1F rod bolt nut cotter pins... why

[ERNRAM]

Howdy,

As I was dropping the oil pan on a 12/67 dated 1F engine for another issue, I noticed the remains of a few cotter pins that retain the rod bolt nuts.

They all seem like they failed at the bend which makes sense

Nothing looks like it got past the strainer, and I'll cut open the oil filter as a sanity check.

So the question is if the cotter is required or a nice to have.

Thanks
Ernie

 

[pjohnson]

I trust the Toyota engineers thinking that they are required.

If the engine has been rebuilt, it could be the pins were re-used or that inferior quality pins were used that were not designed for the purpose.

I bet Mark @65swb45 has some experience here.

 

[ERNRAM]

Agree. I saw on one thread to use stainless. These were likely magnetic, so they are not aluminum and too magnetic to be stainless

 

[ERNRAM]

I'll wait for Mark to chime in with his vast knowledge base

 

[pjohnson]

I would just replace them with OEM and move on.

 

[Steamer]

Toyota 95381-02520

 

[middlecalf]

Seems like it would be really bad if one of those castle nuts loosened up which is what the pins are meant to prevent .

 

[ERNRAM]

Agree