Tearing into my 123
 

I'm hoping for a quick tear down into the engine for a little refreshment. She smokes a little. I'm praying she is within specs and I can get away with just a set of new rings, valve lap, and a good cleaning. The carb already been rebuilt. So far, the piston top, cylinder wall, and head look good, but that could be deceiving. Only proper measurements will judge. Here are some pics, cause I know you's all enjoy the pics. Also... piston has a B on it??

a few more. the dirt on the frame where the engine was is dirt from my grandads. he bought it new and its been in the family since.

i will try to keep the pics movin along as i go. thanx for lookin.

Lookin good!
Make sure you mic the crank! the spec should be 1.500
Have fun with the rebuild!:beer2:

You're off to a good start! Please keep the pics and updates coming.

I agree, enjoying the pictures :beerchug:

It's great that it's been kept in the family! I like see your progress, too and especially the pics that include "Made in the USA".

Cub Cadet 123

Great start! Keep the pictures coming.

Me too!

Yes it is!:beerchug:

is the "B" on the piston original piston. i didnt see any other numbers yet. still have to finish cleaning it off

I have never seen a B on any of the kohler i have built. Could you get a good pic of it?

head is also stamped with a B same as piston. the pic at the end is my favorite cause i was just unloading it at home after a mile xmas parade the night before. thank goodness it didnt happen then. cc123 was leading the stampede.

hang on its coming up...

measurements of bore from top to bottom one way then the other.
3.374-3.372-3.370
3.373-3.374-3.373
top mid bottom

crank- 1.499 and 1.498

the manual says everything should be in good specs. right?

i see in the manual it talks about a type C and D piston but no B.??
got new gaskets made for the oil pan and valve cover. lapped the valves. cleaned things up a bit and welded the infamous crack in the frame over the front axle. just waiting on piston, rod, and rings. sorry, i forgot to take pics!!
what is the little cover on the block to the right of the points and cam cover. about the size of a fifty cent piece. its a window to the cam shaft centered over a lobe????

This information is from a Kohler service manual.
Cylinder Bore:
New cylinder bore is 3.3755/3.3745
Maximum cylinder wear is 3.378
Maximum out of round is .003
Maximum taper is .002

Crankshaft: (crankpin should be check in 6 places)
Crankpin diameter new is 1.500/1.4995
Maximum wear limit is 1.4990
Maximum out of round is .0005
Maximum taper is .001


Is the engine a K301?
What gages did you use to measure cylinder?
If the engine is a K301 the measurements should be the same or more than the new engine specs.

There is .004 difference in your cylinder bore measurements. That tells me the cylinder needs bored at least .010.

Minimum crankpin diameter is 1.4990. One of your crankpin measurements is 1.498. The crankpin needs undersize .010.

The picture of your piston indicates the piston is burnt in the exhaust valve area.

The picture of connecting rod (Inside diameter where the crankshaft and connecting rod meet has a shinny area in the middle. I would like to see a picture of the crankpin journal.

If I was rebuilding this engine I would do or recomend the following:
1. Bore engine at least .010.
2. Undersize crankpin .010 and a use connecting rod for a .010 under crank.
3. New governor (if yours is plastic)
4. New head bolts.
5. New bearing plate bolts.
6. New push rod pin (old one is usually aluminum-can be mushroom out)
7. Check valve guides-replace as needed.
8. Check head for flatness-rework as needed.
9. Check the top of the block for flatness-rework as needed.

This engine/Cub Cadet lasted roughly 45 years with no internal work done to the engine. You will be better off in the long run rebuilding the engine the right way. Some will say you can get by just reringing the engine. That may last a few years before it starts smoking again or worse yet rod flys apart.

It's your Cub Cadet...your choice

thanx for the info merk. i used to measure with bore gauges and digital caliper. some day in the near future i plan to do a full restore on her. she is the only tractor i have at the moment. she doesnt have a lot of down time to do it now at least until i get another tractor to fill in for a while. when the cc123 is down for the restore.

The crank will need turned.

putting her back together and fire it up. started just fine. burned the oil out from assembly. ran her for a bit with varying rpms just sittin in the garage. a little seeping and some air bubbles coming from around new head gasket. once she is cooled down all the way i will retorque head bolts. shouldnt be bubblin any more then. next time i fire her up i will take it for a little spin and then change oil. check head bolts again. then i will start to load her up with snow removal. and hope she stays together. :biggrin2:

she has got new boots up front now too. v61's. 5 ribs

Looking good!

Nice tires! :beerchug: