motor 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.
10+ Years
10+ Years
Posts: 31
Joined: Mon Jun 21, 2004 8:25 am

motor rebuild

Postby bigjohn » Fri Mar 04, 2005 8:59 am

Thinking about rebuilding my cubs motor this year. Runs good buts smokes like crazy, she'll run through a quart of oil after mowing maybe 20 acres. I saw some cub pistons on ebay, they are .010 over, aluminum and have a hump on them. Mine is a 48 cub. Will these fit mine assuming .010 is enough overbore to get everything round?

5+ Years
5+ Years
Posts: 145
Joined: Fri Nov 13, 2009 6:44 pm
Zip Code: 07419

Postby bobburke » Fri Mar 04, 2005 10:08 am

Those forged pistons have been know to cause clearance problems in olded heads. Do a search to see what has been done to fix this. I think you can only get these new( I may be wrong on that) and thay don't make the old cast ones.

Jim Becker
Team Cub
Team Cub
Posts: 13459
Joined: Sun Feb 02, 2003 2:59 pm
Zip Code: 55319
Circle of Safety: Y
Location: MN

Postby Jim Becker » Fri Mar 04, 2005 10:08 am

The domed pistons MAY bump into a early cylinder head like yours. You need to check and if there is a problem you can relieve the head for adequate clearance.

User avatar
John *.?-!.* cub owner
Team Cub Guide
Team Cub Guide
Posts: 22627
Joined: Sun Feb 02, 2003 2:09 pm
Zip Code: 63664
Tractors Owned: 47, 48, 49 cub plus Wagner loader & other attachments. 41 Farmall H.
Location: Mo, Potosi

Postby John *.?-!.* cub owner » Fri Mar 04, 2005 10:12 am

Have you pulled the head yet to make sure it doesn't already have oversize pistons in it? A large number of them have already been rebored at least once. top of piston is normally marked with size if overbored. example .010 or 020.
If you are not part of the solution,
you are part of the problem!!!

User avatar
Steve Butram
Cub Pro
Cub Pro
Posts: 2078
Joined: Mon Feb 17, 2003 7:53 am
Zip Code: 47906
eBay ID: steveb05
Tractors Owned: 1947 in well used condition
1948 restored
1949 for sale
Nice original 1950 just out of the Demo Range
628 2 wheel Trailer
1950 Demo
Circle of Safety: Y
Location: IN West Lafayette

Postby Steve Butram » Fri Mar 04, 2005 5:21 pm

Big John ,the aluminium pistons required a different part# for the rods. You will have to use the cast pistons If you plan on using the rods in the 48 engine.But first you may want to pull our head and do some measuring on the bores to to see if you need to bore or if you are lucky it may just need a set of rings. I too thought I could buy the aluminum pistons and up the HP. but the cost of the rods was prohibitive. After all the machine work .20 over pistons and a rebuilt crank I have over $600. in the engine on the 1949 Steve
Be prepared to be unprepared Seth Goden

  • Similar Topics
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: No registered users and 4 guests