, and longevity in their LS-series engine.

### Pros and Cons of Buying a GM 12630431 Engine Crankshaft

1. **Compatibility** The GM 12630431 crankshaft is designed specifically for certain GM engines, ensuring a precise fit with minimal modifications required. This reduces the risk of installation errors and improves performance reliability.

2. **Performance Enhancements** If the crankshaft is a performance or aftermarket variant (e.g., forged, balanced, or with optimized weight distribution), it can improve engine power, torque, and durability, especially in high-performance or modified applications.

3. **Durability** High-quality crankshafts, particularly those made from forged steel or alloy materials, are engineered to withstand higher stress levels, extending the engine s lifespan under heavy loads or extreme conditions.

4. **OEM Replacement Option** If the original crankshaft failed due to wear or damage, purchasing an OEM or high-quality aftermarket replacement ensures the engine retains its intended specifications, preventing compatibility issues with other components.

5. **Cost-Effective for Repairs** In some cases, replacing just the crankshaft (rather than the entire engine) can be significantly cheaper than a full engine rebuild or replacement, making it a practical solution for engine failures.

6. **Warranty Coverage** Reputable manufacturers or dealers may offer warranties on crankshafts, providing peace of mind against premature failure due to defects in materials or machining.

7. **Customization Potential** For enthusiasts, aftermarket crankshafts may offer custom stroke lengths, counterweights, or balancing options to fine-tune engine performance for specific applications (e.g., drag racing, towing, or daily driving).

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1. **High Cost** A quality crankshaft, especially a performance or forged variant, can be expensive often costing several hundred to over a thousand dollars, depending on the engine type and material. This can be prohibitive for budget-conscious repairs.

2. **Installation Complexity** Replacing a crankshaft requires specialized tools, expertise, and often a full engine disassembly. Improper installation can lead to catastrophic engine failure, so it s best left to experienced mechanics.

3. **Additional Wear on Related Components** If other engine parts (e.g., bearings, rods, or seals) are worn or damaged, replacing just the crankshaft may not fully resolve the issue. A full inspection and potential replacement of related components may be necessary, adding to costs.

4. **Limited Availability** Some GM engines may have discontinued or hard-to-find crankshafts, especially for older or less common models. Purchasing from unreliable sources could result in counterfeit or mismatched parts.

5. **Potential for Counterfeit Parts** The aftermarket for crankshafts can be saturated with low-quality or counterfeit products. Buying from untrusted sellers may lead to premature failure, voided warranties, or compatibility issues.

6. **Time-Consuming Process** The repair process can take days or even weeks, depending on the mechanic s workload and whether other components need replacement. This downtime can be inconvenient for vehicle owners.

7. **Risk of Overkill for Mild Issues** If the crankshaft failure was caused by a minor issue (e.g., oil starvation, improper maintenance), replacing it may not address the root cause, leading to repeated problems if the underlying issue isn t fixed.

8. **Weight and Balance Considerations** Aftermarket crankshafts may have different weight distributions compared to OEM parts. Improper balancing can lead to vibration, reduced longevity, or even damage to the engine block or mounts.

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The decision to purchase a GM 12630431 crankshaft depends on the specific situation, budget, and technical expertise available. For **OEM replacements** in standard applications, the crankshaft is a practical and reliable choice, provided it is sourced from a trusted supplier. For **performance modifications**, a high-quality aftermarket crankshaft can offer significant benefits but requires careful selection and professional installation.

However, the **high cost, installation complexity, and potential for additional repairs** make this a decision that should not be taken lightly. It s crucial to:

- **Verify the exact model and compatibility** before purchasing.

- **Inspect other engine components** to avoid recurring issues.

- **Use a reputable dealer or mechanic** for installation to ensure proper fitting and balancing.

- **Consider the total cost of repair**, including labor and potential additional parts.

If the engine failure is severe or the vehicle is older, weighing the cost of a crankshaft replacement against the engine s remaining value or the cost of a used replacement engine may be more economical.

1. **For OEM Replacement:** Purchase the crankshaft from a **GM-authorized dealer or a trusted aftermarket supplier** (e.g., Crane, JE, or Summit Racing) with a warranty. Ensure the part number matches exactly (12630431) and confirm compatibility with your engine build year and modifications.

2. **For Performance Applications:** Choose a **forged or high-performance crankshaft** from a well-reviewed manufacturer (e.g., JE, Eagle, or Scat). Have a **professional mechanic** perform the installation, including full engine inspection and balancing.

3. **For Budget or Minor Repairs:** If the engine has other failing components (e.g., rods, bearings), consider a **full engine rebuild or used engine replacement** as a more cost-effective solution in the long run.

4. **Always Prioritize Quality Over Cost:** A cheap or counterfeit crankshaft may save money upfront but could lead to **expensive failures, voided warranties, or engine damage**. Invest in a reputable part and professional installation to ensure reliability.

5. **Document the Repair:** Keep records of the crankshaft purchase, installation, and any warranties to protect against future disputes or recalls.

Details:

Call Us at #214 342 4724. Shipping Carrier substitutions may be made at our determination in an attempt to reduce shipping cost the customer.

part #: 12630431 prices

• $1176.85-$1515.70

specifications cranshafengin:

• brand: Gm
• mpn: 12630431
• part type: Engine Crankshaft
• manufacturer warranty: 1 Year
• fitment type: Direct Replacement
• genuine oem: Yes

seller cranshafengin:

• rating: 99.6%
• city: Dallas, Texas
• # reviews: 9124

returns cranshafengin:

• policy: Returns Accepted
• time: 30 Days
• paid by: Seller

payments cranshafengin:

• other
• wallet: Paypal
• credit card: Diners-club

shipping cranshafengin:

• type: Fixed
• class: Standard
• cost: $66.25
• service: Standard
• transit: 14-22 Days

general cranshafengin:

• condition: New
• Car Truck Parts Accessories > Engines Engine Parts > Crankshafts

offer cranshafengin:

• availability: In Stock
• sold: 0
• quantity: 1
• started: May 30, 2026
• options: Ship-to-home

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