Has anyone out there ever installed there own wrist pin bushings? If so, How? I did my own cam bearings buy freezing them and then gently tapping them with a hard plastic hammer. They slid right in. Could I do this with my wrist pins? Then hone the inside to the proper size for the pin? Any thoughts out there?

 

Try it and let us know

 

Wrist pin bushings have to be honed to exact tolerances. Here on Long Island, my machine shop sent them out to a guy who does aircraft work.

When they are pressed in, they are too small of an ID for the pin to fit through. The bushing needs to be honed out to the right size before the pin will even go through. Too much clearance and you're going to have that ole wristpin noise...

Leave it to a professional...

ak

 

yeah the tolerance was like .0003-.0005 and i said forget it and took it to the shop.

 

Not to mention getting the hone perpendicular to the rod length.



ak

 

some things you just cant do on your own.

 

Getting the pin bore inline with the big end is pretty easy if ya got a rod vise and rod alingment tools to "adjust it" with . Some people really don't like it when they see their rods being bent around a bit thought

 

Some guys also recommend "swedging" before honing -- basically a little roller replaces the honoing mandrel to upset or swedge the metal into place.

I've done mine, along with resizing the big end, polishing the beams, weighing/matching both ends, etc. under the guidance of a master-machinist friend who granted me temporary shop access.

It not only requires attention to detail, it's just plain hard work. We used an old manual Sunnen and my right wrist is still sore from wrestling the big-end back and forth on the honing machine.

It was interesting, but honestly, I don't know how the guys who do this for a living deal with the repetitive stress injuries.

Like someone said, leave it to the experts.

--Matt

 

Mlf72f250, swedging is usually only needed if the pin bushing does not have a steel backing, because without it the hammering of the pin will drive the softer materials into the imperfections in the small end bore thereby making the hole bigger.
It sounds like you may have had a little to much pressure on the rods when you honed them, unless you just have limp wrists , how you hold the rods can make all the difference at the end of the day.

 

Thanks for the clarifications.

On the wrist issue, I've been called worst. ;-) But seriously, I think it was more of being a newbie at it and using bad ergo form. I was really focusing on clamping it only between two fingers and thumb to make sure I didn't rock it on its axis. In the future I'd prpbably loosen up and let the hone do most of teh work.

 

very interesting conversation guys!

 

Pin bushings are easy if you have the right equipment....if you don't, I'm thinking it would be almost impossible. For the fellow who got tired wrists doing his, yer right, you weren't holding them correctly. At the shop where I work, the owners wife does all the rods, and she ain't that big of a gal. Never heard her complain about tired hands. DF

 

Yep, having the right equipment is a must, thought I've heard of some pretty scary attempts to do it without the right stuff.
For ergonomics the two things I've noticed most often at our Community College are students actually trying to stroke the rods with their wrists intsead of their arms and excessive stone pressure. The most common problem is high stone pressure, once those rods get going they just don't want to stop, which puts a real strain on the arms when you're trying to reverse their direction.

 

Yes, now that you mention it, I think that I may have had too high of a stone feed rate.

The small ends were pretty simple, even for me.
But honing the big ends takes a lot more finesse -- something I don't have much of. ;-)

 

Glad your learning how to do this stuf. As for the finesse, well I'm pretty much in the same boat, it took a lot of trial, error and measuring before I was satisfied with my ability to reman rods.