k301 questions

[Fast N Red 5]

Hi everyone i need your help.

So i have a k301 motor in my c-120 puller i pulled the head after i cout it out of storage and well its going to need a rebuild. I can move the piston back and forth in the bore(standard). I was told that the magnum Piston and rod is stronger than the k? is it true? Is it worth it? I plan on buying a LP head, Copper head gasket, and a nice port and polish. is there anything else i can to to crank some more horses out of it? Any help is much appreciated.

 

FastNRed

 

 

[MarkPalmer 80]

A slight amount of rocking back and forth in the directions against the wrist pin and slight sideways movement is normal with the piston.  This is the piston moving in its ring grooves and is necessary for piston expansion as it gets hot.  You probably don't have a problem unless the bore or piston are excessively worn which will show as scuff marks on the cylinder and there will often be a lot of oil consumption associated with this from worn rings.  The newest style "D" piston that was used on late K series and most (but not all) Magnums is the strongest, it is a forged piston made by Mahle.  If you install one of these you'll notice it will fit even looser than the old style pistons as the forging needs even more expansion room.  These "D" pistons do work very well in both the K series and Magnum engines, and they run a little cooler because they have thinner rings.  All Magnums used the Posi-Lock rod that uses retaining nuts instead of long bolts.  It isn't any stronger than the older style rods, it's design is just less prone to the rod cap coming loose because the cap is secured in to the proper position by small pins.   

 

I don't know if you are familiar with Brian Miller's pulling pages, but they have several lifetimes worth of valuable information on using Kohler K's for pulling: 

 

 

http://gardentractorpullingtips.com/engine.htm

 

 

-Mark-

[Fast N Red 5]

Mine smokes at start up but when warm it barley does

[MarkPalmer 80]

Startup smoke is the sign the engine is beginning to get tired.  Its cylinder is likely glazed (worn smooth with oil cross-hatches worn off) and the rings are getting worn.  To see what needs to be done, you’ll need engine measuring tools in a micrometer and telescoping gauge, half way decent sets are available at Harbor Freight for little money.  There is NO other RIGHT way around this if you wish to do the parts replacement and assembly yourself, as any other way is just guessing and/or assuming parts are useable.  If you don’t want to take it apart and measure the bore and piston to bore clearance yourself along with all the other internal items than it will need a trip to the machine shop for sure.   If you measure your engine parts comparing the readings to the service manual to find out what is out of tolerance, you’ll know what needs to be replaced and what needs to go to the shop for machining.  This saves you some money, and is a lot of fun to boot.  Plus you can then put the engine back together yourself, which is very satisfying. 

 

-Mark-

[Fast N Red 5]

I have a mic and everything my dad used to build motors for a living  ill see and im told i have the d piston so maybe it just needs rings.

[MarkPalmer 80]

I have a mic and everything my dad used to build motors for a living  ill see and im told i have the d piston so maybe it just needs rings.

 

That is perfect, you have everything you need to fix it right.  It might just need a quick de-glaze, and a new set of rings.  I'll always measure the bore in several places and piston thrust face with the engine apart, and make sure the piston to bore clearance is within spec. 

 

-Mark-

[baerpath 517]

I wouldn't go to far with the port and polish. Some turbulance in the air is a good thing. And unless your over 5,000 rpm and run no filter I wouldn't do it