Author Topic: K321s Help please!  (Read 2969 times)

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Offline thomas_c

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K321s Help please!
« on: June 15, 2010, 01:04:09 AM »
Okay so I have a 108 cub cadet that i turned into a pulling tractor I swapped the stock 10hp for this 14hpkohler I rebuilt this engine...new conecting rod and wrist pin and piston and rings of course. I finally got it together and ran it for a couple minutes and decided it was blowing too much white smoke.. So I took the head off and on every stroke it picking up oil on top of the piston. My rings are staggered like they are supposed to be. Any thoughts on what I should do? Or does it just need to be broken in?

Offline Big daddy

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Re: K321s Help please!
« Reply #1 on: June 15, 2010, 06:22:30 AM »
Need a few questions answered first. Was the bore in good shape?, i.e. did you rebore the engine? Is it a standard bore? If no rebore then did you hone the bore? What is the bore measurements top,middle and bottom? How long did you run the engine? Did you let it idle or did you load the motor heavily when you ran this engine? Also did you change oil pans for this engine? K241 pan for narrow frame will be a flat bottom pan, the K321 will have a deep sump to clear the oil dipper. Are the valve guides in good shape? Let us know the answers to these question and I am sure there will be more. But it will help better determine what the problem is.
Bruce Litton


Wheelhorseracer

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Re: K321s Help please!
« Reply #2 on: June 15, 2010, 09:37:07 AM »
Big Daddy covered a ton of the points. Right on the top of my list was the valve guides.


Offline thomas_c

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Re: K321s Help please!
« Reply #3 on: June 15, 2010, 02:02:30 PM »
OKay so the valve guides are in good shape. the bore looked descent no rebore and i didnt hone it either. I just let it idle when i started it. didnt get a chance to even run full throttle. it has the deep sump oil pan (stock). dont know about the bore measurement I really dont want to tear it down again this week unless i have to. another peice of info with the head off and cranking the engine i can look at the piston and see oil being picked up on every stroke. so i dont think it has anything to do with the valves

Offline Big daddy

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Re: K321s Help please!
« Reply #4 on: June 15, 2010, 02:15:56 PM »
Always hone the bore when installing new rings! A cylinder bore can look good but still be egg shaped from wear and heat, when in doubt or if you buy the block used>ALWAYS measure the bore! Unless you ran this motor from when it was new you do not know for sure the history of this engine. It may have been rebored and you might have put a standard piston in it not knowing any different. If you had re-honed the bore before you installed new rings I can tell you that just by idling the engine a few minutes you did not seat the rings. I start the engine, let it idle until it obtains approximate running temperature, then I hammer it. Load it as much as you can!! Those rings have to expand under good pressure to seat properly against the cylinder wall. I would measure the bore, and if the bore matches the size piston you put in it then I would re-hone the bore prior to assembly/wash out. Chances are you can still use the rings you have if the bore is the proper size. Do a proper engine break in then see how it acts.

Bruce
Bruce Litton

Offline thomas_c

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Re: K321s Help please!
« Reply #5 on: June 15, 2010, 08:02:07 PM »
okay so now i have a bigger problem. Im pretty sure i got the end cap on the connecting too tight and i chewed up the crank. should i try to polish it out or buy a new crank? Also where can i get a crank?


Wheelhorseracer

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Re: K321s Help please!
« Reply #6 on: June 15, 2010, 10:13:19 PM »
The larger Kohlers have bearing inserts, so if you destroyed the bearing on the crank I bet you will need to grind the crank and go with an over-sized bearing. The bearing is the cheap part here..

You can talk to the guys at http://www.mytractorforum.com and go through the different sections and talk to the guys about the Kohler. Many guys have 10 or more tractors in their collections and can really help you find the parts you need. I would try the Wheelhorse and Cub Cadet sections first in your search for parts.

Offline Big daddy

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Re: K321s Help please!
« Reply #7 on: June 16, 2010, 06:31:56 AM »
You can have the crank reground, and if you want the bearing in the rod you will have to have the rod machined for a bearing insert. You can get the rod bearing from either Vogel Manufacturing or Midwest Super Cub.
http://www.vogelmanufacturing.com/store/index.php?main_page=index
http://www.midwestsupercub.net/default.asp
The factory rod does not have a bearing insert, finding a shop that can machine the rod correctly may be a little tricky. Try to find a shop that does a lot of connecting rod work, and chances are they can fix you up.

Measure the crank pin first in a spot that is fairly clean. Factory spec. is 1.500". If it measures 1.4800" then you will need to get another crank, they are not too hard to find. A crank from a K301,K321,K341,and a K361 will work in that engine. Some small engine shops may have one laying around that is used, or you may find one on E-bay or Craig's list. The last new crank I bought for a K series Kohler was in 1987, and it was around $150. I have not bought a new Kohler crank since.
Bruce Litton