- Joined
- Sep 1, 2020
- Messages
- 1,593
My older brother has a 1972 cub cadet 128 that needed a rebuild. It burnt a quart of oil for every tank of gas.
I stripped it down to the block with my grandpa. He helped me with this whole project today. Degreased it and put it on the mill. It had a .020” over piston in it with extreme waffling and completely out of round.
I got it centered on the ring where the piston rings don’t touch. I moved the indicator down four sides and it was squarish but it was a whopping 0.017” larger near the bottom while 90 degrees at the same depth was 0.011”. My brother did not want to go larger than 0.040” so there is a very small spot at the very bottom where the piston doesn’t even go that is two thou larger.
My mill has 5” of travel and the cylinder was 6” deep. The bore was 3.395” and the spindle of my mill is 3.400”, it was close. I cut as far as I could go, then retracted the spindle, raised the knee two inches then locked it again. You can’t even see where I started the cut again.
I then decked the block using a boring bar holder in the boring head that held a piece of HSS to get a fly cutter. Touched off then did three thou, four thou, then three thou to finish it. I set the power feed super slow and did some math. 0.0014” per revolution on the finish pass.
Still need to chamfer the bore then get the piston to see if I need to bore it any larger before I hone it.
Before
Setup for boring, clearance is clearance
Bored, decked, and soaked in $27.99 of WD40. 45 degree boring bar to chamfer it tomorrow.
I stripped it down to the block with my grandpa. He helped me with this whole project today. Degreased it and put it on the mill. It had a .020” over piston in it with extreme waffling and completely out of round.
I got it centered on the ring where the piston rings don’t touch. I moved the indicator down four sides and it was squarish but it was a whopping 0.017” larger near the bottom while 90 degrees at the same depth was 0.011”. My brother did not want to go larger than 0.040” so there is a very small spot at the very bottom where the piston doesn’t even go that is two thou larger.
My mill has 5” of travel and the cylinder was 6” deep. The bore was 3.395” and the spindle of my mill is 3.400”, it was close. I cut as far as I could go, then retracted the spindle, raised the knee two inches then locked it again. You can’t even see where I started the cut again.
I then decked the block using a boring bar holder in the boring head that held a piece of HSS to get a fly cutter. Touched off then did three thou, four thou, then three thou to finish it. I set the power feed super slow and did some math. 0.0014” per revolution on the finish pass.
Still need to chamfer the bore then get the piston to see if I need to bore it any larger before I hone it.
Before
Setup for boring, clearance is clearance
Bored, decked, and soaked in $27.99 of WD40. 45 degree boring bar to chamfer it tomorrow.
Braeden , are you over on OCC ? If not , maybe you should be . 
Ive done about 50 Cubs and IHs over the years . There are a few members here that are members there also . The jug looks great !