steve-ooo 0 #1 Posted January 31, 2014 Hi, i have a 1974 kohler k181 on my trail horse b80 and i sometimes run at verry high rpms, is thhere any kind of conecting rod out here thayt will hold up better than my stock one or will it hold up consittering i change oil often? Any tips to strengthen My 8 horse for high rpms? thanks, Steve Share this post Link to post Share on other sites
rmaynard 14,907 #2 Posted January 31, 2014 As it comes from the factory, the K181 was not designed to run at RPM's higher than what is recommended in the book. It's not only the connecting rod that could fail. 1 Share this post Link to post Share on other sites
steve-ooo 0 #3 Posted February 1, 2014 So what can or Shuld I do to beef it up? Share this post Link to post Share on other sites
rmaynard 14,907 #4 Posted February 1, 2014 My opinion is, nothing. Run it at 3600 RPM as designed. This is not a big block like the K241, 301, 321, and 341 that can be run at higher RPMs with proper modification. 1 Share this post Link to post Share on other sites
steve-ooo 0 #5 Posted February 1, 2014 (edited) You wouldent hapin to have any big blocks for sale would you? Orknow of somone with one?:-) Edited February 1, 2014 by steve-ooo Share this post Link to post Share on other sites
MalMac 1,328 #6 Posted February 1, 2014 Not sure what you need all the RPM's for, but as most of the applications go for the use of these tractors the factory set RPM is plenty. Now if your using the tractor for something other than what it was design for like pulling or qualifying for Indy then you are going to have to do some big changes to the motor. Maybe you should look for something other than a old cast Kohler. With that said I know the old Kohler's are used a lot in pulling but there modified. Even then sustained high RPM takes some engineering. Kinda like NHRA drag racing. Those engine turn some RPM and go like a bat of hell, Then they need to be tore down and inspected and parts replaced to run that short !/4 mile. A engine in a Indy car turns some high RPM but they are designed to last 500 miles doing it. So whatever your application is for a tractor you got to design that engine for it. Remember the higher the RPM the $$$$ it takes.The old racers saying " How fast you wanna go? How much you wanna spend." Share this post Link to post Share on other sites
rmaynard 14,907 #7 Posted February 1, 2014 You wouldent hapin to have any big blocks for sale would you? Orknow of somone with one? I have a 10 hp and two 12 hp's, but due to your location, the cost for the engine and the shipping would probably be prohibitive. However, there is quite a bit of modifications necessary to create an engine capable of running at higher RPM's. For more info, you might want to go to: http://gardentractorpullingtips.com/engine.htm and read about engine modification. Share this post Link to post Share on other sites
steve-ooo 0 #8 Posted February 2, 2014 Are there any stinger connecting rods out there that would hold up better than the stock one in my k181? Share this post Link to post Share on other sites
Agage1 83 #9 Posted February 3, 2014 Like Bob said you would be better off with swapping motors and it would be cheaper too. The parts you would need to support higher RpMs in a k181 would be far more expensive than a used big block. A billet flywheel for example can be costly Share this post Link to post Share on other sites
steve-ooo 0 #10 Posted February 3, 2014 Alrighty, thanks guys Share this post Link to post Share on other sites
squonk 38,947 #11 Posted February 3, 2014 Put a HF clone in it and when you blow it up, get another Share this post Link to post Share on other sites
steve-ooo 0 #12 Posted February 3, 2014 I want an engine that I can run pritty hard, but yet hold up Share this post Link to post Share on other sites