Head Studs - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 06-01-2016, 05:41 PM   #1
Senior Member
Thread Starter
 
mmmjesse's Avatar
 
Join Date: Aug 2007
Posts: 568
Total Cats: 43
Default Head Studs

I am curious to know if anyone has a confirmed limit to the factory head bolts. I am in the middle of prepping a VVT motor for my car. i am doing a head gasket and didnt know if arp head studs were really necesary for my goals. Stock bottom end, so i will be keeping it under 250wtq.
mmmjesse is offline   Reply With Quote
Old 06-01-2016, 06:00 PM   #2
Elite Member
iTrader: (1)
 
Join Date: Jun 2014
Location: Austin, TX
Posts: 2,843
Total Cats: 271
Default

I don't hear often of the heads lifting or bolts stretching...

I'd call it a "while I was in there" job and still put them in if you can afford it.
Girz0r is offline   Reply With Quote
Old 06-01-2016, 06:25 PM   #3
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,775
Total Cats: 1,106
Default

Not needed at all. Spending that $120 on rods or ****** would be a better use of the cash.
shuiend is offline   Reply With Quote
Old 06-01-2016, 09:17 PM   #4
Senior Member
Thread Starter
 
mmmjesse's Avatar
 
Join Date: Aug 2007
Posts: 568
Total Cats: 43
Default

Quote:
Originally Posted by shuiend View Post
Not needed at all. Spending that $120 on rods or ****** would be a better use of the cash.
****** it is!!!
mmmjesse is offline   Reply With Quote
Old 06-01-2016, 10:16 PM   #5
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,476
Total Cats: 114
Default

I think stock bolts are good for somewhere past the 400hp / 350ft-lb mark but most people putting those numbers out put ARP in anyway because they already spent way more than that on there build and the added cost is negligible in comparison.
bbundy is offline   Reply With Quote
Old 06-01-2016, 10:17 PM   #6
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,576
Default

yep, and because stock bolts technically shouldn't be re-used
18psi is offline   Reply With Quote
Old 06-01-2016, 11:21 PM   #7
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by 18psi View Post
yep, and because stock bolts technically shouldn't be re-used
I always assumed this, but the FSM doesn't actually mention them as being TTY. I have reused them with no ill effect on stock-output rebuilds.

With boost added, consider the rest of the cost of your setup, then ask yourself if you want to be the guinea pig who finds out exactly where the limit of stock head bolts are.
Savington is offline   Reply With Quote
Old 06-01-2016, 11:23 PM   #8
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

Why? They're not torque to yield bolts. They're reusable.
curly is offline   Reply With Quote
Old 06-01-2016, 11:31 PM   #9
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,576
Default

really?
I stand corrected tehn
18psi is offline   Reply With Quote
Old 06-01-2016, 11:38 PM   #10
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Stock head bolts can be reused, if you're confident they were installed properly and were not stretched into the plastic range by overheating the engine and warping the head. They are not TTY, the FSM is quite explicit about which parts need to be replaced and the head bolts are not tagged that way.

--Ian
codrus is offline   Reply With Quote
Old 06-02-2016, 03:39 AM   #11
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,476
Total Cats: 114
Default

The stock head bolts are probably stronger than the head. ARP studs can easily provide more clamp load than the head can stand. Torquing ARP bolts to ARP's torque spec will crush your head and you run the risk of turning it into a paperweight by cracking the bosses under the washes. been there done that.
bbundy is offline   Reply With Quote
Old 06-02-2016, 07:21 AM   #12
Junior Member
iTrader: (1)
 
Downmented's Avatar
 
Join Date: Oct 2014
Location: Annapolis, MD
Posts: 485
Total Cats: 59
Default

Quote:
Originally Posted by bbundy View Post
The stock head bolts are probably stronger than the head. ARP studs can easily provide more clamp load than the head can stand. Torquing ARP bolts to ARP's torque spec will crush your head and you run the risk of turning it into a paperweight by cracking the bosses under the washes. been there done that.
Is this really a thing? I just bolted my head down on my new motor about two-three weeks ago with ARP hardware, torqued in sequence order per the FSM, however I torqued them down in multiple passes, first pass I did 20ft/lbs then loosened them all in order per FSM removal sequence, second pass i did 40ft/lbs, then loosened, third and final i did 65ft/lbs and stopped.

Did I miss an important chunk of "common knowledge" in regards to these heads + ARP hardware?
Downmented is offline   Reply With Quote
Old 06-02-2016, 10:45 AM   #13
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,009
Total Cats: 583
Default

The "common knowledge" is that ARP specifies 80 ft-lbs in their instructions vs. 55-60 ft-lbs per FSM. Use the FSM value. Also, the ARP washers have a smaller diameter than the OEM washers, so it's better to use the OEM washers.

The one thing I like about the ARP studs is the consistency of the clamp load. With the OEM bolts, you need to be meticulous about making sure the threads in the block are clean and lubricated to get a consistent clamp. Shouldn't be an issue when assembling freshly machined parts, but when swapping a HG down the road it might be.
hornetball is offline   Reply With Quote
Old 06-02-2016, 01:09 PM   #14
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,476
Total Cats: 114
Default

Quote:
Originally Posted by Downmented View Post
Is this really a thing? I just bolted my head down on my new motor about two-three weeks ago with ARP hardware, torqued in sequence order per the FSM, however I torqued them down in multiple passes, first pass I did 20ft/lbs then loosened them all in order per FSM removal sequence, second pass i did 40ft/lbs, then loosened, third and final i did 65ft/lbs and stopped.

Did I miss an important chunk of "common knowledge" in regards to these heads + ARP hardware?
FSM torque spec is Ok its its the torque spec ARP gives for the studs that is nuts. Higher quality threads, finer thread pitch and the fact you are turning a nut with ARP moly on it rather than a bolt means the clamp load you get is way higher than stock even at the stock torque spec.
bbundy is offline   Reply With Quote
Old 06-02-2016, 01:22 PM   #15
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,576
Default

Quote:
Originally Posted by Downmented View Post
Is this really a thing? I just bolted my head down on my new motor about two-three weeks ago with ARP hardware, torqued in sequence order per the FSM, however I torqued them down in multiple passes, first pass I did 20ft/lbs then loosened them all in order per FSM removal sequence, second pass i did 40ft/lbs, then loosened, third and final i did 65ft/lbs and stopped.

Did I miss an important chunk of "common knowledge" in regards to these heads + ARP hardware?
you're fine. we all usually do 55-65
18psi is offline   Reply With Quote
Old 06-02-2016, 04:07 PM   #16
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by hornetball View Post
The one thing I like about the ARP studs is the consistency of the clamp load. With the OEM bolts, you need to be meticulous about making sure the threads in the block are clean and lubricated to get a consistent clamp. Shouldn't be an issue when assembling freshly machined parts, but when swapping a HG down the road it might be.
Yup. You'll see that inconsistency when you install the studs into the block. If you aren't chasing every thread with a tap/chaser, there's zero consistency in the stock head bolt torque.

When I used my first set of ARP studs in 2009, the instructions said 65lbs. I opened a box somewhere around 2011-2012 and the instructions suddenly said 80ft.lbs, which I knew to be bullshit. I torque to 65lbs in 3 steps (20-40-65).
Savington is offline   Reply With Quote
Old 06-02-2016, 06:15 PM   #17
Senior Member
Thread Starter
 
mmmjesse's Avatar
 
Join Date: Aug 2007
Posts: 568
Total Cats: 43
Default

you guys are great, thanks for all the information.

EDIT: As thanks i have now become a proud supporter.

Last edited by mmmjesse; 06-02-2016 at 06:59 PM.
mmmjesse is offline   Reply With Quote
Old 06-03-2016, 02:38 AM   #18
Senior Member
 
Join Date: Jun 2015
Location: TAMPA, FL
Posts: 644
Total Cats: 27
Default

I put in the arp studs because the head was already off. I think that's why 90 percent of us do it.

I think it's a good thing because it's more consistent than using bolts. You don't have to fiddle around in the bolt hole getting it clean and chasing the threads. They're just sitting up top, easy to clean and lube before you put in the nuts.

I have always torqued to about 60-65 ft lbs in three steps.
AlwaysBroken is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
MP62 - Not faster than stock!? Frenchmanremy Supercharger Discussion 23 08-08-2016 12:27 AM
Oversize valves OK with stock cams? halfrican Engine Performance 5 06-06-2016 01:28 PM
HELP!! Coolant lines keep leaking! BBV DIY Turbo Discussion 11 06-05-2016 09:13 PM
Wheels, MAC Boost Solenoid, MSM Springs, ARP, Trigger Wheel jbguillo Miata parts for sale/trade 2 05-30-2016 07:23 PM
Custom motor mounts captain_kjr Engine Performance 2 05-27-2016 07:48 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:36 AM.