Author Topic: Moving the wirst pin  (Read 3572 times)

0 Members and 1 Guest are viewing this topic.

Offline outlawmower

  • Turf Warrior
  • **
  • Posts: 538
  • Karma: 3
  • Gender: Male
    • View Profile
Moving the wirst pin
« on: March 02, 2008, 01:53:49 PM »
SO I have been taking CNC classes over a CPCC Community College here in Charlotte, and I have access to the CNC for my own projects at nights when I don’t have classes. I have made a couple billet rods for my 10HP Kohler and so far they have held up. But I want a little more power so here’s my question,

How much pop up would be good? .050? I can move the wrist pin up .090 and would like to know what would give me all the power I can get.... Any suggestions?

Thanks,
Outlaw


PUT YOUR GAME FACE ON!!!

Offline mightymowe

  • Turf Warrior
  • **
  • Posts: 752
  • Karma: 0
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #1 on: March 02, 2008, 09:49:33 PM »
Find a piston with a higher pin that fits your bore and then make a longer rod to fit it,and give you a zero deck height.Remember to give yourself about .030 clearance from the piston and head.A longer rod will get you some more power and possibly a lighter piston.
David Peters

Wheelhorseracer

  • Guest
Re: Moving the wirst pin
« Reply #2 on: March 06, 2008, 08:32:13 PM »
Your very lucky to have access to that type of equipment.. you should make everything you can..

Have you ever thought to make a billet flywheel with fins for the K-Series engines?


Offline outlawmower

  • Turf Warrior
  • **
  • Posts: 538
  • Karma: 3
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #3 on: March 07, 2008, 05:49:42 PM »
Making a billet flywheel with fins is out of the question for me... The billet to such is a little pricey right now... Steel on the other hand I get a discount on because my uncle works at Jorgenson steel company.... So I will be making flywheels, rods, cranks, and cam blanks
PUT YOUR GAME FACE ON!!!

Wheelhorseracer

  • Guest
Re: Moving the wirst pin
« Reply #4 on: March 07, 2008, 05:59:45 PM »
What engines are you gonna make most of your parts for?

Offline outlawmower

  • Turf Warrior
  • **
  • Posts: 538
  • Karma: 3
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #5 on: March 07, 2008, 06:40:42 PM »
Im looking at making parts for 10-12 hp Kohler K-SERIES only... Rods I know will be for 10's and Im not sure for rods on the 12's YET! Cam blanks fit 10's through 16's Crank is a one off only part! Same with the flywheels for now. I may sell some parts later but for now just one off parts....
PUT YOUR GAME FACE ON!!!

Wheelhorseracer

  • Guest
Re: Moving the wirst pin
« Reply #6 on: March 08, 2008, 12:31:03 PM »
The nice thing about the K-Series is that the 10 hp can fit the 18 hp crank, and you can swap pistons and rods among the series..

If you can make a nice 18 hp camshaft blank..that would make a great power cam for the 10 hp..

If you can mill heads that would be a great selling point...





Offline Big daddy

  • Turf Warrior
  • **
  • Posts: 302
  • Karma: 0
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #7 on: March 17, 2008, 02:35:24 PM »
You can pop the piston up until you get 0.030-0.040" from the top ring, then you will start burning the rings. Remember this-the 10 hp. uses a 2.75" stroke and a different pin diameter than the 12-18 hp, which uses a 3.25" stroke. The longer the rod you can use the better, (but you will have to get a different piston-Chuck Vogel sells all the stuff you would need if you don't want to make it yourself.) I think the 12-18 hp. with a stock stroke falls off on performance when you get past 6.00" in rod length. But the longer rod will actually slow down the piston slightly at TDC and BDC giving the air column more time to get in to the cylinder once it is moving. As far as fins on the flywheels, they really aren't necessary unless you plan on driving them around the pits alot, when going down the track the engine will build more heat than what the fins can dissipate, plus you may run the risk of spinning one off. Some associations have actually banned fins on the steel flywheels. Sounds like you are on the right track though, just test your parts exhaustively on the track before you sell them. One bad part or someone getting hurt can really sour your business plans.
 Good luck!
Bruce Litton

Offline outlawmower

  • Turf Warrior
  • **
  • Posts: 538
  • Karma: 3
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #8 on: March 17, 2008, 03:22:38 PM »
You can pop the piston up until you get 0.030-0.040" from the top ring, then you will start burning the rings. Remember this-the 10 hp. uses a 2.75" stroke and a different pin diameter than the 12-18 hp, which uses a 3.25" stroke. The longer the rod you can use the better, (but you will have to get a different piston-Chuck Vogel sells all the stuff you would need if you don't want to make it yourself.) I think the 12-18 hp. with a stock stroke falls off on performance when you get past 6.00" in rod length. But the longer rod will actually slow down the piston slightly at TDC and BDC giving the air column more time to get in to the cylinder once it is moving. As far as fins on the flywheels, they really aren't necessary unless you plan on driving them around the pits alot, when going down the track the engine will build more heat than what the fins can dissipate, plus you may run the risk of spinning one off. Some associations have actually banned fins on the steel flywheels. Sounds like you are on the right track though, just test your parts exhaustively on the track before you sell them. One bad part or someone getting hurt can really sour your business plans.
 Good luck!

The reason he asked about fins where hes a roundy round guy. I am having 4 rods made
1 STD Length
1 .020 pop-up
1 0.030 pop-up
1 .040 pop-up
PUT YOUR GAME FACE ON!!!

Offline Big daddy

  • Turf Warrior
  • **
  • Posts: 302
  • Karma: 0
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #9 on: March 18, 2008, 05:23:55 AM »
I see what you mean about the fins now, sorry. Midwest super cub sells a nice little fan motor that does no pull too many amps that can be used to cool the motor down if you still have problems with cooling. As far as the piston pop up, we generally pop the piston up 0.125" for about all classes from stock stroke to the 50 in" singles. The rod length (to a certain point) helps the engine run harder and the pop up with the piston helps bring cylinder pressure up. You just have to maintain around 0.045-0.060" head clearance when doing so. If you pop up more than that you will have to remove the top ring. Remember when making the rods to not make a really long dipper, about 1 1/2" is all you need. Good luck.
Bruce Litton

Offline outlawmower

  • Turf Warrior
  • **
  • Posts: 538
  • Karma: 3
  • Gender: Male
    • View Profile
Re: Moving the wirst pin
« Reply #10 on: March 18, 2008, 06:31:01 AM »
Yup! I talked to some other guys who have machined some of these rods and they helped me on getting that programmed.
Thanks for all the help!

Outlaw
PUT YOUR GAME FACE ON!!!