Summary

When we're balancing the big end of a connecting rod, can we remove weight from the fastener instead of grinding the rod? Probably not something that I would recommend. The conrod fasteners, the big end fasteners are probably some of the most stressed fasteners in the engine.

00:00 - Pierre has asked, when we're balancing the big end of a connecting rod, can we remove weight from the fastener instead of grinding the rod? Probably not something that I would recommend.
00:12 The conrod fasteners, the big end fasteners are probably some of the most stressed fasteners in the engine.
00:17 So you'd be wanting to be very very careful about doing anything to remove material from the fastener and effect their reliability.
00:26 The other thing is that quite often we will be using a stretch gauge to actually tighten the connecting rod bolts.
00:34 So if we did anything like shortening the fastener to remove material from it, then that's going to also affect our ability to use a stretch gauge.
00:42 Let me just grab a conrod though and I'll show you where we should be removing the material.
00:49 So when we're balancing a connecting rod, quite often I see a lot of engine machinists, even professionals grind these little ribs on the end of our big end cap.
01:00 Now that's not where we want to remove that material.
01:03 What we actually find is that there ribs are there to increase the strength and rigidity of our cap, so by grinding these it's going to effect that and it can allow the big end journal to flex and distort, particularly at high engine loads.
01:19 So what we want to do instead is remove material very carefully from the chamfer or edge down the side of the big end of the connecting rod where the fastener goes through, so that's the correct area to remove material.
01:33 On the small end on the other hand, what we want to do is very carefully linish around the outside diameter of the small end of the rod.
01:39 We want to remove as little material as we can and we wanna do that evenly around the outside so we're not focusing our efforts on one place and removing more material than we need to.
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