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#15
by
Turbinepowered
on 15 Aug, 2008 15:06
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sounds scary to me. I would NOT want to torque the studs as the bentley says to do the stretch bolts. I think the ARP tech is not what it should be. I could be wrong, but when the torque to yeild bolts start "yeilding" it sounds bad...if you did that with a 8740 chromemoly stud I think the head or gasket would be screaming instead. Probably wouldn't be good on the blocks threads either, but I as I am not the expert I would be more inclined to listen to the raceware people.
Sorry for not being more helpful on where to find the undercut stud in the original post.
Keep in mind I was using studs in a
non torque-to-yield application, and said as much. That was part of my "what I'm doing with them" explanation.
Sorry, that was my fault for not including that here.
Basically, I said I had ARP # 204-4701 stud kit from a VW 8v that I'm putting in my 8v VW diesel, and "do I need to do anything special to torque them down, or do I just follow the 36-50-65 ft-lb torquing procedure in the book?"
I don't think my little arms would make it to the yield strength on a stud. My little 150 ft-lbs torque wrench certainly wouldn't!
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#16
by
burnt_servo
on 15 Aug, 2008 17:33
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am i missing something here
?
on my brothers 1.6 td in his samuria we used arp studs ( the ones marked ford cosworth )
and in the instructions included it said to torque them to 130 foot pounds , which we did in gradual steps . ( actually i had him take them up to 140 foot pounds , i forget why , but we had to take the head off after he torqued them the down the first time .....)
where are you guys getting 80 foot pounds from ?
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#17
by
captainpartytime
on 15 Aug, 2008 22:54
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I just pulled out the installation instructions for my ARP Ford Cosworth Sierra/Escort Head Stud (251-4701). It says to torque the nuts to 80 ft. lbs. w/ ARP moly assembly lube and 120 ft. lbs. w/ 30wt motor oil.
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#18
by
riddleyo
on 16 Aug, 2008 08:11
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I don't think I would feel secure with only 50 ft. lbs holding my head on.
I torqued my ARP Ford Cosworth Sierra/Escort Head Studs to 30-50-65-80 ft lb increments.
Any head stud or and head bolt needs to be torqued down gradually to prevent the aluminum cylinder head from warping. That is what I thought "multi-torquing" meant anyway. Sometimes you can loosen and re-torque to break any friction that messes up the final torque value.
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#19
by
DieselKraut
on 16 Aug, 2008 15:59
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When useing ARP or Raceware studs do you hand thread them in to the block and thats it or are the torqued?
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#20
by
Turbinepowered
on 16 Aug, 2008 16:25
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When useing ARP or Raceware studs do you hand thread them in to the block and thats it or are the torqued?
I hand-threaded the studs and torqued the nuts.
... that sounds painful!
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#21
by
Loud&Obnoxious
on 16 Aug, 2008 21:06
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Clean the threads in the block with a tap or chaser, install the studs hand tight, torque the nuts down as ARP says to and then do a hot torque. A hot torque is done after the engine has been ran and heated up to normal driving temps, shut it off and let it cool down to around 140* and retorque one at a time (break it loose and retorque). I usually add about 10ftlbs of tq over what ARP suggests.
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#22
by
saurkraut
on 17 Aug, 2008 12:31
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I don't think I would feel secure with only 50 ft. lbs holding my head on.
I torqued my ARP Ford Cosworth Sierra/Escort Head Studs to 30-50-65-80 ft lb increments.
Any head stud or and head bolt needs to be torqued down gradually to prevent the aluminum cylinder head from warping. That is what I thought "multi-torquing" meant anyway. Sometimes you can loosen and re-torque to break any friction that messes up the final torque value.
"multi-torquing" is my word for tightening/loosining/retightening that was specified in one of the myriad of ARP torqueing procedures.
The raceware studs are torqued in 3 or 4 progressive stages too, with an optional retorque after cooldown from the first run. I have the sheet somewere if anyone is interested.
The Raceware studs and fasteners have a proprietary anti friction coating on them. People have overtorqued them thinking that 50 ftlbs wasn't enough too and warped heads and/or stripped the studs.
Torq value only loosly relates to clamping force. The Raceware studs need less torq to achieve the same clamping force that the ARP studs need (choose one) 70, 80, 90, 100, 110, 120, 130, 140 ftlbs to achieve.
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#23
by
Smokey Eddy
on 18 Aug, 2008 02:02
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I just pulled out the installation instructions for my ARP Ford Cosworth Sierra/Escort Head Stud (251-4701). It says to torque the nuts to 80 ft. lbs. w/ ARP moly assembly lube and 120 ft. lbs. w/ 30wt motor oil.
That makes a lot of sense. There has been SO much speculation on this thread but i think this is the most feasible route to follow.
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#24
by
chrischris
on 18 Aug, 2008 19:23
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Ok guys, I have the studs and I am going to get my head drilled to allow the larger 12mm studs.
Now I am faced with the problem of finding washers to fit the new 12mm bolt recess holes. I lost my old washers and my new arp washers are too large. I found a spare washer that fits in but seems a little too small.
Are tight fitting washers important?
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#25
by
Jet A
on 18 Aug, 2008 21:49
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sounds scary to me. I would NOT want to torque the studs as the bentley says to do the stretch bolts. I think the ARP tech is not what it should be. I could be wrong, but when the torque to yeild bolts start "yeilding" it sounds bad...if you did that with a 8740 chromemoly stud I think the head or gasket would be screaming instead. Probably wouldn't be good on the blocks threads either, but I as I am not the expert I would be more inclined to listen to the raceware people.
Sorry for not being more helpful on where to find the undercut stud in the original post.
To shed some more light on this....
Provided the thread pitch is the same, 30ftlbs is 30ftlbs regardless of the material of the bolt or stud is made from.
Also, that is why studs are resuable. They do not exceed the yeild of the material therfore they do not stretch.
You are applying slightly more clamping force on a stud, when using a torque wrench at the same setting for a bolt. Some of the torque actually goes into twisting the bolt, where as in a stud you do not get that. (thats why you get the difference in values when using different lubes)
As for ARP and different torque values. When part numbers are called out from a different vehicle and you apply them to your vw, why would you expect to get a straight anwser?
Comparing apples to apples, if the thread pitch is the same on the arp vs the raceware. the torque values should be the same.
Best procedure i have seen for studs....bottom tap your block. clean the holes. screw in the stud to bottom. back out 1 revolution. install gasket and block. using 3 or 4 steps, torque the head. warm it up, let it cool a bit, and retorque.
Try to lift the head....(its the skinny pedal)
Im running ARP studs in a truck making over 700 rwhp....so i am a little biased.
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#26
by
Jet A
on 18 Aug, 2008 21:51
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Ok guys, I have the studs and I am going to get my head drilled to allow the larger 12mm studs.
Now I am faced with the problem of finding washers to fit the new 12mm bolt recess holes. I lost my old washers and my new arp washers are too large. I found a spare washer that fits in but seems a little too small.
Are tight fitting washers important?
Not as important as the correct alloy.
Dont be subsituting grade 2 hardware in there..... :shock:
Phone call to arp is probably the correct approach.
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#27
by
theman53
on 19 Aug, 2008 10:07
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I guess to maybe shed some light to what I meant was....
The head bolts for the vw are torqued then torqued and then through the series of 1/4 turn and 1/2 turn and 1/4 turn then the 1,000 mile 1/4 turn ...... I don't have my bentley in front of me but just from my memory that is something like it, I might have an extra 1/4 turn in there but the point is.....
That is what the manufacturer calls for on their head bolts, to my knowledge there is no torque value for the head bolts. If there is let me know. If ARP or whoever says " just do what the manufacturer does for the head bolts " I think it would be too much. After the 1/2 turn I think things would start to get difficult and ugly. This is what I was thinking in my response earlier, no offense to anyone, but just the way I was thinking. The 8740 chromemoly wouldn't yeild and the aluminum head or head gasket probably would or the threads in the block might not like it.
Like everything else I am probably overthinking and wrong, but I hope I am a little more clear on what I meant earlier is that ARP probably shouldn't say just do what the stock bolts call for. Lucas
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#28
by
Jet A
on 19 Aug, 2008 20:49
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I guess to maybe shed some light to what I meant was....
The head bolts for the vw are torqued then torqued and then through the series of 1/4 turn and 1/2 turn and 1/4 turn then the 1,000 mile 1/4 turn ...... I don't have my bentley in front of me but just from my memory that is something like it, I might have an extra 1/4 turn in there but the point is.....
That is what the manufacturer calls for on their head bolts, to my knowledge there is no torque value for the head bolts. If there is let me know. If ARP or whoever says " just do what the manufacturer does for the head bolts " I think it would be too much. After the 1/2 turn I think things would start to get difficult and ugly. This is what I was thinking in my response earlier, no offense to anyone, but just the way I was thinking. The 8740 chromemoly wouldn't yeild and the aluminum head or head gasket probably would or the threads in the block might not like it.
Like everything else I am probably overthinking and wrong, but I hope I am a little more clear on what I meant earlier is that ARP probably shouldn't say just do what the stock bolts call for. Lucas
Got ya.
Probably best to get a straight reasonable anwser from arp.
Actually, maybe i will sit down with a calculator tommrow and just figure it out. anybody have the thread pitch of the arp studs? are they the same as the block threads?
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#29
by
arb
on 19 Aug, 2008 21:00
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My so called VW head bolts have a sholder before the captive washer. THis causes a problem as when you try to incert them, the washer hits the cam bearing cap,,,