[Joe K]

Um. Cotter pins are the belt to go along with your nut suspenders.

And new cars generally don't use cotter pins but they do use various other "retention" schemes including Loctite, inserts, prevailing torque schemes, upset threads. I would guess with one known exception those that use nothing and rely on bolt tension alone are none.

The VW TDI of my former affections used "stretch bolts" which TECHNICALLY must be changed for new on each re-do, but most who work on their TDI diesels never do (Including VW Dealerships) instead relying upon Loctite Blue and perhaps half the near 300ft-lbs of torque required to set the passenger side engine mount bolts (necessary by design to change out the timing belt - not one of VWs most intelligent designs.) Without a calibrated air wrench one runs the risk of knocking the car off the jack-stands trying to achieve that 300ft-lbs "the old fashioned way."

I myself have told my story of the Model A engine which was SERIOUSLY egg-shaped in the crank. I had shaved the caps several times and finally took to the expediency of filing to the point where the rod caps "just bound" as one passed certain pressure points on the egg-shaped rod journals.

Driving the Mid-Cape Highway at the then maximum speed of 55 all of a sudden the engine started to make a terrible racket. So I slowed down and let the traffic pass me by. Fortunately I was not far from my home and limped home not pressuring the engine in any way.

On disassembly, I found the cotter pin in pieces in the oil pan, and the loose nut alongside. The rod was being held by ONE nut.

Of course in "wearing in" that engine I created a situation that the vibration wore upon the cotter pin and caused its demise, followed by undoing of the nut. This was a nut which was "snugged up tight" to begin.

So as an Engineer I can appreciate Jim's comment (above) where local distortion can bring a connecting rod nut to that "near prevailing torque" condition - but I'm not sure I would wish to count on that alone.

If it's any consolation to the board, I do own both belt and suspenders - but I NEVER wear them together lest I be accused of being "that sort of guy." But the rod nuts in my engine are not seen so perhaps it doesn't come to mind of observers?

Joe K