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perry

kohler engine warning

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perry
a word about kohler engines with balanceing gears. i am working on my Allis 914 and the 14hp kohler K321 engine has a bad rattle knocking noise. check with a buddy who is cetified kohler mechanic. here is what he said. the Balance gears have absolutely no influence on how well the engine runs or how long it will last - unless one of them shatters and comes out through the side of the block. They're called grenade gears for a reason. My vote is - and always has been - to remove them. The bottom one will pull right off the stub shaft - but you'll have to break the "weak" side off the top gear to get it past the crankshaft. I use a chisel - and sometimes the gear will actually split in half and fall off. (it's not like we want to save the gear, right? top gear removed
[img]http://i270.photobucket.com/albums/jj112/Sorekiwi/Tractor/14%20Auto/IMG_3463.jpg[/img]

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quote:
Originally posted by perry
a word about kohler engines with balanceing gears. i am working on my Allis 914 and the 14hp kohler K321 engine has a bad rattle knocking noise. check with a buddy who is cetified kohler mechanic. here is what he said. [b]the Balance gears have absolutely no influence on how well the engine runs or how long it will last - unless one of them shatters and comes out through the side of the block. They're called grenade gears for a reason.
Does Kohler have a sevice bulletin on it? Something that serious, the factory would have said something about it.

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dentwizz
Does the "Synchro-balance" by Briggs have such notice? It almost sounds like there was an excess hardening issue during production. I've seen that happen quite a few times but it's usually followed by a recall or bulletin like Bob said.

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sammiefish
according to the expert these have no impact on the engine longevity but then contradicts himself to say they become grenades... this is not a production issue.. I retain my balance gears when rebuilding.... I make sure they are to spec... ya know.. 40+ years and all...

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Chris727
My Machinist is something of a "kohler expert." He has also suggested removing them and that they are unecessary. The problem with the gears is not a design flaw. They are an additional point of wear that are often overlooked when people perform "rebuilds." The needle bearings, retaining rings, and pins get worn and need replacing sometimes before the rest of the engine wears out. When these parts fail, it puts the crank and cam in a bind, resulting in the cam getting pushed out of the block.

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perry
quote:
Originally posted by sammiefish
according to the expert these have no impact on the engine longevity but then contradicts himself to say they become grenades...
meaning they have no effect on how the engine runs or last when the gears are removed.

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rbstuartjr
So now I am confused, should they be removed or not. I just "rebuilt " a k321 for my AC 914 and she rattles and knocks at idle but smoothens out under load and is a beast. I did replace the needle bearings on the balance gears, but she still knocks. So should I go back on and pull them out or leave it alone because I don't want my motor to grenade. On a side note, my AC 910 with a k241 of the same vintage, which also rebuilt at the same time runs like a sewing machine and also has the balance gears.

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perry
quote:
Originally posted by rbstuartjr
So now I am confused, should they be removed or not. I just "rebuilt " a k321 for my AC 914 and she rattles and knocks at idle but smoothens out under load and is a beast. I did replace the needle bearings on the balance gears, but she still knocks. So should I go back on and pull them out or leave it alone because I don't want my motor to grenade. On a side note, my AC 910 with a k241 of the same vintage, which also rebuilt at the same time runs like a sewing machine and also has the balance gears.
make sure to check the timeing on the engine. it will spark knock if not set correctly. how to set timeing - http://gardentractorpullingtips.com/ignition.htm#timing

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perry
quote:
Originally posted by larry8200
LOL, maybe I'll perform this operation on the K-301S in my 7112H, thanks.
after one has seen many kohlers with the balanceing gear promblems and since is does not effect the engine , i think i would take the gears out rather than takeing a chance just knowing maybe those gears may let go. article taken from brian millers pulling site. Don't (re)install the balance gears in an engine if it's going to turn above 4,000 rpm! (The factory maximum rpms for virtually all small gas engines, including all of Kohler engines is 3,600.) The high rpms could cause them to break and destroy the engine! So when building an engine that's going to turn above 4,000 rpm, these gears (and spacers) MUST be permanently removed! Remember - "An ounce of prevention is worth a pound of cure." It's okay to leave the stub shafts in the block. Or if you want, drive out the balance gear pins from the block (from the PTO end), cut 1/4" NPT threads and install a couple of 1/4" NPT Allen pipe plugs from outside the block. Be sure to use silicone sealer too, to prevent an oil leak. Or, the holes can be welded up solid. And if a stock OEM-type piston assembly and connecting rod is going to be (re)used, there's no need to re-balance the crankshaft/piston/rod assembly if these gears are removed. If you want, leave the balance gears out. Actually, they're more trouble reinstalling and align with the crankshaft than they're worth. You won't notice that much difference in the vibration of the engine, either. It won't damage anything and it won't hurt anything. The engine will operate just fine without them. By the way - I've seen balance gears in the 10hp, 12hp, 14hp and 16hp engines, but not every one of them have balance gears. I've even seen some 16hp Kohler Magnum engines have three balance gears! Anyway, it seems that Kohler was selective in which engines they put them in. Perhaps they only put them in engines that was installed in a "luxury-type" of garden tractor to help reduce operator discomfort. And every balance gear I've ever seen appear to be exactly the same weight and design. For most single cylinder Kohler engines, balance gears isn't really necessary. Leaving them out shouldn't have a noticeable effect on engine vibrations, but they do help to reduce engine vibrations somewhat. So if you choose to reinstall or leave them in an engine that will never turn more than 4,000 rpms (this is the maximum rpms for pulling in stock classes or doing ordinary yard work), make sure that the bearings in the [balance] gears and the stub shafts that they spin on are in good condition. If the bearings are worn and if the balance gears wobble, they'll wear the crankshaft gear teeth and they could break, possibly destroying the engine. By the way - you can get the balance gears alignment tool (timing gage) from your local Kohler engine dealer. The part number is 10355 or Y-357. It's much easier to use this tool when aligning the balance gears in time with the crankshaft. See the drawing to the right for correct identification of this tool. Once, just for curiosity, after I've rebuilt a 12hp (K301) Kohler engine, I've ran the engine with the balance gears installed. Then we took them out to see if the engine would vibrate more. (It wasn't a lot of work to remove the gears. WE just removed the oil pan, snap rings, washers and spacers, rotated the crankshaft a certain way, and then lifted the gears right out.) Anyway, we found that without the balance gears, the engine vibrated EXACTLY the same as when the gears were installed! Makes ya wonder why Kohler installs them in the first place. ???? The balance gears in a 12hp Kohler engine can be removed without removing the crankshaft. What's needed is a heavy duty snap ring pliers with 90º tips to remove the snap rings. Be sure to remove the spacers (if equipped) and shims from the shafts, too. The counterweights on the 12hp crankshaft are machined off, allowing room to remove the balance gears. But on a 14 and 16hp engine, the counterweights may be in the way. If it is, try driving the pins from the PTO end of the block instead and then plug the holes from the outside with a couple of 1/2" cup-shaped expansion plugs.

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rbstuartjr
I believe timing is correct, but will double check. Don't know what spark knock is though. After first rebuild, motor was real noisy knocking. Then pulled it again and replaced needle bearings on balance years. Definately quieted down some but knock there at idle. Does go away at mid throttle. I will probably pull them. Not looking forward to pull that motor again.

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sammiefish
quote:
Originally posted by perry
quote:
Originally posted by larry8200
LOL, maybe I'll perform this operation on the K-301S in my 7112H, thanks.
after one has seen many kohlers with the balanceing gear promblems and since is does not effect the engine , i think i would take the gears out rather than takeing a chance just knowing maybe those gears may let go. article taken from brian millers pulling site. Don't (re)install the balance gears in an engine if it's going to turn above 4,000 rpm! (The factory maximum rpms for virtually all small gas engines, including all of Kohler engines is 3,600.) The high rpms could cause them to break and destroy the engine! So when building an engine that's going to turn above 4,000 rpm, these gears (and spacers) MUST be permanently removed! Remember - "An ounce of prevention is worth a pound of cure." It's okay to leave the stub shafts in the block. Or if you want, drive out the balance gear pins from the block (from the PTO end), cut 1/4" NPT threads and install a couple of 1/4" NPT Allen pipe plugs from outside the block. Be sure to use silicone sealer too, to prevent an oil leak. Or, the holes can be welded up solid. And if a stock OEM-type piston assembly and connecting rod is going to be (re)used, there's no need to re-balance the crankshaft/piston/rod assembly if these gears are removed. If you want, leave the balance gears out. Actually, they're more trouble reinstalling and align with the crankshaft than they're worth. You won't notice that much difference in the vibration of the engine, either. It won't damage anything and it won't hurt anything. The engine will operate just fine without them. By the way - I've seen balance gears in the 10hp, 12hp, 14hp and 16hp engines, but not every one of them have balance gears. I've even seen some 16hp Kohler Magnum engines have three balance gears! Anyway, it seems that Kohler was selective in which engines they put them in. Perhaps they only put them in engines that was installed in a "luxury-type" of garden tractor to help reduce operator discomfort. And every balance gear I've ever seen appear to be exactly the same weight and design. For most single cylinder Kohler engines, balance gears isn't really necessary. Leaving them out shouldn't have a noticeable effect on engine vibrations, but they do help to reduce engine vibrations somewhat. So if you choose to reinstall or leave them in an engine that will never turn more than 4,000 rpms (this is the maximum rpms for pulling in stock classes or doing ordinary yard work), make sure that the bearings in the [balance] gears and the stub shafts that they spin on are in good condition. If the bearings are worn and if the balance gears wobble, they'll wear the crankshaft gear teeth and they could break, possibly destroying the engine. By the way - you can get the balance gears alignment tool (timing gage) from your local Kohler engine dealer. The part number is 10355 or Y-357. It's much easier to use this tool when aligning the balance gears in time with the crankshaft. See the drawing to the right for correct identification of this tool. Once, just for curiosity, after I've rebuilt a 12hp (K301) Kohler engine, I've ran the engine with the balance gears installed. Then we took them out to see if the engine would vibrate more. (It wasn't a lot of work to remove the gears. WE just removed the oil pan, snap rings, washers and spacers, rotated the crankshaft a certain way, and then lifted the gears right out.) Anyway, we found that without the balance gears, the engine vibrated EXACTLY the same as when the gears were installed! Makes ya wonder why Kohler installs them in the first place. ???? The balance gears in a 12hp Kohler engine can be removed without removing the crankshaft. What's needed is a heavy duty snap ring pliers with 90� tips to remove the snap rings. Be sure to remove the spacers (if equipped) and shims from the shafts, too. The counterweights on the 12hp crankshaft are machined off, allowing room to remove the balance gears. But on a 14 and 16hp engine, the counterweights may be in the way. If it is, try driving the pins from the PTO end of the block instead and then plug the holes from the outside with a couple of 1/2" cup-shaped expansion plugs.
Im familiar with this article. Im glad to see it posted here in its entirety its a nice explanation of what to consider with this concern. Very nice citation.

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perry
got the engine back in the Allis today and running great and no more rattle's. dang thing sounded like it had marbles in it. i pulled the outter balance gear off and then two hits on the inner gear with a big punch and it broke in half . made sure to get any small piece's out with a long magnet.

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osenga
Yes they are a small gear. But being a small one they do leave one heck of a BIG hole in a block . on mine when it let go it didn't hurt anything else . So I cut and formed a peice of sheet metal and my F-I-L nickel welded it back up and a buddy of mine is still running that motor and has been problem free ever since. And if a cast block does crack use a stick welder and nickel rod and low heat takes a while but will hold great and the nickel don't react to the cast

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sliderxc
I just rebuilt my k341 and put new balance gears in it and new pins hope it will be ok why did you break the gear they come right out if you remove the gears don't throw the away send them to me I will use them

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perry
quote:
Originally posted by sliderxc
I just rebuilt my k341 and put new balance gears in it and new pins hope it will be ok why did you break the gear they come right out if you remove the gears don't throw the away send them to me I will use them
The bottom one will pull right off the stub shaft - but have to break the "weak" side off the top gear to get it past the crankshaft.

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mike_sdak
Much ink has been spilled on this topic over at the deere forum. See, for instance: http://www.weekendfreedommachines.com/discus/messages/335/98027.html Also, David Kirk has written on removing the gears and rebalancing the crank. See the articles on rebuilding a "killer kohler" in the links on this page: http://www.ihcubcadet.com/forum/messages/103/103.html I hope my K321 holds up long enough to pull it apart and make a decision on the gears.

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mike_sdak
I should have mentioned, the K321 is in a JD 140! I would be less concerned if JD didn't use such hard-to-repower odd-spec engines as OEM. (unlike simplicity) My briggs 16 in the Allis is much less of a concern.

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rbstuartjr
So I pulled the motor and removed the balance gear. I ended up breaking the upper gear into pieces to remove, rather than removing the crank. There was quite a lot of metal material on the gears, and after removing the spacers did notice there was a good amount of wear on the pins. I did notice more wear in the clearance between the connecting rod and the crankpin journal. The rod moves easy side to side and the clearance turned out to be .12 of an inch. The machine shop I took it to said the crank was in spec. This is a new piston, rings and rod. The cylinder is bored .10 over. and the rod is the standard size. I have the kohler manual, but I can"t find where it states what the clearance wear limits are. The camshaft endplay is .15. That being said, I put it back together and the the engine is a bit quieter but vibrates a little bit more, but you can definately hear the rod slapping the crank journals. I will live with the knocking for now and use it for snowblowing this winter. This is my 910 6 speed repowered with Kohler 321. Sorry for the long post.

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msiebern
There were two styles of balance gears. I can't help but think the redesign has to do with the failure of the gears. Note the new style vs. old style seems to be a lot more solid with fewer areas that could develop stress cracks leading to failure.


I have searched my Kohler service manual for the recommended side clearance on the rod to crank journal can find no specifications for side clearance, only the rod to connecting rod journal.

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rbstuartjr
Yeah, I couldn't find the specs either. I guess I will just deal with the knocking for now. Can't see it hurting anything for now. Thanks for checking. Those balance gears are pretty brittle. One wack from a 3 lb hammer and a cold chisel and a chunk of gear broke right off. Now that the gears are out, the engine may vibrate a little more at idle but it also seems to accelerate quicker. Seems like the gears were binding against the crank and balance gear pins.

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