Rebuild of a k301 with a half twist

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BigMike
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Rebuild of a k301 with a half twist

Post by BigMike »

Bear with me if some of this is foggy, I started this in 2008.....nothing like a race to get it done :lol:
I am going to rebuild a K301, bored, decked(block and head), new valves(valves faced & back cut and seats ground). So beyond the obvious of a new piston and rod I am using Total Seal gapless rings, back cut the valves, very light valve pocket relieving and, the flywheel balanced and may be adding a little something in cam action. What is my goal?....good solid long lasting power plant with a little extra power.
I thought about having the crank balanced but that is much more involved than I feel is worth it. If you would like to have something done at that level and do not have the service available close by these guys are awesome and can handle just about anything you can throw at them,
http://www.pipestonesmallenginemi.net/
After everything is back from the machinist(did not know about Pipestone then) it is time to measure....why?
.010 bore of a K301 would be 3.385. How would you like a piston that is 3.371?.....hmmm, shouldn't that be 3.378?. Well, yes Virginia it should but b y mic'ing the piston that came with the rebuild kit from Ridge NAPA in Niles Michigan 3.371 is just fine :? Isn't that only .004?.....ummm, yea. The moral here is machine work is the machinists job, your job is to make sure your new engine does not have severe piston slap right out of the ole bucket. All is good, Kevin at Pipestone set me up with a proper sized piston :beer:
So back on track, bore is good, piston is good, valves are good, new parts clean now we assemble.....oh, once we have a cam(small problems)
Image

In my teaser in DAGs thread about the never ending rebuild of a Mag 20 it was asked why gapless rings. An internal combustion engine is an air pump for those that may not know. Any added sealing of the rings in the cylinder will help efficiency. Standard rings have a gap, loss of efficiency. Gapless rings have a step in the ring with a second thinner rail to offset and close the gap.
Image
Image

Hope this does not turn into a dead end thread :lol:

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

My 127 needs it next so....This is perfect! Im really excited because I think all kinds of factory and aftermarket parts r available for that engine. The mag was frustrating in the parts department.
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 »

OK....For the last three days I have been waiting for an update....
So..I guess anyone can answer my question. I thought flywheels were balanced? Henc the several drill holes... And cranks too? Is this just taking it to a tighter tolerance?
Feel free to post back in a year or two....No rush :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 »

Sorry, I forgot you are from the days of racing covered wagons :lol:
I had it balanced to a level higher than mass production does.
Now that peanut gallery has spoken, on with the show.

After some consulting and googlefu research I am going with a stock cam. It does not look like I would gain much for the expense....and I have a good cam and lifters all ready to clean and install and hope to do that tonight.

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Re: Rebuild of a k301 with a half twist

Post by JMotuzick »

What no pics?

It's only a single.

Engine mike and I rebulit the engine for my 169 over Christmas Eve dinner a few years back...basically just the short block but no lie, he came over we laid out the parts, went up for apatizzers went. Back down and installed some parts. Up for dinner back install more up for desert down for install. By this point we where almost done!

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Joe...This would have been good info for me to have about a year ago :lol: . I would have given him a four course meal to have it finished in a day. Anyone with the name Engine must b fast :shock:
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 »

Having all the small parts at hand and cleaned helps speed things up. Go to put in the governor gear.....stop, go dig out a cross pin, governor shaft, gear shim then clean and install slows things to the point it could take me a year to assemble this.....well, not year only a real slacker would stretch it out that far.
Block got washed by hand with hot water and soap, well dried and machined surfaces oiled. Got the valves and governor installed, lifters are in and cam ready to check end play.

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

..."on with the show"...This aint no show.......this is like a boring novel that my 5th grade teacher made me read. :cry: U started off with a nice cover pic.....now its all words? :x
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

Klapatta
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Re: Rebuild of a k301 with a half twist

Post by Klapatta »

Well some projects take longer than others. And it depends on how much it's really needed as well.
My narrow frame hydro lift pump took seven years to complete. There was something like eight source vendors involved.

A question though, where can these gapless rings be obtained?

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BigMike
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Total Seal will sell direct.
http://www.totalseal.com

Not much done tonight but I did take some pics so DAG will understand what's going on,
Image
Image

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Re: Rebuild of a k301 with a half twist

Post by DaveKamp »

The most important ingredient in Chili, is TIME.
To properly add the most important ingredient, one must have PATIENCE...

:beer:
Yes, I'm a Mad Scientist... but I'm usually happy, even when things ain't goin right.

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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Not much done lately, had to swap an engine onto a snowthrower in case we get any more measurable snow.
Dug out a bearing plate and a blower housing. Got the housing all cleaned up only to find a couple of cracks where the coil mounts. Tonight I welded it up.
Image
Takes a small tungsten for material that thin,
Image
A six inch scale, 1/8" tungsten and a .040 tungsten.
Honest Dag, I'll be back on track soon :D

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dag1450
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

What do u mean dug out?? Don't tell me this build is from parts just lying around here and there. I was told ( probably by Tom) "a proper engine rebuild has all the pieces: found, cleaned, and laying in order bagged and tagged". Sounds like u have the opposite going on up there. :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 »

Ok I gotta keep on schedule or I will run over my allotted year :)
Actually I want get this thing buttoned up so I can work on the vacuum chuck for my woodturning :o
So I got the crank installed and end play set,
Image
Image
and the piston and rod installed, rod cap over torqued, loosened and torqued to spec.
Image
Guess I am a slow eater :lol:

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chzuck
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Re: Rebuild of a k301 with a half twist

Post by chzuck »

BigMike wrote:Bear with me if some of this is foggy, I started this in 2008.....nothing like a race to get it done :lol:
I am going to rebuild a K301, bored, decked(block and head), new valves(valves faced & back cut and seats ground). So beyond the obvious of a new piston and rod I am using Total Seal gapless rings, back cut the valves, very light valve pocket relieving and, the flywheel balanced and may be adding a little something in cam action. What is my goal?....good solid long lasting power plant with a little extra power.
I thought about having the crank balanced but that is much more involved than I feel is worth it. If you would like to have something done at that level and do not have the service available close by these guys are awesome and can handle just about anything you can throw at them, http://www.pipestonesmallenginemi.net/
After everything is back from the machinist(did not know about Pipestone then) it is time to measure....why? .010 bore of a K301 would be 3.385. How would you like a piston that is 3.371?.....hmmm, shouldn't that be 3.378?. Well, yes Virginia it should but b y mic'ing the piston that came with the rebuild kit from Ridge NAPA in Niles Michigan 3.371 is just fine :? Isn't that only .004?.....ummm, yea. The moral here is machine work is the machinists job, your job is to make sure your new engine does not have severe piston slap right out of the ole bucket. All is good, Kevin at Pipestone set me up with a proper sized piston. So back on track, bore is good, piston is good, valves are good, new parts clean now we assemble.....oh, once we have a cam(small problems)
Couple of questions: Not familiar with some of what you are doing. What are back cut valves? Did you need to machine the inside of the head to compensate for the material you took off the head and block? Could you explain balancing procedure for the flywheel?
A problem I ran into on a rebuild of a 14 hp Kohler. The aftermarket piston had a heavier walled wrist pin than stock and that engine vibrated to the point I had things come loose on the tractor and I contributed the crack at the gas tank fuel outlet to that excessive vibration. I replaced it with a good used one and much less vibration.

I have another 14 hp Kohler that I want to rebuild and may incorporate some of what you are doing. Appreciate your posts.
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Yea Mike? Throwing around all this fancy engine talk. I don't think u r talking about the same seat grinding I had as a boy....when I fell off my motorcycle :o And a valve pocket relieving....Well I won't even go there... :lol:
Thanks for setting BM straight Charlie!
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 dag1450 »

Oh....and the picture to word ratio is getting better.... Thanks :beer:
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 chzuck »

dag1450 wrote:Yea Mike? Throwing around all this fancy engine talk. I don't think u r talking about the same seat grinding I had as a boy....when I fell off my motorcycle :o And a valve pocket relieving....Well I won't even go there... :lol:
Thanks for setting BM straight Charlie!
Just trying to learn. I have never ventured into hopping up an engine. I have always just overhauled engines. Big Mike has me interested in warming up my 14 hp just a little. Not looking to through extreme amounts of money into it.
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147 with 48" mower deck & 42" QA snow thrower
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

chzuck wrote:Couple of questions: Not familiar with some of what you are doing. What are back cut valves? Did you need to machine the inside of the head to compensate for the material you took off the head and block? Could you explain balancing procedure for the flywheel?
A problem I ran into on a rebuild of a 14 hp Kohler. The aftermarket piston had a heavier walled wrist pin than stock and that engine vibrated to the point I had things come loose on the tractor and I contributed the crack at the gas tank fuel outlet to that excessive vibration. I replaced it with a good used one and much less vibration.

I have another 14 hp Kohler that I want to rebuild and may incorporate some of what you are doing. Appreciate your posts.
Charlie, a traditional 3 angle valve job includes 3 angles on the seats and 2 angles on the valve. The point is the ease resistance and increase flow. The primary face on a valve head is the seating/sealing and heat transfer surface, the second or "back cut" is simply to help flow.
There is some latitude in how much you can take off the surface of the head before you start to cause clearance issues.....I only had it surfaced enough to make sure it is flat and has a good sealing surface for the head gasket.
Balancing of the flywheel is done to help longevity of the engine. If you have seat of the pants vibration issues you have mismatched parts and a short lived engine.
Wrist pin wall thickness caused engine failure? did the machine shop tell you that or the parts seller?

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Re: Rebuild of a k301 with a half twist

Post by chzuck »

BigMike wrote: Wrist pin wall thickness caused engine failure? did the machine shop tell you that or the parts seller?
No, I caused a failure that caused me to tear down the engine and I remembered reading a post by David Kirk on an aftermarket piston he bought that had a heavier walled wrist pin and how much more it weighed than original. So I found a very good used wrist pin and replaced it and some of that vibration was gone.

Did you balance the flywheel yourself? How is that done?
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Balancing the flywheel was done by Pipestone Small Engine. In my opinion it would be a very rare that a home shop would have the equipment to do balancing.

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Re: Rebuild of a k301 with a half twist

Post by chzuck »

BigMike wrote:Balancing the flywheel was done by Pipestone Small Engine. In my opinion it would be a very rare that a home shop would have the equipment to do balancing.
So do they bolt on the flywheel, connecting rod and piston and then balance?
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Since I only had the flywheel done Kevin put it on the balancer(machine) and spun it, found the out of balance and drilled it.

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Re: Rebuild of a k301 with a half twist

Post by chzuck »

BigMike wrote:Since I only had the flywheel done Kevin put it on the balancer(machine) and spun it, found the out of balance and drilled it.
Thanks. Please keep posting your progress.
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Re: Rebuild of a k301 with a half twist

Post by dag1450 »

Looks good Mike! I guess that's assembly grease your using.....I used oil but kinda wishing I used a grease. The oil is probably all down in the sump by now :oops:
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

I didn't take pics of them because who has not seen main bearing from one of these but I bought new ones. One was nice and clean(and rolls smooth as silk) the other is packed with grease. I will have to change the oil very quickly after start up.
If the engine was going to be installed and started in a few weeks oil would be ok but grease will "hang" longer and I doubt this will get installed and started until spring....at least :lol:

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Re: Rebuild of a k301 with a half twist

Post by DaveKamp »

chzuck wrote:So do they bolt on the flywheel, connecting rod and piston and then balance?
When working with 'balancing' a reciprocating engine, there's nothing 'simple' about it.

Think about it this way... when the engine is running, what position is the piston and rod in, in relation to the crankshaft and it's counterweight?

You cannot, because the relationship is constantly changing.

The piston, and wrist pin, only move on one plane. In a Kohler K-single, the piston and wrist pin move straight up and down.

The crank throw moves in a circular motion... The counterweight of the crank throw moves in a circular motion, and is diametrically opposite the counterweight. One could 'balance' the crank simply by making the crank throw and counterweight equal, so that the crank spins empty with no vibration...

But the BIG end of the rod moves in a circular motion with the throw... so if you were to 'match balance' anything, it would be matching the weight of the BIG END of the rod, with the counterweight. SO... we could make an arbitrary guess of the big-end of the rod, and add that much weight to the crank throw, THEN balance the crank. I say 'arbitrary', because what many would do, is take an old connecting rod, whack the big end off, and bolt it to the crank (with enough shim stock between the cap and throw to 'clamp' it on good), and balance away...

But a fair chunk of the rod is moving up and down (primary plane) and of course, swinging side to side (secondary plane)... but the secondary plane really isn't a plane, because it's actually oscillating in a CIRCLE, and with the rod angle CHANGING, it's oscillating in different planes at different amplitudes... and since the engine's turning in one direction, it's actually trying to 'hop'... and all this aside, the weight of the piston and wrist pin, on the primary plane, has been totally ignored.

IF you were to make that crankshaft counterweight heavy enough to counteract the piston reciprocation, then your primary plane balance would be less... but the secondary would become enormous... because you have all this additional weight swinging around in a circle, but it's only supposed to be counteracting the vertical plane.

Kohler did something that the Japanese motorcycle manufacturers did with their vertical twins... they added two 'balance shafts... one on either side of the crank, and these shafts had flying weights that were intended to counteract the spinning mass of the rod, and reciprocating mass of the piston. Unfortunately, the K-singles' counterbalance weights got the name 'grenade gears' for a reason... idea excellent... execution was... not so great sometimes.

Engine balance is an elusive beastie. :lol:
Yes, I'm a Mad Scientist... but I'm usually happy, even when things ain't goin right.

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Re: Rebuild of a k301 with a half twist

Post by chzuck »

dag1450 wrote:Looks good Mike! I guess that's assembly grease your using.....I used oil but kinda wishing I used a grease. The oil is probably all down in the sump by now :oops:
I have used an assembly lubricant by Sealed Power that is similar to STP. Assembly grease is far less messy and all of it stays where you put it.
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Re: Rebuild of a k301 with a half twist

Post by chzuck »

Dave Kamp,
Many people say those "grenade gears" make no noticeable difference. What is your take on them?
Thank you for your explanation on single cylinder balancing. Sounds very expensive and unnecessary for the average GT owner.
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Re: Rebuild of a k301 with a half twist

Post by BigMike »

Dave, you said it waaay better than I ever could so that's why I did not try to go to deep in depth.

Chuck, I am not an engineer but what I have see of "balance" gears has made me take them out of any tractor I have had they were in. and I would NEVER spend the time, let alone the money, to put them back in.

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