VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Connecting Rod Nuts

Hi all,

I need a few replacement connecting rod castle nuts. I’ve checked around local auto parts stores, and couldn’t find anything through The Filling Station.

Anyone known where I might find a few?

Thanks,
Steve

Do you need the 3/8 fine?

I would replace all with lock nuts.

The nylon self locking type? Do they need to be specific type like hardened, or other specific makeup? Not sure what would be needed for this application and thought of those.

Thanks

I should have some, let me know the size, how many, and depth you need.


Dave

Hello SteveEC,
I do not suggest that nylon lock nuts (nylocks) be used on or in hot area locations. At one time, Ford used nylocks with their turbo diesel turbo hose clamps. Hot and cold, cold and hot, over and over and the nuts would loosen by themselves until BOOM! broke down on the side of the highway until the hose and clamps could be reconnected. Not fun. The fix was to double nut the clamps using all metal lock nuts.

The nuts and bolts if needed can likely be purchased from your local Chevy (or other makes) dealer using current types of the same size. Harrys is correct do not use nylok style.

Hi Dave - I’m not sure what size they are, I’ll have to figure that out. I know I need at least one, but thought I’d replace all 12 if I could find new. I’ll check back with you when I know size, and if I can’t find locally. Thanks!

Thanks all for the input on this! I’ll check local Chevy dealer parts.

I also saw somewhere using blue thread lock and non-castle nuts. Thoughts on that?

Chevrolet used the cotter pin set up up to 1939. After thar they used heavy duty nut and a stamped steel jamb nut that locked the threads.

You will want connecting rod bolts and nuts as mentioned in another thread. That way they are matched and you will not have a problem of having a soft bolt and a hardened nut as that can lead to thread damage. The head of the bolt may need a little grinding to fit properly. The lock nut is what is called a "distorted thread" design and if you google that you can get a good explanation.

At one point we called them "pal nuts", and older dealerships may know them as such. They are 3/8" fine thread.

A "pal nut" is a thin spring steel type of nut that is used as a locking devise with a standard nut. A distorted thread nut is used alone.

ok, i believe that a Pal Nut and a 'Distorted Thread' Lock Nut are totally different.

Pal Nut is a thin Stamped steel (other Material) nut with a sorta slot in the top. Also a trade name of Tinnerman, now Raymond Tinnerman :)

'Distorted Thread' Lock Nut looks much like a standard nut but with the last few threads distorted or squished so that you can start by hand then will need to wrench once the distorted threads start.

few picts below :)

we use both at work depending on application and requirements !!

Hello SteveEC,
I would not trust using a liquid thread lock application to secure fasteners that are in constant contact with lubricating oil. Somehow it seems to pit one against the other in my opinion. Distorted Thread nuts get my vote.

I completely agree. All the thread lockers that I am aware of lose that property with heat!

I found my connecting rod bolts and nuts. Some of the nuts are taller than others (.400 vs .420) not sure why the difference but I have plenty of both and the bolts if you decide to go old school with the cotter pins.

Dave

Dave - I sent you a PM. Thanks!

All torqued and cotter pinned, and the pan is back on. Thanks again Dave!!

For some time now, I have thought the subject of this chat would make a great name for a car club!