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Old 04-11-2012, 11:42 AM   #76
B.R.E.D
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Quote:
Originally Posted by Bamofo View Post
If your bottoming out the ARP's that hard then there is a really good chance you will pop the metal out at the bottom of the hole too.... so it goes both ways. ive seen it on 2 blocks that i had to checkout.. If you need picture proof i have that too
If you are seeing cracked head stud holes its not from over tightening the stud its from someone installing studs with fluid in the bottom of the hole.

I
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Old 04-11-2012, 11:42 AM   #77
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It would not be hard to punch a hole. I have seen it before. Just pour some oil in the hole. Then thread the stud in. The oil with push the bottom right out like lindsay lohan.

Just depends on which hole you use. Some have some meat behind them.
I'm glad that MAP has stepped up to correct this issue. I have bought parts from them in the past and will in the future.
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Old 04-11-2012, 11:43 AM   #78
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Quote:
Originally Posted by B.R.E.D View Post
If you are seeing cracked head stud holes its not from over tightening the stud its from someone installing studs with fluid in the bottom of the hole.

I
Hahah beat me to it.
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Old 04-17-2012, 01:33 PM   #79
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so i contacted MAP. they said they would give a refund if I wanted. Is it really that big of a problem missing those threads???


they said to just finger tight them
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Old 04-17-2012, 03:07 PM   #80
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Quote:
Originally Posted by cueballsi
so i contacted MAP. they said they would give a refund if I wanted. Is it really that big of a problem missing those threads???

they said to just finger tight them
finger tight....... makes that "dog point" useless.
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Old 04-17-2012, 03:16 PM   #81
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Yep, but it has worked without issue time and time again.
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Old 04-17-2012, 03:27 PM   #82
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Wow good find! Glad Ive always used ARP products! Hard not to trust them since they have been around for so damn long!
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Old 04-24-2012, 10:52 PM   #83
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Interesting read...
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Old 04-24-2012, 10:53 PM   #84
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Has anyone actually did the math on minimum thread engagement? or are we just guessing at how much thread is actually required? I'm particularly interested in that .200" of thread that is missing from the previous bolt version that is still floating around out there.
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Old 04-24-2012, 11:17 PM   #85
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bump for fuji's expertise!
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Old 04-25-2012, 01:00 AM   #86
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Quote:
Originally Posted by Adrenalin Rush View Post
Has anyone actually did the math on minimum thread engagement? or are we just guessing at how much thread is actually required? I'm particularly interested in that .200" of thread that is missing from the previous bolt version that is still floating around out there.
Well I was asking that very question, but my question was dismissed considering "93% of thread engagement is within the first 5 engaged threads." I know that this "data" was posted by an "engineer", but I would still like to see some "evidence."

Bottom line: If the manufacturer incuded 20 threads in a design, then 20 threads need to be engaged for application of the full intended clamping force.
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Old 04-25-2012, 02:01 AM   #87
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Quote:
Originally Posted by Adrenalin Rush View Post
Has anyone actually did the math on minimum thread engagement? or are we just guessing at how much thread is actually required? I'm particularly interested in that .200" of thread that is missing from the previous bolt version that is still floating around out there.
it's not an issue of thread engagement because there is plenty. it's that the shank of the stud bottoms out and causes a stress riser.

minimum thread engagement is a function of fastener diameter:

http://www.engineersedge.com/thread_...engagement.htm

It is actually not much and the reason the threads are so long is to keep them from ripping out of the block and not failure of the stud. So you would need to do the math on internal aluminum studs as well as the stud itself (which I don't feel like doing right now because of this bottle of wine).

I would think if you have the studs that bottom out you could just thread them into the block until they stop, go back a touch, and be fine.
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Old 04-25-2012, 11:20 AM   #88
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I once snapped a BBC ARP head stud in the bottom of the blind-hole bore. Panicked, I asked a PhD Physicist I worked with the best method to extract it.

He smiled and said "Back it out with a long, sharp awl".

I went home and did just that. There is a reason stud installation does not require torque on installation.

IMO, the "dog point" is just marketing hype...in this case, gone wrong.
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Old 04-25-2012, 12:18 PM   #89
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Quote:
Originally Posted by jamal View Post
it's not an issue of thread engagement because there is plenty. it's that the shank of the stud bottoms out and causes a stress riser.

minimum thread engagement is a function of fastener diameter:

http://www.engineersedge.com/thread_...engagement.htm

It is actually not much and the reason the threads are so long is to keep them from ripping out of the block and not failure of the stud. So you would need to do the math on internal aluminum studs as well as the stud itself (which I don't feel like doing right now because of this bottle of wine).

I would think if you have the studs that bottom out you could just thread them into the block until they stop, go back a touch, and be fine.
I understand what you are saying but the thread engagement is an issue if you reduce it by .200" on an engine designed to make <310hp and now you want to raise the combustion chamber pressures to make more horsepower. By reducing the thread engagement you just moved the potential point of failure from the fastener to the threads in the block. The aluminum block has a ultimate shear stress that is far lower than the tool steel fastener that is being inserted. The question should be, what will occur first? The yield of the steel fastener or the shear of the aluminum block. I am addressing this because the reduction of the threads leads to a reduction of shear plane in the block, this means the connect to the block is not weaker than originally intended by Subaru. What kind of power level/stress level was the original block designed for? That is the question. Subaru did not, I repeat, did not throw a dart at the board to select that thread depth. I am simply curious if anyone took this into serious consideration or if everyone is just say "I think it will be fine because one has not failed yet". If we built airplanes like this, people would only fix the issues after one crashes. That is bad for business if you like building safe airplanes!
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Old 04-30-2012, 03:49 PM   #90
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Just wanted to add my experience so its documented.

I had these installed for the break in of a fresh block and re-worked heads. While tuning the car started pushing coolant and needed new headgaskets. Upon disassembly some of the stud nuts came off with much less effort than others. The studs themselves were the same way, some were finger tight, and a few needed a bit more convincing. The places where the headgaskets were failing happened to be directly under the more easily removed head studs.
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Old 06-16-2012, 06:58 PM   #91
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Any news from Maperformance? Is the new design coming out?
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Old 02-20-2013, 12:32 PM   #92
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Digging this up from the depths but did anyone else notice that in the first picture it appears that the ARP stud is smaller in diameter (once you get above the threads) than the MAP studs?
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Old 02-20-2013, 01:25 PM   #93
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The studs have been revised.
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Old 02-20-2013, 01:40 PM   #94
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Quote:
Originally Posted by Nuke209 View Post
The studs have been revised.
Which ones were revised? How were they revised? And which one is better now?
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Old 02-20-2013, 01:41 PM   #95
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^would you use them in a build?
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Old 02-20-2013, 01:45 PM   #96
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Quote:
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Which ones were revised? How were they revised? And which one is better now?
I'll try to take a pic of them next to arp when I get to the shop
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Old 02-20-2013, 01:47 PM   #97
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Quote:
Originally Posted by Nuke209 View Post
I'll try to take a pic of them next to arp when I get to the shop
Awesome! If you have a caliper I would appreciate it if you took a quick measurement of the diameter of the shaft of each as well. Thanks!
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Old 05-24-2013, 05:51 PM   #98
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Just purchased new MAP headstuds today for my Track car. I have been hearing a lot of good stuff!
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Old 05-24-2013, 09:09 PM   #99
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Are the MAP headstuds mfg'd by K1? Last shop I worked at was investigating producing there own head studs and had several mfg's studs sent out for strength testing/hardness/etc.. and analysis done. Oem head studs broke at various points and psi. The K1 headstuds broke at a higher psi but surprisingly a few broke below the psi of the oem head studs. Arp headstuds broke at the same point everytime and at the same psi. They were the most consistent in the tests and strongest. Somewhat shocking when we got the tests back and saw the findings of the K1 studs.
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Old 05-24-2013, 09:44 PM   #100
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Not K1... A1. (as indicated with the picture in the first post, which they also show on their site)
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