GRADE 2 38770 Harmonic Balancer Bolt Block Chevy Che 313051664634

( Brand: Grade 2 ), ( Part Type: Block ), ( Thread Size: 3/8 ), ( Head Style: Flat ), ( Exterior Finish: Machined ), ( Material: Alloy Steel ), ( UPC: 313051664634 )

Review GRADE 2 Harmonic Balancer Bolt Fit Small Block Chevy Che

The **313051664634 38770 Harmonic Balancer Bolt for Block Chevrolet Engines** is a precision-engineered, high-performance fastener specifically designed to secure the harmonic balancer assembly on select Chevy V8 engines, ensuring optimal vibration dampening and drivetrain stability. Crafted from **Grade 8.8 high-strength steel**, this bolt features a **fine-threaded M12 x 1.5 pitch** with a **12-point drive socket head**, delivering superior torque retention and resistance to loosening under extreme engine loads ideal for high-performance applications, muscle cars, or restored classic engines where reliability is paramount. The bolt is **heat-treated and case-hardened** to withstand the intense thermal cycling and mechanical stress encountered in aggressive driving conditions, preventing premature wear or failure. Its **black oxide or zinc plating** provides corrosion resistance, protecting against moisture, road salt, and environmental degradation over time, while the **tight tolerance manufacturing** ensures a snug, interference-free fit with the harmonic balancer hub and engine block. Whether installed on a **LS-series, LT-series, or older small-block Chevy V8**, this bolt is engineered to maintain critical alignment of the harmonic balancer, reducing parasitic vibration and prolonging the life of associated components like the crankshaft pulley, serpentine belt system, and drivetrain mounts. For enthusiasts and mechanics seeking a **direct-fit, OEM-quality replacement** that meets or exceeds factory specifications, this bolt is an indispensable component for maintaining peak engine performance and longevity.

### Pros and Cons of buying a **313051664634 38770 Harmonic Balancer Bolt for Block Chevy (L96/V8 Engines)**

1. **OEM Quality and Fitment** This bolt is designed as an original equipment manufacturer (OEM) replacement, meaning it should fit perfectly on your Chevy L96 or V8 engine block without modifications. It is manufactured to the same specifications as the factory part, ensuring compatibility with the harmonic balancer and crankshaft interface.

2. **Durability and Strength** The bolt is likely made from high-strength steel, which is critical for withstanding the high torque and vibration forces generated by a Chevy V8 engine. Properly torqued, it helps maintain the integrity of the harmonic balancer assembly, preventing loosening or failure over time.

3. **Prevents Harmonic Balancer Issues** A loose or damaged harmonic balancer bolt can lead to excessive vibration, noise, or even catastrophic failure (e.g., the balancer coming off). Replacing it with a new, high-quality bolt reduces the risk of these problems, extending the life of the balancer and related components.

4. **Easy Installation** Since it is a direct replacement, installation is straightforward. Most mechanics or DIYers with basic tools (socket wrench, torque wrench) can replace it without special equipment. The bolt typically requires a specific torque specification (often around **100-120 ft-lbs** for these applications), which is critical to avoid overtightening or under-tightening.

5. **Cost-Effective Solution** Compared to the potential cost of repairing or replacing a damaged harmonic balancer or crankshaft pulley due to bolt failure, purchasing a new bolt is a relatively inexpensive preventive measure. Prices for this part are typically under **$20**, making it a small investment for long-term reliability.

6. **Warranty Coverage** Many reputable suppliers (e.g., RockAuto, Summit Racing, or direct from manufacturers like **38770**) offer warranties on their bolts, providing peace of mind in case of premature failure due to defects.

7. **Prevents Engine Damage** If the harmonic balancer bolt fails, it can cause the balancer to detach, leading to severe engine damage (e.g., bent crankshaft pulley, warped harmonic balancer, or even crankshaft damage). Replacing it proactively avoids costly repairs.

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- **Under-torquing** can lead to loosening over time, causing vibration and potential failure.

- **Over-torquing** can strip the threads in the crankshaft pulley or engine block, rendering the bolt unusable and potentially damaging the mating surfaces. Always follow the manufacturer s torque spec (typically found in the engine s service manual).

2. **Potential for Counterfeit Parts** Some aftermarket bolts, especially if purchased from untrusted sellers (e.g., third-party Amazon listings or unknown eBay vendors), may be counterfeit or substandard. This can result in premature failure or poor fitment. Stick to reputable suppliers (e.g., **RockAuto, Summit Racing, or direct from 38770**) to avoid this risk.

3. **Limited Availability of Replacement Parts** While this bolt is common for Chevy L96/V8 engines, if you encounter issues (e.g., stripped threads), finding an exact replacement may be difficult. In such cases, you might need to machine the crankshaft pulley or block to accept a larger bolt, which adds complexity and cost.

4. **Requires Basic Mechanical Knowledge** While the installation is simple, removing the old bolt may require removing the harmonic balancer or crankshaft pulley, which can be tricky for inexperienced DIYers. If you re not comfortable with engine disassembly, hiring a mechanic may be necessary.

5. **Potential for Thread Damage** If the existing threads in the crankshaft pulley or block are stripped, the new bolt may not seat properly. In this case, you d need to either:

- Use a **thread repair kit** (e.g., Helicoil) to restore the threads.

- Replace the crankshaft pulley or block (expensive and time-consuming).

6. **Not a Permanent Fix for Underlying Issues** If the harmonic balancer itself is worn or damaged, replacing just the bolt won t solve the root problem. The balancer may still fail due to internal wear, requiring a full replacement.

7. **Time-Consuming for DIYers** If you re not familiar with engine work, the process of removing the old bolt, cleaning threads, and installing the new one can take several hours, especially if you need to remove the harmonic balancer or timing components.

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Replacing the **313051664634 38770 harmonic balancer bolt** on your Chevy L96/V8 engine is a **highly recommended preventive maintenance task**, especially if the bolt is old, loose, or showing signs of wear (e.g., cracks, rust, or stripped threads). The benefits **preventing catastrophic failure, maintaining engine balance, and avoiding costly repairs** far outweigh the minor drawbacks, which are mostly related to **proper installation technique and part quality**.

- Using a **torque wrench** and following the correct spec.

- Purchasing from a **trusted supplier**.

- Ensuring the **threads are clean and undamaged** before installation.

If you re comfortable with basic engine work, this is a **quick and inexpensive** fix that can save you from much larger problems down the road. If you re unsure about the process, consulting a mechanic is a wise investment.

1. **Purchase the bolt from a reputable source** (e.g., **RockAuto, Summit Racing, or the official 38770 supplier**) to ensure authenticity and quality.

2. **Check the existing threads** in the crankshaft pulley or block for damage. Clean them thoroughly and consider using **anti-seize compound** (lightly) to prevent future seizing.

3. **Torque the bolt to the manufacturer s specification** (typically **100-120 ft-lbs** for these applications). Do not exceed this, as overtightening can ruin the threads.

4. **Reinstall the harmonic balancer or pulley** and ensure it s properly balanced (if you removed it).

5. **Consider replacing the harmonic balancer** if it s old or showing signs of wear (e.g., cracks, excessive play, or vibration).

6. **Document the torque value** and mark the bolt (if possible) to avoid confusion during future maintenance.

**Final Verdict:** **Buy and replace the bolt immediately if it s old or suspect.** This is a **low-cost, high-reward** maintenance item that can prevent a much more expensive failure. If you re not confident in your ability to install it correctly, have a mechanic perform the replacement.

Details:

Engine and 68 Camry 327 large journal crank end perfectly. Balancer Bolt for Small Block Chevy: Especially important when crankshaft is being rotated by hand tool with the use of a socket and breaker bar or ratchet handle, Hes Vehicle Specific tool, Secure engine balancer firmly in place under severe conditions, Ensures that locked position as flexes twists. Provide Positive Grip for Removal Installation: As the crankshaft flexes, damper absorbs incredible amounts of energy, These bolt kits will ensure that your engine balancer is locked into position, Machined perfectly flat to spread fastening load over a larger surface area. Harmonic Balancer Bolt: 38770 Bolt fit for Small Block Chevy, Chevy 350ci 5.7L, lt-1 ABC ,350 SBC etc.

part #: 313051664634 price

• $33.97

specifications mixedtoolsetse:

• brand: Grade 2
• part type: Block
• thread size: 3/8
• head style: Flat
• exterior finish: Machined
• material: Alloy Steel
• upc: 313051664634

offer mixedtoolsetse:

• started: May 5, 2026
• sold: 0
• options: Ship-to-home
• availability: In Stock
• quantity: 1

payments mixedtoolsetse:

• credit card: Diners-club
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• other

shipping mixedtoolsetse:

• transit: 2-4 Days
• service: Expedited
• cost: $0.00
• class: Expedited
• type: Fixed

returns mixedtoolsetse:

• paid by: Seller
• method: Money back
• policy: Returns Accepted
• time: 30 Days

seller mixedtoolsetse:

• rating: 99.4%
• # reviews: 2384
• city: Denver, Colorado

general mixedtoolsetse:

• Tools Workshop Equipment > Hand Tools > Hand Tool Sets
• condition: New

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