wrist pin material

[slow6]

What is the wrist pins made out of? Is it stronger than the cast steel connecting rods? I think they're cast steel?

It just blows my mind that the rod bent before the piston or wrist pin broke.

[CDNFB]

Re: wrist pin material

There are soooooo many different materials that a wrist pin can be made of it unbelieveable!

I don't know for sure but I suspect they would be Case Hardened, Low Carbon Steel. Manufactured from rolled bar stock, not cast.

other materials wrist pins can be made of:
Through Hardened, 52100 High Carbon Steel
9310 Nickel Carbon Steel Alloy, forged bar stock (also known as tool steel)
Nickel-cobalt titanium Steel
4340 Steel Alloy

All are hardened and manufactured from cold rolled bar stock or forged.

Wrist pins are seriously tough pieces. Pistons and conrods will fail long before a wrist pin will.

[AZ3.8Camaro]

Re: wrist pin material

There are many factors that determine why the rod bent.
Bent rods are VERY common on hydrolocked motors. More so, I would say than broken pistons.
IMO it has to do with the way the force is applied, what engine speed, etc. While pistons are frequently destroyed due to fuel conditions, etc. rods seem to go when there is an even force distributed on the piston (in your case water getting compressed). The piston can hold quite a bit of force if applied evenly because it is spread over a fairly large area. The rod will usually bend in this situation. I could see a wrist pin breaking or bending, but rods seem to be weaker than wrist pins in this type of situation.

You should be able to tell right away if a piston of wrist pin is damaged. The piston will show cracks, a tightened ring land (the rings don't move easily in the slots), heat marks, scuff marks, etc. The wrist pins will either be broken or bent. You can roll them on a nice peice of glass and see if the wobble (like pushrods). Check for cracks or visable damage. Get the crank checked out by a machine shop. Get new bearings for everything, don't reuse them. New rod or rods (depending on what was damaged) is a must. Check the cylinder walls for damage, especially in the cylinder the bent rod was in. Check the heads for damage in the combustion chamber area (around the valves, etc). Get new gaskets and bolts for everything you can. That should put you on the road for miles to come.

[CDNFB]

Re: wrist pin material

Excellent advice!