Rebuild of a k301 with a half twist

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Tom Scott
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Re: Rebuild of a k301 with a half twist

Post by Tom Scott »

Mike - Nice work, but let's keep it moving! We don't run on dag time around here! :lol:

Eventually dag's gonna drag me through the mud on my 551 blower that "I started working on" three years ago... :roll:

In other news, I worked at a balance shop for a few years. As Dave K. says, lots to consider for engine balance, and in general the oem engineers did a good job. Sometimes, like with grenade gears, not so much.

To give a common balance example, the usual balance formula for a V8 engine was to figure out 100% of the rotating weight and 50% of the reciprocating weight. A weight pack of this total was assembled to each crank throw, then spin it up on the balance machine. Add and remove metal from the crank as needed to achieve neutral balance of that mocked assembly.

We had a special fixture that held the big end of the rod on a roller, with rod horizontal and the small end placed on a scale. The entire rod is also weighed so you now know the weights of the big end and small end with a little math. 100% of big end weight, 50% of small end. Same for pistons, rings, bearings etc. Weigh everything and assign to reciprocating or rotating weight.

And this was after checking all the rods and pistons and making all those numbers match, and within a gram of each other. We would grind on the big and small ends of the rods as needed, chuck the pistons up in the lathe or Bridgeport to cut in safe places to make them all the same. Way better balance than a stock engine. But then again these were generally hot street or race engines, needed to be way better!
1872, 46", 50C decks, Haban dozer blade, 450 snow blower
2182-1, Kwik-Way Loader, 3-pt & rear pto, 442 tiller
2182-2, 54" deck, 551 snow blower
Past tractors:  1541, 2135
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BigMike
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Thanks Tom

Been working on simpler stuff, cam cover. fuel pump cover, set valve lash and installed the breather. I hope this weekend to get the other small stuff installed and spray some primer on it. Then it will set aside until spring when I'll decide whether to put it in the 126, 125.....or maybe the 100.

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Come on BM.....We like pics of the small stuff too :shock:
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Big Mike....just checking in on the half twist. Im posting this to make u feel pressured and uncomfortable! The same way i felt around june......... :twisted:
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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BigMike
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Wah,huh, let me rub the sleep from my eyes :mrgreen:
Got side tracked with a storage cabinet for the shop.....that now has to be cut down 2", stupid tape measure :lol:

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Too funny...I'm also in the middle of a big shelving project for Cub and house junk. Ya know....Wood is much easier to correct when u make a boo boo.
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

:geek: " I knew I had multiple heroes :geek: hey Tom..Your my hero.... :geek: Tom I need a hero " :geek:
BIG DORK!
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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Tom Scott
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Re: Rebuild of a k301 with a half twist

Post by Tom Scott »

dag: Reported. The bus for banned camp is warming up! :lol:
1872, 46", 50C decks, Haban dozer blade, 450 snow blower
2182-1, Kwik-Way Loader, 3-pt & rear pto, 442 tiller
2182-2, 54" deck, 551 snow blower
Past tractors:  1541, 2135
<><

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

:x yea well...The short bus is waiting at the end of your driveway!
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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BigMike
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Ok you two holster your booger launchers :lol:
And Dag put the ammo back where it came from and not from under the seat.

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Here Mike...I'll help and bring this back up to the front page for ya..... :twisted: make it a little easier for u to find :lol:
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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BigMike
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Dag, I would get this thing done if life would stop interrupting.
I honestly don't know what I will do with it once it's done because I really don't need the 126 and have thought about getting rid of it. I could put it in the 125 but I cannot seem to keep belts on it as it is so all this awesome power will likely just make it worse. ;)

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

:lol: you don't have to explain life....or not needing the extra cubs to me. One day I say I will sell all extra....the next day I'm scanning cl for the good deals :oops:
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Not sure if I am running out of time or challenging my self :lol:

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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Dag, I am really disappointed that this is a month over due and no reminder from you :lol:

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

See Mike....I figured out how to buckle down...... you obviously have not
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127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

DaveKamp
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Re: Rebuild of a k301 with a half twist

Post by DaveKamp »

Sorry it took so long to respond to the engine balancing questions...

Yeah, it's a very challenging subject, particularly on a single.

On a multi-cylinder engine, the balancing becomes more involved, but it's more beneficial there. What your'e doing, like on an inline four or six, is getting all the counterweights the same, so the crankshaft doesn't whip like a rope... then you make all the rod big ends and little ends the same weight... then make all the pistons and wrist pins the same weight.

THEN you have something that runs with natural symmetry.

Realize, that when these things come out of the factory, they're not subjected to any substantial balancing. Every decimal place you add in a part's precision, adds TWO decimal places to it's manufacturing cost, so the obvious choice, is to choose manufacturing methods that yield the best CONSISTENCY without any additional operations. A first-operation part is always the least expensive... one that requires many operations after the initial (ie.e a casting), means not only more expense, but more depenancy in keeping TOLERANCES.

If you really wanna know how involved it gets, I'm gonna need a classroom, some samples, and a BIG inkboard... that's Industrial Engineering 306...

So with regard to the balancing gears... the concept is that the single cylinder has TWO primary planes of oscillation... up and down (piston vs counterweight) and side to side (because the counterweight swings sideways, the rod swings opposite, but the piston stands still at the extremes...

The balance gears spin in opposite directions, and are weighted and timed such that they either:
-counteract EACHOTHER when in vertical plane, but counteract the BIG END/COUNTERWEIGHT imbalance in the horizontal... or...
-counteract eachother in the horizontal, and counteract the big/counterweight in the vertical.

Counterbalance shafts go back a LONG way in history. My first motorcycle was a Kawi KZ400, and it used balance weights.

THere's nothing wrong with the concept, but if the castings, forgings, or gears have any weak spots, they fail in ghastly ways.

I left them out on the 12hp I built for Loader-Mutt, and I set that governor to 4200rpm limit... and ran it there mercilessly, with substantially more than stock compression, for what... 18 years... before it finally expired. It did very well IMO, but that isn't a recommendation for anyone ELSE to do it. Wear protective equipment!!! :lol:
Yes, I'm a Mad Scientist... but I'm usually happy, even when things ain't goin right.

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