K 301 first engine rebuild ever HELP!!!

[LFR]

I have a k301a motor that is out of the cub. It is well worn out! It sounds like the crankshaft is done and it also seems like the thing needs push rods( it knocks SO BAD that I why I only ran it at idle to keep batt charged). Now I am 14 and have never rebuilt an engine but know a lot about them it never burned oil and was pretty solid, piston to the top of motor but I need any info on rebuilding this motor FAST I AM REBUILDING IT THIS WEEKEND. ANY INFO IS HELPFUL a few questions I have are: I want to bore the block .010 over if I can is it easy? How hard is it to get this kohler k301 apart? Are push rods pretty easy to find? Is there any other parts that hold the rods together? I need answers so anyone that comes on say anything helpful! Thanks,LFR

[Dave C]

Well more than likely your knocking is from the rod to the crank... and if this is the case your gonna need to get the crank turned down 010 under. Not something that can be done even in a well outfitted shop. As far as your pushrods these engines dont have pushrods, pushrods exist in overhead valve engines. These kohlers have tappits, alot of times the top of these get dished from pounding on the valves..... so they can usually be touched gently in a lathe and then its just a matter of adjustment. Boring the engine can be done at home with a drill and a bore hone and a good bore gauge... but it takes alot of practice to get good at that. A job better done at a machine shop. Certainly not really a job that can be done in a weekend. hardest part about getting these engines apart is usually getting the genertor pulley off and getting the flywheen off. You will also need a valve spring compressor to get the valves out. i think harbor freight has cheep ones that work ok.

[LFR]

Ok that is really helpful Dave is the tappets easy to remove and is the motor itself easy to work on and should I just get new valve tappets and crankshaft, it would probably be easier but I want his done right so I am going not go cheapo anything that I may need I will get. My cub cadet and kohler dealer are about 2 miles down the road so it is helpful any other info bombard me with anything PLEASE anyone can respond!!!!!!!!

[chearn]

As expensive and for as long as they have been out of production by Kohler I think you should do the job once and do it right. If you do it right it should last another 30 to 50 years.

These engines are pretty easy to work on. The only problem I have is everything is small and sometimes you don't have a lot of room to work in.

The first thing to do is go to kohler's website and download their service manual. It will have all the spec's and required tools that you will need. Study this manual, then tear it down and inspect it. If you don't have access to micrometers and snap gauges or don't feel confident using them, take the block and crank to a machine shop, or have a machinist buddy measure it. Once you know the condition of the parts you will know what you have to buy.

The block may clean up with a hone job, might need to be bored. If it was knocking the rod needs to be replaced, and the crankshaft may have to be turned .010 under.

You can leave the block and crank at the machine shop and buy parts (piston if needed, connecting rod.....)

One area to keep in mind is the valves and the seats, they require special equipment. You have to have a valve grinder to grind the valves or most people this day just buy new valves. The valve seats also require a special machine, and the machine shop can do this for you. As for lapping the valves you can do that yourself. I like to do it before i wash the block.

Once you have the machine work done and the parts in hand, wash the block in HOT soapy water, and get it dry immediately after you are done washing it and lube any machined surface with oil to prevent surface rust. My machinist told me WD40 was fine.

Now is the time for the fun part, assembly. Follow the previously described service manual and you shouldn't have any problems.

I've been known to run a lathe and a mill from time to time I am comfortable with micrometers and calipers, but I have not mastered snap gauges yet, guess I need to practice with them. With my limited machining skill I wouldn't want to tackle a bore job with the equipment that I have. You want someone to do this that has some experience. That reminds me, I have a junk block I may bolt to the mill and see if I can do it.

[LFR]

I will not bore a engine that's where napas handy I need to get a new crank, piston and internals I will work on these I haven't mastered micro meters or gauges or anything like that but I will work on it

[BigMike]

I don't mean to sound contrary but I would never use any machine shop that made a cylinder bigger with a hone.....hones are for finishing. Bores are made larger with a cutter. The point of boring is to make the bore round and 90 degrees to the crank journal.
Valve faces and seats need ground......even new valves. I have never seen guides in a K series that needed attention.
With all that said Lorin find a machine shop you want to work with and go over what you want. You may find they can supply your parts at a good price and if they cannot will they use parts you sourced somewhere else. I would never have machine work done without the shop having my parts as I would expect them to check the piston before they size the bore and check the rod before grinding the crank,some shops don't do that but good ones do. I am VERY fortunate to have a guy near me that is the bees knees, he is easy to talk to,can do almost any shop funtion needed and is priced fair.
The big thing is don't get in a big hurry,do it right and do it once.

[LFR]

Ok thanks big mike anything other helpful would be nice

[cheifsix]

I don't think it can be stressed enough to take your time and do this right the first time. Follow the manuals and talk to a machinist near you. At the least they can give you some pointers to lead you in the right direction.

It is good to see someone so young taking an interest in Cubs and good hard honest work. That being said none of us would want to see you get discouraged by taking on too much in a rush or making an expensive mistake.

Just take your time, take photos along the way, keep asking questions, and have fun.

[LFR]

I want to do this right and will post on YouTube how I did it and you guys can watch what I do and THANKS SO MUCH Matt I WANT TO ACHIEVE ALOT SO I WILL TAKE MY TIME AND REALLY DO IT LFR WAY I will take pics and do as much as I can any more info is well wanted

[tbdavis123]

Just a couple thoughts. As mentioned earlier it's best to have your new piston, etc. before any machining is done. This ensures everything fits properly. And, before you purchase anything you need to have the bore, crank, etc. measured so you know what needs replaced. For example, if the motor is already bored 30 over you may have to sleeve it which adds to the expense. Second, once it's assembled you need additional measurements, namely cam and crank end play. So, my advice is take it to whoever will be doing the machining, have them measure and determine what needs repaired/replaced, gather your parts, put it back together per the Kohler manual, then run it by the shop again to check end play, etc. hopefully it's just a straightforward rebuild but you won't know till everything has been sized up. Oh, and as mentioned before, get your hands on the service manual. It'll walk you through each and every step. With a little patience and luck you'll have that puppy purring again in no time.

[Dave C]

Lorin,

Well a quick step by step process.

First remove the engine from the tractor and remove carb and coil... stuff a rag in the intake and then powerwash the crap out of it... the cleaner you get it now the easier to work on later.... drain the oil and start removing parts... small tinwork, head,muffler, pto, sunflower pulley, front engine coupler and screen, valves and springs... now the big sheetmetal will come off. pull the flywheel.. a $20 steering wheel puller from harbor frieght works good for this. Now you can pull the bearing plate and unbolt the rod from the crank tap the rod and piston out the top with a chunk of wood and a hammer... pull the crank out. Then drive the pin for the cam out the bearing plate end and remove the cam.. and tappets.. then remove the governor... you should now have a stripped block. bring it and the crank with a new 010 rod and 010 piston... so long nothing has already been done to this engine... this is where some measureing tools will come in handy. to the machine shop.... should cost around 200 bucks for the work... then the reassembly... which takes alot longer!

[Dave C]

oh forgot to add... on the reassembly....which is a while down the road, the gasket kit comes with like 5 gaskets for the bearing plate to adjust endplay of the crank... measure these and note down the measurements then install ALL of them tighten down the bolts and measure the end play... then figure out where u are and where u need to be... i shoot for the middle. lossen up the bolts and tear out the ones you dont need! then sock it down and double check.
It sure beats installing one checking it... taking it apart... adding another etc much less time consuming

[LFR]

That is what I was lookin for. Instructions! I am now in a pinch, either buy my sandblasted unit or rebuild motor. I want the blaster for the engine so I will probably get that then when I get paid I will redo the motor. It costs a ton for getting a 40x80 pole barn built its expensive. Thanks Dave regards,LFR

[Dave C]

If you blast then engine.. be sure to block off all the holes in the block... oil pan etc etc.... you dont wanna mess with the inside of the block. then after you blast it...remove all the blockouts and powerwash it... clean it.. powerwash it, clean it... powerwash it...clean it.. get the idea?

[Dave C]

oh then while painting... be sure not to paint the cooling fins of the block or the head... a light coat of primer is ok.. but you dont wanna prevent the fins from doing what they are saposse to do... cool the engine!

[LFR]

I know that and I also know that on a hot day you must rev the Koehler up a little bit to keep the fan moving

[tbdavis123]

Curious about that fan?

[LFR]

What the cooling fan

[tbdavis123]

Are you referring to the hydro fan?

[LFR]

Nope the engine cooling fin fan

[Dave C]

Let me clear things up... everyone is talking about the Flywheel fins that cool the motor.

[LFR]

Yep exactly