Dayton Murdock 127 #1 Posted November 2, 2016 Hi All Well it looks like I get to overhaul or re-ring my Kohler K301 I will start today and take lots of Pic's 6 Share this post Link to post Share on other sites
Ed Kennell 35,151 #2 Posted November 2, 2016 Looking forward to following this overhaul. Share this post Link to post Share on other sites
Dayton Murdock 127 #4 Posted November 2, 2016 I started the tear down Look at the oil on top of the piston and the small divots in the piston I measured the bore and it is round at 3.389" and straight at 3.389" What piston size should I buy? 2 Share this post Link to post Share on other sites
lynnmor 6,707 #5 Posted November 2, 2016 So what sort of matter was bouncing around in there? 2 Share this post Link to post Share on other sites
KC9KAS 4,741 #6 Posted November 2, 2016 @Dayton MurdockThat tractor sure looks nice....don't scratch it while doing the rebuild! 2 Share this post Link to post Share on other sites
WHX?? 46,405 #7 Posted November 2, 2016 I guess I don't see why you are going thru it looks good from here other than those marks lynn mentioned? Smoke.. knock?? I would go just the minimum .010. It doesn't appear to have been replaced before and the bore is "square"? Check the existing ring end gap for more suggestions/clues. 2 Share this post Link to post Share on other sites
Hossenfeffa 49 #8 Posted November 3, 2016 (edited) Standard bore for the K301 is 3.375. If your bore is 3.389, then you are .014 over stock. A .010 over piston won't do you any good. What did you use to measure the bore? You could possibly have a worn (by .004) .010 over bore now. I would recommend you use a good bore gauge for an accurate measurement. The top of the piston indicates oil consumption. If, in fact, the 3.389 is an accurate measurement, then you are going to need to go with a .020 overbore, provided that the cylinder has no taper. It has without a doubt inhaled something into the cylinder at one time. You will also need a good accurate bore gauge to measure the big end of the rod. Don't skimp on making sure the rod to crankpin clearance is correct. Kohler specs only allow for about .002 of wear in that department Edited November 3, 2016 by Hossenfeffa 1 Share this post Link to post Share on other sites
Dayton Murdock 127 #9 Posted November 3, 2016 13 hours ago, Hossenfeffa said: Standard bore for the K301 is 3.375. If your bore is 3.389, then you are .014 over stock. A .010 over piston won't do you any good. What did you use to measure the bore? You could possibly have a worn (by .004) .010 over bore now. I would recommend you use a good bore gauge for an accurate measurement. The top of the piston indicates oil consumption. If, in fact, the 3.389 is an accurate measurement, then you are going to need to go with a .020 overbore, provided that the cylinder has no taper. It has without a doubt inhaled something into the cylinder at one time. You will also need a good accurate bore gauge to measure the big end of the rod. Don't skimp on making sure the rod to crankpin clearance is correct. Kohler specs only allow for about .002 of wear in that department Thanks for the reply I used a Starrett telescoping gauge with 3"-4" mike to measure the bore and I am very confident with the measurement. A .010 over setup will get with in .004 would that not be a improvement? The puzzle I have is the piston measure 3.370 to 3.368 OD ?. I believe after boring out the cylinder they used the stock piston My intention is to hone the bore change the piston/rings and get thru the season. Spring time I will do a complete overhaul on this engine. This Kohler is definitely worth the time and effort to rebuild. 2 Share this post Link to post Share on other sites
Dayton Murdock 127 #10 Posted November 3, 2016 Here are some more Pic's The compression ring end gap was .057 and it should be .010-.020 the wiper ring end gap was .139 and also should be .010-.020 Share this post Link to post Share on other sites
oldredrider 2,547 #11 Posted November 3, 2016 Piston rings should be at least 1" below the block deck to measure ring gap. Measuring at the top of stroke in the cylinder (unless it has been bored) is not a representative diameter of the cylinder. Share this post Link to post Share on other sites
WHX?? 46,405 #12 Posted November 3, 2016 6 hours ago, Dayton Murdock said: they used the stock piston That might explain the end gap and no .010 stamp on the piston. 6 hours ago, Dayton Murdock said: Kohler is definitely worth the time and effort to rebuild. Agreed, the rest looks good. Share this post Link to post Share on other sites
Hossenfeffa 49 #13 Posted November 3, 2016 At .019 piston to cylinder wall clearance, that thing had to been noisier than all get out! .007 to.010 is stock specs for the K301. Stock size piston is 3.368. A .010 over piston will get you pretty close, piston to cylinder wall clearance wise. That hone job on that cylinder bore is absolutely horrible! You will need to spend some time with a deglazing hone so the rings will seat. I would recommend using cast iron piston rings. Those K 301 engines are without a doubt, worth rebuilding, even rebuilding with some "more horsepower" modifications 1 Share this post Link to post Share on other sites
prondzy 3,866 #14 Posted November 3, 2016 (edited) A re ring at this point will do absolutely nothing except spend your money. look at the thrust side of the piston, that thing has been slapping around for a long time, by putting new rings in you would be doing exactly waht they did and you will end up with the same results. you cannot put a round piston and rings in and expect them to fit an oval bore. machine it and do it right. and for piston size you wont be able to tell until you have looked for scratches. Edited November 3, 2016 by prondzy 1 Share this post Link to post Share on other sites
Hossenfeffa 49 #15 Posted November 4, 2016 On 11/3/2016 at 6:07 PM, prondzy said: A re ring at this point will do absolutely nothing except spend your money. look at the thrust side of the piston, that thing has been slapping around for a long time, by putting new rings in you would be doing exactly waht they did and you will end up with the same results. you cannot put a round piston and rings in and expect them to fit an oval bore. machine it and do it right. and for piston size you wont be able to tell until you have looked for scratches. He did state that the bore was round and straight. If the cylinder will clean up, the slightly loose piston to cylinder wall clearance could be improved by knurling the new piston. I have used that trick to get by for awhile more than once. Share this post Link to post Share on other sites
Dayton Murdock 127 #16 Posted November 5, 2016 I think that the piston to bore being at the upper limit and the ring end clearance in to spec should be an improvement over what I started with .020 of piston clearance and .054+ of end gap. I will post my first start after I get back from Cabo. Share this post Link to post Share on other sites
JAinVA 4,617 #17 Posted November 5, 2016 Forget knurling anything.That is something you might do if you wanted get it to appear that all was right with the engine.Based on the pictures of the tractor the engine deserves to be done right.Have the block bored and honed.Do it right and it will out last you.The K series Kohlers are tough all nails.JAinVA 3 Share this post Link to post Share on other sites
Shynon 7,427 #18 Posted November 5, 2016 I personally would throw out those balance gears while you have it open unless you want one of these. 4 Share this post Link to post Share on other sites
Dayton Murdock 127 #19 Posted November 5, 2016 6 hours ago, Shynon said: I personally would throw out those balance gears while you have it open unless you want one of these. Holy smokes that left a mark, maybe the governors was set too high🤔 Share this post Link to post Share on other sites
Dayton Murdock 127 #20 Posted November 15, 2016 Hi All I am back from 7 days in Cabo with my family. On my door step was a box with the parts I ordered ( Yea! ). Here are the photos of the piston, in the cylinder and the engine going back together. 3 Share this post Link to post Share on other sites
Dayton Murdock 127 #21 Posted November 23, 2016 It is finished and ready to go to work 1 Share this post Link to post Share on other sites