BlackBeast Posted December 31, 2014 Share Posted December 31, 2014 I am currently about to replace head and thought I might need to replace head bolts also on my 2.5 89..I can't find these bolts ..I Did however talk to the Arp bolts dealer and they said they could get me some but I'm sure they will be pricey.I also am sure the bolts haven't been reused and the books say u can re use once ! So what's ur thoughts and advice about reusing them or getting new and where u get or others get there's . Thanks. Link to comment Share on other sites More sharing options...
nitroxsteve Posted December 31, 2014 Share Posted December 31, 2014 I reused the ones in my 4.0 with no problems. I don't see a problem with reusing them once. Link to comment Share on other sites More sharing options...
gogmorgo Posted December 31, 2014 Share Posted December 31, 2014 The ones you don't ever want to reuse are torque-to-yield fasteners. Generally speaking, if the torque spec for the bolt is XX ft-lbs + XX°, it means it's a torque-to-yield bolt, which means that you tighten the bolt until it yields; that is, it becomes permanently deformed. I haven't looked up the torque spec for you, but if it's just a straight ft-lbs number, then you should be able to get away with reusing them, provided none of them are stripping, or necking, or otherwise look damaged. It's usually still better to be safer than sorry, though. Link to comment Share on other sites More sharing options...
Minuit Posted December 31, 2014 Share Posted December 31, 2014 My 1991 FSM says head bolts can be re-used once. I would get new ones personally, but that's up to you. Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 31, 2014 Share Posted December 31, 2014 They are not pricey, $24 at Summit, call them if you cannot find it online. Order the ones for a '97 and you'll get the 12 point bolts. Or you can get a set for the 4.0, same bolts just more of them. No, do not reuse 25 year old bolts. Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 31, 2014 Share Posted December 31, 2014 Image Not Found Link to comment Share on other sites More sharing options...
BlackBeast Posted December 31, 2014 Author Share Posted December 31, 2014 Great thanks guys I will check summits bolts out! I have heard people re use them without problems and am aware they aren't torque to yield. But it's 110 lbs or 100 and that's enough to make me weary on a old bolt! I no I have 4 1/2 inch by 1/2 and a 3 3/4 inch length by half diamter..and I haven't measured them all but they are 1/2 bolts. 13 thread I think. But I will order from summit and call them if there that cheap and gives me a better feeling! Link to comment Share on other sites More sharing options...
Eagle Posted December 31, 2014 Share Posted December 31, 2014 Great thanks guys I will check summits bolts out! I have heard people re use them without problems and am aware they aren't torque to yield. But it's 110 lbs or 100 and that's enough to make me weary on a old bolt! Do you replace your wheel studs every time (or every second time) you rotate your tires? They are 1/2" and the torque spec (depending on what year FSM you look at) is anywhere from 85 pounds to 115 pounds. By the way, the word is "wary." "Weary" means extremely tired. Link to comment Share on other sites More sharing options...
kook911 Posted December 31, 2014 Share Posted December 31, 2014 I reused mine also. Each is there own Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 31, 2014 Share Posted December 31, 2014 Read- http://www.federalmogulmp.com/en-US/Technical/Documents/How%20To%20Prevent%20Head%20Gasket%20Failure%20-%20Low%20Clamping%20Force.pdf A bolt will lose more than 50% of it's clamping force when reused, interesting read on Ubolts here- see second page. http://www.suspensionspecialists.com/techinfo/Ubolt_Information.pdf Link to comment Share on other sites More sharing options...
HOrnbrod Posted December 31, 2014 Share Posted December 31, 2014 Great thanks guys I will check summits bolts out! I have heard people re use them without problems and am aware they aren't torque to yield. But it's 110 lbs or 100 and that's enough to make me weary on a old bolt! Do you replace your wheel studs every time (or every second time) you rotate your tires? They are 1/2" and the torque spec (depending on what year FSM you look at) is anywhere from 85 pounds to 115 pounds. By the way, the word is "wary." "Weary" means extremely tired. As in: This thread is making me weary. Link to comment Share on other sites More sharing options...
Comanche County Posted December 31, 2014 Share Posted December 31, 2014 I think they're a sorta hybrid TTY bolt and can be re-torqued 2-3 times max Link to comment Share on other sites More sharing options...
Eagle Posted January 1, 2015 Share Posted January 1, 2015 A bolt will lose more than 50% of it's clamping force when reused,[/url] Horse manure. A bolt only loses clamping force if it's stretched beyond its elastic limit, into the plastic range (which is another way of describing a torque-to-yield bolt). The 2.5L and 4.0L Jeep engines do not use TTY head bolts. interesting read on Ubolts here- see second page. http://www.suspensio...Information.pdf Nope. It's completely unfair, unrealistic, and useless to compare lubricated, undamaged threads against dry, damaged threads. That's essentially like saying it's more difficult to skate on sandpaper than it is to skate on ice. The statement is true, but it's useless and meaningless. Further, I can't recall ever seeing a factory service manual that called for lubricated threads. All I've ever seen is a requirement for clean, DRY threads. Torque specs generally tell you to reduce the specified torque by 15% to 25% (the percentage will vary depending on the size of the bolt and the thread pitch) if the threads are lubricated. Link to comment Share on other sites More sharing options...
Jeep Driver Posted January 1, 2015 Share Posted January 1, 2015 A bolt will lose more than 50% of it's clamping force when reused,[/url] Horse manure. A bolt only loses clamping force if it's stretched beyond its elastic limit, into the plastic range (which is another way of describing a torque-to-yield bolt). The 2.5L and 4.0L Jeep engines do not use TTY head bolts. interesting read on Ubolts here- see second page. http://www.suspensio...Information.pdf[/url] Nope. It's completely unfair, unrealistic, and useless to compare lubricated, undamaged threads against dry, damaged threads. That's essentially like saying it's more difficult to skate on sandpaper than it is to skate on ice. The statement is true, but it's useless and meaningless. Note that that comment was regarding Ubolts, I have both of these in my library and I pulled them out and posted here as "interesting read". I know you don't like me, but please read and comprehend before you jump my $#!&. Link to comment Share on other sites More sharing options...
Jeep Driver Posted January 1, 2015 Share Posted January 1, 2015 BTW, OP, Do what ever the hell you want, it's yours. I just gave my $24 opinion, the cost of the Felpro head bolts, which you are free to dismiss and you will be charged nothing. Link to comment Share on other sites More sharing options...
Eagle Posted January 1, 2015 Share Posted January 1, 2015 Note that that comment was regarding Ubolts, I have both of these in my library and I pulled them out and posted here as "interesting read". I know you don't like me, but please read and comprehend before you jump my $#!&. I don't like or dislike you. I don't know you. I DID, however, study graduate-level structural engineering and strengths of materials. And I read your links, how else would I have picked up that they are comparing new, lubricated bolts to used, dry bolts with damaged threads? Doesn't really matter if it's head bolts, u-bolts, wheel studs or any other bolt that has a specified torque. Except for torque-to-yield bolts, the specified torques are intended to generate the required clamping force while keeping the bolt within its elastic limit. And I think if you check the XJ or MJ FSM you'll find that the torques for both head bolts and u-bolts are specifically given as for "clean, dry threads." Lubricate them, and if you don't reduce the specified torque you run the risk of torquing the bolt beyond the elastic limit. That puts it into the plastic range, which is where you get permanent deformation. Link to comment Share on other sites More sharing options...
BlackBeast Posted January 1, 2015 Author Share Posted January 1, 2015 Wow u corrected my spelling thankyou it helped a bunch! Can you tell me moderator why the book says to only use them once again? You are probably right about tightening and maybe your smarter than us aall. Or maybe you drinking to much lol! Link to comment Share on other sites More sharing options...
Eagle Posted January 1, 2015 Share Posted January 1, 2015 Wow u corrected my spelling thankyou it helped a bunch! Can you tell me moderator why the book says to only use them once again? You are probably right about tightening and maybe your smarter than us aall. Or maybe you drinking to much lol! No, I can't tell you why they say you can re-use them only once. I've lost contact with the last AMC factory engineer I knew several years ago. I would guess that taking them to the specified torque must be very close to the elastic limit and that it's just a risk to push your luck with them. There are three elements involved, any one of which can fail. There the bolt itself, that can be stretched beyond the elastic limit. Once that happens, it yields (stretches), and you lose the clamping force you're trying to develop. And then there are the threads, in both the block and the bolt. The shaft of the bolt is in tension as you torque it, but the threads are acting in shear. Steel has different limits for tension, compression, and shear. And the bolt alloy is likely different than the block alloy, so the limits are also probably different. Over-torquing or over-using the bolts may just strip the threads off the shank, or maybe strip the threads out of the block. I haven't seem either mode of failure in the flesh, but I have seen a head bolt literally pull the rear corner off the block. That was ugly -- you can't fix that with a helicoil. Don't get me wrong -- using new head bolts is always better. But the factory says they can be reused once, and I've rebuilt any number of engines using the original head bolts, including a couple of race engines, and didn't have any failures. I've never rebuilt the same engine a second time but, if I did, I would believe the factory engineers and not try to use the same head bolts a third time. Link to comment Share on other sites More sharing options...
MuddFoot Posted January 1, 2015 Share Posted January 1, 2015 rockauto.com has them for around 18 bucks for the 4.0 on a 96 cherokee and a head set for your 89 for 16.87. if it was me this is the way id go Link to comment Share on other sites More sharing options...
lunghd Posted January 1, 2015 Share Posted January 1, 2015 Good grief. For $20 +/- who the hell wants to risk the cost of a replacement engine? I've reused them on engines that had a known maintenance - ie: never rebuilt or torn down. After that - replace them. Any doubts - replace them. Don't think some internet expert will replace your engine if he's wrong and has convinced you to re-use them?... - replace them. they aren't gonna pay for your motor if it fails (and neither will I)! :D $20 is cheap insurance. Link to comment Share on other sites More sharing options...
Keyav8r Posted January 1, 2015 Share Posted January 1, 2015 The purpose of this forum is to transfer accurate information, knowledge and experience among a diverse group of owners with differing plans and intententions for the use of their trucks. In that process there WILL be differences of opinion and different interpretations of information presented. Exploring those differences expands our understanding of the care, repair, improvement and use of our trucks. If we can't acept that others have different technical abilities, training, educational experiences and opinions and we aren't willing to consider that someone else may actually know more about a specific topic than we ourselves know, we will fail to learn and grow. Nothing is gained by exhibitions of hostility, animosity or other "smartass" behavior. There are already enough Jeep forums where the primary activity seems to be flaming anyone who dares to disagree with a stated opinion. We don't need to be one more of those. Our corporate goal for the forum in 2015 should be to raise the level of civility in discussions and exhibit more co-operation instead of contention. Just my personal observation and opinion. You're welcome to agree, disagree, or ignore as you please. Link to comment Share on other sites More sharing options...
lunghd Posted January 1, 2015 Share Posted January 1, 2015 Huh? I'm not sure if that was aimed at me or not but since I only posted a minute ago I'll bite... What does ANY of that have to do with headbolts? The guy is going to deal with rebuilding his engine with new or used headbolts... Maybe I'm missing something but what does social theory have to do with that? Hoss - I work for a bunch who preach 'diversity training' while leading quite exclusive lives after work where folks like us (grimy off-roading types, etc) are not welcome. In a nutshell: Folks like that want nothng more than to squelch anything that disagrees with their mindset or that forces them deal with people as individuals instead of labeled groups. The heck with that. If you Jeep - I'll help you. If you're worried about "the right sort" - I'm outta here. Seriously: Who was being 'uncivil' and just what the heck is your "corporate goal"? More importantly: what the hell does any of that have to do with going "RARRR! THIS IS FUN!!!" while wheeling over some rocks out in the woods? We're Jeepers!! Good grief! We should help out anyone - (even a broke down Land Rover owner - ha ha, you know who you are!) if he's having half as much fun as I am! (Hint: Land Rover owners usually have very, VERY large coolers! :yes: ) Again - I may have missed something... or you may be a forum troll - dunno. Don't care. All I can say is that if I can help someone keep their RENIX Jeep alive - I'll do it & I'll encourage them to spend the $25 vs not when it can save them a repeat teardown. Hope we're on the same page. Link to comment Share on other sites More sharing options...
Wesleypipesyo Posted January 1, 2015 Share Posted January 1, 2015 My name is Jeffy and I like to eat apples. Link to comment Share on other sites More sharing options...
lunghd Posted January 1, 2015 Share Posted January 1, 2015 Apples are good. I like pop tarts. Link to comment Share on other sites More sharing options...
BlackBeast Posted January 1, 2015 Author Share Posted January 1, 2015 I agree with Keyav8r we all have different opinions and I listen to them all. Thankyou for all of them. Link to comment Share on other sites More sharing options...
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