Align Boring vs. Align Honing: What's the Difference?

Align Boring vs. Align Honing: What's the Difference?

Align Boring (AKA Line Boring) and Align Honing (AKA Line Honing) are both processes used to ensure that the main bearing bores in an engine block are perfectly aligned, but they differ in the method and amount of material removal.

Align Boring:

Purpose: Align Boring is used to correct significant misalignment or damage in the main bearing bores of an engine block. It is often necessary when the bores are severely out of round, have been damaged, or when oversized main bearings are required.

Process: Align Boring involves using a boring bar to machine the main bearing bores. This process removes more material than honing and is used to bring the bores back to their correct centerline and roundness.

After the block is set up in a boring machine, a boring bar is passed through the main bearing bores to cut them to a new, larger size. This process ensures that all the bores are concentric and in alignment.

Because Align Boring increases the diameter of the bores, it usually requires the use of oversized main bearings or bearing caps that are then Align Honed to the final size.


Applications: Align Boring is typically used in situations where the bores are too far out of spec to be corrected by honing alone. It's also used when new main caps are installed, as they often require the bores to be resized and aligned.

Align Honing:

Purpose: Align Honing is used to fine-tune the alignment of the main bearing bores and achieve the final desired size and surface finish after any major corrections have been made by Align Boring.

Process: Align Honing uses a honing machine with abrasive stones to remove a small amount of material from the main bearing bores. This process is less aggressive than boring and is used to achieve precise alignment and the correct surface finish.

ย Align Honing is often performed after Align Boring to achieve the final dimensions and ensure that the bores are perfectly aligned and round.


Key Differences:

  1. Material Removal:
- Align Boring removes a significant amount of material to correct major misalignment or damage. It increases the diameter of the bores, requiring either oversized bearings or additional honing.
- Align Honing removes a minimal amount of material, focusing on fine-tuning the bore size and alignment after boring or as a standalone process when the misalignment is minor.
  1. Precision:
- Align Boring is used for major corrections and initial sizing.
- Align Honing is used for final precision and surface finish.
  1. Applications:
- Align Boring is necessary when the bores are significantly out of alignment or when new main caps are installed.
- Align Honing is used after boring or when only minor adjustments are needed.

In summary, Align Boring is the more aggressive process used to correct major issues, while Align Honing is the finishing process that ensures the bores are precisely aligned and correctly sized.

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