VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 216 Pal Nuts

I am wondering why the 216 has pal nuts and if they are really needed. My guess is that they are related to using rods with shims, sort of an insurance policy against the rod cap coming undone.

I would recommend using pal nuts.Also it was recommended to use new ones each time rods were "unbolted".Up until 1939 they used drilled rod bolts and cotter pins.This meant you either needed to slightly loosen or over tighten the rod nuts to align hole.What a pain.The modern 6 cyl. used self locking rod nuts.I have converted some of my cars to these and replaced the rod bolts to the nondrilled type and use pal nuts on the rest.The pal nut locks by the nut defroming and wedging itself into the threads of the rod nut.That is why the shouldn't be reused.

I am not aware of any Chevrolet engine that does not use either, pal nuts, lock nuts, cotter keys, or lacing to secure the rod caps. Sure does become embarrassing when a cap comes off and you can inspect the rod from outside, through the hole in the block.

Pal nuts were used on all 216-235-261 engines.The 194-230-250-292 used the self locking nuts of the same size.That is what I have used.

OK, so my experience is with the more modern 235s, 261s and the 194. I do remember the knurled rod bolts but this is my first go around with pal nuts.

What would I call them when I go to a jobber ?

What is the difference between the 216 nuts and the self locking nuts.

I prefer not to see the rods after the pan is on!

If you go to a jobber and ask for pal nuts be prepared to get a strange "look".He may be thinking of something else.I believe that they are available from Chevs of the 40s but also a large hardware store may have them.Look for stamped jamb nuts.An alterative would be to order a set of self-locking nuts for a later 194-230-250 as they are of the same size.

If you go to a jobber and ask for pal nuts be prepared to get a strange "look".He may be thinking of something else.I believe that they are available from Chevs of the 40s but also a large hardware store may have them.Look for stamped jamb nuts.An alterative would be to order a set of self-locking nuts for a later 194-230-250 as they are of the same size.

Another term for pal nuts is speed nuts.Suppliers to body shops have them so check there for info.Spaenaur in Kitchener Ontario,not far from you,is a fastener manufacturer.

Beware here-a pal nut is not really the same as a speed not.The pal not is designed to have the stamped ears of the "threads" to jam in to the rod nut threads and I not sure if I would trust a speed nut to do this.

I never heard the name "pal nuts" before (although I have some friends that might qualify) and wonder what they are?? Could somebody post a picture or at least describe them? I looked in my 1940 parts book and they list several different con rod nuts. One style is a castellated nut, which a cotter pin goes through and one appears to be a castellated type that is self-locking. Is this latter style what you are refering to as a pal nut? Nowhere do I see the term "pal" nuts used. Is it a regional term?

Couldn't modern aircraft style locking nuts be used (the ones with the nylon inserts)? If they're good enough for a plane, they should hold a Chevy together, even tho' mine really flies!!!!! -Bob

Boetie Bob,
the term "palnut" comes from the shop manual. It describes a thin stamped nut that looks to me exactly like a speed nut. There is an item in Ebay, #2400203462 which shows a photo of some rod bolts with speed nuts and also some rod bolts with the old pinned type nuts. I will Email you the photo.

In this discussion, I assume that the self locking nuts are the "normal" rod nuts, not the kind of nuts that have a nrrowed area to create friction and prevent unwanred rotation.

Self locking nuts were first used by Chevrolet on the 1955 V8s.They are not distorted as are normal self locking.Pal nuts were first used in 1940.Prior to that castellated nuts and cotter pins were used.Chevrolet also refered to the pal nuts as stamped nuts and the appear in the standard parts section in group 8.921 part #107823. (1952 book).I remember them well as when I pulled the parts for an engine overhaul or rod adjustment the mechanics always got 12 new pal nuts and an oil pump screen -which was a good container to hold the pal nuts.

This is a bit off topic but:

On Ebay today, I noticed that there were some rods for some very old engines, not Chev, for sale. They had dippers that pointed almost straight down. I assume that this was a dipper design that didn't use troughs. Did Chev ever use this type of dipper ?

I have never seen a dipper engine that didn't use troughs.With out a trough the oil would all be at one end of the pan or the other on hills etc.Most had an oil pump to at least keep the troughs full.If I remember correctly Hudsons had a long dipper built "into" the rod.Used up to 1947 on the 6 and 1952 on the 8s.