| Diagram | Fig. 1 — CRANKSHAFT, CAMSHAFTS AND CONNECTING RODS · ref 23 |
| Subsystem | engine bottom |
| Listed in parts books | 1983, 1985 |
Self locking nut
A 5/16 UNF self-locking nut used in the crankshaft and connecting rod assembly.
21-7091 is a self-locking nut that shows up in the crankshaft and connecting rod assemblies in the catalog. It's a 5/16 UNF fastener, the kind that has its own built-in resistance to backing off rather than relying on a separate lock washer or tab.
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In these figures it's used down in the bottom end, holding rotating or reciprocating components together where a fastener working loose would cause real damage. That's exactly the kind of spot where a self-locking nut earns its keep instead of a plain nut.
Our catalog record ties this one to figures from the mid-1980s. If you're working on something outside that window, give us a call and we'll confirm it's the right nut for your crank and rod assembly before you order.
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