Rebuilding a K321 engine for a 149

[jwjones]

I've got the engine on the bench and a brand new engine and parts manual so I think I'm ready to get the process started.
My bother in-law bought this cub a year ago and it seemed in great shape. He ran it all last summer and didn't have any problems until....he called me up and asked me to come take a look at it because it wouldn't start. I grabbed my tool bag and went over. First thing i did was check for adaquate spark, that was good. Checked for fuel, that was good. hmmm, I pulled the spark plug, looked good. hmmm, I looked in the plug hole and turned it over...the piston didn't move, it was stuck at TDC. ugh, I thought to myself. I told him this was not good and that I could get it fixed for him but he wanted to bring it to a "professional". I said ok but it's gonna cost ya. Despite my words of wisdom he brought it down to the local repair shop and the guy quoted him 700.00!! He finally brought it to my house last week and wants me to get it fixed in a couple months before the grass starts growing again.
I haven't got the engine apart yet but I'm thinking the Connecting rod broke somehow. I guess I will see once I get the pan off. Feel free to offer some insight to this project. I work on Large Bore 16 cylinder CAT gensets that have been converted to run on Methane from the local landfill. So I'm very familiar with engines but this is my first one cylinder project. Just trying to save my brother in-law some money.

 

[dmerkle]

Working on a single cylinder Kohler will be a piece of cake compaired the Cat motors.

The Kohler manual will have all the needed infomation to rebuild the motor. Odds are the cylinder will need bored and crank journal will need to be undersize .010. I replace the governor gear when I rebuild a motor. The gear is plastic and usually brittle by now. The head bolts are replaced when I rebuild any motor.

I would toss the balance gears in the trash if the motor still has them.

You can go up to .030 over on the stock bore. Any motor I've done that needs to go more than .030 over stock bore gets a sleeve installed.
I prefer Kohler replacement parts when I rebuild a motor. They may cost a little more...long run there wort it.

 

[jwjones]

Yeah, it should be a fairly easy job. Acouple days before he brought the cub over I ordered the engine/parts manuals. They are nice, everything you need to know in there. I was impressed with the parts manual. Parts exploded views and everything.

I had a heck of a time finding the last two motor mounts on the 149. Turned out they were under the front axle. I didn't have my gear wrench handy so I had to turn those 3/8 bolts a quarter turn for what seemed like an eternity with an open end wrench.

I have a model 81 of my own and it looks funny next to the 149. It's like little and big brother sitting next to eachother in the shop

 

[aschumacher]

I was curious on how big a 12 cyl engine with a generator attached was.
Look here and see what Jarrod likes to play with.
www.cat.com/0to12
wow!
Your Cub engine should look to you, like a model airplane engine to the rest of us.

 

[jwjones]

Allen, They are quite large...To put a better perspective on how large they are I posted some pics of them on the off topic tractor forum.

The Website you posted had a 20 cylinder engine that my company runs at different plants. It was the pic on the right hand side of the page. I maintain the 16 cylinder engines at my plant. I actually like the 16's a lot better...a lot less sensors and less nonsence shutdowns in the middle of the night. Our 16 cyl. make 800Kwh and the 20's make 1600Kwh

 

[kmcconaughey]

Jarrod, regarding your BIL's Kohler, I'm gonna guess that the top off the piston broke off. I had one that it happened to, though it happened before I took possession of it. It has since been rebuilt.

 

[jwjones]

Kraig, Ahh that sounds a lot more logical than what I was expecting to see. I will let you know what I find

 

[dmerkle]

Along with my other post I will remove the valves and and check them out when I rebuild a motor. Section 11.4 thru 11.7 in a Kohler manual has some good infomation on the valves, valve seats and valve guides.

 

[wmiller]

Jarrod J. When I o'hauled my 301 and 321 I left the valves,springs and retainers in the engines when they went to the machine shop to be bored out, and let them take them out to grind the valves. The camshaft can be removed and reinstalled with the valves in place and I didn't need a valve spring compressor. I left the balance gears out,but if you put them back in, that might be more difficult. Those two models have adjustable lifters, but some of them don't,then you would need the camshaft and lifters in place to set the valve clearances. I also kept track of which lifter went where. On the one engine I had the lifters refaced on the valve end. Before I retired, I spent 30 yrs working on EMD and GE locomotives,so your piston looked kind of similiar to what I used to find.

 

[jlhayes]

Allen S. check out this Hemi powered air raid whistle.

http://www.victorysiren.com/x/index.htm

Go to the second page and hear it run.

 

[aschumacher]

Jim, WOW! That thing is so big I cant even make a joke about putting it on the front of a car!

 

[jwjones]

Well I've got everything apart and on the bench...


Bad news..The connecting rod snapped into three pieces and the crank is whipped....Gonna need a new crank, piston, rings and everything that goes with that.

Damn I wish my brother in-law would've given this to me to repair in the fall like I suggested to him....I've got about a month or so to get this thing done and on the lawn, mowing.


I'm having a little trouble with the parts manual....I'm not a parts guy so

 

[mgonitzke]

Jarrod-

Are you sure the crank can't be turned, or even just cleaned up? Most of the time, you can remove the aluminum buildup and still be within spec. If not, you can have the crank turned .010" under and get an undersize connecting rod.

 

[jwjones]

Matt, It's pretty bad but I'll suggest that to the Machinist though. Thanks

It's my brother in-laws and he's pretty hard on his things. It doesn't look like he changed the oil...ever

Very thick and very black

I can't find the part number for the crankshaft anyway. I checked on opeengines.com , I found all the other parts I'll probably need, except that one

Another question: The parts manual says that there are two different styles of pistons, a Mahle design and the old style. Which should I use? Is that design better than the old?

 

[digger]

Jarrod,
I don't spose you thought about contacting one of our fine sponsors to get Kohler parts did ya?

 

[wmiller]

Jarrod A friend of mine had a Kohler rod modified for rod brgs from a Toyota or something,which allowed them to turn the crank about .020 under. He says the engine has been running for several years that way. He mows and blows snow with it,so it has got a lot of use. The Car Quest (a local parts place) machine shop in Nebraska City, Nebraska does/did the mod. Maybe somebody closer to you knows that trick,too.

 

[jwjones]

Hi guys, thanks for all the valuable information you have given me it helped a lot during the process of rebuilding the "killer Kohler" 321.

After months of waiting on money from my brother in-law to get parts and the engine bored and the crank cleaned I finally got it all together and the engine is back in it's rightful place.

I attached all the needed parts and was on my way to firing her up. I had the battery on charge the night before so I thought I was good to go. I stepped on the clutch pedal and turned the key....nothing. I can hear the soleniod engage and the power going to the generator/starter but it won't turn. I figured maybe I have to hand turn it to get some more oil onto the moving parts but that didn't seem to help. It turns over fairly easy with a strap wrench but the starter cannot turn it. Is there a ground issue that I'm not aware of? I checked all wires and leads for tightness and all check out. Ugh...I just want this baby to fire so I can start adjusting the carb and get her out of the garage and back to doing some work.

 

[mbounds]

Why are K321's and a 149 being discussed in the Lawn Tractor page?? Neither are anywhere related to a tractor style lawnmower.

Both of these should properly be discussed on the IH Garden Tractor page....that's the first one at the top on the index page...

Geeesh...That a tractor has a belly mower doesn't make it a lawn mower even though you can mow your lawn with it...It's a tractor !! ...

Myron B

 

[jwjones]

Well....Sorry about the confusion, I was just continuing the thread...Didn't think that it would really bother anyone since the 9 other people didn't seem to mind....Geesh

 

[mbounds]

And 9 wrongs make a right???

Myron B