1950 Cub Engine Rebuild

Farmall Cub Forum -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

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.
DRShahan
Posts: 42
Joined: Wed Jan 06, 2016 12:06 pm
Zip Code: 20770
Tractors Owned: 1950 Farmall Cub
Kubota B7100 with 1630 loader
International 2444
Location: Greenbelt, MD

Re: 1950 Cub Engine Rebuild

Postby DRShahan » Mon Feb 29, 2016 6:07 pm

That requires removing the front bolster, splitting the tractor, pulling the fan belt pulley, etc. Correct?

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 16260
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: 1950 Cub Engine Rebuild

Postby Eugene » Mon Feb 29, 2016 6:25 pm

DRShahan wrote:That requires removing the front bolster, splitting the tractor, pulling the fan belt pulley, etc. Correct?

Yup.
I have an excuse. CRS.

User avatar
Glen
5+ Years
5+ Years
Posts: 1976
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: 1950 Cub Engine Rebuild

Postby Glen » Mon Feb 29, 2016 8:16 pm

Hi,
Pardon me guys, but smaller bearings for a crankshaft are called undersize bearings, not oversize bearings. .002 undersize, .010 undersize, etc. Always good to use the right terms.
If you don't want to remove the engine from the Cub, you could try using the plastigauge twice on each crankshaft journal. Use the plastigauge once, then turn the crankshaft 1/4 turn, and use the plastigauge again on the same journal. That should mostly show if the crankshaft is out of round. Maybe not perfect, but close, I think.
I'm not sure if you can get to the connecting rod cap nuts in the position that would be turned, but maybe. You don't want to turn the engine with the plastigauge in the bearing. :)

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 16260
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: 1950 Cub Engine Rebuild

Postby Eugene » Mon Feb 29, 2016 10:05 pm

Glen wrote:Pardon me guys, but smaller bearings for a crankshaft are called undersize bearings, not oversize bearings. Always good to use the right terms.
Automotive Mechanics, Heitner, 1967 uses the term undersize. However, if you look on the internet you will find the term oversize used. Your choice. I don't think either term is incorrect. Pretty sure you can use either term at the parts store you will get the needed bearings.

Plastigage is oil soluble and won't hurt the engine. However, you should clean up as much plastigage as possible.
I have an excuse. CRS.

DRShahan
Posts: 42
Joined: Wed Jan 06, 2016 12:06 pm
Zip Code: 20770
Tractors Owned: 1950 Farmall Cub
Kubota B7100 with 1630 loader
International 2444
Location: Greenbelt, MD

Re: 1950 Cub Engine Rebuild

Postby DRShahan » Tue Mar 01, 2016 10:10 am

Thanks guys. I'm going to try plastigaging to check roundness and see if I have clearance for the undersized bearings. For the rod bearings I should be able to measure at 45 deg either direction rather that BDC and 90.

At some point I'm going to do a full tear-down, but it's going to wait until I'm in a shop and have time to go over everything. If I split the tractor and pull the block out I'm not going to be able to resist doing way more than I should.

User avatar
artc
Cub Pro
Cub Pro
Posts: 1860
Joined: Sun Mar 30, 2003 10:25 am
Zip Code: 06457
eBay ID: cmtelephone
Tractors Owned: Restored: 1950 Cub, 1950 Cub Demo, 1948 super AI, 1935 Silver King, 1946 Oliver 60 RC, John Deere M

In working clothes:
1950 cub, 1948 cub, 1941 A, 1948 H, 1963 B414, 1958 240U, 1947 Oliver 60 industrial, Oliver 70 industrial. IH 450,
Location: CT, Middletown

Re: 1950 Cub Engine Rebuild

Postby artc » Tue Mar 01, 2016 1:23 pm

I do not believe any machine shop would turn a crank to .002 under. .010 is the minimum typically to clean up a crank. that being said, you can simply replace the bearings with STD bearings IF the journals are clean and look nice (and your old bearings say STD on them). but beware of babbit clinging to the journal. once they are changed, you can measure it again with plasti-gage if you like, or live with what you have.

Make sure when you are done that the crank turns freely.
'If they're tappin', they're not burnin'
http://www.ZagrayFarmMuseum.org

User avatar
Glen
5+ Years
5+ Years
Posts: 1976
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: 1950 Cub Engine Rebuild

Postby Glen » Tue Mar 01, 2016 8:04 pm

Hi,
Eugene, I should have said in my post above, as far as I know, they are called undersize. That's all we ever called them. Wasn't trying to say you didn't know the right term, I guess the term differs in different places, or between other people. Guess I didn't take the time to write that above. :)

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 16260
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: 1950 Cub Engine Rebuild

Postby Eugene » Tue Mar 01, 2016 8:40 pm

Glen wrote:Hi, Eugene, I should have said in my post above, as far as I know, they are called undersize.
No problem. I have always called them and heard them called oversized.
I have an excuse. CRS.

DRShahan
Posts: 42
Joined: Wed Jan 06, 2016 12:06 pm
Zip Code: 20770
Tractors Owned: 1950 Farmall Cub
Kubota B7100 with 1630 loader
International 2444
Location: Greenbelt, MD

Re: 1950 Cub Engine Rebuild

Postby DRShahan » Sat Mar 26, 2016 2:31 pm

Almost got everything back together, but I have a quick question. Are the nuts on the rods supposed to be lock nuts? I thought that was the purpose of the notching, but several spin on by hand.

DRShahan
Posts: 42
Joined: Wed Jan 06, 2016 12:06 pm
Zip Code: 20770
Tractors Owned: 1950 Farmall Cub
Kubota B7100 with 1630 loader
International 2444
Location: Greenbelt, MD

Re: 1950 Cub Engine Rebuild

Postby DRShahan » Sun Mar 27, 2016 6:28 pm

Everything's back together! Just letting all the various sealants set up over night. Pump is moving oil and the battery still has enough juice to turn it over. Tomorrow is the day!

User avatar
Glen
5+ Years
5+ Years
Posts: 1976
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: 1950 Cub Engine Rebuild

Postby Glen » Sun Mar 27, 2016 7:35 pm

Hi,
Good to hear that you got it together again. :)


  • Similar Topics
    Replies
    Views
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: jpcubs and 2 guests