Flex plate nuts?

[showbizkid]

When I took my engine apart, the old flex plate was held on with castellated nuts:



Reading the parts manual, what's specified is "Lock Nut - 3/8" x 24." Can I just use plain 3/8" nuts with lock washers, or do I need to hunt down something esoteric?


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Clark in San Diego
'63 F2/Lark Standard

http://studeblogger.blogspot.com

[Roscomacaw]

They LOOK castellated, but they're actually self-locking nuts. The "castled" part is crimped ever-so-slightly to effect a grip on the threads. I'd find something similar. They make self-locking nuts without those cuts or fibre or plastic inserts. Shouldn't be TOO hard to find.

Miscreant adrift in
the BerStuda Triangle


1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

[sbca96]

You most likely want a grade 8 self locking all steel nut. I wouldnt
use a nylock due to the heat it will be exposed too. Napa carries a
wide selection of nuts and bolts at most their stores. The one you
are looking for will look like a regular nut, but be rounded & crushed
on one side. If you look at the threads on the crushed side you will
see that the threads are closed in a little. I used this type on my
700 R4 conversion in the hawk some years ago, and when I removed the
GM flexplate off the Stude crank - they were snug as a bug in a rug.

Tom

'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

[hank63]

They are actually called "deformed locknuts" and are oval to max 40% of the nut height (if my memory serves me correctly). It is sometimes possible to see the imprints from the jaws used to squash.
I seem to recall they should not be re-used, just as for the nyloc variety.
/H

[showbizkid]

Here's what I got from NAPA. Doesn't look like the originals, but they swear it will work. Will this do the trick?




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Clark in San Diego
'63 F2/Lark Standard

http://studeblogger.blogspot.com

[Roscomacaw]

That'll do it!

Miscreant adrift in
the BerStuda Triangle


1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

[sbca96]

showbizkid, thats the one I was trying to describe - did I come close?[:I]

Tom

[showbizkid]

Yeah, Tom! Looks just like what you described. Funny - when I went into NAPA, I told the counterkid that I wanted "3/8-inch-24 deformed steel lock nuts." He went and found 'em, and then he asked me "why are they called deformed steel lock nuts?" So I told him it was because the nut was actually deformed by pressure to form the lock.

He looked at me and said "Oh. We just call 'em lock nuts." [)]


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Clark in San Diego
'63 F2/Lark Standard

http://studeblogger.blogspot.com