Anybody use crankshaft balancing?

TheFlyingCub · #1 08-13-2018, 01:50 PM

Hey all-

I've got two engines pulled apart (part of my 105/125 restoration) a K241 and K301 and I had a question.

I assume you guys are familiar with Kirk Engines, anybody use Kirk engine's crankshaft balancing kit? Started looking at it and while the parts are at the machine shop it would make life easy for me to do it now.

I'm just looking for anyone that has it installed or has ran a tractor with it installed to see if it's worth it. Obviously the K series is fine without it, but if it really takes away some of the vibration, that would be nice too. Let me know.

olds45512 · #2 08-13-2018, 01:57 PM

I've never used that kit or had one balanced but the local guy that turns our cranks can also balance them and he told me his 126 at wot is as smooth as a twin cylinder, I think I'm going to spend the extra money on the next engine and give it a try. I would think having it done by somebody who's knows what they're doing would yeild better results than a one size fits all kit.

TheFlyingCub · #3 08-13-2018, 02:01 PM

Nice, thanks olds. I'll see what my shop can do on that end, and I agree with you on that most likely being the better option.

J-Mech · #4 08-13-2018, 03:17 PM

The K series really wasn't balanced all that well, it is true. While a balanced engine does run smoother, and by all rights should last longer, the K series seems to be pretty durable already. Tim is correct in saying that a individually balanced engine is far bether than a bolt on kit. Yes, you can smooth them up a lot balancing them. That said..... it costs money, and in a standard application it really isn't worth the cost. Now, if you are planning on really speeding the engine up, that's different. Nothing wrong with it, but I'm not going to do it on every engine I overhaul.

finsruskw · #5 08-13-2018, 04:27 PM

Mr. Kirk told me as much in an e-mail several years ago, Jon.
I searched and could not find it though or I would post up a copy.

Also, he used to offer the installation service if one was to ship a crank to him but has forgone that as his machinist that did that for him has retired.

Although I am still tempted to have that don on an AQS341 That is bound for the shop this week.

olds45512 · #6 08-13-2018, 04:41 PM

Quote:

Originally Posted by J-Mech

The K series really wasn't balanced all that well, it is true. While a balanced engine does run smoother, and by all rights should last longer, the K series seems to be pretty durable already. Tim is correct in saying that a individually balanced engine is far bether than a bolt on kit. Yes, you can smooth them up a lot balancing them. That said..... it costs money, and in a standard application it really isn't worth the cost. Now, if you are planning on really speeding the engine up, that's different. Nothing wrong with it, but I'm not going to do it on every engine I overhaul.

I wouldn't do it to every engine I build either but if it were a tractor I planned to keep forever and I was going to use it a good bit then the extra cost would be worth it, if it we're just a show tractor it definitely wouldn't be worth it.

J-Mech · #7 08-13-2018, 04:52 PM

Quote:

Originally Posted by olds45512

I wouldn't do it to every engine I build either but if it were a tractor I planned to keep forever and I was going to use it a good bit then the extra cost would be worth it, if it we're just a show tractor it definitely wouldn't be worth it.

The extra cost would be worth it just so you didn't feel a little shake in your tushy?
A properly rebuilt engine will likely last you and I's lifetime, so is it worth it?

twoton · #8 08-13-2018, 07:32 PM

Quote:

Originally Posted by TheFlyingCub

.....anybody use Kirk engine's crankshaft balancing kit?......

https://www.onlycubcadets.net/forum/...029#post391029

finsruskw · #9 08-13-2018, 09:26 PM

This from Mr. Kirk regarding my recent inquiry about his balance plate and whether it would produce a significant difference in an AQS 341.

With his permission...

Difficult to quantify "significant" but everything you can do to counteract the high recip forces in the K341 (due to the heavy piston assembly mass) makes an improvement. I have some customers that state it made a huge improvement, others state that it wasn't worth the expense. The important thing is to use a genuine Kohler piston assembly when you rebuild this engine as the aftermarket equivalent is much too heavy, especially in the thick walled wrist pin. If you use the genuine part, the counterweight plate has a favorable affect on reducing transmitted vibration.

The plate that I sell is the same for the K301, K321 and K341. The variable is the crankshaft counterweight mass and piston mass. The K301 has lighter counterweights, but also the least massive piston. The K321 and K341 use the same crankshaft/counterweights in conjunction with more massive piston assys. Thus the counterweight plate has approximately the same improvement in recip balance factor for all three models.

Hope I didn't confuse the issue?

TheFlyingCub · #10 08-13-2018, 09:33 PM

Quote:

Originally Posted by J-Mech

The extra cost would be worth it just so you didn't feel a little shake in your tushy?
A properly rebuilt engine will likely last you and I's lifetime, so is it worth it?

Completely agree. Both tractors are roughly 30 years older than me, and they're both still running. They didn't need factory balancing when they were new, and they don't really need it now. But maybe I have a wicked sensitive tush??

But in all seriousness, thanks all. I guess when I get a $# I'll make up my wind if its worth it or not. Getting excited to start throwing pictures up on the 105 restore, she went first.