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Location:
Sydney
Registered:
September 2004
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4agte head torque settings with ARP studs?
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Sat, 06 August 2005 11:47
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Hey all. Well it's finally getting to that time and the engine's ready to be assembled. Just want to confirm the torque specs for the head.
I've got a latter block with a bigport head, HKS 1.6mm metal HG with ARP head studs. I've read the page ARP have on the torque settings:
http://www.arp-bolts.com/pages/tech/images/fasttor q.pdf
but i'm not 100% sure on which one to use. There's a piece of paper with installation proceedures on it but it says its for "190,000 Psi, 10mm Diameter" and i'm fairly certain these studs are 12mm.
Just wanting to know from people that have used ARP studs, what torque settings did you use? Does it matter that the gasket is thicker than normal or that the engine will be turboed?
Eddie.
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Location:
northern beaches
Registered:
August 2002
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Location:
Sydney
Registered:
September 2004
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Re: 4agte head torque settings with ARP studs?
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Sat, 06 August 2005 23:02
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| cri_ag wrote on Sun, 07 August 2005 02:30 |
wouldent you just follow the head gasket torque settings?
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Well i've also tried looking up HKS torque specs but can't find those either. I think it's more important to get the torque correct for the bolts because the bolts will have a specific stretch capacity regardless of what head gasket is used.
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p.s. where did you get it and how much if you dont mind me asking
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The HG was around $170ish including shipping from Japan. I got some other stuff with it though to save on the postage. The studs are about $220 or so.
Eddie.
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Location:
Adelaide
Registered:
May 2003
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Re: 4agte head torque settings with ARP studs?
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Sat, 06 August 2005 23:37
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Im pretty sure that ARP bolts are 60Nm, although when i say it it sounds wrong. I cant find my little slip of paper either.
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Location:
Sydney
Registered:
September 2004
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Re: 4agte head torque settings with ARP studs?
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Sat, 06 August 2005 23:53
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| takai wrote on Sun, 07 August 2005 09:37 |
Im pretty sure that ARP bolts are 60Nm, although when i say it it sounds wrong. I cant find my little slip of paper either.
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Are you sure it's 60Nm or 60ftlbs?
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Location:
Melbourne
Registered:
January 2003
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Re: 4agte head torque settings with ARP studs?
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Sun, 07 August 2005 01:40
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This is really starting to sound very scary 
Lets see the standard torque setting is 22ft / 29nm ?
The required clamping force required on the head from the factory bolts is 300kg-cm , which equals 4266psi .
Now the Arp list torque settings for 10mm stud , lets say you are just torquring with oil not there special  grease
1. 170,000psi , 54 ft lbs x 1.356 = 73.22nm
2. 190.000psi , 61 ft lbs X 1.356 = 82.71nm
3. 220.000psi , 68 ft lbs x 1.356 = 92.20nm
now the preload of those settings are
1. 10.680 , 751 05kg
2. 12.015 , 844.94kg
3. 13.350 , 938.82kg
Bloody imperial US crap , had to do the coversions myself and its been 10years sice i had to do these loody maths , oldcorolla better check them  .
Now do you 60nm , or 44.24 ft lbs setting = 44.24 x 16.01846
= 708.65 = 10077psi
Now lets look at the stress on the block from 4266psi to 10077psi , 5811psi difference 408.65 kg .
To give you a idea of vehicles that might need a head torque of 60+nm , you would have to look to some engine with huge long headstuds under huge stresses , mostly caused thermal expansion . In short air cooler engines , most having 30>40cm long head studs . Not the piss short 4age ones 
What happens if you over torque head fixings , easy this has been around since the days of people increasing compression of side valve V8's The block pulls in around the area , ie you get oval of square bores , yes with a mega solid v8 block with large cylinder spacing . This has been fixed by the later v8's having five studs per cylinder to lower the required clamping force per stud . Shit even "Smokey yunick" didn't even see that coming for the newer generation of v8's .
Stud are different in the torquing to bolts , mostly due to the twisting forces and stretch , but i am not going into a what is a huge debate .
But looking at the facts , can a 4age block withstand the extra force - the stud stretch without becoming oval/square ? ,ahh more maths which can be worked out via there listing of stretch via arp part numbers .
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Location:
Adelaide
Registered:
May 2003
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Re: 4agte head torque settings with ARP studs?
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Sun, 07 August 2005 03:49
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Found the little slip which came with my ARP bits... it most certainly does say 60Nm
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Location:
Sydney
Registered:
September 2004
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Re: 4agte head torque settings with ARP studs?
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Sun, 07 August 2005 08:24
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Hmm... my slip of paper tells me:
"PRELOAD (TORQUE) RECOMMENDATIONS:
Torque values are based on 75% of the fasteners yield strength. Use the manufacturers sequence but do not use the engine manufacturers torque specs. Torque the nuts to 60 ft. lbs for ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER)"
Looks like i'll just email arp to confirm the specs then.
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Location:
Melbourne
Registered:
January 2003
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Re: 4agte head torque settings with ARP studs?
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Sun, 07 August 2005 09:51
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Yeah will be interesting to see how much they over torque the head in true US overkill style , wonder how long the piston and rings last in a oval 4ag block ,75% of 190.000 psi = 142500psi thats still not 60nm . Did they just randomly pick a figure because there workings really dont make sense
More pressure with the expansion of the head etc under the normal rules applying to expansion of alloy with heat will out result in : more pressure being applied on the heat gasket working the gasket with every change between hot and cold , and more pressure on the block fixing points causing distortion of the block . With metal head gasket don't be surprised in those stages for there to be leakage especially coolant , externally and if you do have a fibreoptic lighted view you might be able to see internally in the cylinder as the two metals contract at different rates .
Should toyota have fitted stud and a higher loading ? well i think there engineers would have been light years ahead of some small company selling what is really just aircraft grade materials , nothing new that changes the rules of engine building .
Basically if you think a stronger grade of material and a higher torquing is going to stop a turboed 4ag from blowing headgaskets , you need to research the other causes of blown headgaskets in all high output engines . Maybe start with cosworth since the 4age is near a complete rip off in the combustion area and the valve base . They didn't just throw more material or strong material or more force to the headgasket at the problem when going for 300hp per litre.
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Location:
Sydney
Registered:
September 2004
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Re: 4agte head torque settings with ARP studs?
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Wed, 10 August 2005 09:55
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For anyone that's interested, i got word back from ARP the other day... definately 60 ft lbs.
Eddie.
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Location:
Melbourne
Registered:
May 2002
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Re: 4agte head torque settings with ARP studs?
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Wed, 10 August 2005 10:14
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| Big T wrote on Sun, 07 August 2005 18:24 |
Hmm... my slip of paper tells me:
"PRELOAD (TORQUE) RECOMMENDATIONS:
Torque values are based on 75% of the fasteners yield strength. Use the manufacturers sequence but do not use the engine manufacturers torque specs. Torque the nuts to 60 ft. lbs for ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER)"
Looks like i'll just email arp to confirm the specs then.
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and with engine oil?
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Location:
Sydney
Registered:
September 2004
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Re: 4agte head torque settings with ARP studs?
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Wed, 10 August 2005 11:00
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70 ft lbs with 30W engine oil. But it's a big NO NO from ARP  They say "NOT RECOMMENDED"
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Location:
Montrose, VIC
Registered:
May 2002
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Re: 4agte head torque settings with ARP studs?
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Wed, 10 August 2005 12:36
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Well, several engine building folk that I have talked to have all spoken highly of moly lube, and against engine oil, for assembling bolts. Some claim to have tried both, and seen great differences, and seeing as I'm not really in a position to argue, I won't. Still, I can't know entirely the basis of any claims they make.
Also, I generally presume manufacturers to get it right in most cases, but there are some things I seriously do wonder about...
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