Boreable Vs. Honeable Connecting Rod (Piston Pin) Bushings

March 2, 2023

The ultimate goal when servicing diesel connecting rods is to ensure the full set of rods are straight, on size and of the correct length. They should be machined back to the original OEM specifications.

Honeable bushings are acceptable if no other connecting rod large end machining has been performed and is recommended to only hone the bushing inside diameter.

Boreable bushings are required if modification has been performed on the connecting rod large end. Since the rod center-to-center length has been modified, this measurement has to be re-established for the full set of rods.

Maintaining the rod center-to-center length is key to keep compression ratio and cylinder combustions temperatures uniform. The final step in either bushing use should be to install the piston pin and check the alignment of the piston pin to the large end of the connecting rod. Assembly of the connecting rod and piston in the cylinder block assembly will then give you the protrusion/recession specifications to compare with the OEM specifications.