[ratrodjoey]

I found a 312 about a year ago that was burning tremendous amounts of oil. It was dirt cheap. It could be a parts tractor but I decided to give it a quick restoration. Upon inspecting the cylinder, I found deep scratches in the walls. I honed it some but discovered that the piston was cracked. Is it possible to use a larger bore piston from a 314? Is the 314 stroke the same as a 312. The cylinder has to be machined more, so I figured now would be a good time to increase power. Thanks

 

[deereman84]

Joe-
A machinist more than likely won't let you go to a 14 HP piston. That is a big size jump and there won't be enough cylinder wall. You can always have the engine sleeved. I have a 300 that is getting it done since it also has very deep scratches in the cylinder wall.

 

[trav1s]

A K301 takes a different crank/rod/piston than the k321 in the 314. I bought a 312 with a busted rod and in the process of rebuilding the k301 I discovered the block and crank are bad. I found a replacement block and I am hunting down other parts.

Did you try to get an oversized piston for it? I believe you can get a .010" or .020" over piston on eBay.

 

[ratrodjoey]

I'll look on ebay. The prices I found at Jacks were crazy. Thanks for the help, men. Joe

 

[johndeerenuts]

The crank and rod in the k301 and the k321 are the same. You can get .010 and .020 under sized rods. The pistons come in .010 .020 .030 over sized. Thanks George

 

[redington]

The cranks are the same stroke but have different counterweights. Here is a good read on crankshafts for the Kohler.

http://gardentractorpullingtips.com/balance.htm

Rodney

 

[trav1s]

Rodney nailed it - the larger K series share the same stroke but counterweights are different.

Joe, I might have an extra oversized piston and undersize rod that will not work for me because the old crank and bore were WAY out of spec. I will check specs at home.

 

[ratrodjoey]

OK Travis, that sounds good. Is there any measurements I need to take. I don't have any measuring tools, but my neighbor does. The rod has no damage that I can tell. Thanks again to everyone.

 

[ratrodjoey]

Rodney, that is a good read on single cylinder engines. I would like to make a puller, but we don't have any local puller associations down here near Houston (that I know of). Lots of John Deeres,though.

 

[ratrodjoey]

I have my 312 running and not smoking; thanks WFM. Found 10 over piston and rings for cheap on ebay. However, as a 300 series tractor, it just doesn't look right without engine side panels. Am I right thinking that 314 panels are compatible with that frame design? I can easily modify muffler to exit out of the right panel. Thanks.

 

[schweitz]

Glad to hear you got the 312 fixed, Joe. My first JD was a 312 I've now had almost 30 years and is still my go-to mower. My son (aircraft mechanic) rebuilt the engine several years ago so is still going strong.

But it's interesting to note your preference for side panels. Since I started with 312 I prefer the looks without side panels (now have 5 additional JD's). Restored a 214 and decided to leave the panels off.

Have a great new year!!

 

[jd2854020]

Joe,
Here are two pulling clubs in case you are interested..
Pulls around Dallas/Ft Worth http://www.lsgtpa.com/
Pulls in Port Lavaca, Gonzales, Columbus http://www.tmtpa.com/

 

[dayers]

I was told too never sleeve an engine like a cast iron kohler because it makes the cylinder extremely thin and it may(will) break and they make .040 ever pistons at least until they discontinued the engine direct through kohler according to the machinist and engine parts guy at work. but that said you can still find aftermarket or nos kohler parts places as far as I know.
this was true last winter when I had them look at my k301 and give me the options.
then they obsoleted them.