Wrist Pin Rod Bushings

Farmall B & BN Tractors, 1939-1947
Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
User avatar
arlen
Cub Star
Cub Star
Posts: 134
Joined: Sat Jan 16, 2021 3:47 pm
Zip Code: 55975

Wrist Pin Rod Bushings

Postby arlen » Mon Mar 01, 2021 5:00 pm

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
501 Club
501 Club
Posts: 1353
Joined: Wed Jan 20, 2021 8:21 pm
Zip Code: 44410
Tractors Owned: 1968 Cub Fast Hitch
LF-1 Platform Carrier
144 Cultivators
L-F194 Plow(s)
F38 Disk
L-F3 Spring Tooth Harrow
Fast Hitch CS Bell 60 Grain Mill
Home Made Fast Hitch Potato Plow
54A Blade

Couple 1948 Cubs
172 Runner Planter
53 Fertilizer
Cub-3 Field Cultivator
Cub-189 Two Way Plow
Cub-22 Sickle Bar Mower
Mechanical Transplanter with side mount barrel (needs a fast hitch adapter) :)

Misc Belly Mowers

Wish List
International 100 Fast Hitch Blade
Mott Fast Hitch Flail Mower

Wish Wish Wish List
Fast Hitch Rotary Hoe
4E hammer mill
Location: Ne Ohio

Re: Wrist Pin Rod Bushings

Postby SamsFarm » Mon Mar 01, 2021 5:44 pm

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
10+ Years
10+ Years
Posts: 4639
Joined: Tue Jan 12, 2010 2:08 pm
Zip Code: 12514
Circle of Safety: Y

Re: Wrist Pin Rod Bushings

Postby tst » Mon Mar 01, 2021 7:31 pm

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

Gary Dotson
Team Cub Mentor
Team Cub Mentor
Posts: 4917
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Wrist Pin Rod Bushings

Postby Gary Dotson » Tue Mar 02, 2021 9:04 am

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.

User avatar
arlen
Cub Star
Cub Star
Posts: 134
Joined: Sat Jan 16, 2021 3:47 pm
Zip Code: 55975

Re: Wrist Pin Rod Bushings

Postby arlen » Tue Mar 02, 2021 3:10 pm

Gary Dotson wrote: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!

User avatar
arlen
Cub Star
Cub Star
Posts: 134
Joined: Sat Jan 16, 2021 3:47 pm
Zip Code: 55975

Re: Wrist Pin Rod Bushings

Postby arlen » Wed Mar 03, 2021 11:02 pm

Gary Dotson wrote: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
Team Cub Mentor
Team Cub Mentor
Posts: 4917
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Wrist Pin Rod Bushings

Postby Gary Dotson » Thu Mar 04, 2021 8:15 am

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.

User avatar
arlen
Cub Star
Cub Star
Posts: 134
Joined: Sat Jan 16, 2021 3:47 pm
Zip Code: 55975

Re: Wrist Pin Rod Bushings

Postby arlen » Thu Mar 11, 2021 6:04 pm

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
501 Club
501 Club
Posts: 1353
Joined: Wed Jan 20, 2021 8:21 pm
Zip Code: 44410
Tractors Owned: 1968 Cub Fast Hitch
LF-1 Platform Carrier
144 Cultivators
L-F194 Plow(s)
F38 Disk
L-F3 Spring Tooth Harrow
Fast Hitch CS Bell 60 Grain Mill
Home Made Fast Hitch Potato Plow
54A Blade

Couple 1948 Cubs
172 Runner Planter
53 Fertilizer
Cub-3 Field Cultivator
Cub-189 Two Way Plow
Cub-22 Sickle Bar Mower
Mechanical Transplanter with side mount barrel (needs a fast hitch adapter) :)

Misc Belly Mowers

Wish List
International 100 Fast Hitch Blade
Mott Fast Hitch Flail Mower

Wish Wish Wish List
Fast Hitch Rotary Hoe
4E hammer mill
Location: Ne Ohio

Re: Wrist Pin Rod Bushings

Postby SamsFarm » Fri Mar 12, 2021 8:10 am

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
Team Cub Mentor
Team Cub Mentor
Posts: 4917
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Wrist Pin Rod Bushings

Postby Gary Dotson » Fri Mar 12, 2021 8:35 am

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

SamsFarm
501 Club
501 Club
Posts: 1353
Joined: Wed Jan 20, 2021 8:21 pm
Zip Code: 44410
Tractors Owned: 1968 Cub Fast Hitch
LF-1 Platform Carrier
144 Cultivators
L-F194 Plow(s)
F38 Disk
L-F3 Spring Tooth Harrow
Fast Hitch CS Bell 60 Grain Mill
Home Made Fast Hitch Potato Plow
54A Blade

Couple 1948 Cubs
172 Runner Planter
53 Fertilizer
Cub-3 Field Cultivator
Cub-189 Two Way Plow
Cub-22 Sickle Bar Mower
Mechanical Transplanter with side mount barrel (needs a fast hitch adapter) :)

Misc Belly Mowers

Wish List
International 100 Fast Hitch Blade
Mott Fast Hitch Flail Mower

Wish Wish Wish List
Fast Hitch Rotary Hoe
4E hammer mill
Location: Ne Ohio

Re: Wrist Pin Rod Bushings

Postby SamsFarm » Fri Mar 12, 2021 9:05 am

Gary Dotson wrote: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! :lol:

SamsFarm
501 Club
501 Club
Posts: 1353
Joined: Wed Jan 20, 2021 8:21 pm
Zip Code: 44410
Tractors Owned: 1968 Cub Fast Hitch
LF-1 Platform Carrier
144 Cultivators
L-F194 Plow(s)
F38 Disk
L-F3 Spring Tooth Harrow
Fast Hitch CS Bell 60 Grain Mill
Home Made Fast Hitch Potato Plow
54A Blade

Couple 1948 Cubs
172 Runner Planter
53 Fertilizer
Cub-3 Field Cultivator
Cub-189 Two Way Plow
Cub-22 Sickle Bar Mower
Mechanical Transplanter with side mount barrel (needs a fast hitch adapter) :)

Misc Belly Mowers

Wish List
International 100 Fast Hitch Blade
Mott Fast Hitch Flail Mower

Wish Wish Wish List
Fast Hitch Rotary Hoe
4E hammer mill
Location: Ne Ohio

Re: Wrist Pin Rod Bushings

Postby SamsFarm » Fri Mar 12, 2021 9:30 pm

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
Team Cub Mentor
Team Cub Mentor
Posts: 4917
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Wrist Pin Rod Bushings

Postby Gary Dotson » Sat Mar 13, 2021 8:34 am

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
501 Club
501 Club
Posts: 1353
Joined: Wed Jan 20, 2021 8:21 pm
Zip Code: 44410
Tractors Owned: 1968 Cub Fast Hitch
LF-1 Platform Carrier
144 Cultivators
L-F194 Plow(s)
F38 Disk
L-F3 Spring Tooth Harrow
Fast Hitch CS Bell 60 Grain Mill
Home Made Fast Hitch Potato Plow
54A Blade

Couple 1948 Cubs
172 Runner Planter
53 Fertilizer
Cub-3 Field Cultivator
Cub-189 Two Way Plow
Cub-22 Sickle Bar Mower
Mechanical Transplanter with side mount barrel (needs a fast hitch adapter) :)

Misc Belly Mowers

Wish List
International 100 Fast Hitch Blade
Mott Fast Hitch Flail Mower

Wish Wish Wish List
Fast Hitch Rotary Hoe
4E hammer mill
Location: Ne Ohio

Re: Wrist Pin Rod Bushings

Postby SamsFarm » Sat Mar 13, 2021 12:11 pm

Gary Dotson wrote: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
Team Cub Mentor
Team Cub Mentor
Posts: 4917
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Wrist Pin Rod Bushings

Postby Gary Dotson » Sat Mar 13, 2021 1:55 pm

.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.


Return to “Farmall B & BN”

Who is online

Users browsing this forum: No registered users and 0 guests