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Old 07-21-2007, 11:00 AM   #1
cdigerlando
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Default ARP Main Bolts Necessary?

Any opinions related to ARP Main bolts? They are pretty darn expensive, but I don't want to cut any corners on my build. Any opinions on how necessary they are?

Thanks

Chuck D.
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Old 07-21-2007, 11:08 AM   #2
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Well, I spent the money and got mine for $280...did my shopping too...they are cheap compared to the 14mm head studs...

How much power are you trying to make? that will determine whether you are going tear your block apart or not
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Old 07-21-2007, 01:21 PM   #3
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FYI, people are making plenty of power on stock blocks, which include OEM headbolts.

I paid less then $100 online for a full set.
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Old 07-21-2007, 03:10 PM   #4
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Quote:
Originally Posted by Starkiller View Post
FYI, people are making plenty of power on stock blocks, which include OEM headbolts.

I paid less then $100 online for a full set.
he also said case/main bolts
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Old 07-21-2007, 04:04 PM   #5
cdigerlando
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Default APR Bolts.

Yes I was refering to the main bolts, not the head bolts. I will probably go with standard size APRs for the head bolts and APR replacements for the mains. Anyone even used APRs on the mains?
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Old 07-21-2007, 07:07 PM   #6
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ops sorry, but same thing though. OEM is still probably good enough for what your doing.
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Old 07-21-2007, 07:31 PM   #7
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I still ask, what kind of power are you trying to make?
they may not be needed for you goals...the stockers are quite strong.
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Old 07-22-2007, 04:48 PM   #8
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Quote:
Originally Posted by Homemade WRX View Post
I still ask, what kind of power are you trying to make?
they may not be needed for you goals...the stockers are quite strong.
Probably no more than 600+ HP. I doubt they are necessary since guys are making this on 5 bearings and I have 7.
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Old 07-22-2007, 04:48 PM   #9
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Does anyone know anyone who uses ARP main bolts? Any idea what their application is? Anyone had problems with the stock bolts?
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Old 09-11-2012, 02:44 PM   #10
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Bump from the dead! Above is inconclusive. Has anyone actually had an issue with OE main fasteners that could be attributed to power or RPM? Example of symptom would be evidence that the case halves are walking, exhibited typically as shiny spots on the surface of where the case halves come together. Oil pressure flutter/drop at high load/RPM? This is a question for the guys running north of 500whp and doing enough tear downs to actually notice if this were an issue.
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Old 09-11-2012, 11:40 PM   #11
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For the builds that I do that run them, they are motorsports oriented, get a rebuild, already are having a fresh bore and hone after decking between the case halves (part of the sleeving process), shuffle pins, etc....so getting the case bolts are a drop in the bucket and good security in building the best foundation for your engine.

With that being said, it is a high power or high RPM component. Your 600whp street car isn't going to need it. For an engine getting extended abuse, like a big time time attack car or drag car, is more when they apply IMO. Again, think of it as a few hundred more for added insurance.

To take full advantage, you do have a higher torque and you will need a fresh bore and hone on the mains, on top of the build.

-Micah
'Homemade WRX'

P.S. I hope that made sense. I'm running on near zero sleep right now
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Old 09-12-2012, 01:29 AM   #12
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I have to agree with what Micah said. We rarely put them in unless its a time attack build that will see lots of abuse or a very high hp drag race application.

If it will occasionally see 600hp I wouldn't worry about it.

Matt
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Old 09-12-2012, 10:33 AM   #13
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Appreciate the response guys thanks. Main ovaling from the added torque, cleaned up by case-split decking and re-align bore, at higher ARP torque is part of why I dont want to run these fasteners unless I "have" to. Is this a hard and fast requirement when torqueing to ARP main specs because the mains WILL oval, or sometimes they oval, your mileage may vary type of deal? With my component selection and assuming minimal .004/.004 clean-up on the firing-deck/case-split deck, puts me very close to piston protrusion. Im dead set on OE head gaskets and not wanting to cut pistons (keep parts as close to off the shelf as possible). Avoiding the case split decking for align bore ensures Im at a reasonable piston:deck-height.

Still no mention of a failure attributed to an issue with the OE main fasteners? Im going to put these in the nice to have column pending some evidence of a failure or negative symptom attribute to the OE fasteners.
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Old 09-15-2012, 05:43 AM   #14
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I do not think anyone has been able to point the finger at the case bolts being an issue. When the motor fails it goes big.

I have seen a few broken cranks and one that did show signs of case walk. But that was also a drag / street car. And it made 500whp and high rpm.

If the motor is built correctly I think you would be just fine.
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Old 09-15-2012, 05:51 PM   #15
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I'm using ARP Case Bolts and Main studs then went to 625ARP Head studs, with AEBS sleeved I'm expecting this block to hold just fine...
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Old 09-15-2012, 08:09 PM   #16
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No question about ARPs being the better choice. My concern is that I will loose too much deck. Not a big deal if your building around the deck and doing custom rods/pistons or shaving the domes. I want to stick to off the shelf parts. My concern is more that using the main bolts will require an align bore and corisponding split shave. .004 on the firing deck is no big deal, but double that if you gotta align bore because the ARP torque ovals the mains.
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Old 09-16-2012, 03:53 AM   #17
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Arp case bolts will need to machine the mains. They distort the case when tighten fown to spec. But the whole case should be squared up with them installed.
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