# VR6-T When are ARP rod bolts required?



## phatvw (Aug 29, 2001)

I see lots of folks with moderate power VR6-turbo setups with ARP rod bolts. At what HP/Torque do the oem rod bolts generally fail? I can understand getting ARP head studs for anything over 9PSI for more durability, but are new rod bolts necessary as well?


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## leebro61 (Nov 7, 2001)

*Re: VR6-T When are ARP rod bolts required? (phatvw)*

I can't quote you a power figure to answer your question, but I will say that ARP recommends resizing the connecting rods when you are switching to their bolts. Obviously this requires removing and machining them, so if you follow their advice, it's not a drop the pan and swap them ordeal


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## phatvw (Aug 29, 2001)

*Re: VR6-T When are ARP rod bolts required? (leebro61)*


_Quote, originally posted by *leebro61* »_I can't quote you a power figure to answer your question, but I will say that ARP recommends resizing the connecting rods when you are switching to their bolts. Obviously this requires removing and machining them, so if you follow their advice, it's not a drop the pan and swap them ordeal









Thanks for the response. Thats interesting. What are you supposed to re-size exactly? Do the new bolts weigh more or something and you have to shave off a little metal to have proper balance?
Ok maybe a better question to ask is what is the weak link on the VR6 bottom-end? And at what hp/torque will the weak link fail? Or at what hp/torque does the reliability of the bottom-end fall below acceptable for a daily driver threshold?


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## leebro61 (Nov 7, 2001)

*Re: VR6-T When are ARP rod bolts required? (phatvw)*

To resize the rod they cut down the big end and rebore the hole, or at least that is how it was explained to me. As far as what is going to fail and at what power level, I'm not sure, but keep in mind that RPM will be a determining factor. If you plan on spinning the motor significantly higher than stock you might be smart to look into the rod resizing/ARP combo at the very least. http://****************.com/smile/emthup.gif


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## BubonicCorrado (Jul 24, 2003)

*Re: VR6-T When are ARP rod bolts required? (leebro61)*

SHUT UP, ALL OF YOU!!!
NO RESIZING IS NECESSARY!!!
Just put them in, one at a time.
Untourqe one rod bolt at a time, and install new bolt, that way the bearings don't move.
I've done this twice.
Around 400whp is when most shops recomend to upgrade to the ARP rod bolts.
Personaly I recomend, you do it at 350whp.


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## Vdubsolo (Apr 11, 2004)

*Re: VR6-T When are ARP rod bolts required? (BubonicCorrado)*


_Quote, originally posted by *BubonicCorrado* »_SHUT UP, ALL OF YOU!!!
NO RESIZING IS NECESSARY!!!
Just put them in, one at a time.
Untourqe one rod bolt at a time, and install new bolt, that way the bearings don't move.
I've done this twice.
Around 400whp is when most shops recomend to upgrade to the ARP rod bolts.
Personaly I recomend, you do it at 350whp.

I also never head of having to cut the rod bolts?







just replace them one by one..
How long dose ths take to swap the rod bolts witht eh ARP bolts??
and what about Main Studs..should those be done as well??


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## leebro61 (Nov 7, 2001)

*Re: VR6-T When are ARP rod bolts required? (Vdubsolo)*

You don't cut the rod bolts, so please don't give me the rolleyes if you aren't familiar with the terminology. I don't want to sound rude, I just hate that icon







. Again, I said that IF you follow ARP's advice... not that you had/have to. Obviously by mentioning the resizing it seems I am trying to talk him out of the drop the pan and swap job, this is not entirely the case. I know that if it were me, I would at least want to hear all sides of the story before making a decision.
For the record, I will say that I have heard of PLENTY of times where people simply swapped the bolts without issue. Sorry for the confusion http://****************.com/smile/emthup.gif


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## BLKBOX (Jan 17, 2005)

*Re: VR6-T When are ARP rod bolts required? (leebro61)*


_Quote, originally posted by *leebro61* »_You don't cut the rod bolts, so please don't give me the rolleyes if you aren't familiar with the terminology. I don't want to sound rude, I just hate that icon







. Again, I said that IF you follow ARP's advice... not that you had/have to. Obviously by mentioning the resizing it seems I am trying to talk him out of the drop the pan and swap job, this is not entirely the case. I know that if it were me, I would at least want to hear all sides of the story before making a decision.
For the record, I will say that I have heard of PLENTY of times where people simply swapped the bolts without issue. Sorry for the confusion http://****************.com/smile/emthup.gif 

I read up on ARPs sight and they do say you should have your rods resized when replacing the OEM bolts with their rod bolts but I said, "meh" and just swapped 'em one by one. It takes a bit because of the three-peat tightening sequence but it's just peace of mind. Took maybe 30 minutes.


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## radoboy (Oct 2, 2000)

*Re: VR6-T When are ARP rod bolts required? (phatvw)*

I've always had my rods resized just for good measure when installing ARP rod bolts (because the entire motor is apart as I'm ususally doing other stuff to the motor as well). I've heard of plenty of people just swapping them in, but if you have the bottom end apart, what is a few more bucks to have the big ends resized as per ARP's recommendation? Don't know that I would disassemble the entire bottom end just to install rod bolts though, but I've never done that personally.


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## maxslug (May 22, 2005)

i have a set for sale... I ended up w/ a set of cunningham rods which come w/ their own bolts, so i didn't use the ARP set I bought.
-m


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## Vdubsolo (Apr 11, 2004)

*Re: VR6-T When are ARP rod bolts required? (leebro61)*


_Quote, originally posted by *leebro61* »_You don't cut the rod bolts, so please don't give me the rolleyes if you aren't familiar with the terminology. I don't want to sound rude, I just hate that icon







. Again, I said that IF you follow ARP's advice... not that you had/have to. Obviously by mentioning the resizing it seems I am trying to talk him out of the drop the pan and swap job, this is not entirely the case. I know that if it were me, I would at least want to hear all sides of the story before making a decision.
For the record, I will say that I have heard of PLENTY of times where people simply swapped the bolts without issue. Sorry for the confusion http://****************.com/smile/emthup.gif 








you asked for it


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## Shinko (Jul 18, 2009)

Greetings,

Sorry to bump an old thread, but I wanted to help with a possible conclusion concerning this matter since people will still come back to this thread for advice.
ARP Does not require re-sizing, but does recommend it.

Here are the directions as per ARP:

Cap Screw without Washer - Rod Bolt Installation
[1] Please check the part-number(s) for your application
against the part-number(s) listed on the instruction sheet.
[2] Make sure there is an adequate chamfer around the bolt
hole on the connecting rod cap to clear the radius under
the head of the bolt.
[3] Use ARP Ultra-Torque Fastener Assembly Lubricant
to lubricate the threads of the bolt and the under head of
the bolt. Then install the bolts and tighten them hand
tight.
[4] ARP recommends using the STRETCH METHOD when
tightening rod bolts. Following the instructions for using a
stretch gauge, Stretch the bolts to . 0075 - . 0080 .
[5] If you do not have a stretch gauge, torque the bolts to
_ 40 ft-lbs using ARP Ultra-Torque Fastener
Assembly Lubricant.
[6] The connecting rods *should* always be re-sized after new
rod bolts are installed.
[7] A log should be kept on the original non-torqued length
of each bolt. Bolts that have any permanent deformation
or have increased in non-torqued length by more than
.001 in. should be replaced.​
ARP offers two different methods of connecting rod bolt installations:

Torque to 40 ft-lbs
My guess is most people are doing this method, and though it does provide a strong clamping force, I would imagine it's not enough to cause a significant Out-of-Round Issue with the Rods.​
 Torque to Yield Point
Since this method uses a stronger amount of clamping force (Strong enough to take the bolts to the yield point) the recommendation should probably be followed.​


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## APCXxstovetopxX (Jul 9, 2009)

Well put , thanks for the info, it should also be mentioned ive seen N/A VRs with rod bearing failures wether that was due to poor oiling or rod bolt stretch i do not know but i personally install ARP rod bolts in every VR for peace of mind no matter the hp level


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## vergessen wir es (May 12, 2010)

*


Shinko said:



Torque to Yield Point
Since this method uses a stronger amount of clamping force (Strong enough to take the bolts to the yield point) the recommendation should probably be followed.​

Click to expand...

*Just FYI ARP says torque to stretch, not torque to yield.
Yield means the material permanently deforms and can't return to original form (length).
The ARP bolts will return to original length if done right.
Which they say right there in the instructions...if the bolts don't return within .001" then they are damaged.
And we really don't know how close to yield we are without more info.

Just saying.


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## Jeebus (Jul 8, 2001)

We've done both.

We found that on a high KM motors it was fine chucking them in without honing, on a low KM motors it was a problem.


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## 24vGTiVR6 (Sep 14, 2010)

yeah the argument continues lol..... I'll say this:

in my local crew someone installed ARP rod bolts by just dropping the pan and replacing them one by one. his motor suffered multiple rod failures 3 weeks later.

another buddy in the crew did the same thing, and he was fine for like ~2 yrs..... but then his motor blew up too - not sure of the cause as he just basically let the car rot after that

so.... it's a 50/50 scenario methinks.

but- if you will be running power that would necessitate ARP rod bolts, why not just do it right? By "right" I mean hone the rod ends at a machine shop, or buy better rods with ARP bolts already included. I mean, you're already there, why cut corners and spend the $$$ on the bolts just to take the chance with the bottom end? the problem is, ARP rod bolts are stronger and the required torque values are greater than OEM. when you torque these things down they may deform the "roundness" at the end of the rod, where the bearings sit. if the rod end is out of round, i.e. is an oval instead of a circle, then your bearing wear will accelerate as it will probably be rubbing at certain points on the crank journal, and the bearings may spin as the indent in the rod / bearing may come loose due to the oval-ized rod end. Yes, oval-ized is a word, now. 

I'd say anything above 400 WHP would need better fasteners. If you are below that, just run the thing until it blows up (cuz it will blow up eventually), then swap another motor in there. Trust me, been there, done that.... about 5 times now - that's why I built my latest motor and it's been going strong for a good 2.5 years now @ 28 psi - and I run it HARD in competitive time attack sessions. If you can, buy a stretch gauge instead of relying on a tq wrench..... it's MUCH more accurate re: rod bolts.


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