Author Topic: Kohler Magnum Build  (Read 7490 times)

0 Members and 1 Guest are viewing this topic.

Wheelhorseracer

  • Guest
Kohler Magnum Build
« on: October 13, 2008, 07:47:10 AM »
Now that we are in the off season.. I'm going to try to make a few more ponies out of the magnum..

This engine pushed my to a 3rd place in points in my rookie year..

This is the rules allowed for flatheads in our club.

Anything can be done to this engine as long as I use OEM parts.. I can cross brand as long as it was available in a lawn tractor engine. Dual carbs are allowed as long as they were available in a lawn tractor.

You can not regrind the cam, and billet flywheels are allowed as a safety feature.

This is what I have done so far:

Custom intake with a #26 Kohler carb with high end adjustment, 3 angle valve job, lightly ported only because I only had a short amount of time to work on them, shimmed springs, and cold lash tightened up.
Stepped headers from 1 inch to 1 1/4, to 3 inch tail pipe...

Everything else is still stock.

The engine works well out of the corners, but almost always loses the drag race against the vanny, even with a 7.90 gear on a 140ft straight...

Since I have time to work on it... give me your suggestions..

Lets get creative  :woo:





Offline Big daddy

  • Turf Warrior
  • **
  • Posts: 302
  • Karma: 0
  • Gender: Male
    • View Profile
Re: Kohler Magnum Build
« Reply #1 on: October 13, 2008, 10:31:08 AM »
Is this a single or a twin?
Check part numbers to the casting number on the flange of your carb. Check to see if it is the same one used on the 18hp. single, there are 3 different carbs. made for this engine. The 18 hp. single cylinder has a bigger carb, than the others on the the Kohler "K" series singles.
Bruce Litton

Offline George Herrin

  • aka SUPERMAN
  • Superman
  • Highly Mowtivated
  • *
  • Posts: 17732
  • Karma: 102
  • Gender: Male
  • I am going to Race Every Race like its my last one
    • View Profile
    • BTMRA Home/Forum An Independant Club.
Re: Kohler Magnum Build
« Reply #2 on: October 13, 2008, 11:46:35 AM »
its a twin
George Herrin #6
Indian Power.. You gotta Go big to beat em or Go HOME
8 time ARMA National Champion
4 time USLMRA National Champion
Retired from BP
www.herrinmowersports.yolasite.com
www.allamericanmowerchampionships.yolasite.com
My other racer is a 1/5th scale Dirt Late Model!!!!


Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #3 on: October 13, 2008, 12:47:50 PM »
I have the 16 HP carb.. it's a #26 the #30 would be the one that would be on the 18.... but they are hard to find as the K-series pullers grab them up..

I might go twin #26's next year.

Thanks George... it is an opposed twin..

Offline CaseRacer969

  • Turf Warrior
  • **
  • Posts: 243
  • Karma: 1
  • Gender: Male
    • View Profile
Re: Kohler Magnum Build
« Reply #4 on: October 13, 2008, 02:09:47 PM »
You can get a M-20 crankshaft, rods and pistons.  The bore is the same but this will increase the stroke from 2.75 to 3.06.  That will bring you up from 42 inches to about 47.  That block has removable cast iron jugs.  From my research it can be bored a bunch.  I haven't done it yet but 50 some inches would be no problem.  It also has a pretty good full pressure oil system.

Jack Jones
Hard Case Racing
USLMRA IMOW & B/P #969    ARMA SS AND Super Sportsman #969

Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #5 on: October 13, 2008, 03:25:11 PM »
I thought about using the 20 guts... The only thing I'm thinking though is that the piston would pop up too much above the deck... unless the 20 uses a different compression height on the piston...


Offline CaseRacer969

  • Turf Warrior
  • **
  • Posts: 243
  • Karma: 1
  • Gender: Male
    • View Profile
Re: Kohler Magnum Build
« Reply #6 on: October 13, 2008, 04:37:50 PM »
I don't remember the specifics but the crank. rods and pistons will work.  I bought the complete set-up all on ebay for about 75.00 including shipping.  I bought the parts to see what could be built from it.  If I were to build it to race I would look to find pistions with alot shorter compression height than the stock ones and longer rods.


Jack Jones
Hard Case Racing
USLMRA IMOW & B/P #969    ARMA SS AND Super Sportsman #969


Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #7 on: October 13, 2008, 04:38:50 PM »
I wondering what could be used for a billet flywheel?

Offline kohler guy

  • Turf Warrior
  • **
  • Posts: 306
  • Karma: 2
  • Old Skool Racing
    • View Profile
Re: Kohler Magnum Build
« Reply #8 on: October 13, 2008, 07:27:05 PM »
7075 T-5 Billet I beileve... Might want to check on that... OR have a lightened steel flywheel made such as Midwest Super Cub sells...
Craftsmen
Old Skool Racing #45
http://www.alleghanymowerracingassociation.com/

Stock Flathead Class

Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #9 on: October 13, 2008, 07:31:53 PM »
I wonder if a Command Flywheel could be made to fit.. Midwest makes finned ones now..

Offline kohler guy

  • Turf Warrior
  • **
  • Posts: 306
  • Karma: 2
  • Old Skool Racing
    • View Profile
Re: Kohler Magnum Build
« Reply #10 on: October 13, 2008, 07:34:52 PM »
I would first try to find a flywheel off a command and try and see if it fits first and then go from there that would be your best bet.
Craftsmen
Old Skool Racing #45
http://www.alleghanymowerracingassociation.com/

Stock Flathead Class

Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #11 on: October 13, 2008, 07:37:10 PM »
We have a guy with a command engine... he runs a billet now.. so I will see if I can borrow his stock flywheel to see if it fits...

Offline Slick Rick

  • Turf Warrior
  • **
  • Posts: 362
  • Karma: 0
  • Gender: Male
  • Rick Capuano
    • View Profile
Re: Kohler Magnum Build
« Reply #12 on: October 13, 2008, 09:48:01 PM »
It wouldn't fire the same as an opposed, because an opposed fires 180* of each other, while a v-twin fires at 90*.
Here is what i mean http://www.heymow.com/index.php?topic=4706.0 :)
Rick Capuano

"Racing is a matter of spirit not strength."
- Janet Guthrie

Offline George Herrin

  • aka SUPERMAN
  • Superman
  • Highly Mowtivated
  • *
  • Posts: 17732
  • Karma: 102
  • Gender: Male
  • I am going to Race Every Race like its my last one
    • View Profile
    • BTMRA Home/Forum An Independant Club.
Re: Kohler Magnum Build
« Reply #13 on: October 14, 2008, 05:07:19 AM »
It is possible to work Gienger used a V-twin billet wheel on an apposed engine. ALL Briggs of course.
George Herrin #6
Indian Power.. You gotta Go big to beat em or Go HOME
8 time ARMA National Champion
4 time USLMRA National Champion
Retired from BP
www.herrinmowersports.yolasite.com
www.allamericanmowerchampionships.yolasite.com
My other racer is a 1/5th scale Dirt Late Model!!!!

Wheelhorseracer

  • Guest
Re: Kohler Magnum Build
« Reply #14 on: October 14, 2008, 05:51:48 AM »
Ya.. I guess using the Kohler stuff is uncharted territory...