Wrist Pins. I have questions you have answers

[jgedde]

For my Panther Pup build, I have made many design chnages. One of which was to add a bearing to the ends of the connecting rods. I'm in the middle of making the pistons now and am wondering what's best...

1) Wrist pin pressed into the connecting rod small end.
2) Wrist pin pressed into the piston.
3) Wrist pin floating in both the piston and the conn rod.

Why I'm asking is I really don't relish the use of the wrist pin hole in the aluminum piston being used as a bearing surface. I'm leaning towards option 2... Material for the wrist pin will likely be drill rod - maybe hardened.

Thanks!
John

 

[xpylonracer]

Hi John

My choice would be pressed into piston, you say you already have a bearing in the rod. Use Drill rod for the pin hardened and polished, you may be able to drill the pin full length to save some weight.

Emgee

 

[stevehuckss396]

My preference is to use a hardened drill blank. I press the pin into the rod and float the piston. I figure the piston has a lot more contact area so it will wear longer.

 

[michael-au]

I like to have the pin floating in the rod and piston
I hold the pin in place with circlips made from piano wire
See photo
View attachment ImageUploadedByModel Engines1454888310.735871.jpg

I have a bronze bush in the top of the rod
The piston in the photo is from my silver bullet

Michael