tommy3horse 3 #1 Posted September 29, 2010 Hello to all: I wanted to share a story that started with the purchase of a 1978 C-161 auto with a hyd. lift from RS member barns1. I saw the ad on craigs list and the accomanying picture. It looked so good, I had to go and at least look. Ok, I bought it right away. The sheet metal was in great shape, and the tractor was overall in great condition. Barns1 said it had a "knock" and needed a complete rebuild. I got it running and heard the noise he spoke of. I got it home and tore right into it. I pulled and benched the motor and dissambled it. As I pulled the piston and rod out I noticed that the piston was loose on the rod. The pin was worn badly. Probably the "knock" that was noticed. The rod was STD. and looked new and I was puzzled. I mic'd the crank and it was .018 under? Now thats where the knock was! I broke-down the engine to the bare block and noticed that under the bearing cover was primed gray, like a factory replacement. I began the mic the cylinder. It was .001 out of round and no wear at all. I kinda pieced together the what might have occured to the PO before barns1. It must have threw a rod and cracked the block beyond repair and a new block was obtained from Kohler. Then a new aftermarket rod was purchased. The original STD piston and pin was used and quickly re-assembled without tending to the crank, piston or pin. I am having the crank ground and have ordered a Kohler piston , rod and rings...all STD. I should have it up and running in a week or so. Just goes to show that attention to detail and careful measurements go a long way to insure that your motor will last many years to come. I learn something new everytime I open-up a Kohler. And, yes, I am leaving the balance gears OUT. Tom :USA: Share this post Link to post Share on other sites
rmaynard 14,952 #2 Posted September 29, 2010 I mic'd the crank and it was .018 under? Now thats where the knock was! I am having the crank ground and have ordered a Kohler piston , rod and rings...all STD. Tom, Am I missing something here? You said that the crank pin measured at .018 under. If you are having it ground, I assume it's going to .020 under. You say you are using a new STD rod. Shouldn't it be a .020 under, and doesn't Kohler limit their rods to .010 under? Bob Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #3 Posted September 29, 2010 You can go to .030" under on the rod journal IF the rod is machined for a bearing insert. I'm not so sure this is the case here though????? Perhaps he's having the rod journal welded up & reground to "STD" diameter? :USA: Share this post Link to post Share on other sites
tommy3horse 3 #4 Posted September 29, 2010 Hello Bob: My bad, the rod will be ground to .020 under and a new Kohler .020 rod will be ordered by the machine shop doing the work, based on what he ends-up with. He (the machinist) stated that he would order the proper rod after he is done grinding the crank and also said that an insert may be necessary. Thanks for pointing that out, i may have confused some. Detailed rebuilding is much different than detailed writing Tom :USA: Share this post Link to post Share on other sites
tbbahner 27 #5 Posted September 30, 2010 Let me know where he gets that .020 rod. I need one for a K181 that is past what I thought was the .010 limit. Knocks like crazy Tom B Share this post Link to post Share on other sites
