Wrist Pin Rod Bushings

[arlen]

I am going through the whole B motor, ground crank, new bearings, sleeves, pistons, and valve job.
Would you typically replace the wrist pin rod bushings, or is that one of those items that doesn't wear much.
They don't cost much, but I see they have to be pressed in, then honed to fit.

[SamsFarm]

It depends on whether they measure within spec or not!

They need measured in multiple positions to determin if they are out of round!

[tst]

sometimes rods need to be burnished , the hole can get out of round for the bushing

[Gary Dotson]

Slip one of your new wrist pins through the bushing and see if you can feel measurable movement. If not, they are probably good to go but if feel even slight wiggle, you should have your machinist take over.

[arlen]

Slip one of your new wrist pins through the bushing and see if you can feel measurable movement. If not, they are probably good to go but if feel even slight wiggle, you should have your machinist take over.

Thank You!

[arlen]

Slip one of your new wrist pins through the bushing and see if you can feel measurable movement. If not, they are probably good to go but if feel even slight wiggle, you should have your machinist take over.

Your test was telling. I could wiggle them pretty good one way, and they were tight the other way, so they are egg shaped and need replacement.

[Gary Dotson]

Very good! They are easy enough to press out and back in but the machinist will have to size them anyway. If you don't have the proper pressing tools, there's no good reason for you to mess with them.

[arlen]

Just dropped the rods, bushings, and a wrist pin off at the machine shop.
I see the service manual calls for .0007 clearance. They don't have a tolerance listed.
The guy at the machine shop says that they typically shoot for .0008-.001 for clearance, which seems reasonable to me. What are your experiences?

[SamsFarm]

Did you tell the guy that the manufacture's specs was .0007?

I would think there IH had a reason to call out .0007 and not .0008 / .001.

Look at it this way, the bigger the hole in the bushing, the more slap the piston will have as it changes directions!

More slap equals faster wear! Will it matter in your lifetime??? Hard to say!

But if it was me in your shoes, I would want it right, not just "close enough"!

[Gary Dotson]

Most shops shoot for that .001 number for clearance. Trust your machinist, it will be just fine.

[SamsFarm]

Most shops shoot for that .001 number for clearance. Trust your machinist, it will be just fine.

I am a Tool & Die maker, I trust myself!

[SamsFarm]

In the service manual for the A & B located in the pdf manual section, International gives the specifications for:

Page 9; Piston pin diameter .9192 to .9195"

Page 10; Piston pin bushing bore .9196 to .9199"

Running clearance specified as .0007"

By the book, I would say more than .0008+ is out of spec.

Good luck!

Just for fun today I looked in my IH Cub service manual and the rod bushing clearance is listed as .0003 to .0007"!

[Gary Dotson]

O K, have it your way but that has no bearing on what the automotive industry does. I'm not a tool and die maker but I worked in the automotive service industry, all my life, I guess I just never learned anything.

[SamsFarm]

O K, have it your way but that has no bearing on what the automotive industry does. I'm not a tool and die maker but I worked in the automotive service industry, all my life, I guess I just never learned anything.

Dont get mad! I am just stating the facts.....

International made the specifications, not me!

Now if the new part manufacturers have their own tolerances in with the instructions, you should probably follow them!

If arien is comfortable with sloppy automotive tolerances that is his call, not mine. It is his money!

After all we are working on tractors, not cars! Right?

Have a great day!

[Gary Dotson]

.001 is hardly sloppy automotive tolerance. But I concede, in 40 yrs. doing this kind of work I'm still a total idiot. What, you think tractor tolerance should be tighter than automotive? More likely, the opposite is true. That 1600 RPM tractor is no where near as fussy as a high RPM small block performance engine. Find another soap box, I'm done with this one.