Notices

Rods

Old 12-16-2015 | 07:09 AM
  #131  
Banned
 
Joined: Oct 2015
Posts: 277
Likes: 1
Default

Originally Posted by MILD THUNDER
The molnar rod's recommended stretch value for a ARP 7/16 1.800 long bolt, is .007-.0075. Eagles stretch value for that same ARP2000, 7/16 1.800 long bolt, is .064-.068. K1 Technologies spec for same setup, is .068-.072. Scat, doesnt provide a stretch value, just a torque spec.

Why is that? I really don't know, just trying to learn about this topic.


Molnar's bolts are not the same as the "shelf" ARP bolts like Eagle uses, and probably K1. His bolts are made to his specs by ARP, even thought he calls them a "2000".
Scat torques their bolts to their spec before honing them. They do have a "not to exceed" stretch limit.
Always remember that if you're torquing your bolts and not stretching, you need to cycle the bolts through at least 5 torque cycles. This "mates" the threads and the surface between the under-side of the head of the bolt and the flat part of the rod cap.

Last edited by horsepower1; 12-16-2015 at 07:27 AM.
horsepower1 is offline  
Reply
Old 12-16-2015 | 07:26 AM
  #132  
Registered
20 Year Member
 
Joined: Aug 2003
Posts: 1,129
Likes: 32
From: Racine, Wisconsin
Default

Originally Posted by MILD THUNDER
The molnar rod's recommended stretch value for a ARP 7/16 1.800 long bolt, is .007-.0075. Eagles stretch value for that same ARP2000, 7/16 1.800 long bolt, is .064-.068. K1 Technologies spec for same setup, is .068-.072. Scat, doesnt provide a stretch value, just a torque spec.

Why is that? I really don't know, just trying to learn about this topic.

The bolts are all ARP2000 but different designs unique to the rod.
kvogt is offline  
Reply
Old 12-16-2015 | 08:53 AM
  #133  
14 apache's Avatar
Platinum Member
20 Year Member
Platinum Member
 
Joined: Apr 2005
Posts: 2,150
Likes: 15
From: Northport N.Y.
Default

Originally Posted by MILD THUNDER
Technologies spec for same setup, is .068-.072. Scat, doesnt provide a stretch value, just a torque spec.

Why is that? I really don't know, just trying to learn about this topic.
Think that has to be a typing error.
14 apache is offline  
Reply
Old 12-16-2015 | 09:03 AM
  #134  
Registered
20 Year Member
 
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
Default

Originally Posted by 14 apache
Think that has to be a typing error.
Just going off their literature. Eagle, k1, and molnar
Attached Thumbnails Rods-screenshot_2015-12-15-22-15-45.jpg   Rods-screenshot_2015-12-15-22-30-20.jpg   Rods-p1768661223-4.jpg  

MILD THUNDER is offline  
Reply
Old 12-16-2015 | 09:52 AM
  #135  
Banned
 
Joined: Oct 2015
Posts: 277
Likes: 1
Default

Originally Posted by MILD THUNDER
Just going off their literature. Eagle, k1, and molnar
I think he's talking about the fact you're missing a zero on a few of those numbers...I wouldn't want to try and stretch a bolt .068".
horsepower1 is offline  
Reply
Old 12-16-2015 | 10:03 AM
  #136  
Registered
20 Year Member
 
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
Default

Originally Posted by horsepower1
I think he's talking about the fact you're missing a zero on a few of those numbers...I wouldn't want to try and stretch a bolt .068".
Duh, yea, that would be bad ! Yes typo on my part lol
MILD THUNDER is offline  
Reply
Old 12-16-2015 | 10:24 AM
  #137  
Registered
15 Year Member
 
Joined: Oct 2007
Posts: 8,439
Likes: 93
From: yorkville,il
Default

when you buy a bolt from arp that sais ARP2000,this is the material the bolt is made from.just like a L19 bolt is made from L19 material.a lot of rods made by a lot of company,s have arp put their name or something on the bolt but at the end of the day if it sais ARP2000,that is the material the bolt is made from.scott ,you are correct,i always torque,loosen,and re torque new rods 4 times in the rod vise before installing it in the engine and i never go by a torque spec but always by bolt stretch.also,all rods are torqued before they get final hone when they are made.on a side note,oliver doe,s not list a torque value with their rods,just a stretch amount.i have used scat rods and they did list a stretch value but i have not used any scat rods in over a year so that may have changed.EDIT IN,i just finished a 565 that got new callies ultra rods,callies already torques&retorques the rods before shipping so the end user does not need to.this is stated in the directions they come with.ps,they come with arp2000 and it also sais callies on the bolt.

Last edited by mike tkach; 12-16-2015 at 10:29 AM.
mike tkach is offline  
Reply
Old 12-16-2015 | 10:36 AM
  #138  
Registered
20 Year Member
 
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
Default

I guess my question was , lets say one was to torque an eagle rod, for .0075 stretch, like the molnar spec, although eagle says max is .0068. Both being arp 2000 bolts of the same length. Would the extra clamping force required to get that stretch, change the shape of the big end ?

Kind of like if you took an 8740 bolt out, and installed an arp2000 in its place, and never recheck the roundness of the big end ?

Not sure if im making any sense with that question

Last edited by MILD THUNDER; 12-16-2015 at 10:38 AM.
MILD THUNDER is offline  
Reply
Old 12-16-2015 | 10:39 AM
  #139  
Registered
15 Year Member
 
Joined: Oct 2007
Posts: 8,439
Likes: 93
From: yorkville,il
Default

i will also say,we all have a favorite brand that we like the best and for me it is hands down,OLIVER.some think because it is an i beam and not a H beam it is inferior.some of the best engine builders choose oliver for a reason and at 1400,bucks retail per set it is not because they save money using them,it is because they can take the abuse drag racers throw at them.i have seen nitrous engines melt pistons from detonation but the oliver rod survived.
mike tkach is offline  
Reply
Old 12-16-2015 | 10:59 AM
  #140  
Registered
15 Year Member
 
Joined: Oct 2007
Posts: 8,439
Likes: 93
From: yorkville,il
Default

Originally Posted by MILD THUNDER
I guess my question was , lets say one was to torque an eagle rod, for .0075 stretch, like the molnar spec, although eagle says max is .0068. Both being arp 2000 bolts of the same length. Would the extra clamping force required to get that stretch, change the shape of the big end ?

Kind of like if you took an 8740 bolt out, and installed an arp2000 in its place, and never recheck the roundness of the big end ?

Not sure if im making any sense with that question
joe,good question.if you removed the 8740 bolts from dan,s rods and installed arp2000 and torqued to spec the housing bore would no longer be round and would need to be shaved&re honed.i also forgot to mention earlier that arp,s recomended stretch is 75% of total yield,they do this because if you over stretch a rod bolt it is rendered useless.this is why some rod makers show different stretch value,but it is still in arp,s spec if that makes ant sence.guess i should mention,total yield is the point that a rod bolt will brake when over stretched.also,the tighter a bolt is torqued the more clamping load it exerts.
mike tkach is offline  
Reply

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.