1979280zx Posted November 18, 2008 Share Posted November 18, 2008 what is l28et head bolt Torque secuance an the torque for head bolts Quote Link to comment Share on other sites More sharing options...
1 fast z Posted November 18, 2008 Share Posted November 18, 2008 Work from the center out. Quote Link to comment Share on other sites More sharing options...
josh817 Posted November 18, 2008 Share Posted November 18, 2008 Should be from the center out, 65lbs. Don't torque right to 65 though, do 25 for all of them, bump it up to 45 and do them all again, and then finally the 65 for all of them. This makes it a gradual change rather than a sudden 65lbs. Use antisieze lube on the threads because torque specs are done on lubricated threads. Lastly when you are torquing anything down, do a continuous turn until your wrench clicks. If you stop and lets say its at 60lbs, then you start again, you have to apply a force greater than 60lbs to turn the bolt. Your wrench will click, saying you have applied 65lbs and the bolt is done when in reality the bolt is at 60 and you are having to exert 65+lbs. If that happens, loosen the bolt and start over. Quote Link to comment Share on other sites More sharing options...
Careless Posted November 19, 2008 Share Posted November 19, 2008 work from the outside in when removing the head too, if you've not done that yet. when you flatten a gasket, you want to flatten it starting in the middle, so any movement is pressed to the edges of the surface and flattened out. if you do it backwards, you will end up with the "excess" movement from the gasket pent-up in between the middle cylinders, which will cause the gasket to curl a bit or even become un-settled easily after a few hard runs. when removing a cylinder head, start from the OUTSIDE in, as starting from the inside (like installing) will cause the middle of the head to pop up due to the heat-cycling causing it to expand. It will cause the head to pent-up in the center and most likely crack or shift valve seats. some get away with it, and sell their car to someone else who will never have good luck with the engine because of errors like this. also, as josh817 said. always pull towards, and don't use anti-seize. use molybdenum disulfate grease (extreme pressure moly grease) or ARP lube. honda uses it and it's spec'd in their manuals as lube of choice. some oils are useable. if you do stop, but you haven't gotten close to the tightening torque yet, you can resume your swing. But if you're almost there and you slip, loosen the bolt a touch and then start your swing again. Once it clicks over, work the wrench back and make it click over about 3 or 4 times before moving to the next bolt or torque setting. You'd be surprised at how many millimeters a bolt will move between clicks. even after finishing the head torque sequence, I like to leave the valve cover on the engine but not fastened. I then like to come back in a day or two and tighten those bolts in sequence again with the same torque setting that you last used. The sad part is that temperature is never where it should be. Quote Link to comment Share on other sites More sharing options...
josh817 Posted November 19, 2008 Share Posted November 19, 2008 :0! Did I supremely screw up by using anti-seize/oiled threads?! My dad told me to oil the threads when I did the main journal bolts, and then we smeared the greyish stuff that comes in a can, the lid is used as a brush, on the head bolts and such. Is that not what I was suppose to do?! Ruh-roh! Quote Link to comment Share on other sites More sharing options...
Careless Posted November 19, 2008 Share Posted November 19, 2008 it will be fine. just not something I would use. I shopped around and confirmed with grumpyvette that molybdenum disulphide grease is the berries! also, the moly grease tube allows you to not be chintzy with the grease. i was lubing up the bolts and a friend came over just at the right time to strike a good point. The whole movement of the head during torquing can cause the bolts to run the sides of the block, gasket, or head. Doing so with no grease will eventually cause the torque value to be read incorrectly. So lube up the entire bolt, ESPECIALLY under and over the washer. The shaft, threads, and washer are the most important parts (and coincidentally, they are ALL the parts. LOL). A lot of torque value is lost through the base of the bolt head and the washer, as well as the base of the washer and the engine head. Quote Link to comment Share on other sites More sharing options...
josh817 Posted November 19, 2008 Share Posted November 19, 2008 You know that makes sense because when I took apart and tightened down the bolts, when you start getting up into the 55+lbs you hear it slipping and catching and slipping again. Scared me at first cause I thought I had broken a bolt or cracked something! Ever since I saw my dads first motor topple over and break a head stud I am quite frightened by snapping a bolt in a major area. And actually when I went to tear down my old spare L24 which sat around for maybe 2 years, because I didn't use a Craftsman 10mm allen wrench drive thing, I wound up breaking the socket! It was made in China but boy thought scared me into thinking the same thing. :[ Thats one thing I absolutely HATE about aluminum, especially with the aluminum bell housing of the T5 and when I went to put the starter motor on, thought I had stripped it but then it caught again. :0! I also surprised that the aluminum heads we use don't have depressions where the washer sits, being soft metal and all. Oh well though, if I blow a head gasket that gives me an excuse to pull the head and do more work on it as I'm not fully satisfied with what I have done. Oh and 1979280zx, I hope we answered your question amongst our conversation! Quote Link to comment Share on other sites More sharing options...
blue72 Posted November 19, 2008 Share Posted November 19, 2008 Just be aware that different types of grease all have varied properties. I have one of those little black books at home that shows how much to vary the torque applied to a fastener based on which grease/oil/lube you use on the threads. Quote Link to comment Share on other sites More sharing options...
1979280zx Posted November 25, 2008 Author Share Posted November 25, 2008 thanks for all the replys an what is the torque for the main caps an rods thanks Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 25, 2008 Administrators Share Posted November 25, 2008 You do have a shop manual of some sort right? Haynes manual even? ALL of the critical engine torque values are in there. As professional engine builder/machinist, I do NOT recommend assembling and engine without some sort of shop manual. The shop manual should be followed while assembling the engine. Even guys that have built hundreds or thousands of engines still refer to a shop manual, if only for torque values. A forum really is not a replacement for a shop manual... Do yourself and your car a huge favor. Go to the local parts store and get a haynes manual for your Z car. Good luck and I hope your engine turns out fine. Quote Link to comment Share on other sites More sharing options...
blue72 Posted November 25, 2008 Share Posted November 25, 2008 It's 33-40 ft-lbs for the main cap bolts, starting from the center and working out. Rod Nuts are 20-24 ft-lbs for the 8mm type and 33-40 ft-lbs for the 9mm type. Do you not own the How to Rebuild Your Nissan & Datsun OHC Engine book? It has lots more details like which way the main bearing caps should be facing, acceptable side clearance figures for the rods, etc... Quote Link to comment Share on other sites More sharing options...
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