Fordiesel69 232 #1 Posted January 4, 2014 Was an idiot, pulled head, saw a .010 stamp with no arrow and thought, yep Style A piston. Order the rings for it on ebay, and when I tore it apart, somone has a narrow rod designed for a MAHLE Style D piston on it. There is some wear on the wristpin in the center as a result of the rod being narrow. So now what...reuse the rod and get a new mahle piston & pin. Or get a new style A wide rod. Leave it alone and slap a set of rings on it and be done. The problem was that I can see, is the rubber hose rotted off the air filter housing, and dust got in a cuased bore polishing. There is NO crosshatch, and the rings are razor sharp. Amazingly, the bore is still within spec for a .010 Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #2 Posted January 4, 2014 I'd probably ring it & run it. A new rod would be the lesser ($) of two evils though. It seems like the last couple years of K series production and the first few of the Magnums are a crap-shoot when it comes internals, and more than a few virgin engines have surprised me with "that's not right" parts. The last 341 I freshened up took three tries to get the correct rings - which ended up not being either set listed in the parts book. I think Kohler was cleaning off the shelves when they assembled some of these engines. Share this post Link to post Share on other sites
Fordiesel69 232 #3 Posted January 4, 2014 Will the narrow rod damage the wide wristpin on a style A piston? Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #4 Posted January 4, 2014 I can't see where it would actually hurt anything as long as the rod to wrist pin clearance isn't out of spec. Once the piston is in the bore and the rod is on the crank journal, the lateral movement is minimal. Share this post Link to post Share on other sites
shorts 182 #5 Posted January 4, 2014 You probably should put a matched set piston, rings and rod in the engine, since their were several different versions/combinations my guess would be that Kohler was trying to solve some type of problem with the reciprocating assembly, most likely a piston ring wear issue, any how by changing the rod length "center to center" the wrist pin can pe moved up or down on the piston to allow for different size ring packs. It is possible to put the wrong piston/rod combination in and either have the piston to high or low in the cylinder and cause compression or clearance issues with the cylinder head. The narrow small end in the rod suggests that the rod was narrowed to allow for extra length to keep the rotating weight the same for balancing issues. This is just proof that all of the manufacturers buy at least some of their parts and assemble their products. Share this post Link to post Share on other sites
shorts 182 #6 Posted January 4, 2014 I forgot, make sure to hone the cylinder before installing new rings, if you're not going for a rebore to .020 just hit it with a dingleball hone to get a crosshatch pattern Share this post Link to post Share on other sites
Fordiesel69 232 #7 Posted January 5, 2014 (edited) Video here: http://youtu.be/eGjwrS0KcN8 I decided to leave it alone and just hone & put new rings on. It should be ok as the wrist pin was only a slight bit worn. Has the same slight kohler rattle as before. The rod & crank look great, not scoring and nice and shiney. Cylinder is .002 away from max wear which is after I honed it. I never measured it before. Piston feels prettly tight compared to some other kohlers I have worked on. The oil rings were worn, and the rings overall were NOT staggered correctly, thus the reason for the oil smoke upon acceleration. With the quick hone job and the new rings I am glad to report no more smoke at all. The rattle I can live with as it is just a spare enigne I bought locally. I may plan to put it on a GT-1642 when the valve seats come loose. Haha.... Edited January 5, 2014 by Fordiesel69 Share this post Link to post Share on other sites
Fordiesel69 232 #8 Posted April 28, 2014 **Vibration** Lets revisit this topic as I have mounted this engine on my 312-8 just so I could run it for a bit & at least break it in. I have put about 4 hours on it, and it runs absolutly great with no oil buring, and the kohler rattle is not even noticable, especially at full throttle. However there is vibration felt in the tractor at any RPM. It is not a terrible vibration, or one that leads me to beleive it will fail, but certainly somthing that grabbed my attention. 1.) Kohler uses a Style "A" piston with the wide rod, or uses a Style "D" MAHLE piston with the narrow rod. Never any other combo. If the parts do not match, I would assume a dealer or owner has been into it. 2.) I did check the balance gears and they were in sync, and the bearings were tight. I was going to remove them, but the bearings were tight. I do not beleive they are off. Does anyone have specific weights of the rods or pistons? Reason I ask is because the weight added to the style "d" piston to make the wrist pin boss stronger, has been removed from the rod. So I would think running the style "a" piston which theroretically is lighter, and running the style "d" narrow rod which is also lighter, could be part of the problem. I am unable to make a video as if I were to show the vibration on the camera, I do not want to swap my 12HP back on to make another video showing no vibration. Is it also possible the 14HP just vibrates more? Share this post Link to post Share on other sites
oldredrider 2,547 #9 Posted April 28, 2014 It's been my experience that the 14hp Kohlers DO vibrate more than the 12 or 16's. It doesn't seem to matter whether the balance gears are in or out. Did a rebuild on a GT-14 that had a vibration, took balance gears out and still vibrates. Runs strong as an ox but still feel the vibration. Same story on a C-141 but the cradle mount deadens it a bit. Maybe just the nature of the beast. Share this post Link to post Share on other sites
Fordiesel69 232 #10 Posted April 28, 2014 My 314-H is a hydro, and have a larger pulley and runs with the belt enguaged. I will disenguage the belt to tonight and see how it compared. It is hibernating now, but it should be too hard to get it out. Share this post Link to post Share on other sites
pfrederi 17,193 #11 Posted April 28, 2014 My C141 vibrated very badly when i got it home from the auction...3 missing fins on the flywheel had something to do with it.... Share this post Link to post Share on other sites
Fordiesel69 232 #12 Posted April 28, 2014 Makes sense. This is a round flywheel without fins, and has a plastic fan, which looked perfect when I had it apart. I know the feeling, I had a 3HP pushmower that someone broke some fins off. Share this post Link to post Share on other sites
leeave96 487 #13 Posted May 1, 2014 The problem was that I can see, is the rubber hose rotted off the air filter housing, and dust got in a cuased bore polishing. There is NO crosshatch, and the rings are razor sharp. Amazingly, the bore is still within spec for a .010 This rubber hose design into the carb has to be one of the most stupid ideas to come out of Kohler since the K17 Series I. I've got a Troybilt tiller I bought new and it has a Magnum 8 on it. I was pulling the tins and carb on it for a rebuild and found that rubber breather hose (which sets near the exhaust) has melted!!!!!!!!!!! Were it not melted closed, there would have been an OPEN path for dirt (imagine the dirt and dust from a tiller) to bypass the filter and go STRAIGHT into the bore!!!! Needless to day, I will be retrofitting to eliminate that design to something more like what would have been on a K series engine. I've also read the Magnum single cylinders have balance gears. I might pull my engine and yank those things out - including the M14 on my 314-8. I can live with more vibration, but a window in the block would cause me much angst! Share this post Link to post Share on other sites
Fordiesel69 232 #14 Posted May 1, 2014 Two things: 1.) The breather on k-series just vents to the outdoors like a diesel road draft (kind of), this does allow to some extent dirty air to come in the crankcase. The routing of the blowby into the clean air side is a great idea on the Magnums, just the rubber is not of good quality. Briggs does the same, but the rubber just gets rock hard instead of falling apart. This is actually a maint item to be check while doing the air filter. 2.) The balance gears on the magnums are the "new style" and if ran at the proper 3600RPM or lower will be fine. The K series with the old style gear were more prone to this. Magnum 8 does not have balance gears. On your 314 model, it wouild be a good idea to de-sludge the oil pan anyways, so you can inspect the gears. If they are loose, definatly yank them. Mine were tight on this spare M14, so I left them. Share this post Link to post Share on other sites
