October 3, 20178 yr I'm about to pull the head off of my 93 Legacy 2.2h4 non turbo and I need to know the torque specs for the bolts any advice is much appreciated.
October 3, 20178 yr See the second to last page of the attached PDF. It's for a 96, but same procedure as its the same engine. For some reason it's not allowed to upload a PDF so I put it in a zip file... head_bolt.zip
October 3, 20178 yr Author 987687 Thank you. you wouldn't happen to have anything on clutch adjustment would you?
October 3, 20178 yr The clutch info is spread throughout the clutch section, so I just attached the whole folder. CLUTCH.zip
October 3, 20178 yr Author The clutch info is spread throughout the clutch section, so I just attached the whole folder. Thank you so much this is wonderful if you don't mind me asking where did you get all this info it's amazing
October 3, 20178 yr I don't remember exactly where I got the FSM files. I've had em for a while now. There are either links on this forum under the repair manual section. There a ton of useful links in there. Or just google something like "1993 subaru fsm pdf". Since there's questionable legality in sharing an entire service manual you're supposed to pay for, hosting for these downloads comes and goes. I doubt the place I got it from still exists, etc.
October 5, 20178 yr Author If the torque on the bolt is set 8.7+-0.7 ft lbs would ten ft lbs be ok or to far
October 6, 20178 yr I'm assuming you're asking because you have a big burly torque wrench that only goes down to 10 ft/lbs. The issue with that is, bigass torque wrenches aren't very accurate at the ends of their range anyway. Either way, nobody besides the team of engineers that designed the engine can say with authority that 10 ft/lbs it too much or not... The only thing anyone else in the world has to go off is what the service manual says, anyone who says otherwise is talking out of their rump roast and you shouldn't trust anything they say. Would it work in the short term? Yea, probably. would it cause an issue in the long term? maybe... Your mileage literally may vary. Edited October 6, 20178 yr by 987687
October 6, 20178 yr Torque values on fasteners that small are based entirely off thread diameter, pitch, engagement, bolt grade, mating thread material, and thred lubrication..... You can safely consult any machinist handbook for a chart of this information. No need for an FSM. FSM comes into play for gasket crush, and tightening sequence questions. The "engineers" use the machinists handbook for all the other values. How else would they know what torque to put in the FSM? GD
October 6, 20178 yr Definitely more to torquing head bolts than the torque value. FSM probably easier to find for most Internet users than a machinist handbook. Some experienced people can accurately use that source but FSM has the torquing procedure as well as the values in one place. I work in the aviation industry where the most accepted source is the Aircraft Maintenance Manual. The FAA frowns upon using any sources other than that. I do enjoy working on my car much better than airplanes, way less paperwork involved.
October 6, 20178 yr It's good to use the appropriate references for sure. Sometimes they aren't available.... also it's important for anyone doing this type of work to understand that the "engineers" aren't divine beings who's reasoning for a torque value cannot be understood by mere mortals and so must be read verbatim from the holy FSM. For the majority of fasteners, an SAE/Metric torque chart by fastener size is all you need. They make these in the form of posters you can hang on the wall. I have several in my garage. That said, once you do this on a daily basis for a couple decades, you only pull out the Snap-on $700 digital torque wrench for things like head bolts, case half bolts, etc. And most of these deal with both torque and angle (thus the $700 digital torque/angle wrench) so a torque wrench isn't even the only thing you need.... But for 99% of a car - the torque is "1/4 turn before it breaks", or "tighten till you hear the casting crack, and back it off 1/4 turn"..... And for really critical fasteners like connecting rod bolts we actually measure the stretch of the bolt because torque depends on friction which depends on lubrication. Bolt stretch is independent of friction and therefore perfectly accurate and repeatable. So when you ask torque - you need to specify lubed or dry. And if lubed - with what? Anti-seize is not going to give the same torque as assembly lube, or penetrating oil, etc. Given the number of factors at play - even reading the FSM they leave out so much information like lubed or dry.... coupled with the general innacuracy of +/- 5% or even more on a typical mechanic shop mechanical torque wrench.... worrying about fractions of a Ft/lb is lunacy. Your instrumentation hasn't got even close to the granularity or accuracy required nor are the threads even close to the laboratory conditioned needed to divine the difference between 8.7, 9.4, 10, or 10.7 Ft/lbs. That's CRAZY talk. Your average street corner mechanic has his torque wrench calibrated exactly.... never. Fortunately the Snap-On guy has a torque wrench tester hanging on the wall of his truck... and my space age digital torque wrench seems to need go go back in for service every year or so anyway so I'm good.... But your average guy that's not an engine builder probably has a click type wrench he bought sometime in the last two decades and it gets tossed around in and out of his tools box.... never been calibrated since it left the factory. And what will happen is this wrench will fail and over torque some fastener. The tech may break it off or he may realize that it's gone too far, pull it out, show it to his boss who tells him "looks ok, put it back in and use my wrench" and then the unit goes into service somewhere in southern CA, where after 6 hours of operation the bolt fails catastrophically and causes about $25k in damage to the machine and a bunch of downtime for the customer.... But I digress. GD Edited October 6, 20178 yr by GeneralDisorder
October 6, 20178 yr Good post, GD. IIRC, torque tables in machinist's handbooks are for NEW & DRY threads. Add some lube (even just a bit of oily residue), and it will be easier to turn the nut, and the bolt will stretch more, and get closer to failure. Assembling threads using torque values is always problematic. Better to use crush-washers that are designed to measure the actual stretch of a bolt; but not practical for most applications.
October 7, 20178 yr Your average street corner mechanic has his torque wrench calibrated exactly.... never. Fortunately the Snap-On guy has a torque wrench tester hanging on the wall of his truck... and my space age digital torque wrench seems to need go go back in for service every year or so anyway so I'm good. Speak for yerself. I get mine calibrated by the Cornwell tools guy. Or checked anyway, it's never been out of calibration. It's a click type, but a really good one. I assemble engines out of car so figuring 90 degrees is pretty easy to do visually.
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