Winter Project 122

[J-Mech]

Ok,

So to reiterate, I pointed out David Kirks "Killer Kohler build". I wanted you to read through it so you can see how far he went to have an outstanding "stock" motor.

While I think David did a great job, I don't think all he did was necessary. That said, I will explain. When building a true "hot rod" motor (whatever application, racing, pulling, ect) there are a lot of things you can do to gain a little HP, here and there. One small thing done doesn't necessarily make a big difference, but done in conjunction with several small things they start to add up. Again, David did a great job..... but as most car "hot rodders" do when they move into a tractor world, is they fail to build according to application. They carry over things they do to high horsepower, high RPM motors thinking that every engine needs those things to be "great". Well.... they don't. Practical application is everything..... building a motor for a pulling tractor IS NOT the same as building a race car engine. Building a stock class pulling engine for a GT IS NOT the same as building a good running plow tractor engine. A plow tractor has to be expected to perform for hours on end, under load, and varying loads. Not really something that happens on a pulling or race track. Tractor pulling engines run 300' and get shut off. Done. Maybe started back up and pull another 300' then they get shut off, and so on. I think you get the picture.


All that said, here are some things I have found with David's build that hold a lot of weight and make more difference than you would think.

Before I start on that though, just a few overhaul tips. I'll explain some more details below, but just to get you started, you don't need to spend a hunk of money on Kohler parts. I get all my overhaul kits from ebay. I buy off one buyer in particular. Here is a link to his ebay store. I already linked you up to the Kohler section on his page. I don't order off ebay, I call him directly. His number and business hours are listed. I just tell him what I want, give him my card number and I get it in a couple days. Get the most inclusive overhaul kit for the K301. Valves, tune up, the hole shebang. Order new valve guides too. For another like $35 it's worth it. Kevin is a good guy, and I've had no issues whatsoever with aftermarket parts. (From him, or any of the other hundred(s) of motors I've built.)

Bore it. Don't skip that. Have the machine shop tell you what size you are going to need BEFORE ordering the kit.
Grind the crank. Only reason I wouldn't do this is if the crank shops says you don't need to. Most always they need ground. Again, do this BEFORE placing an order for the overhaul kit.

*IF* the engine still has balance gears, remove them. Throw them over your shoulder and don't ever touch them again, unless it's to move them to the scrap pile. They aren't worth putting back in, and they can grenade leaving all the hard work for naught.

Otherwise, standard rebuilt stuff. I'll cover the "fun" stuff,,,,,,, now.


Valvetrain:
*David talked about using a file on the edge of the valve and adding a radius to the valve reliefs. It does help. Radius them like he suggested. It will make the gas flow better.

*Port/polishing: Do it. It helps. Do the intake, and exhaust. You don't have to "hog" them out, just try and get them as smooth as you can. I use a Dremel with the handheld wand to do it. It's easier to do with the valve guides removed. I also suggest polishing the cast threaded adapter to the muffler. (Unless you go to a header/stack pipe with a MWSC adapter. More on that later.)
David talk about working the intake port lead in where the carb mounts. This is a good thing and he is correct that the factory design can be improved. I would tear the carb down and install it with the butterfly out and look in the hole. See if you can do some grinding to improve it, then let it go. If you want to take the time to fill it with JB and make a smooth transition, then go ahead. I think it will make a difference, but as of yet, I haven't done it.

*Do a 3 angle valve job. David stated he didn't. If you can't do that yourself, then have the shop boring it to do the valves. If they argue, tell them to do what you want. I had one shop tell me it wasn't necessary. I told them I didn't ask for help on how to build it, only asked them to do the work I requested. (Usually I do it myself, but my valve equipment was down.)

*While we are on valve train, spend the extra bucks and put in all new guides. I ALWAYS replace valves on an overhaul. Going to grind the new ones anyway, so doing the 3 angle is just part of the new deal.


Piston:
*Mahle pistons are great, but you aren't building a pulling motor or a hot rod. Whatever piston comes in the overhaul kit will be fine. If you want to pay big bucks for a Mahle piston, or Kohler one, that's up to you, but I don't think it's necessary. For a plow tractor, it will be just fine.


Block:
*Doing that deburring David talks about in the valve area on the cooling fins for improved cooling flow.... that's a good idea. I haven't done that in the past, but I think I will on my next custom build. Can't hurt a thing, and my Dremel will be faster than David's hacksaw blade and file, lol.

*I check the deck surface with my glass sheet I use to plane heads. I simply set it on top of the deck and work it to see if the deck starts to polish flat. If it doesn't I keep going until it does. There are faster ways of doing this, but they cost money if you are paying for them. You don't need to take off a lot of metal, but you will see the pulled metal around the head bolt holes. You can file it down with something bigger, then go ahead with the glass until yo use that it is going to be flat. If you notice a large area that isn't flat, look into getting the block decked. Machine shop can do that, but don't take off any more than necessary, and make sure they tell you how much they took off. Never seen a Kohler need any more than just some sanding to the deck with the glass sheet.... I'm just making a general statement on what to do if you encounter it.

*Continued due to over size limit for a post*

[J-Mech]

Crank:
*David talked about polishing his crank until it was smooth for less air restriction..... that's one of those things carried over from a car application. It isn't going to make that much difference at 3800 RPM. Skip it. Just make sure the crank is in good shape.


Head:
*Get a head with the spark plug over the exhaust valve. The 122 didn't have it there. They changed it later. Those heads seem to get a better burn. You will also have to change out the upper engine tin that covers the head with the correct one. You may have to drill holes in it for the fuel tank mount. It's not fussy.

*Bead blast it. Make sure it's clean. Plane it on a sheet of glass, or if you wish, take .040" off of it and raise the compression a bit. I don't, or haven't yet, and I think my motors are fine with the stock compression. You're just plowing, not racing or pulling.

*Do, index the spark plug. Do make sure that the plug threads are good. If they are not, install a repair insert. Make sure that it is flush where the plug seals. I've seen a lot of heads that have been damaged around the plug hole and it won't seal up good. There are a lot of ways you can mill it flat again. Use good judgement on how to do it. A mill is best.


Cam:
*This one is fun. You can run the stock cam and it will be fine. If you have the cash, and want a really good cam, check out Zach Kerbers Gov 1 and Gov 2 cams. He has a Gov 3, but you have to do some more changes to the engine to use those. The Gov 1 and 2 both work with the stock lifters. I have yet to use one, but I plan to on a personal build. I know guys who have used them, and report good results. Some people use them alone as an "upgrade" but I think you get a lot more out of the mods already mentioned when used with that cam. Don't think you need to use them.... I just mention them because they are the most affordable upgrade you can do with the cam and not change anything else. Another guy and I (Don Vogt) have discussed them at length, and agree they are a good build, but as I have not used one I can't verify how much more difference it will make. As I stated, I plan to use one in the future, I just have yet to want to spend the extra money on one as I've been very happy with the other mods.


Carb:
*This one is tricky. You will very likely not quite get enough fuel with the other mods made. If you use the Kerber cam, I can about guarantee you won't. I'd put on a freshly rebuilt carb and test run/tune it. If you can't get enough fuel, pull it off, tear it down and drill out the main jet with the next size bit (use a good drill bit set that goes up in small increments). If you have to screw out the main jet needle more than 2.5-3 turns, you need to drill the jet. DO NOT go to a bigger carb (#30). You want the #27 carb.


Timing:
You can likely run the stock timing, but I would play with it. Set it to stock then move it around and see how it acts. Just a note, too far advanced will make it really hard to start. Find the sweet spot. Don't be afraid to move it around. You may or may not be able to tune it by ear. If you have a really good timing light, you can check the exact timing by using the advance on the light to see where it is. I do, then I note it so that I can reset it there if need be. You can also just measure the point gap and record it once you find the timing you need. If you are running a stock cam, it may or may not need something other than stock. The stock camshafts timing was all over the place. Not very uniformly manufactured, so setting the timing to a custom spot isn't very unusual at all.


Well...... that's a lot of info, and you are a long way away from that build. So, process that, ask questions and have fun! I think you will find the K series Kohler to be a pretty impressive engine. If you think all this was cool, you ought to see what can be done with them for garden tractor pulling!
I don't normally take time to be this in depth as it just flies over most guys heads. Hope you caught a lot of that. I prefer just to build a motor and get paid. Maybe you can process it and end up with a good build.


Jeff in PA is the da'man on parts. DO holler at him for driveline needs, or any other machine work you might need. He won't BS you. If he says he can do it, he can. While on the subject, he makes a really nice Brinly adapter. Much nicer than what you have. Not knocking your custom hitch there...... but I'd find an IH hitch and Brinly adapter. There are some things yours is lacking that the correct hitch isn't. Plus, it's kind of big and out there.....

I'll make another post on the clutch.

[johncub7172]

Originally Posted by cadetmike

I sort thought it might be... thanks for the insight

The under drive gear box was designed to slow down the garden tractor for equipment such as a snow thrower, or rear tiller, NOT to be used so much as to be hauling/pulling heavy loads. The idea of the creeper can often be mis used, which could result in worn parts.

Been doing it since 1961



edit: Very nice wright up Jon!

[J-Mech]

If you need parts for the clutch, talk to Jeff in PA. I know I already said that, but do it.

That said, get a heavier spring from MWSC here. Red is fine.
Also, buy a Kevlar disc and use it. It's cheaper than a stock disc, and will have smoother engagement. Yes, it has 6 holes in it. You will just use 3 unless you upgrade your driver, but for the HP your going to be at, it isn't necessary.


You mentioned installing a creeper. You can. But for what you are planning on doing with it, you won't need it. If you truly only plan to plow dirt and snow with this tractor, I'd look at removing 1st gear and installing the low speed second gear in it's place, and putting the high second gear in the second gear spot. You will plow dirt in 2nd, and that would give you two choices of plowing speed. A slow and fast. There are 3 different ratio's of stock second gears. You just need to find one of each and swap them out. Plowing snow..... depending on how far you are plowing, you may be in 3rd doing that anyway, so it won't matter. Only time you will miss first gear is loading it on a trailer, and pulling it in the garage. If you wanted you could always put on a creeper and still have a slow range. Creepers don't scare me.


How's that for info?

[J-Mech]

Originally Posted by cadetmike

looks like I will need to drill out the spindle holes to 7/8 and install bushings, then I think I will build WF style spindles as they are stronger, with 1" shafts to take 4 bolt trailer hubs... sounds like a lot of work but I hate sloppy steering and such. And why didn't they ever put a grease fitting in the beam for that center piviot?

Originally Posted by DeltaCub

Early production did not have grease zerks for the axle kingpin. Last spring I had two 102's in my shop...one was a 1965 with no grease zerk and the weird brake pedal. The other was a last 1967 that had the zerk, different pedal and a serial number tag on the back side of the transmission.
If you want to avoid the sloppy draglink issue and want stronger spindles, put a wide frame axle with 1" spindles and you will be satisfied. Bolt on hubs look cool but are overkill. Have fun with your toy!

Man, Beth nailed it.

Ad a zerk, it's not fussy.

And think about the whole bolt on tire deal. Beth is right.... it's a waste of money. What do you gain? A better wheel bearing is all. I've got tractors with but loads of hours on them and original wheel bearings, so you aren't going to gain much in that department. Still the same spindle size, still the same axle pivot size and still the same spindle kingpin size used with the bolt on hub wheels. They are good for....... looks? Maybe, if you want to look like you spend a bunch of money that could have been spent on the rear end or the engine. Stick with the stock tires and wheels.

[zippy1]

Originally Posted by J-Mech

Man, Beth nailed it.

Ad a zerk, it's not fussy.

And think about the whole bolt on tire deal. Beth is right.... it's a waste of money. What do you gain? A better wheel bearing is all. I've got tractors with but loads of hours on them and original wheel bearings, so you aren't going to gain much in that department. Still the same spindle size, still the same axle pivot size and still the same spindle kingpin size used with the bolt on hub wheels. They are good for....... looks? Maybe, if you want to look like you spend a bunch of money that could have been spent on the rear end of the engine. Stick with the stock tires and wheels.

Well said between Beth and Jon.
Oh, and great write up there "Master Mech"

[Terry C]

To the OP:
That was a ton of good advice right there.
The thing about Cubs is that 99% of the time with ground engaging implements, you run out of traction before you run out of HP. No matter what HP you have.
I’ve plowed with my 782 that has a 20hp Kohler. I’ve also plowed with a 102.
I’d rather plow with the 10hp 102. It’s a tired 102 also.
This is just my opinion and I’m not trying to talk you out of engine mods, but I’d rather have an ultra reliable engine than one tweaked for max Hp.

[twoton]

Wow, way to go Jonny! You must have some seriously sore thumbs after that one!

[jbrewer]

Originally Posted by Terry C

To the OP:
.
The thing about Cubs is that 99% of the time with ground engaging implements, you run out of traction before you run out of HP. No matter what HP you have..

This is worth re-reading about 10 times.

[cadetmike]

wow... my head hurts, lol not really. I will tell you that NONE of that went over my head, just so you don't feel like it was a waste of time.

I think I will go with most of your recommendations on the engine build and clutch. I don't plan on upgrading the cam although it is tempting, I just don't think I will have the money for it. Fortunately I know someone who can do all the machine work whom I trust, so that is a big plus.

The reason I am going to such lengths on the front end is because my rims are shot and so are the kingpins and kingpin bores. I prefer to overbuild than have to readdress failure in the future. Tapered roller bearings far exceed the ball bearings available for stock application. Besides that, by the time I buy a WF axel, and rims to fit, I figure I will have about the same into it as going with the 4 bolt hubs. (they are only $38 per side for hubs, bearings, and a weld on spindle)