Author Topic: has any one built a kohler k181  (Read 4980 times)

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Offline mr.smitty_78

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has any one built a kohler k181
« on: March 08, 2010, 08:34:38 PM »
hey im a new member and ive looked all over and really cant find much on it so im gonna ask you all has any one built a k181 cast  kohler i am building one and i was woundering what anyone who has built one has done thanks


Josh Smith

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Re: has any one built a kohler k181
« Reply #1 on: March 09, 2010, 09:46:35 AM »
I have built one..

I zero decked the block, took .006 off the head since there isn't any meat on it so we just trued it up. New .020 pistons and undersized rod ( there is no bearing so you need an undersized rod). 

I only cleaned up around the valves in the head. I didn't unshroud the valves too much as I want the charge to move up the ramp and not pool around the valves. I polished the chamber and smooth the lip at the top of the ramp. I did not cut a fire slot ( mostly because at that time I didn't know about it) I left the spark plug in the stock location.

As far as i know they do not make copper head gaskets for these.

Had the crank turned. Ported and good 3 angle valve job. I left the threads in the exhaust port only because I wanted the ability to adapt different exhausts.

You can not regrind these cams do to the location of the compression release.

There are no billet flywheels available. They like a hot spark so I used a Crane external coil with a 1.5 ohm ballast resistor to bring it down to 9 volts. That is the nice thing about running the points as you can adapt and external coil to it easily.

You can run the #26 carb if you make an adapter and the bolt holes do not line up with the stock carb. You can make the stock carb work and you need to clean up the casting as it comes up to the venturi.




Offline mr.smitty_78

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Re: has any one built a kohler k181
« Reply #2 on: March 11, 2010, 04:42:15 PM »
thanks that some very good info how did it run and what did you use it for
Josh Smith


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Re: has any one built a kohler k181
« Reply #3 on: March 11, 2010, 08:02:46 PM »
Just used it around the yard for pulling a trailer and the lawn sweeper and in parades. But when my Cummins pickup truck need a tow across the yard so I could fix it it had no problem and the truck weighs 6500 lbs.

I love this old tractor. I only run this engine governed once I learned about how these flywheels can come apart and I would like to keep my leg

I used to pull with it.












Offline mr.smitty_78

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Re: has any one built a kohler k181
« Reply #4 on: March 12, 2010, 09:24:04 AM »
that sounds cool iv heard from a few guys that some one might build me a billet fly wheel like vogel what would it hurt to have the cam ground i know earlier in the topic you said you couldnt but what would it hurt or has anyone tried it
Josh Smith

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Re: has any one built a kohler k181
« Reply #5 on: March 12, 2010, 10:16:29 AM »
I sent my to a cam company that regrinds cams and they said they couldn't. You would have to make one from a blank and then figure out how to make a compression release to get it to start.

If you do get a billet, you want one with cooling fins, most by Vogel and others for puller engines don't have any. You might want to call midwest cub and see if they can help you.

Offline mr.smitty_78

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Re: has any one built a kohler k181
« Reply #6 on: March 14, 2010, 08:39:18 AM »
is there any other way you could get the valves to open up more besides the cam i know that an engine is like an air pump the better and more smoothly it moves air along with fuel in and out the more power you can make out of it thanks
Josh Smith


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Re: has any one built a kohler k181
« Reply #7 on: March 14, 2010, 08:50:11 AM »
This engine is very small. I even looked in putting in the larger valves.. but you would have to offset the guides and still the ports won't flow much more without really opening them up.

The cam is very limited. With the larger K-series engines (10-18) you can swap in the 18 hp engine cam which doesn't have more lift, but a longer duration.

Even with all the work don't to mine. I might have only picked up 4 or 5 hp at governed RPM. The cam is a major hold back on the little engine.

You could mill the head a bit but since there isn't much meat on them you can only take under 0.010 off and you won't find much of a difference in power.

Make sure the gap is correct on the points and that they are clean.

Offline mr.smitty_78

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Re: has any one built a kohler k181
« Reply #8 on: March 15, 2010, 08:46:12 PM »
what do you mean a fire slot  and how would you go about cutting one and where. what is its pourpose thanks
Josh Smith

Offline cubcadet70

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Re: has any one built a kohler k181
« Reply #9 on: October 30, 2010, 02:51:55 PM »
the cam can be re ground! the guys are just too lazy to weld around the compression realse! a machine shop localy does them for 60 bucks! forgot who and name! but i got a cam getting made right now from tim isky! 2 peice and billet and adjustable design!