BoostedBalls Posted January 4, 2006 Share Posted January 4, 2006 Thanks 211 for the insight. I always called it "bolt enlongation"; not sure where I came up with the term though. I've always retorqued my head bolts on anything that I would consider high performance, and always on copper gaskets. I've never had a HG fail that I've installed but that's not proof that the retorque kept them from blowing. Quote Link to comment Share on other sites More sharing options...
211 Posted January 5, 2006 Share Posted January 5, 2006 Thanks 211 for the insight. I always called it "bolt enlongation"; not sure where I came up with the term though. I've always retorqued my head bolts on anything that I would consider high performance, and always on copper gaskets. I've never had a HG fail that I've installed but that's not proof that the retorque kept them from blowing. And not to say that a retorque isn't a good thing either! In a perfect world we should retorque all our engine components, but because the soob's head bolts are not the easiest thing in the world to access... if you don't mind going through the extra effort do to the job right, by all means, go for it! And props to who does. Quote Link to comment Share on other sites More sharing options...
robm Posted January 5, 2006 Share Posted January 5, 2006 That graph is good science, but the terms used to describe the effects are not quite right. In material science, "yield" means the object being stretched doesn't come back to the original length. The effect noted on the graph is due to the torque being released. The strain (the amount the bolt stretches or deforms) is due to torsion (twisting) and overall elastic stretching of the bolt. Once the twist is removed, all that is left is the stretch. I would expect the remaining "relaxation" that occurs over the next few hours to be due to further release of torsion effects, as the bolt head adjusts itself. Well lubricated bolts show less of the torsion effect, and reach their final elongation quicker. Well lubed head bolts, with modern gaskets, will probably not need to be retorqued. True "stretch" bolts that cannot be reused actually do yield as they are torqued. They will be longer when removed. Most bolts are not "stretch" bolts, and will be the same length when removed as when they started. Quote Link to comment Share on other sites More sharing options...
blownbimer Posted January 24, 2006 Share Posted January 24, 2006 Anyone able to order one of subaru special tools? I just tried at my local dealer and they said they could have one by the end of feb....I was hoping for one a little sooner... any ideas? when I put the number into one of the subaru web sights they freek out. Thanks Erik Quote Link to comment Share on other sites More sharing options...
WJM Posted January 24, 2006 Share Posted January 24, 2006 Anyone able to order one of subaru special tools? I just tried at my local dealer and they said they could have one by the end of feb....I was hoping for one a little sooner... any ideas? when I put the number into one of the subaru web sights they freek out. Thanks Erik Thats just the way it is. You cannot get the tools from SUBARU at all...SUBAUR dealers order then thru kentmoore. After subaru sends the tools out to the dealers, kentmoore buys all of them up and inflate the prices....subaur dealers can still get them, but only thru kentmoore. YOU can get them from kentmoore if you have the PN. SUBARU still lists information for the PN...but the tools are always listed as 'inactive' and 'obsolete'...so you cannot order them from subaru anymore. Quote Link to comment Share on other sites More sharing options...
Ross Posted January 24, 2006 Share Posted January 24, 2006 SUBARU still lists information for the PN...but the tools are always listed as 'inactive' and 'obsolete'...so you cannot order them from subaru anymore. I got mine a few months ago, and it came straight from subaru japan. Thats an ea81 one, dunno if they're the same... Quote Link to comment Share on other sites More sharing options...
jdlmodelt Posted March 11, 2009 Share Posted March 11, 2009 I'm curious, I haven't read anything about the 90 degrees of rotation of each head bolt times two? Are you guys just torquing to 50 ft-lbs and not doing any of the 90 degrees of rotation after that? I'm putting one of these back together this weekend and don't want to fudge it up. Thanks, james Quote Link to comment Share on other sites More sharing options...
Gloyale Posted March 11, 2009 Share Posted March 11, 2009 I'm curious, I haven't read anything about the 90 degrees of rotation of each head bolt times two? Are you guys just torquing to 50 ft-lbs and not doing any of the 90 degrees of rotation after that? I'm putting one of these back together this weekend and don't want to fudge it up. Thanks, james The 90 Degree stuff is for the newer EJ engine series. You are probably reading specs from a Haynes or Chiltons that is covering both types of models, and you are reading from the wrong portion. Or the Typo'd it, which is common for both books. Now that you have mentioned it though...... I have recently done a few EA82s were I used a modified version of the EJ proceedure to torque my Headgaskets. THIS IS MY METHOD.....THESE ARE NOT FACTORY TORQUE SPECS.....USE AT YOUR OWN RISK: Use the factory tightening pattern for bolt sequence, but with modified torque 1. Torque all bolts to 20 ft/lbs, ..... then to 35 ......then to 45. 2. Next, loosen all bolts 180 degrees (Just once, loosening them 180 twice is just rediculous, even on the EJs...I think) 3. Retighten the middle 3 bolts, between the cylinders, to 20 ft/lbs. (bolts 1,2,3 in the factory sequence) 4. Retighten the remaining bolts to 18 ft/lbs 5. Tighten all bolts by 80-90 degrees 6. Tighten all bolts by an additional 80-90 degrees.(no more than 180 total) AGAIN, THIS IS A METHOD INVENTED OFF THE TOP OF MY HEAD ADAPTING THE NEWER EJ SCIENCE TO THE OLD GEN. NO WARRANTY EXPRESSED OR IMPLIED Quote Link to comment Share on other sites More sharing options...
robm Posted March 11, 2009 Share Posted March 11, 2009 I would think that torquing head bolts is a function of the bolt, the head design and the gasket design. I would be leery of adapting a new procedure to old bolts, heads and gaskets. Just out of curiosity, Gloyale, have you checked the head bolt torque subsequent to tightening them with the EJ procedure? Quote Link to comment Share on other sites More sharing options...
torxxx Posted March 12, 2009 Share Posted March 12, 2009 The torq specs on the EJ series motors end up slightly higher than EA series head specs. I always overtorq mine about 8 ft/lbs on my EA 82 and have had no problems. I also dont see a problem with the EJ series sequence and not re tightening them because step 2 and 3 seats and unseats the head to the gasket making the imprint and then backing it off simulating the re-torque. Also the EA-81s require retorq but I dont think the 82's ever called for it. I've done 100's of those motors without retorqing it Quote Link to comment Share on other sites More sharing options...
Gloyale Posted March 12, 2009 Share Posted March 12, 2009 (edited) Just out of curiosity, Gloyale, have you checked the head bolt torque subsequent to tightening them with the EJ procedure? It ends up being around 60 ft/lbs. Hard to tell, cause I'd have to overtorque it more to find out just how much there is. But I really believe that tightening by angle get's the the head to the most even compression. Torque can too easily be affected by bolt friction. Espescially with reused bolts in old threads that have been torqued who knows how many times. I've done 2 EA82s(one is turbo) this way so far, and both are holding up fine. Long term, the jury is still out.....but I am quite confident they it's okay. Edited March 12, 2009 by Gloyale Quote Link to comment Share on other sites More sharing options...
robm Posted March 12, 2009 Share Posted March 12, 2009 (edited) One is supposed to chase the threads, clean the bolts, and lubricate everything when torquing head bolts. That should reduce variability of torque vs. compression force generated by the bolt, which is what we are really trying to achieve. Having thought about it, I agree that torquing by angle has its points. The question is if the tightening by that angle stretches the bolt (elastically) enough to give the required force, or too much. This is a function of thread pitch, bolt diameter and length, and material. Should be fairly easy to calculate. Too much will stretch head bolts permanently (beyond yield, into plastic flow). Too little will allow headgasket leaks, and break headbolts by fatigue. How much difference is there between the headbolts of the EJ and EA82's? Edited March 12, 2009 by robm Clarifiy "stretch head bolts" Quote Link to comment Share on other sites More sharing options...
idosubaru Posted March 13, 2009 Share Posted March 13, 2009 i've seen too many ghetto head jobs hold up just fine to think it matters that much, sounds like a good plan to me though i'll just stick to the old methods...if i ever do an EA engine again. as far as i know the PT Felpro's with the standard overtorque hold up extremely well, so why are you changing from that? Gloyale, have you had some come back with problems, is that why you're doing this? Quote Link to comment Share on other sites More sharing options...
Gloyale Posted March 13, 2009 Share Posted March 13, 2009 Gloyale, have you had some come back with problems, is that why you're doing this? The materials are nearly the same. The engine design is very similar. The set, loosen, tighten to angle method just seems better. They switched to it for a reason. I sometimes feel I have tightened the bolt sufficiently, but the torque hasn't reached spec and I have ended up loosing threads(stripped) Other times, the torrque is quite high on one bolt, even when I haven't turned it as far as the others. Just a hunch really. I figure it was worth a shot rather than just overtorquing or having to retorque (which I've done, but I don't like doing) using off brand gaskets and such. I didn't say I recommend it. Just trying it on my wheeler. Just trying to use up a pile of EA82s I've got. Quote Link to comment Share on other sites More sharing options...
robm Posted March 13, 2009 Share Posted March 13, 2009 I came across an interesting article on this topic: http://www.acl.co.nz/Tech/Torque%20To%20Yield%20Headbolts.pdf Are the EJ's using "stretch" bolts? However, I can't see why it won't work on EA's, as long as the stress in the bolt stays below the elastic limit. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted March 13, 2009 Share Posted March 13, 2009 I came across an interesting article on this topic: http://www.acl.co.nz/Tech/Torque%20To%20Yield%20Headbolts.pdf Are the EJ's using "stretch" bolts? However, I can't see why it won't work on EA's, as long as the stress in the bolt stays below the elastic limit. No, Subaru's don't use "stretch" bolts. EA82 bolts are actually beefier than EJ bolts. M11 EA vs. M10 EJ Quote Link to comment Share on other sites More sharing options...
spikedbeetle Posted February 5, 2010 Share Posted February 5, 2010 (edited) The FSM says to re-torque the head bolts after warming the engine up when you do HG's. I've heard mention of a special socket to reach the headbolts without taking off the cam cases. Do I need this, or can I just grind down a regular socket? Also, should I do this right away or wait a bit so the engine can go through several heat-up cool-down cycles? And finally, the FSM also says to turn the bolts back 60 degrees and re-oil them before torquing. What is the point in this and how on earth can the oil get down to the threads? Thats just the way it is. You cannot get the tools from SUBARU at all...SUBAUR dealers order then thru kentmoore. After subaru sends the tools out to the dealers, kentmoore buys all of them up and inflate the prices....subaur dealers can still get them, but only thru kentmoore. YOU can get them from kentmoore if you have the PN. SUBARU still lists information for the PN...but the tools are always listed as 'inactive' and 'obsolete'...so you cannot order them from subaru anymore. Here is the Special tool. Edited February 5, 2010 by spikedbeetle Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 5, 2010 Share Posted February 5, 2010 Yeah - if anyone wants a "special" socket for doing it - send me one and I'll turn it down on my lathe . I have carbide tooling for just such occasions. GD Quote Link to comment Share on other sites More sharing options...
robm Posted February 5, 2010 Share Posted February 5, 2010 Re: oiling the bolts on retorque: It is probably not the threads that are being oiled, but the bolt heads, so that the torque is not absorbed by friction, it actually goes to the thread and stresses the bolt. Quote Link to comment Share on other sites More sharing options...
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