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Old 04-21-2017
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Jimjordan2 Jimjordan2 is offline
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Default Piston rod nuts

So, I ordered new nuts for the rods for this engine I'm building, and never noticed which way was up or down. I see that there's a Hex section, and a round section. The round section has slots milled into it. I'm assuming this section would go down and the slots would act as a lock washer or something? Or the other way?
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Old 04-21-2017
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Jimjordan2 Jimjordan2 is offline
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Here's what I'm talking about.
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Old 04-21-2017
RootesRacer RootesRacer is offline
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The hex goes against the rod. The smaller end is to lock the threads.
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Old 04-22-2017
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Jimjordan2 Jimjordan2 is offline
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Thanks Racer,
I can see where you would want the solid (hex) part of the nut against the rod cap, but I don't quite see how the slots lock the nut. Can't seem to get my brain around it. How do it know?
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Old 04-22-2017
RootesRacer RootesRacer is offline
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Quote:
Originally Posted by Jimjordan2 View Post
Thanks Racer,
I can see where you would want the solid (hex) part of the nut against the rod cap, but I don't quite see how the slots lock the nut. Can't seem to get my brain around it. How do it know?
Not 100% sure but my guess is that they stretch the end of the nut when they thread it to make an interferance thread that acts like a spring to the rest of the nut.
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Old 04-23-2017
Tom H Tom H is offline
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The slots in the round portion allowed that end to be "pinched" inward when manufactured making for an interference fit. The WSM notes that during re-assembly if the nuts can be installed with finger pressure they must not be reused.

Tom
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Old 04-23-2017
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Jimjordan2 Jimjordan2 is offline
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Thanks all, puts my mind at ease a bit now. Tom, that explains a bit more to me. OK, now where's my torque wrench?
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