Main Bearing Kit (0.010" Undersize) – Fits Volvo Penta AQ/BB/MB Series (Replaces 271215)
Main Bearing Kit (0.010" Undersize) – Fits Volvo Penta AQ/BB/MB Series (Replaces 271215) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Main Bearing Kit (0.010" Undersize) – Fits Volvo Penta AQ/BB/M...
Product Details
This is a high-quality aftermarket Main Bearing Kit (0.010" Undersize) designed for specific Volvo Penta gasoline engines. It fits B17, B19, B20, B21, and B23 4-cylinder engines used in various AQ, BB, and MB series marine applications from approximately 1963 to 1985.
This kit serves as a direct replacement for Volvo Penta part numbers 271215, 276695, 276699, 418224, 418230, 418318, and ORB11215.
- Specification: 0.010" (0.254 mm) Undersize for machined crankshafts.
- Installation: Installs into the engine block to support the crankshaft.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Volvo Penta | 271215 |
| Volvo Penta | 276695 |
| Volvo Penta | 276699 |
| Volvo Penta | 418224 |
| Volvo Penta | 418230 |
| Volvo Penta | 418318 |
| Volvo Penta | ORB11215 |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
This bearing kit is compatible with an extensive list of vintage Volvo Penta AQ, BB, and MB series engines.
| Brand | Model | Stroke | Years | OEM Part No. |
|---|---|---|---|---|
| Volvo Penta | AQ90 | 4-Stroke | 1963–1968 | 271215 |
| Volvo Penta | AQ105A | 4-Stroke | 1968–1969 | 271215 |
| Volvo Penta | AQ115A | 4-Stroke | 1969–1970 | 271215 |
| Volvo Penta | AQ115B | 4-Stroke | 1970–1975 | 271215 |
| Volvo Penta | AQ120B | 4-Stroke | 1977–1980 | 271215 |
| Volvo Penta | AQ125A | 4-Stroke | 1983–1984 | 271215 |
| Volvo Penta | AQ130A | 4-Stroke | 1968–1970 | 271215 |
| Volvo Penta | AQ130B | 4-Stroke | 1968–1970 | 271215 |
| Volvo Penta | AQ130C | 4-Stroke | 1969–1975 | 271215 |
| Volvo Penta | AQ130D | 4-Stroke | 1975–1977 | 271215 |
| Volvo Penta | AQ140A | 4-Stroke | 1975–1977 | 271215 |
| Volvo Penta | AQ145A | 4-Stroke | 1979–1985 | 271215 |
| Volvo Penta | BB100 | 4-Stroke | 1963–1968 | 271215 |
| Volvo Penta | BB115A | 4-Stroke | 1969–1970 | 271215 |
| Volvo Penta | BB115B | 4-Stroke | 1970–1975 | 271215 |
| Volvo Penta | BB115C | 4-Stroke | 1975–1977 | 271215 |
| Volvo Penta | BB140A | 4-Stroke | 1975–1979 | 271215 |
| Volvo Penta | BB145A | 4-Stroke | 1979–1985 | 271215 |
| Volvo Penta | MB20A | 4-Stroke | 1969–1971 | 271215 |
| Volvo Penta | MB20B | 4-Stroke | 1969–1975 | 271215 |
Technical Specs
- Product Type
- Main Bearing Kit (0.010" Undersize)
- Fit
- 0.010" (0.254 mm) Undersize
- Application
- Engine Block Crankshaft Bearings
- Fuel Type
- Gasoline
- Product Dimensions
- 16.5 x 8.5 x 8.5 (units not specified)
- Package Dimensions
- 16.5 x 8.5 x 8.5 (units not specified)
Installation Notes
- Disconnect the battery and drain all engine oil.
- Safely access the engine's crankshaft by removing the oil pan and any other necessary components.
- Carefully remove the old main bearing caps and bearings, keeping them in order and noting their original orientation.
- Thoroughly clean the crankshaft journals and bearing saddles in the engine block. Do not use abrasive materials.
- Use a micrometer to measure the crankshaft journals to confirm they have been machined to the correct 0.010" undersize specification.
- Apply a quality engine assembly lubricant to the new bearings and the crankshaft journals.
- Install the new main bearing shells into the engine block and the bearing caps.
- Reinstall the bearing caps and torque the bolts to the manufacturer's specified values and sequence.
- Check for proper crankshaft rotation; it should turn smoothly by hand without binding.
- Reinstall the oil pan with a new gasket, followed by all other components that were removed.
- Refill the engine with the manufacturer-recommended grade and amount of fresh oil.
- Reconnect the battery. Start the engine, check for leaks, and verify proper oil pressure immediately.
Troubleshooting & FAQ
How do I know if I need undersize bearings?
Undersize bearings are used when the crankshaft has been machined (ground) to a smaller diameter during an engine rebuild. You must measure your crankshaft's main bearing journals with a micrometer to determine the correct bearing size. This 0.010" kit is specifically for crankshafts that have been machined 0.010 inches below the standard factory diameter.
What are the signs of a failing main bearing?
Common symptoms include a deep, rhythmic knocking sound from the engine, consistently low oil pressure readings, and the presence of metallic shavings or particles in the engine oil and oil filter.
Will this fit my BB115C engine?
Yes, this kit is specified to fit the Volvo Penta BB115C model, which was produced from 1975–1977. However, always double-check by cross-referencing part numbers and visually comparing the old bearings to the images provided on this page.
Does this kit include the thrust bearing?
Yes, a complete main bearing kit includes all the necessary bearing shells for the crankshaft mains, which incorporates the thrust bearing designed to control the crankshaft's axial movement (end-play).
Can I install these myself?
While possible for highly experienced mechanics, installing engine main bearings is a precision task that requires specialized tools like a torque wrench, micrometers, and plastigauge. To ensure engine longevity and prevent catastrophic failure, professional installation is strongly recommended.
What is the OEM part and is this an aftermarket part?
This is an aftermarket replacement part, not an OEM component. It is engineered to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function, using comparable materials. Our parts are produced in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.
What are the shipping times and costs?
We ship worldwide. Typical transit time is between 5–15 days for most regions. Standard shipping is free. Expedited shipping options, if available for your location, will be presented at checkout.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal operating conditions. If you encounter an issue, please contact our support team with your order number. Returns are accepted within our standard return window for items that are unused and in their original packaging. Please see our full policy page or contact us for detailed instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model is listed as compatible—do not order.
- This is a high-quality aftermarket replacement part and is not an OEM component.
- Professional installation is strongly recommended for this part to ensure safety, proper fitment, and optimal performance.
About Sea Sierra
- Pro-Grade Standards: We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world durability and performance.
- Fast Global Fulfillment: We offer free standard delivery to most regions, with typical transit times of 5–15 days.
- Manufacturer-Direct Value: By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
Payment & Security
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