Pin Bushing Finsih

[nathanhouse]

Are there any downsides to having a pin bushing polished? Not because I specifically want polished bushing but because I'm probably going to have the rod super finished and the bushing are already to size. Any downsides? I know you can usually run tighter clearances with the smoother finish. I guess I could always put a bolt and a couple washers to block it off if necessary...

[mag2555]

Hone cross hatch is needed to retain oil in the pin Bore just as on the cylinders , so yes ,
do something to not have that process change that .

[dwilliams]

Lamborghini made a big deal out of roller-burnishing and polishing their rod bushings, but I'm not persuaded there were any real benefits past swaging the bushings into the rods, which could just as easily have been done with the usual press fit.

[Newold1]

Are your pin bushings new and untouched and undamaged.? Do these pin bushings now measure and provide the correct pin to bushing clearances? If the answers to these questions are both YES. Then leave the pin bushings alone ! If they AIN"T BROKE, DON"T FIX EM!!

[Walter R. Malik]

Hone cross hatch is needed to retain oil in the pin Bore just as on the cylinders , so yes ,
do something to not have that process change that .

Not true ... it is a plain bearing surface which will rely upon a continuous and complete oil film, not a wear surface needing some surface to surface connection.

Just like the pins ... make them as fine a finish as you can get. An extremely smooth burnished finish will have the most load carrying capability.

[modok]

I have not seen any real difference honed VS bored
I do prefer to have a honed finish if running clearance on the low side of spec (min usually .0005 per inch)

A honed finish is not necessarily "smoother" , in fact RMS wise it might be rougher, but will be more dimensional consistent where it counts, and less apt to gall.

[nathanhouse]

Pin bushings are new and honed to size. It's a small pin at 15mm (.5905") with .0006" clearance. Like I said, im not really looking to polish the bushing for any reason but am going to have the rods super finished. So the bushings will get done in the process unless I put some washers over them and a bolt through the pin bore or something. It's a 35 year old inline 4 air cooled motorcycle that I'm hoping will push about 2.4hp/in³. It's a street bike that hopefully will see a few track days.