Head Bolt/Stud Tech thread...
Thread Starter
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Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 30
From: Maple Valley, WA
Ok ARP 7.3 Stud detail time....
These are the 8740 190Kpsi bulk studs that you get through Typ4 or R&D....
7.000" @0ft/lbs
7.014" @90ft/lbs
7.015" @100ft/lbs
7.017" @110ft/lbs
7.019" @120ft/lbs
7.020" @130ft/lbs
7.022" @140ft/lbs
7.023" @150ft/lbs
Check- No stretch- 7.000" @0ft/lbs
7.023" @150ft/lbs
7.023" @160ft/lbs
7.026" @170ft/lbs
7.028" @180ft/lbs
Check- .005" stretch- 7.005" @0ft/lbs
7.028" @180ft/lbs
7.031" @190ft/lbs
7.038" @200ft/lbs
Got 1 click at 210ft/lbs of torque, and then it just kept turning...
By these results, I would say that its plenty safe to go to 160ft/lbs without stretching the stud, and probably up to 180ft/lbs if you really wanted to chance it.
I wanted to test the 7.3 head bolt tonight, but just didn't feel like it, so Ill do that tomorrow along with the 9/16" head stud.
These are the 8740 190Kpsi bulk studs that you get through Typ4 or R&D....
7.000" @0ft/lbs
7.014" @90ft/lbs
7.015" @100ft/lbs
7.017" @110ft/lbs
7.019" @120ft/lbs
7.020" @130ft/lbs
7.022" @140ft/lbs
7.023" @150ft/lbs
Check- No stretch- 7.000" @0ft/lbs
7.023" @150ft/lbs
7.023" @160ft/lbs
7.026" @170ft/lbs
7.028" @180ft/lbs
Check- .005" stretch- 7.005" @0ft/lbs
7.028" @180ft/lbs
7.031" @190ft/lbs
7.038" @200ft/lbs
Got 1 click at 210ft/lbs of torque, and then it just kept turning...
By these results, I would say that its plenty safe to go to 160ft/lbs without stretching the stud, and probably up to 180ft/lbs if you really wanted to chance it.
I wanted to test the 7.3 head bolt tonight, but just didn't feel like it, so Ill do that tomorrow along with the 9/16" head stud.
Posting Guru
Joined: Sep 2011
Posts: 1,523
Likes: 5
Hmmm that is interesting. Thanks for all the updates and research! You have truly pushed the idi platform to new levels! I look forward to seeing what the 9/16 studs do. That should allow for some nice holding strength.
Thread Starter
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Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 30
From: Maple Valley, WA
Ok Stock 7.3 Head bolt detail... And actually surprising.... To me anyway...
6.425" @0ft/lbs
6.441" @65ft/lbs
6.446" @85ft/lbs
6.448" @105ft/lbs
6.451" @110ft/lbs..... Spec
6.453" @120ft/lbs
Check- .005" stretch- 6.430" @0ft/lbs
6.453" @120ft/lbs
6.460" @130ft/lbs
6.465" @140ft/lbs
Check- .020" stretch- 6.445" @0ft/lbs
6.470" @140ft/lbs..... .005" stretch from last 140ft/lb measurement...
150ft/lbs clicked after 1 full turn...
Broke the bolt at 160ft/lbs....
Bottom line, I wouldn't trust the 7.3 bolts past spec, its just too unpredictable, even if I tested a weak bolt. Based off of this bolt, the stock bolts are pretty much TTY units, even if they aren't officially that way from the factory....
I will probably test another one just verify the results, but im pretty sure this is the way it is....
9/16" stud next...
6.425" @0ft/lbs
6.441" @65ft/lbs
6.446" @85ft/lbs
6.448" @105ft/lbs
6.451" @110ft/lbs..... Spec
6.453" @120ft/lbs
Check- .005" stretch- 6.430" @0ft/lbs
6.453" @120ft/lbs
6.460" @130ft/lbs
6.465" @140ft/lbs
Check- .020" stretch- 6.445" @0ft/lbs
6.470" @140ft/lbs..... .005" stretch from last 140ft/lb measurement...
150ft/lbs clicked after 1 full turn...
Broke the bolt at 160ft/lbs....
Bottom line, I wouldn't trust the 7.3 bolts past spec, its just too unpredictable, even if I tested a weak bolt. Based off of this bolt, the stock bolts are pretty much TTY units, even if they aren't officially that way from the factory....
I will probably test another one just verify the results, but im pretty sure this is the way it is....
9/16" stud next...
Posting Guru
Joined: Sep 2011
Posts: 1,523
Likes: 5
This really makes me think I want to go with the 9/16" studs if they show better than the 1/2". What would have to be done to make this work on a 7.3 in your opinion? Would the 7.3 have to be drilled at 6.9 depth? And with that depth do you think that there would be issues with thread interference or anything?
Thread Starter
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Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 30
From: Maple Valley, WA
This really makes me think I want to go with the 9/16" studs if they show better than the 1/2". What would have to be done to make this work on a 7.3 in your opinion? Would the 7.3 have to be drilled at 6.9 depth? And with that depth do you think that there would be issues with thread interference or anything?
Posting Guru
Joined: Mar 2012
Posts: 1,011
Likes: 4
From: MI
So 110 is stock torque spec on the head bolt? aka if you wanna run more boost head studs are required? (15-20 psi on stock compression)
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Thread Starter
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Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 30
From: Maple Valley, WA
Stock bolt spec is 110, and I tested it farther, and it hit yield right where the 6.9 bolt did. I expected more out of the bolt, so I don't know, either way, I wouldn't go past 120 on the bolt.
Senior User
Joined: Feb 2012
Posts: 445
Likes: 6
From: western Oregon
Humm.... I thought that 7.3NA was 100 spec and 7.3 turbo was 110 spec and the bolts are the same. Just added torque for the turbo pressure.... I went to 115 on my stock bolts. I think I'm good at that... for 18psi into a decompressed J2 cam Engine at 90cc's .... My next build will get studs for sure...
New User
Joined: Jan 2016
Posts: 12
Likes: 0
Arp head bolt
Hi,
I'm new please forgive!
First diesel, second post on site.
I'm new to diesels and been reading a lot of info from this site. THANK YOU!
I need to replace the coolant and I believe the head gasket might be leaking.
Obviously from the above posts, ARP are the best. Where do I get these from and what size? I have not taken anything apart yet.
What head gaskets do you recommend? And where to buy?
I got the thermostat information from the "6.9l diesel tech info page" but I guess I missed the gasket and head bolts info.
Additionally any info regarding doing this job will be much appreciated.
Thank you!!
I'm new please forgive!
First diesel, second post on site.
I'm new to diesels and been reading a lot of info from this site. THANK YOU!
I need to replace the coolant and I believe the head gasket might be leaking.
Obviously from the above posts, ARP are the best. Where do I get these from and what size? I have not taken anything apart yet.
What head gaskets do you recommend? And where to buy?
I got the thermostat information from the "6.9l diesel tech info page" but I guess I missed the gasket and head bolts info.
Additionally any info regarding doing this job will be much appreciated.
Thank you!!
Laughing Gas
Joined: Sep 2014
Posts: 830
Likes: 39
From: Whittier
Go to ebay for your parts. The stock head gaskets are fine. Confirm that the heads are not warped. If you don't have a good straight edge, Bring the heads to a good diesel machine shop to have them tested.
Lead Driver
Joined: Apr 2008
Posts: 6,938
Likes: 13
Hi,
I'm new please forgive!
First diesel, second post on site.
I'm new to diesels and been reading a lot of info from this site. THANK YOU!
I need to replace the coolant and I believe the head gasket might be leaking.
Obviously from the above posts, ARP are the best. Where do I get these from and what size? I have not taken anything apart yet.
What head gaskets do you recommend? And where to buy?
I got the thermostat information from the "6.9l diesel tech info page" but I guess I missed the gasket and head bolts info.
Additionally any info regarding doing this job will be much appreciated.
Thank you!!
I'm new please forgive!
First diesel, second post on site.
I'm new to diesels and been reading a lot of info from this site. THANK YOU!
I need to replace the coolant and I believe the head gasket might be leaking.
Obviously from the above posts, ARP are the best. Where do I get these from and what size? I have not taken anything apart yet.
What head gaskets do you recommend? And where to buy?
I got the thermostat information from the "6.9l diesel tech info page" but I guess I missed the gasket and head bolts info.
Additionally any info regarding doing this job will be much appreciated.
Thank you!!