# VR6 arp rod bolt Question???



## dubdriver808 (Sep 22, 2006)

Is it a simple unscrew and screw or do i need to work my rods to fit the bolts in?? I hear got to recondition my rods, then some say you could jus chage it out without work??? Which is it? My block has a lil over 60,xxx miles. just turboed it still finishing up some loose ends...


----------



## dasbeast3.0 (Aug 15, 2007)

You should really pull the rods and have them line bored w/ the ARP's if you are concerned about longevity. I simply swapped them out in my 80k block 3 weeks ago and have been driving around at 500+ whp no prob. I don't care about this motor so its more of a "see how long it lasts" type thing. Do a quick search here, you'll find a bunch of info.


----------



## GinsterMan98 (May 19, 2008)

Agreed with above, Tim is now in the 9's with the bolts just swapped in. My opinion FWIW is if its a tight fresh motor with new rods, I would have them resized. If it was a well worn oem block that has been around you should be fine. I think the key here is original parts in the motor. 

Also FWIW my old supervisor made 420hp on a D16Z6 with Eagle rods/ARP's that were just swapped in. He knows more about engine building than me and he said he buys three sets of rod bearings and plasti gauges all the bearings. Then he pics the bearings that are all reading similar clearance from the three sets. That motor has been together for 4 years with lots of low 11 sec passes and DD duty/beatings. We all know Honda single slams like to eat rod bearings, he seems to be ok running them this way. 

I have read a bunch about this and have decided I am just going to swap them in. To many people have not had problems and the ones that have were on fresh builds. Things are always more likely to fail when new and tight. Lots of variables can kill a new motor or wipe out fresh bearings, not just rod bolt choice. 

This is just my opinion, ultimately its your car. It comes down to what you feel comfortable with.


----------



## [email protected] (Jan 2, 2009)

Do you want round rods and proper crush on your bearings? If not, by all means throw them in there and crank'er down. 

Anybody with a sunnen gage can quickly show you how far out of round they will be with the ARP bolts and no reconditioning work... It can very easily be .0005" at the joint- 25-50% of your bearing clearance. 

Sure, if it's already super loose it will probably work. Or it might not. But doing an entire rebuild to save like 10 bucks a rod is so worth it. :screwy: :laugh:


----------



## GinsterMan98 (May 19, 2008)

Like I said, it's your car and your decision to make. I am not an expert or an engine builder. I do see what works and what does not. You make your bed and sleep in it, I will sleep well.:beer:


----------



## dubdriver808 (Sep 22, 2006)

Can i do it with the block in the bay??


----------



## dubdriver808 (Sep 22, 2006)

Can i do it with the block in the bay?? I actually have the rod bolts on the side. Its a matter of the easiest way of getting it done. I mean will i have to tear down my motor or can i just drop oil pan?


----------



## cant get a password (Sep 24, 2004)

I did not take my arp bolts to the machine shop when I had my machining done put the engine together with new bearings and the arp bolts....... Lasted 1,500 miles before it spun a bearing. After getting a new crank and replacement rod when all 6 rods were checked with the arp bolts in 4 were out of round.


----------



## dubdriver808 (Sep 22, 2006)

cant get a password said:


> I did not take my arp bolts to the machine shop when I had my machining done put the engine together with new bearings and the arp bolts....... Lasted 1,500 miles before it spun a bearing. After getting a new crank and replacement rod when all 6 rods were checked with the arp bolts in 4 were out of round.


question why does it have to be round? or wat is round??? wat is the right way??


----------



## root beer (Jun 22, 2004)

I've put arp bolts in several blocks without machining without issues or spun bearings.

There's one making 700+hp, and going 9's with no line bore.


----------



## dasbeast3.0 (Aug 15, 2007)

Like its been said, its extremely stupid to do it on a new motor, just have everything machined properly for $10-20 a rod. On a worn motor with more forgiving clearances, youll be okay for a while. Sometimes time/effort/long term goals play big factors in doing things like this...Personally I dont have the time to pull the entire car back apart just to get my factory rods line bored for ARP's , then put it all back together. Not much benefit when there's 80-100k on the block and it sees 28-30lbs of boost regularly. By the time I tear it all down I'd just swap in my beefed up motor. 

Swap the bolts out, enjoy it till you spin a bearing, then build a motor the right way. If you want it to last for another 30-50k then have the rods re-sized. Pull the oil pan, and replace one bolt at a time. torque 3x to account for stretch, replace pan and enjoy driving.


----------



## masterqaz (Oct 5, 2007)

someone with a degree in engineering should step in.......


----------



## vergessen wir es (May 12, 2010)

I don't plan on tearing into a vr real soon but if someone wants to send me a rod or more I will inspect them with stock and arp hardware. I can supply the arps. Really any coordinate measuring machine can put this to bed in a hurry. What do most places do to correct the big end? I would assume jig grinding is preferred, but maybe single pointing is more common.


----------



## root beer (Jun 22, 2004)

I've really RACED a motor for years like this. As have others. I just think it's pretty funny that the guys that sell rods around here are the ones that say it's a problem.

Not denying that they can oval. But it's not very often that they spin bearings.

If you're just jamming random new bearings and rods and bolts together, well you deserve a spun bearing. I've seen far more of these motor's built "the right way" go south than jammed together stock junk.


----------



## cant get a password (Sep 24, 2004)

If you look in the arp catalog on pg 32 it says it is recomended to resize the rod end when using their rod bolts. I agree that you probably will not have issues with a used motor and arp bolts. I saw with my own eyes how out of round mine were when the machine shop did them on my second build. I did not know about the whole out of round issue when I built my first vr and I did plasi-gauge my bearing clearance and it was good. Good luck to anyone who wants to put them in and hope for the best but I would not do it on a fresh rebuild. I am just stating my experience with my first time using arp stuff I have done many motors with stock bolts before so I am not new to motor work so I know this didn't happen because I didn't know how to put an engine together.


----------



## [email protected] (Jan 2, 2009)

masterqaz said:


> someone with a degree in engineering should step in.......


I already did. :laugh: The rods will be tight at the cap and may also have some misalignment cap to rod. 

The error can easily be 50% or so of the bearing clearance oil at the joint. They will always be tight at the joint, misalignment will be luck of the draw. :thumbup:


----------



## V-dubbulyuh (Nov 13, 2005)

cant get a password said:


> If you look in the arp catalog on pg 32 it says it is recomended to resize the rod end when using their rod bolts. I agree that you probably will not have issues with a used motor and arp bolts.


You are correct, all the ARP rod bolt packages that I have bought do have instructions stating to resize the rods. 

From a practical standpoint though, as many times as I have installed them and then run high boost and never had any issues (even with new bearings) I think I will stay with just direct installation. I installed some just within the past week and again, no resizing.

A slight technicality though, everyone keeps stating that ARP bolts don't "stretch". The installation instructions tell you directly that a "stretch" method of installation is preferred. :banghead:


----------



## [email protected] (Jan 2, 2009)

The ARP bolts operate below the yield point of the material... In other words, they stretch- but they will spring back to their original length when released. The OEM bolts go past the yield point and will be permanently deformed. 

If you lean on a giant steel I beam, you are still stretching it somewhat. The number will just be very very small. It acts like a spring up until the yield point. 

The ultimate strength is past the yield point- so by going that far, the OEM bolts get away with using cheaper material. Multiply by # of rod bolts per car, millions of cars- the savings are significant.


----------



## dubdriver808 (Sep 22, 2006)

V-dubbulyuh said:


> You are correct, all the ARP rod bolt packages that I have bought do have instructions stating to resize the rods.
> 
> From a practical standpoint though, as many times as I have installed them and then run high boost and never had any issues (even with new bearings) I think I will stay with just direct installation. I installed some just within the past week and again, no resizing.
> 
> A slight technicality though, everyone keeps stating that ARP bolts don't "stretch". The installation instructions tell you directly that a "stretch" method of installation is preferred. :banghead:


you just screwed them in den???


----------



## masterqaz (Oct 5, 2007)

[email protected] said:


> The ARP bolts operate below the yield point of the material... In other words, they stretch- but they will spring back to their original length when released. The OEM bolts go past the yield point and will be permanently deformed.
> 
> If you lean on a giant steel I beam, you are still stretching it somewhat. The number will just be very very small. It acts like a spring up until the yield point.
> 
> The ultimate strength is past the yield point- so by going that far, the OEM bolts get away with using cheaper material. Multiply by # of rod bolts per car, millions of cars- the savings are significant.


From what Ive read on stretch bolts they don't pass the yield point. Something like 75-80 percent. Wish i could remember were it was I read it, some magazine. Ultimate power past the yield is a new concept to me, generally when you yield something it changes its strength.

Shoulda mic'd the old bolts from new ones when I had a pair kickin around.

The concept of resizing the rods is understandable when the studs are cranked down more.... no?
I've tossed bearings before and wrecked caps from over torquing with a messed up wrench.


----------



## suburbangeorge (Apr 24, 2004)

dubdriver808 said:


> Can i do it with the block in the bay?? I actually have the rod bolts on the side. Its a matter of the easiest way of getting it done. I mean will i have to tear down my motor or can i just drop oil pan?


 You really don't have a clue do you? Rod bolts don't screw into the rod. They are pressed in. 

Assuming that you can read, why not read the instructions from ARP or do you think that someone on here(no matter how many posts they Have) knows better than the people who make the bolts? 

Old bolts need to be pressed out of the rods. New bolts pressed in(not installed by drawing them in by tightening down the caps). To do this you need to remove the rods from the engine. 

Maybe there's something magical about VW engines that eliminates the requirement to resize the rods after installing new bolts but I don't think so. Other engines require it. 

Find a reputable automotive machine shop(or speed shop) where you live and ask them.


----------



## GinsterMan98 (May 19, 2008)

suburbangeorge said:


> You really don't have a clue do you? Rod bolts don't screw into the rod. They are pressed in.
> 
> Assuming that you can read, why not read the instructions from ARP or do you think that someone on here(no matter how many posts they Have) knows better than the people who make the bolts?
> 
> ...


 Wow, great post. I love this place. You resurface a head each time? You take your block out and have it decked each time? Since your in there why not get new rings. There are many things you can get away with if your smart about it. You have a LSD in your trans? You replace your pinion carrier plate? One time use bolts on that bad boy. Everyone does it that way, doesn't mean it is "correct".


----------



## suburbangeorge (Apr 24, 2004)

vergessen wir es said:


> I don't plan on tearing into a vr real soon but if someone wants to send me a rod or more I will inspect them with stock and arp hardware. I can supply the arps. Really any coordinate measuring machine can put this to bed in a hurry. What do most places do to correct the big end? I would assume jig grinding is preferred, but maybe single pointing is more common.


 They spot face the mating edge of the cap. Then they assemble the cap to the rod and torque it to spec. Since you have removed material from the rod caps, the inner circle is smaller than spec. This smaller circle is align honed back to the propper opening. 

Now you have a round hole and stronger bolts.


----------



## suburbangeorge (Apr 24, 2004)

GinsterMan98 said:


> Wow, great post. I love this place. You resurface a head each time? You take your block out and have it decked each time? Since your in there why not get new rings. There are many things you can get away with if your smart about it. You have a LSD in your trans? You replace your pinion carrier plate? One time use bolts on that bad boy. Everyone does it that way, doesn't mean it is "correct".


 No but I own a straight edge and feeler guages. I check it for flatness. When you keep blowing head gaskets do you just scratch your head and wonder why? 

"Get away with" is a stupid way to build engines unless your( you meant you're) intent is to really build a bomb and watch it blow up. :laugh:


----------



## GinsterMan98 (May 19, 2008)

suburbangeorge said:


> No but I own a straight edge and feeler guages. I check it for flatness. When you keep blowing head gaskets do you just scratch your head and wonder why?
> 
> "Get away with" is a stupid way to build engines unless your( you meant you're) intent is to really build a bomb and watch it blow up. :laugh:


 Ah grammar Nazism, the last stand of a fool behind a keyboard... If you can't be civil with people you should just not post.


----------



## suburbangeorge (Apr 24, 2004)

GinsterMan98 said:


> Ah grammar Nazism, the last stand of a fool behind a keyboard... If you can't be civil with people you should just not post.


 So you resond to my little dig at your misuse of the language but no response to my criticism of your sloppy rebuild standards. 

The op obviously has little understanding of engine building. 

"Is it a simple unscrew and screw or do i need to work my rods to fit the bolts in?? I hear got to recondition my rods, then some say you could jus chage it out without work??? Which is it? My block has a lil over 60,xxx miles. just turboed it still finishing up some loose ends... " 

Maybe I was a little rude but he 'turboed' his engine yet doesn't know how rod bolts install? Auto mechanics, as a hobby, is more than how much WHP you can produce for a minute or so.


----------



## GinsterMan98 (May 19, 2008)

suburbangeorge said:


> So you resond to my little dig at your misuse of the language but no response to my criticism of your sloppy rebuild standards.
> 
> The op obviously has little understanding of engine building.
> 
> ...


 At least you admitted you were rude. You're mistake is you assume people know what you do. 

My examples are not what I practice. Sloppy or not, we have all done things to get by. Unless you are perfect and have deep pockets. 

Op, the facts are here in this thread from both sides of the house. Like everything in life, you choose and take the associated risk. Just saying there are numerous 3,4,5,6,700 hp cars running ARP rod bolts installed "incorrect".


----------



## V-dubbulyuh (Nov 13, 2005)

GinsterMan98 said:


> Like everything in life, you choose and take the associated risk.


 Could not be said more accurately.


----------



## vergessen wir es (May 12, 2010)

suburbangeorge said:


> They spot face the mating edge of the cap. Then they assemble the cap to the rod and torque it to spec. Since you have removed material from the rod caps, the inner circle is smaller than spec. This smaller circle is align honed back to the propper opening.
> 
> Now you have a round hole and stronger bolts.


 What I was asking was how Most shops resize rods. I would only jig grind such a feature but wasn't sure if this was standard, or if honing was more common. 

And yes they take a few thou off the caps so there is material for machining but this is technically not spot facing. Also, you align hone mains not rods - rods are loose so there is nothing to align to except itself.


----------



## Prof315 (Jan 5, 2009)

Not having rods resized after rod bolt replacement is like playing russian roulette with 3 rounds in the pistol. As several others have stated it's only $10-$20 per rod to have it done and in my opinion you're wasting the cost of the bolts if you don't do it.


----------



## suburbangeorge (Apr 24, 2004)

vergessen wir es said:


> What I was asking was how Most shops resize rods. I would only jig grind such a feature but wasn't sure if this was standard, or if honing was more common.
> 
> And yes they take a few thou off the caps so there is material for machining but this is technically not spot facing. Also, you align hone mains not rods - rods are loose so there is nothing to align to except itself.


 Here's a link to the company that is the acknowledged leader in the process http://www.sunnen.com/engine-building-honing/lbb-1660 

"Align hone" may not be technically crorrect but IIRC that's what Sunnen called it back in my youth. There is a mechanism to assure that the bore remains straight otherwise as you torqued the cap the small end would be forced to one side of the cylinder bore or the other. 

I don't know what your training is but these machines need to be designed to operate on many more than just one engine. "Jig grinding" would seem to infer a separate jig for each rod application. Too costly.


----------



## dubdriver808 (Sep 22, 2006)

GinsterMan98 said:


> At least you admitted you were rude. You're mistake is you assume people know what you do.
> 
> My examples are not what I practice. Sloppy or not, we have all done things to get by. Unless you are perfect and have deep pockets.
> 
> Op, the facts are here in this thread from both sides of the house. Like everything in life, you choose and take the associated risk. Just saying there are numerous 3,4,5,6,700 hp cars running ARP rod bolts installed "incorrect".


 :thumbup:


----------



## dasbeast3.0 (Aug 15, 2007)

suburbangeorge said:


> You really don't have a clue do you? Rod bolts don't screw into the rod. They are pressed in.
> 
> Assuming that you can read, why not read the instructions from ARP or do you think that someone on here(no matter how many posts they Have) knows better than the people who make the bolts?
> 
> ...


 lol Vr6 rod bolts screw directly into the rod. The do not press in/out like other styles of rod bolt.


----------



## dubdriver808 (Sep 22, 2006)

dasbeast3.0 said:


> lol Vr6 rod bolts screw directly into the rod. The do not press in/out like other styles of rod bolt.


 thats wat i thought...


----------



## masterqaz (Oct 5, 2007)

dasbeast3.0 said:


> lol Vr6 rod bolts screw directly into the rod. The do not press in/out like other styles of rod bolt.


 Smart :thumbup:


----------



## Prof315 (Jan 5, 2009)

dasbeast3.0 said:


> lol Vr6 rod bolts screw directly into the rod. The do not press in/out like other styles of rod bolt.


 Then they are technically called cap screws and not rod bolts. This makes a big difference as it gives you a much better chance of not blowing up if the rods are not resized.


----------



## GinsterMan98 (May 19, 2008)

WIZARD!!! :thumbup:


----------



## masterqaz (Oct 5, 2007)

I think we're done here now. Unless someones got some more black magic?


----------



## GinsterMan98 (May 19, 2008)

masterqaz said:


> I think we're done here now. Unless someones got some more black magic?


 But I thought we were all wrong?? Huh:screwy:


----------



## masterqaz (Oct 5, 2007)

GinsterMan98 said:


> But I thought we were all wrong?? Huh:screwy:


 No just everyone but you and me  and maybe one other guy lol


----------



## GinsterMan98 (May 19, 2008)




----------



## dasbeast3.0 (Aug 15, 2007)

Prof315 said:


> Then they are technically called cap screws and not rod bolts. This makes a big difference as it gives you a much better chance of not blowing up if the rods are not resized.


 Same difference man, still a bolt that goes in the rod. They should absolutely be re-sized for proper clearance. I cant see them tweaking the cap any less than a bolt through design, still places the clamp load in the same spot.


----------



## Prof315 (Jan 5, 2009)

dasbeast3.0 said:


> Same difference man, still a bolt that goes in the rod. They should absolutely be re-sized for proper clearance. I cant see them tweaking the cap any less than a bolt through design, still places the clamp load in the same spot.


 It's the pressing operation (old ones out and new ones in) that causes the most distortion. If it were otherwise you'd need to resize the rod anytime it was taken apart. 

That being said you should always check connecting rods for clearance /distortion whenever they are taken apart, replaced, or have the bolts or cap screws replaced. If you don't and the motor comes unglued, well you've got no one to blame but yourself.


----------



## [email protected] (Jan 2, 2009)

Prof315 said:


> It's the pressing operation (old ones out and new ones in) that causes the most distortion. If it were otherwise you'd need to resize the rod anytime it was taken apart.
> 
> That being said you should always check connecting rods for clearance /distortion whenever they are taken apart, replaced, or have the bolts or cap screws replaced. If you don't and the motor comes unglued, well you've got no one to blame but yourself.


 
Just the clamping force of rod bolts causes as much as .0015" of distortion in the bore. The tighter you clamp them, the more then swell in at the joint. In this case the reason they need to be re-sized is that the ARP bolts generate more clamping force then the OE ones, which will cause them to be tight at the joint. 

Take a set to somebody with a sunnen rod hone, tighten them to 10 ft-lb, 20 ft-lb, 30 ft-lb - etc. You will be able to see the deformation happen right away. It's very significant. You will be able to find a spot where they are round with the ARP bolts too- it just won't be all the way to the ARP torque spec.


----------

