Kohler K Crankshaft Balancing.

[Ambush]

I just put the engine back into the 149 today. I rebuilt it a couple years ago, not long after getting the tractor and I left the balance gears out at that time. It does seem to shake a lot, but I don't really remember how bad it shook before. I've just found some info on a crank balance kit from an outfit called Kirk Engines. Its basically a weight you add to the crank, particularly if you leave the balance gears out. In his article he discusses differing weights in oversize pistons and pins. I did not compare the complete weight of my oversize piston to the stock one I replaced. He claims the added weight will definitely reduce vibration as they are "poorly" balanced to start with. I can make and install my own weight kit patterned after the Kirk one.

Has anybody static balanced a crank and piston set from a K series, particularly after boring oversize?

I'm probably going to fire it up tomorrow and if the vibration seems excessive, I may just pull the engine again and take it apart.

Just wish I had come across this a week ago when the engine was stripped and the pan and flywheel were off anyway.

[finsruskw]

I have one of those weights from Dave K installed on a 16 HP Kohler in my 1650 tiller rig.
At WOT is is smooth, I'm happy with it.

[Ambush]

Engine balancing used to be a common procedure for the performance guys during the muscle car era. Some voodoo involved or implied.

That’s good to hear you’ve had a positive outcome finsruskw. Firsthand experience is strong especially from someone who has sat in a lot of seats. Have you considered balancing others, or just not worth the money. I imagine the installation would be costly.

Does the Puller crowd balance engines for high rpm’s?

I believe there is a difference between “shake” and vibration. Shake being inherent in a one lunger.

[finsruskw]

Dave told me that installing the plate on a 14 HP Kohler would not yield much difference if at all.

[Ambush]

Good to know. If the guy selling them suggests no benefit, then that's very likely true.

I do wonder if the balance gears were more about counter vibration than balance. The engineers must have had a marketable reason to justify the cost to the sales execs.

[ol'George]

I agree 100% that balance gears offset vibrations.
But not much help balancing rotational unbalance.
Various engine manufacturers go about vibration issues in different ways than Kohler does with varying results, but any vibration reduction is good!

[Billy-O]

It could be that pullers take their motors to extreme RPMs to justify the remediation of heebie jeebies vibration.... Just a thought.

[jbrewer]

I'd think that additional balance would be of marginal improvement on a typical K engine used at typical garden tractor RPMs. (less thank 3K?)

They're all pretty smooth at high RPM, it's just at low/idle where they shake like the thumpers they are.



I'd consider it lipstick on a pig :-)

[dodge trucker]

I have rebuilt my share of cast iron Kohlers. Some came factory with balance (grenade) gears, some of the same size didn't. To date I have left them out of every engine that originally had them. Again some did better than others. Theres a particular 12hp in a QL that I did that shakes horribly that might just come back out to have them reinstalled.
Currently I have another 301 apart, this one original to a 129. Its going back into that 129.
I looked up the price of the bearings in the balance gears and they are prohibitively expensive from Kohler. I got the numbers off of them and put that number in the search at Ebay. Torrington B88 I think they are. I got several hits on them, both genuine Torrington and others. Many around $5/ea. Definitely cheap at that price. Theres a seller that has em in lots of 5 thatw ere "on sale" last week for $12.some . I bought one of his 5 packs and it cost me $17 and change shipped to my mailbox. Enough to do 2 engines with a spare left. For that price I'm about to put my 1st K301 back together with its balance gears included. Its 52 years old, if it lasts half that it'll probably outlast me.
26 years from now (if I'm still around) I'll be 83.... if I make it that long. I have 1 more set around here of balance gears (somehow I can only find 1 of that pair) that may well go into that 1250....

[DSarow]

I have a 301,when I had a guy over haul it I asked him about the balance gears.My crank wasn't even tapped for them.When did Kohler start installing them?