[Shiny]

Originally Posted by mgarblik

Finally had some time to work on the connecting rods for this SD engine. I installed the ARP bolts and stretched them to .0075" stretch as directed by ARP. Then measured the big end housing bores. Each housing bore closed up .0015"-.0018" smaller than the spec. This is NOT unexpected. The ARP bolts are much stronger than even the stock SD bolts and have higher clamping load. The torque to reach that stretch was around 90 ft. lbs. So as a general rule, on any connecting rod, when changing the bolts, plan on honing the rod big ends back to specs. to get nice straight and round bores for the bearings. Should be a fairly easy fix. Will make that happen today and move on to a little block hone touch-up. Then a thorough cleaning.

I apologize for the diversion and ignorance but can someone explain the tools/methods used to hone a rod bore?

I want to understand how an abrasive machining process can return this heavily distorted bore to round. These bolts must apply a LOT more compression than stock bolts to get this much change.

Are the abrasives "rigid" and gradually expanded instead of just following the bore with spring-loaded stones?

Not being familiar with the equipment used, I have a vision of spring-loaded stones which I'd expect to just follow whatever shape is already there. This has to be wrong.

Is a rod hone more like a rigid grinding wheel that is expanded as it progresses?


Mike