Evan Purple240zt Posted July 18, 2001 Share Posted July 18, 2001 I used 60ft lb for final torque. Seems to be leaking from the water jackets slightly. Someone mentioned 80ft lb. Help!!!! Evan Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 quote: Originally posted by Evan Purple240zt: I used 60ft lb for final torque. Seems to be leaking from the water jackets slightly. Someone mentioned 80ft lb. Help!!!! Evan NO. 60 lb-ft is about as high as you should go with the ARP head studs. Actually, it's a little higher that they recommend. For an aluminum head, my ARP instructions say to torque to 35lb-ft if you use the ARP moly lubricant, and 55lb-ft if you use motor oil for the lubricant. Tightening torque has little to do with clamping force when you are talking about head studs vs. head bolts. The studs will offer considerably more clamping force at 55lb-ft than the stock head bolts did at 65lb-ft. It seems to be pretty common for the metal head gaskets to have oil/water sealing problems. Did you use any kind of sealer/coating on the gasket before you installed it? I know James uses the spray on copper coating, and doesn't seem to have any problems. Also, after running the engine up to it's normal operating temp, it's a very good idea to let it cool back down (overnight) and retorque the head studs. Back each one off about 1/8 turn, and retorque. This usually helps the gasket to seal, as the expansion/contraction of the warm engine crushes the combustion chamber sealing ridges a bit. The sealing ridges around the combustion chambers is most likely what is keeping the oil/water passages from sealing properly, BTW. I usually retorque the head two to three times after installing a new gasket, just to be safe. [ July 17, 2001: Message edited by: TimZ ] Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 18, 2001 Author Share Posted July 18, 2001 60 lb-ft is about as high as you should go with the ARP head studs. Actually, it's a little higher that they recommend. For an aluminum head, my ARP instructions say to torque to 35lb-ft if you use the ARP moly lubricant, and 55lb-ft if you use motor oil for the lubricant. Whoa scary scary stuff, i way overtorqued the head then. Man, i heard about 900 different torque values for the studs. It seems to be pretty common for the metal head gaskets to have oil/water sealing problems. Did you use any kind of sealer/coating on the gasket before you installed it? I know James uses the spray on copper coating, and doesn't seem to have any problems. I did NOT use any sealer, because i read not to use sealer (rather someone didnt use sealer, and had no problems). Also, after running the engine up to it's normal operating temp, it's a very good idea to let it cool back down (overnight) and retorque the head studs. Back each one off about 1/8 turn, and retorque. This usually helps the gasket to seal, as the expansion/contraction of the warm engine crushes the combustion chamber sealing ridges a bit. The sealing ridges around the combustion chambers is most likely what is keeping the oil/water passages from sealing properly, BTW. I usually retorque the head two to three times after installing a new gasket, just to be safe. Tim, assuming I didnt damage my studs when i bolted on the head, is it safe to retorque them to the proper specs? Its not even really a leak, it just looks wet. Maybe im not TOO screwed! Thanks tim!- Evan Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 18, 2001 Author Share Posted July 18, 2001 OH btw, why to studs torque so much better than a bolt? Evan Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 quote: Originally posted by Evan Purple240zt: Whoa scary scary stuff, i way overtorqued the head then. Man, i heard about 900 different torque values for the studs. Well, if you only went to 60lb-ft, you weren't too far off. I've heard lots of people quote higher values, too, but as far as I can tell, the values ARP recommends are what I quoted. It wouldn't hurt to double check with them, though. I do know that someone on this list followed the advice of TEP, and torqued his head studs to something like 85 or 90 lb-ft, and promptly broke one of them off in his block. quote: Tim, assuming I didnt damage my studs when i bolted on the head, is it safe to retorque them to the proper specs? Its not even really a leak, it just looks wet. Maybe im not TOO screwed! If you haven't broken them yet, you are probably alright . You did just go to 60lb-ft, right? Anyway, I would think that you should have no problems retorquing to the proper specs. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 quote: Originally posted by Evan Purple240zt: OH btw, why to studs torque so much better than a bolt? Evan My understanding is that it is due to a couple of effects. First, since you are tightening a nut onto a stationary stud, there is considerably less friction, compared to threading a bolt into a hole. With the bolt, you have more threads making contact as it is screwed into the block. Part of the tightening torque gets used overcoming this friction. Also, because the thread pitch is finer on the head studs, a given torque at the nut translates into more clamping force, from the greater leverage the fine pitch provides. Maybe a metallurgist or fastener expert can chime in now, and correct any misrepresentations I have made... Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 18, 2001 Share Posted July 18, 2001 Man, the torque specs for the ARP head studs are as elusive and the Yetti! I called ARP and was told 48ft-lb with moly lube and 65ft-lbs with oil. I know of people saying to go 80-90ft-lbs, but there is no reason to do that and you weaken the studs. I also snapped a stud off in the block torqueing to 65-70ft-lbs with moly lube. Although ARP said it wasn't possible and I must have torque'd it much much more it snapped off. If you used moly lube then retorque to the specs ARP suggests. There torque numbers are based on the stud sizes from what I was told. I actually have to call them tomorrow because 1 of my studs is slightly bent and I will ask for the specific specs again. I won't be suprised if it has changed from what they last told me. BTW, Tim is correct about studs having a much higher clamping force with less torque. Hell, the pitch on the threads is different so stock torque specs immediately go out the window. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 18, 2001 Share Posted July 18, 2001 i wrote earlier that i used 80 ft pounds on my apr studs, i also use a 2mm hks head gasket. the reason that i used 80 pounds is that i started with 65 ft pounds that the instructions read. then when i took it to a well respected zcar specialist in ft worth tx he told me that they should be at 80. This coming from a man that has built race engines. so i'll take his word and first hand knoledge any day. Once again, its up to you to do as you wish Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 18, 2001 Author Share Posted July 18, 2001 I heard 60 recently. The studs are a friggin joke. You think someone would know a good spec. 80? thats pretty high. IMO wouldnt reuse those studs if you go to put on a new head as you had asked. James. post what you find tomorrow. I really need to know so i can fix whatever ive done after work. I torqued to 60ft/lb with moly lube. Thanks guys, you rule- Evan PS how the hell are you supposed to use A bolt stretch gauge on a head stud? am i missing something here? Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 The 45/65 numbers are also on my ARP instruction sheet, but it appears that this is intended for iron heads. Here's the whole quote: PRELOAD (TORQUE) RECOMMENDATOIONS: (a) Torque values are based on 75% of the fasteners yield strength. Use the manufacturers torque sequence but do not use the engine manufacturers torque specs. Torque the studs to 45 ft lbs for ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER) or 65 ft lbs with motor oil. ( Due to the heat expansion rate of ALUMINUM, it is recommended that the preload on the fastener should be 60% of the fasteners yield strength. This torque is 35 ft lbs with ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER) or 55 ft lbs with motor oil. NOTE: If you do not feel comfortable using the 75% of yield figure, the 60% figure can be used but NEVER go below that percentage. After reading this, I think it's pretty evident why there is so much confusion - these instructions are not particularly clear. When I first read it, I thought they were talking about torquing the studs into the block in part (a), and the nut onto the stud in part (. This was not the case - it said elsewhere to 'hand tighten only' when installing the studs into the block. Maybe if I get some time later, I'll transcribe the whole sheet for everyone to see. The thing I don't get is that it seems like I'm the only one that ever got an installation instructions sheet with my studs. Are they not sending them out with instructions anymore? [ July 18, 2001: Message edited by: TimZ ] Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 18, 2001 Share Posted July 18, 2001 Oh lord, another company with their heads up their ass! Well, of the 3 different torque specs ARP told me in 1 conversation, which one do you want to hear? I first asked what was the torque spec with moly lube and was told 60ft-lbs. I then said the last time I called I was told 48ft-lbs and the lady then said, oh yea that is what my catalog says! What the heck. I then proceeded to tell here that Tim's brochure said 35ft-lbs and she then tells me, go with that torque spec. What the hell! I said to her that she had given me 3 different specs within 1 conversation! She thought that was funny and began to laugh. I wish someone would develop a device to where I could shock someone through the phone. I would give her about 10,000 volts! I then ask to be transfered to someone who had a clue about torque specs. The next guy was sorta rude, I guess she gave him the skinny before talking with me. He tells me without a doubt that the spec is 48ft-lbs with moly and 61ft-lbs with oil. I asked him if he is sure and why that is different that what Tim's brochure stated. He said that I must be mistaken and that is what his book says. I did find that ARP only buys the studs and gets the spec's from the actual manufacturer. That is why the lady initially told me 60ft-lbs with moly because the manufacturer was telling them to go higher! What a crappy bunch of folks I spoke with. Can someone else call and let me know what they say? 800.826.3045 Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 BTW, you should notice that from these numbers, 100% of the fasteners yield strength happens at 60 lb-ft with Moly lube and 90 lb-ft with motor oil. I think that 100% of the yield strength is where the fastener breaks... Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 18, 2001 Share Posted July 18, 2001 James... I'll scan the sheet in tonight and e-mail it to you. Maybe you could put it up on your website, so that we could link the image here. I guess they thought I couldn't read? Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 19, 2001 Author Share Posted July 19, 2001 this sucks it must be 61ft/lb with moly lube cause thats what i used! lol Evan I nave not run the motor for more than like 3 minutes after the HG swap. Im going to fix my torque before i fire it again. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 19, 2001 Share Posted July 19, 2001 i am following this thread with some interest, as eventually i want to get some of these head studs. what is not making sense to me is the recommendation of hand-tightening the studs into the block. if you hand-tighten, then you are not realizing the benefits of the studs, which is a large preload partially neutralized by a nut on the top end, reducing stress on the block threads. any further ideas? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 19, 2001 Share Posted July 19, 2001 Well, maybe I didn't explain what I meant well enough. The theory behind the studs is you preload the threads in the block with the stud (bottom it out, and torque it). Then when you torque the nut down, you relieve the stress on the block threads, and you have a net cancellation of forces in the block that will hold the cylinder head down more reliably. Actually, I've heard (not stating a fact), the retention of the stud, or any threaded fastener, is supported only by three threads, and adding any more does not increase the retention force. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 19, 2001 Share Posted July 19, 2001 I had thought the same thing, Sleeper. That was why I had originally misinterpreted the instructions that I quoted earlier. I had originally torqued them in as you stated, but was then told that that was a bad thing, so I pulled them back out and installed them hand tight. I'm starting to think that nobody knows what you are actually supposed to do with these damned things. Actually, you are the first person that I have heard bring the pretensioning issue up. I had read the same thing, either in Maximum Boost, or one of Carrol Smith's books, but was starting to believe that I must have misread it. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 19, 2001 Share Posted July 19, 2001 Yes, I'm pretty sure it was printed in "Maximum Boost". It seems to me that whatever you do to install the studs in the block, it shouldn't affect how you torque the nuts over the cylinder head -- that determines the pressure on the head and the gasket. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 20, 2001 Author Share Posted July 20, 2001 I cant BELIVE what a long thread this has created. It seems very confusing to me. I am going to retorque to 35 ft/lb and hope for the best. Evan Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 20, 2001 Share Posted July 20, 2001 Evan... This is going to sound like sacriledge, but I would just use motor oil, and use the 55 lb-ft number, instead. The reasoning behind this is that after you've run for a while, and need to retorque, you'll have a mix of whatever moly lube is left, and motor oil. Maybe you have that now. If you just stay with good old fashioned motor oil, it seems to me that you will actually end up with more predictable, repeatable results. I originally tried just using the moly lube and 35 lb-ft, and moly or not, that just felt SCARY loose. Also, unless you have a low-torque torque wrench, it's fairly hard to get consistent performance at the low end of the torque wrench's torque range (at least it is on my Crapsman wrench ). I was just much more comfortable using a higher torque setting, where it feels like I'm actually tightening something, and the torque wrench gives a nice, solid CLICK. [ July 19, 2001: Message edited by: TimZ ] Quote Link to comment Share on other sites More sharing options...
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