heymow.com - Lawn Mower Racing Forum
October 20, 2014, 06:20:44 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News:
Want to Join our site? CLICK HERE
 
   Home   Help Search Calendar Staff List Links Login Register  
Pages: [1] 2 3 ... 6   Go Down
  Print  
Author Topic: Re-use rods  (Read 5554 times)
0 Members and 1 Guest are viewing this topic.
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« on: November 28, 2012, 07:39:02 PM »

I have a 42 series 18 hp oppy that I'm rebuilding and it has some wear on the cylinders so I'm going to bore it .020 over. Now I mic'd the crank and its still at factory specs and so is the rods. What would the disadvantage of re using the old rods? I've seen people post don't reuse but don't give a good reason. I will be turning this engine about 4500K and may hit 5k from time to time and I will be running a billet flywheel. Also I'm trying to find Don's video for the oppy but can only find engines 101 or is that one for the oppy? It says for 8hp on up.
Logged

New Holland S8 Oppy powered ModX
carolinablue
Turf Warrior
**

Karma: 2
Offline Offline

Gender: Male
Posts: 353


View Profile
« Reply #1 on: November 28, 2012, 08:11:46 PM »

I dont know much about oppys but if your spending the money for boring and alum flywheel i would spend the extra for a good set of billet rods. Rooster the guy you need to talk too.
Logged

William Glass jr
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« Reply #2 on: November 28, 2012, 08:39:44 PM »

Yeah I know if I'm spending the money get them but if I don't have to spend $120 for new rods I would be a little more happier and so would the misses  rofl
The $350 flywheel and the $100 pistons already put a big dent in my wallet and I haven't got a rebuild kit yet or other parts. So if the rods will last me till next season that would help. The rods look in good shape. It was a grass cutter before I got it and the previous owner took good care of it and was spotless. I was really excited to get this motor
Logged

New Holland S8 Oppy powered ModX
heymow.com - Lawn Mower Racing Forum
« Reply #2 on: November 28, 2012, 08:39:44 PM »

 Logged
FlatheadPuller
Turf Warrior
**

Karma: 12
Offline Offline

Gender: Male
Posts: 940


View Profile
« Reply #3 on: November 28, 2012, 09:37:53 PM »

The stock rods are fine depending on wich ones you have. The dull colored 40 rods are the best. Put the 40 rods on the 42 crank and cut the top of piston off to get zero deck hieght. Lightens the rotating assembly. Just make  your oil clearance is correct and look thru heymow for rod mods to make them live.
Logged

Dennis Bazzett
Grandville Michigan
cycloneracer
Easy Parcheesy!!!!!!!
Global Moderator
Highly Mowtivated
*****

Karma: 36
Offline Offline

Gender: Male
Posts: 3675


Easy Parcheesy!!!!!!!


View Profile
« Reply #4 on: November 28, 2012, 11:38:35 PM »

If you have extra blocks and cams run the used rods.  That way when one blows you only have to buy pistons again.  


When a rod blows it tears up a bunch of stuff!  
Logged

Paul Krueger
#150 SP   (parked for 2013).  Status unknown...,
#150 Worlds First "sidewinder" FX (now dismantled)



#150 BP Sponsored by Zach Kerber Machine.
#150 FXT  Sponsored by Zach Kerber Machine. http://zkbrmachine.com/

Easy Parcheesy Racing
Rooster
Global Pot Stirrer
Highly Mowtivated
****

Karma: 72
Offline Offline

Gender: Male
Posts: 8405


Winning is always fair!!


View Profile WWW
« Reply #5 on: November 29, 2012, 12:45:14 AM »

Lots of oppy's out there running stock rods. keep an eye on them.
BTW…everyone will say "Ask Rooster"…
When Rooster learned, He asked Flathead Puller Wink
Logged

Bert stole my cookies!!
 I think he used them to bribe Ed into something naughty?

http://www.cutlooseracing.com
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« Reply #6 on: November 29, 2012, 05:57:53 AM »

It has 42 rods in it now but I do have a 40 engine that I ran last year so I can reuse those rods. How much of a pop up will that leave me that I have to cut off the new pistons? What's the best way to cut them down? I'm a machinist so I have an array of machines to choose from. Hey Rooster, everybody has to learn from somebody lol thanks for the advice guys
Logged

New Holland S8 Oppy powered ModX
garrywarber
Newbie
*

Karma: 0
Offline Offline

Gender: Male
Posts: 37

Just Garry


View Profile
« Reply #7 on: November 29, 2012, 06:53:52 AM »

Also I'm trying to find Don's video for the oppy but can only find engines 101 or is that one for the oppy? It says for 8hp on up.

Go to the G-Team site if it isn't there in the eBay G-team store.  Same price in the end.  Mine states "Motor 101 opposed" on the dvd case...
Garry
Logged

Garry Warber, Crazed Oppy Cool-Bore Fan
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« Reply #8 on: November 29, 2012, 07:26:31 AM »

OK thanks Gary. By the way if you use 40 rods and mill the piston would all that change the displacement of the engine? If so would it be after all that?
Logged

New Holland S8 Oppy powered ModX
Jeff McKelroy #55A
Turf Warrior
**

Karma: 7
Offline Offline

Gender: Male
Posts: 765


Two wrongs don't make a right, but four lefts...


jeffrey.mckelroy http://lnkd.in/sHn73U mechanicandlemaker
View Profile
« Reply #9 on: November 29, 2012, 10:01:48 AM »

Lots of oppy's out there running stock rods. keep an eye on them.

 Wink
Logged

Jeff McKelroy
Tulsa, OK 74128


Super Bee II - G/P   #55A
Black Hornet - FX/S  #55A
willenglish
Turf Warrior
**

Karma: 2
Offline Offline

Gender: Male
Posts: 196


View Profile
« Reply #10 on: November 29, 2012, 10:13:27 AM »

It would not change the displacement of the engine. Only bore or stroke changes would affect that. It could...and probably would change the compression ratio though.
Logged

William L. English, jr.
Rooster
Global Pot Stirrer
Highly Mowtivated
****

Karma: 72
Offline Offline

Gender: Male
Posts: 8405


Winning is always fair!!


View Profile WWW
« Reply #11 on: November 29, 2012, 10:18:09 AM »

It would not change the displacement of the engine. Only bore or stroke changes would affect that. It could...and probably would change the compression ratio though.
Not a noticeable change in Compression.
Logged

Bert stole my cookies!!
 I think he used them to bribe Ed into something naughty?

http://www.cutlooseracing.com
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« Reply #12 on: November 29, 2012, 11:18:58 AM »

 Oh OK. I didn't know if using .020 over pistons and a longer rod would change anything. I guess milling the piston would keep it close to stock stroke.  lol should I recon the 40 rod to make it fit the 42 crank with .004 clearance? I just plan in lightly sanding the crank journals to make sure they are smooth then polishing it. They want $80 to do that in town. I've got some plastigauge somewhere in the shop I will use before I do anything first to see where I'm at on clearance. Going to get a price today to see how it will cost to bore this thing in my dads friends engine machine shop. I would do it but my cutter only goes down to 3.500 and I think that will be a little too much
Logged

New Holland S8 Oppy powered ModX
Huffy044
Mow-Forum Junkie
***

Karma: 12
Offline Offline

Gender: Male
Posts: 1808



View Profile
« Reply #13 on: November 29, 2012, 11:26:31 AM »

 . I guess milling the piston would keep it close to stock stroke.   

Little clarification: Piston or rod has no bearing on the stroke, to change stroke you must change the location of the rod journal, bring it closer to the centerline ofthe crank and decrease the stroke or move it away from centerline and increase.

Also, longer rods GENERALY are better because, it raises the angle of the wrist pin in relation to the stock agle of the rod allowing less side load on the piston, also makes a longer lever to turn the crank.

Good luck!
Logged

VLMRA Singles Points Champion 2006
VLMRA Mini Champion 2007
VLMRA Sportsman Champion 2007
VLMRA Pro-X Champion 2008, 2009
ARMA Sportsman of the Year 2008
ARMA South East Region Mini 2009, 2010, 2011,2012
ARMA National Champion Mini 2009, 2010, 2011,2012, 2013
Maxton NC Model A Record Holder 118.54
NH Mowster
Turf Warrior
**

Karma: 0
Offline Offline

Gender: Male
Posts: 224


Wabash Valley Mower Racers


View Profile WWW
« Reply #14 on: November 29, 2012, 11:28:48 AM »

Thanks for the info. Learn something new everyday.
Logged

New Holland S8 Oppy powered ModX
Pages: [1] 2 3 ... 6   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!


Google visited last this page October 10, 2014, 04:30:28 PM