fbh31118 Posted August 24, 2022 Share Posted August 24, 2022 The time to get the Cubs out has finally arrived!!! Our 122 has a very special story and is very important to our family and as such is going to be the next in line for a little tlc. We plan on pulling the engine and tear it down to get measured up and get a rebuild started. I would love to do a David Kirk style project but I'm not sure if the parts are even out there let alone for a standard rebuild. What have you seen out there these days? 1 Quote Link to comment Share on other sites More sharing options...
DR.EVIL Posted August 28, 2022 Share Posted August 28, 2022 A buddy of mine and I did Dave Kirk style Killer Kohler rebuilds on 14 HP Kohler's for Cub Cadets. Mine's more "stock", buddy's was much more radical, forged aftermarket piston, Midwest SuperCub forged bullet con-rod, his cam was way more radical too. He put it in his #73 Red & White Cub Cadet which he took to several plow days, and it was a great running tractor and a Stunner on looks. He's sold the tractor now, think it's in Southern Iowa. My 14 hp had a stock +.010 piston & rings, the Alcoa Forged rod Dave Kirk describes in his Killer Kohler write-ups, I ported the block, and used a K361 Kohler cam, slightly longer duration but stock lift. Head was planed a bit. I put a small diameter flywheel, backplate,, and blower housing on the engine so I could fit the 14 hp in my stock #72 frame. I had Dave Kirk install a set of his balance plates on my stock crankshaft. That 14 hp has just slightly less vibration than my stock 10 hp Kohler had. But it pulls like a locomotive! All that went on almost 20 years ago, finding a Alcoa rod would probably be the hardest, but I suspect Midwest SuperCub still has their billet rod available. I was shocked how expensive stock Kohler parts were back then, and I suspect they've had 4-5 price increases since. I've used some Stens parts in a couple rebuilds in the past with excellent results. Con-rod, gaskets, valves, piston&rings. My experience has been the bigger Kohler engines run longer between rebuilds. The 7&8hp engines don't last long as mowing tractors. I got over 1400 hours on my rebuilt 10 hp that included LOTS of full load and Over-Loaded hours mowing foot high grass, blowing foot deep snow. A 12 hp drops right in where a 10 hp was, and a 14 hp needs a flywheel swap with a 12 hp. 1 Quote Link to comment Share on other sites More sharing options...
beekeep15 Posted August 28, 2022 Share Posted August 28, 2022 i know this is off topic , what size tires and rims you have on back, thanks 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted August 28, 2022 Author Share Posted August 28, 2022 Stock size on the front and back. Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted August 28, 2022 Author Share Posted August 28, 2022 4 hours ago, DR.EVIL said: A buddy of mine and I did Dave Kirk style Killer Kohler rebuilds on 14 HP Kohler's for Cub Cadets. Mine's more "stock", buddy's was much more radical, forged aftermarket piston, Midwest SuperCub forged bullet con-rod, his cam was way more radical too. He put it in his #73 Red & White Cub Cadet which he took to several plow days, and it was a great running tractor and a Stunner on looks. He's sold the tractor now, think it's in Southern Iowa. My 14 hp had a stock +.010 piston & rings, the Alcoa Forged rod Dave Kirk describes in his Killer Kohler write-ups, I ported the block, and used a K361 Kohler cam, slightly longer duration but stock lift. Head was planed a bit. I put a small diameter flywheel, backplate,, and blower housing on the engine so I could fit the 14 hp in my stock #72 frame. I had Dave Kirk install a set of his balance plates on my stock crankshaft. That 14 hp has just slightly less vibration than my stock 10 hp Kohler had. But it pulls like a locomotive! All that went on almost 20 years ago, finding a Alcoa rod would probably be the hardest, but I suspect Midwest SuperCub still has their billet rod available. I was shocked how expensive stock Kohler parts were back then, and I suspect they've had 4-5 price increases since. I've used some Stens parts in a couple rebuilds in the past with excellent results. Con-rod, gaskets, valves, piston&rings. My experience has been the bigger Kohler engines run longer between rebuilds. The 7&8hp engines don't last long as mowing tractors. I got over 1400 hours on my rebuilt 10 hp that included LOTS of full load and Over-Loaded hours mowing foot high grass, blowing foot deep snow. A 12 hp drops right in where a 10 hp was, and a 14 hp needs a flywheel swap with a 12 hp. Good point, I had forgotten about MidWest Super Cub. I'm really interested in the crank balancing and deleting the balance gears. It's really been a solid motor the whole time we have run it but it's going through a lot of oil. Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 11, 2022 Author Share Posted September 11, 2022 Got the engine torn down this weekend. It was surprising how good the crank journal and con rod looked. The piston skirts were a little rough looking and possibly the source of the oil blow by but will have to measure to know what's going on. There is zero ridge in this block so I'm leaning towards a possible valve guide issues or the cylinder out of round. I'm also wondering if I should even bother replacing the main bearings. Here's a look at a few pictures I took this weekend. Quote Link to comment Share on other sites More sharing options...
Mr. Plow Posted September 12, 2022 Share Posted September 12, 2022 She was due for a cylinder head servicing....that's for sure!!!!! Are you headed to PD in IL Brian? 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 13, 2022 Author Share Posted September 13, 2022 19 minutes ago, Mr. Plow said: She was due for a cylinder head servicing....that's for sure!!!!! Are you headed to PD in IL Brian? That's my plan. Hoping I can get the 122 back together this month. Lots of oil burning........ Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 18, 2022 Author Share Posted September 18, 2022 Block is empty and the components cleaned up. Guessing it has a Kohler piston but the rod is anyone's guess. At the minimum it's looking like valve seats need to be recut, valves ground, piston, rings and possible .10 over bore. Wrist pin and rod journal looked really good by eye. Waiting to get some tools to measure the parts up and see what we've got. 2 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 19, 2022 Author Share Posted September 19, 2022 Good news! Rod journal and bore are in spec for standard parts. Quote Link to comment Share on other sites More sharing options...
DR.EVIL Posted September 21, 2022 Share Posted September 21, 2022 I may be one of the few, but, I've NEVER replaced one of those big BEEFY roller bearing main bearings, Ever! I had a 12 hp Kohler that somehow got about half the blower fins broke off the flywheel, yes, it vibrated terrible! Dad found me a new flywheel and I pulled the engine and replaced the flywheel, Much smoother at all engine speeds. It was crazy the vibration induced failures I had on that engine & tractor. All 4 engine mount holes pulled the threads out of the aluminum oil pan. The steering console where it bolts to the frame started cracking, I took it off and Dad brazed it up. It was doing well when I last saw it. I've kinda lost track of some engine parts, but I "Think" the main bearings from that K301 are now in my Hot-Rodded K321. That K321 doesn't have any balance gears in it, but I had Dave Kirk install a pair of his balance plates when I rebuilt the engine. The K321 vibrates about as much as a K241 10 hp does, that's a smaller bore shorter stroke engine but the K321 is long stroke big bore. I only live about an hour from Dave Kirk, plus I use his favorite automotive machine shop in Fond Du Lac, WI, I'm sure Dave would install your balance plates for a nominal fee. I had Brian Miller do a tiny bit of machining on my Alcoa forged Kohler conn rod, and he did a terrible job. I've been a Buyer of machining and machined parts of all kinds for around 30 years, If I could have found another Forged Alcoa rod I would have had a good shop off-set bore the big end to install the Clevite 77 rod bearing. Baring a catastrophic failure, next rebuild should only need a new main bearing for a common Continental engine. I've read his entire website, a lot of the stuff he describes is just good housekeeping, keeping things clean. If I wanted a crazy high performance Kohler engine, I'd have Don Vogt or Julian Stahl, owner of Midwest SuperCub build it. 1 Quote Link to comment Share on other sites More sharing options...
Ruby Red Posted September 22, 2022 Share Posted September 22, 2022 From the scoring at the top of your piston is a indicator of your carbs, butterfly shaft and carb housing wore bad, draws unfiltered dirty air in, destroying piston and rings now you have an oil burner. Carl 1 Quote Link to comment Share on other sites More sharing options...
snoshoe Posted September 22, 2022 Share Posted September 22, 2022 If you check top ring groove clearance. I'm sure you will find it out of spec. While Carl is probably right. I have seen the same thing after one and a half hours mowing with wing nut on air cleaner cover not tight. 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 22, 2022 Author Share Posted September 22, 2022 I will say that I have never had this engine apart before so I have no way of speaking to the condition of the parts that went into the engine or the level of attention that may or may not have gone into it. 😉 I have put an exhaust valve and a head gasket on it in years passed to I will pay special attention to the carb when I put it back together. I plan on putting a balance plate in it and ball honing the cylinder with a stock set of rings and piston. I also hope to recut the valve seats and have the valves ground if I can find someone to do them. This is a thumping little engine and I love it! It runs out of traction way before it runs out of power for us. Can't wait to have this back together! 1 Quote Link to comment Share on other sites More sharing options...
Mr. Plow Posted September 23, 2022 Share Posted September 23, 2022 Connie is +/-18 now right? Same age as my daughter? When did we get old? 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 23, 2022 Author Share Posted September 23, 2022 8 hours ago, Mr. Plow said: Connie is +/-18 now right? Same age as my daughter? When did we get old? Yes, she's a senior in high school this year! Doesn't seem possible. 1 Quote Link to comment Share on other sites More sharing options...
Mr. Plow Posted September 23, 2022 Share Posted September 23, 2022 Lots of good times along the way and the kids enjoyed it. Emma is a freshman at Concordia University Mequon this year..... 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted September 23, 2022 Author Share Posted September 23, 2022 10 hours ago, Mr. Plow said: Lots of good times along the way and the kids enjoyed it. Emma is a freshman at Concordia University Mequon this year..... A few from the early days Our oldest Kathleen on the left. Seems like one of the girls was Art A's daughter but not sure about the other. 1 Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted October 9, 2022 Author Share Posted October 9, 2022 Crank has returned with Kirk Engine balance plate installed! Fun times ahead. 3 Quote Link to comment Share on other sites More sharing options...
nate Posted October 11, 2022 Share Posted October 11, 2022 I’ve heard of the Kirk balance plate before. Were the kohler cranks that far out of balance from new? Is he actually balancing each crank or do they all get the same plate? Quote Link to comment Share on other sites More sharing options...
fbh31118 Posted October 11, 2022 Author Share Posted October 11, 2022 22 hours ago, nate said: I’ve heard of the Kirk balance plate before. Were the kohler cranks that far out of balance from new? Is he actually balancing each crank or do they all get the same plate? David Kirk has an entire write up on these engines and the mechanics behind it. I know that there are some who don't agree and others who are convinced. This crank was not individually balanced by anyone. I will report back good or bad. Guess I've done dumber things. 😆 Quote Link to comment Share on other sites More sharing options...
DR.EVIL Posted October 18, 2022 Share Posted October 18, 2022 Dave explained the science behind his balance plates to me. Balancing an engine is actually a compromise because of the forces generated in the engine. Dave has the precision scales to weigh everything, his plates are cut from rolled steel plate that has a thickness tolerance, the holes are drilled which can vary +/- .001" and I'm not sure how he has the plates cut, maybe Laser or wire EDM would be accurate enough too. I bet the capscrews he includes can vary a gram or two also. Kohler designed the crankshaft to be able to use in the 12, 14, and 16 hp engines, a different short stroke crank was used in the 10. Pistons in bigger engines are larger in diameter and heavier and the balance plates should be thicker but a noticeable difference in smoothness results from Dave's plates. Most of my knowledge on reciprocating engine balancing comes from a article in Hot Rod Magazine written by C.J.Baker in about 1975. It's a science, but not an exact one when you factor in all the manufacturing variances between parts. I've removed 2 or 3 sets of balance gears, first set was in a freshly overhauled K301 that I missed the proper timing of the "Grenade Gears" when I installed them, I pulled the engine, turned it upside-down, removed the oil pan and beat and pried till they popped out. That was the engine the flywheel was missing 5 of the 12 blower vanes all in a row, with NO balance gears and a good flywheel it was much smoother. But the hopped-up 14 horse with Dave's balance plates is smoother than a stock 10 hp. I can't remember how much a 7 or 8 hp vibrated, I was young enough back then that "seat time" beat anything except running a BIG tractor. 1 Quote Link to comment Share on other sites More sharing options...
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