msmithmmx Posted June 29, 2008 Share Posted June 29, 2008 I have a HG kit I was using but decided to go with OEM. What a difference, not even close. Is there a correct orentatation for the gasket? which side is which if there is one. Quote Link to comment Share on other sites More sharing options...
Quidam Posted June 30, 2008 Share Posted June 30, 2008 Do have the heads machined by a machine shop weather they need it or not (because they actually do). nipper "If it's aluminum, It ain't straight". Word. I'm back, kinda:) Doug Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 30, 2008 Share Posted June 30, 2008 Heads might need machining even if straight, because gaskets needs a proper surface finish. The block should be checked as well. Of course, any cuts should be as light as possible. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted June 30, 2008 Author Share Posted June 30, 2008 To Confirm is this the proper method for installingt he head? Tighten cylinder head bolts. (1) Apply a coat of engine oil to washers and bolt threads. (2) Tighten all bolts to 29 N⋅m (3.0 kg-m, 22 ft-lb) in numerical sequence. Then tighten all bolts to 69 N⋅m (7.0 kg-m, 51 ft-lb) in numerical sequence. (3) Back off all bolts by 180° first; back them off by 180° again. (4) Tighten bolts 1 and 2 to 34 N⋅m (3.5 kg-m, 25 ftlb). (5) Tighten bolts 3 , 4 , 5 and 6 to 15 N⋅m (1.5 kg-m, 11 ft-lb). (6) Tighten all bolts by 80 to 90° in numerical sequence. Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 30, 2008 Share Posted June 30, 2008 The info I have has the below following step six: Tighten all bolts again in sequence an additional 80° to 90°. The total re-tightening angle should not exceed 180° total. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted June 30, 2008 Author Share Posted June 30, 2008 Hmmmm Under my step 6 is this CAUTION: Do not tighten bolts more than 90°. Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 30, 2008 Share Posted June 30, 2008 Subaru keeps changing the recommended method. I'm not certain which is the latest. Hopefully, someone else will chime in. Okay, I just searched the forum, and found this: http://www.ultimatesubaru.org/forum/showthread.php?t=79989 Here's another variation, which is likely older, from http://www.automotivemachine.com/tech.htm : "On some models, mostly 2002-2005 2.5L DOHC engines, Subaru has had problems with head gasket sealing. The factory has revised the tightening procedure several times... this seems to be the latest version: Make sure the threads in the block are clean and free of oil or coolant. Clean the bolt threads and place a drop of motor oil on the threads, and on both sides of the washers. Install the bolts with washers and tighten them in four steps. First, torque in proper sequence to 22 ft lbs, then 51 ft lbs. Next loosen the bolts, in the reverse order of the tightening sequence, 180 degrees, then another 180 degrees in reverse sequence. Torque all six bolts in sequence to 29 ft lbs. Tighten all addition 90 degrees of rotation. Lastly, turn only bolts 1 and 2 another 45 degrees." Quote Link to comment Share on other sites More sharing options...
frag Posted June 30, 2008 Share Posted June 30, 2008 Subaru keeps changing the recommended method. I'm not certain which is the latest. Hopefully, someone else will chime in. Okay, I just searched the forum, and found this: http://www.ultimatesubaru.org/forum/showthread.php?t=79989 Here's another variation, which is likely older, from http://www.automotivemachine.com/tech.htm : "On some models, mostly 2002-2005 2.5L DOHC engines, Subaru has had problems with head gasket sealing. The factory has revised the tightening procedure several times... this seems to be the latest version: Make sure the threads in the block are clean and free of oil or coolant. Clean the bolt threads and place a drop of motor oil on the threads, and on both sides of the washers. Install the bolts with washers and tighten them in four steps. First, torque in proper sequence to 22 ft lbs, then 51 ft lbs. Next loosen the bolts, in the reverse order of the tightening sequence, 180 degrees, then another 180 degrees in reverse sequence. Torque all six bolts in sequence to 29 ft lbs. Tighten all addition 90 degrees of rotation. Lastly, turn only bolts 1 and 2 another 45 degrees." About underligned passage: that's what I did when I replaced left head on my motor last summer. The stange thing is that when I loosened the bolts according to this procedure, they lost all torque. Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 30, 2008 Share Posted June 30, 2008 About underligned passage: that's what I did when I replaced left head on my motor last summer. The stange thing is that when I loosened the bolts according to this procedure, they lost all torque.Head gaskets, unlike ones for other purposes that are made of rubber, cork, etc., aren't very resilient. As long as you properly retightened the bolts afterwards, that should be sufficient. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted July 2, 2008 Share Posted July 2, 2008 About underligned passage: that's what I did when I replaced left head on my motor last summer. The stange thing is that when I loosened the bolts according to this procedure, they lost all torque. Loosening them a full turn like that, I would expect them to lose all torque. Quote Link to comment Share on other sites More sharing options...
Dickensheets Posted July 3, 2008 Share Posted July 3, 2008 Mine did too. But all is well. Quote Link to comment Share on other sites More sharing options...
davebugs Posted July 4, 2008 Share Posted July 4, 2008 Definately seems kinda weird. Seems to me the last head gaskets that I did on other than a Subaru have a similar procedure but in the last tightening sequence get torqued to specific values. Last 2.5 I did I had a friend with a fancy snap-on electronic torque wrench come over. It is amazing how close the final torque (done by fractions of a turn as per instructions) ended up being. I realize that's the idea but I was still amazed at how close they were. Dave Quote Link to comment Share on other sites More sharing options...
OB99W Posted July 4, 2008 Share Posted July 4, 2008 [...]It is amazing how close the final torque (done by fractions of a turn as per instructions) ended up being. I realize that's the idea but I was still amazed at how close they were.Once the gasket is initially seated there's an advantage to using "fractions of a turn" -- it actually results in a more predictable clamping force, by removing bolt head and thread friction factors to a great degree. It's the reason most spin-on oil filters and some spark plugs are often best installed by turning until the gasket just touches, followed by a specified additional twist. Quote Link to comment Share on other sites More sharing options...
Quidam Posted July 4, 2008 Share Posted July 4, 2008 Once the gasket is initially seated there's an advantage to using "fractions of a turn" -- it actually results in a more predictable clamping force, by removing bolt head and thread friction factors to a great degree. It's the reason most spin-on oil filters and some spark plugs are often best installed by turning until the gasket just touches, followed by a specified additional twist. Uh huh. Wrench every day, and it becomes second nature. Or something. Zen and the Art of Subaru. Measuring bolt streach is consistantly dead nuts accurate, tho. Doug Quote Link to comment Share on other sites More sharing options...
aircraft engineer Posted July 5, 2008 Share Posted July 5, 2008 I think I have said before that a "torque wrench" is a substitute for "turn of the bolt" bolt load measurement. The intention is to have a specific, uniform clamp up bolt stretch. Torque is a secondary measurement of that (and a lot easier to measure, too). It is based on a calculated amount and then measured to get the "actual bolt stretch" (based on the angle of the threads and the material characteristics) "Turn of the screw" is actually always better but it is based on a "very low friction" threaded connection. remember - in reality, that friction can cause torque wind-up in the bolt itself - a line drawn down the bolt will start to "spiral" because the bolt itself is twisting rather than stretching. <bell rings> I have a twisted sense of humor. OK - class over. Quote Link to comment Share on other sites More sharing options...
nipper Posted July 5, 2008 Share Posted July 5, 2008 I think I have said before that a "torque wrench" is a substitute for "turn of the bolt" bolt load measurement. The intention is to have a specific, uniform clamp up bolt stretch. Torque is a secondary measurement of that (and a lot easier to measure, too). It is based on a calculated amount and then measured to get the "actual bolt stretch" (based on the angle of the threads and the material characteristics) "Turn of the screw" is actually always better but it is based on a "very low friction" threaded connection. remember - in reality, that friction can cause torque wind-up in the bolt itself - a line drawn down the bolt will start to "spiral" because the bolt itself is twisting rather than stretching. <bell rings> I have a twisted sense of humor. OK - class over. Excpet on subarus your not stretching the bolt alone (or any HG for that matter). You are compressing a 3 part gasket. The bolts are far stronger then the threads in this case. Thats why you cant reuse a HG if you screw up the pattern, and decide to start over. nipper Quote Link to comment Share on other sites More sharing options...
Gloyale Posted July 7, 2008 Share Posted July 7, 2008 To Confirm is this the proper method for installingt he head? Tighten cylinder head bolts. (1) Apply a coat of engine oil to washers and bolt threads. (2) Tighten all bolts to 29 N⋅m (3.0 kg-m, 22 ft-lb) in numerical sequence. Then tighten all bolts to 69 N⋅m (7.0 kg-m, 51 ft-lb) in numerical sequence. (3) Back off all bolts by 180° first; back them off by 180° again. (4) Tighten bolts 1 and 2 to 34 N⋅m (3.5 kg-m, 25 ftlb). (5) Tighten bolts 3 , 4 , 5 and 6 to 15 N⋅m (1.5 kg-m, 11 ft-lb). (6) Tighten all bolts by 80 to 90° in numerical sequence. The second loosening by 180 degrees is incorrect. You got this from a Chilton or Haynes or other Non-Subaru source didn't you? I've run into this misprint before (In a Chiltons book IIRC)). Only loosen 180 degrees once before retorquing and then turning 90 + 90 more. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted July 7, 2008 Author Share Posted July 7, 2008 The second loosening by 180 degrees is incorrect. You got this from a Chilton or Haynes or other Non-Subaru source didn't you? I've run into this misprint before (In a Chiltons book IIRC)). Only loosen 180 degrees once before retorquing and then turning 90 + 90 more. So I understand.. Step 6 states 90 degree's. Should there be a step 7 that states another 90 degree's for all bolts? That info I pasted in came from a Subaru manual. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted July 7, 2008 Share Posted July 7, 2008 So I understand.. Step 6 states 90 degree's. Should there be a step 7 that states another 90 degree's for all bolts? That info I pasted in came from a Subaru manual. Yeah, mine say's 90+ 90 more. That is from 90 FSM for 2.2, so it may be differnet on differnet EJs, and as was pointed out, they have revised the proceedure a few times. Sooo...IDK....I guess just reef-em down and pray??? Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted July 7, 2008 Share Posted July 7, 2008 Not sure if it's relevant to the engine under discussion or not (what type of engine was that again?) but the following is the FSM procedure for the 2000 OB 2.5 SOHC (EJ252): (1) Apply a coat of engine oil to washers and bolt threads. (2) Tighten all bolts to 29 N·m (3.0 kg-m, 22 ft-lb) in alphabetical sequence. Then tighten all bolts to 69 N·m (7.0 kg-m, 51 ft-lb) in alphabetical sequence. (3) Back off all bolts by 180° first; back them off by 180° again. (4) Tighten bolts (a) and ( to 34 N·m (3.5 kg-m, 25 ft-lb). (5) Tighten bolts ©, (d), (e) and (f) to 15 N·m (1.5 kg-m, 11 ft-lb). (6) Tighten all bolts by 80 to 90° in alphabetical sequence. CAUTION: Do not tighten bolts more than 90°. (7) Further tighten all bolts by 80 to 90° in alphabetical sequence shown in figure below. CAUTION: Ensure that the total “re-tightening angle” [in the former two steps], do not exceed 180°. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted July 7, 2008 Author Share Posted July 7, 2008 Not sure if it's relevant to the engine under discussion or not (what type of engine was that again?) but the following is the FSM procedure for the 2000 OB 2.5 SOHC (EJ252): (3) Back off all bolts by 180° first; back them off by 180° again. Someone on this thread stated that step 3 is wrong and should not read to back them off again 180. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted July 7, 2008 Share Posted July 7, 2008 Someone on this thread stated that step 3 is wrong and should not read to back them off again 180. As long as you got to below the torques indicated in steps 4 and 5, it shouldn't matter, right? Quote Link to comment Share on other sites More sharing options...
aircraft engineer Posted July 7, 2008 Share Posted July 7, 2008 1 full turn loosening will reduce the bolt torque to "zero". The idea of doing it 1/2 turn at a time is to reduce the possible warpage on the head. I will say that the "old" way of doing head gaskets (not Sub and NOT ALUMINUM heads) was to go back and loosen each bolt 1/2 turn and retorque to full torque, start the motor and run it for a while to heat up then go in and torque them AGAIN to full torque We don't loosen bolts in aircraft - they get torqued ONCE and that's it. (but they don't have compressible pieces in them either - like the HG) Quote Link to comment Share on other sites More sharing options...
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