BlueStag Posted February 28, 2012 Share Posted February 28, 2012 Hey guys, So my exhaust flange gasket just does not seem to want to stay tight. Any hints on getting the next one snugged up and hoping to see it stay that way for a good long time? Detail: cast iron manifold off of a 260 to the exhaust pipe. Three studs and nuts. When they get loose, the gasket burns and the next thing you know, you need to buy another. Happily they are $3.00 Still, I'd like it to last a while this time around. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 28, 2012 Share Posted February 28, 2012 The nuts should be self-locking nuts or nuts with lock washers. Whatever they are, they shouldn't loosen. Do you have a complete seal, then the nuts loosen, and the gasket starts leaking, or do you have a partial seal, the gasket burns away, then the nuts loosen? If the sealing surfaces on the manifold or flange are screwed up you might have to get creative with a double gasket or something else. I've made a good seal with a gasket wrapped in crinkled up aluminum foil and I've also cut the center rings out of a gasket to make a double seal under an uncut gasket. Might help to torque the nuts before you mount the rest of the pipe also, if the pipe is bent. Or straighten the pipe so that everything is aligned for sealing. They're often bent from curb, rock or speed bump scraping. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted February 29, 2012 Share Posted February 29, 2012 (edited) Safety wire the nuts. Edited February 29, 2012 by beermanpete Quote Link to comment Share on other sites More sharing options...
BlueStag Posted February 29, 2012 Author Share Posted February 29, 2012 The nuts should be self-locking nuts or nuts with lock washers. Whatever they are, they shouldn't loosen. Do you have a complete seal, then the nuts loosen, and the gasket starts leaking, or do you have a partial seal, the gasket burns away, then the nuts loosen? If the sealing surfaces on the manifold or flange are screwed up you might have to get creative with a double gasket or something else. I've made a good seal with a gasket wrapped in crinkled up aluminum foil and I've also cut the center rings out of a gasket to make a double seal under an uncut gasket. Might help to torque the nuts before you mount the rest of the pipe also, if the pipe is bent. Or straighten the pipe so that everything is aligned for sealing. They're often bent from curb, rock or speed bump scraping. Good points. As for the last, the drive train is in my Triumph Stag, so it is as aligned as the muffler shop made it...... Self locking nuts? Certainly you do not mean nylocks. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 29, 2012 Share Posted February 29, 2012 I believe that original self-locking nut was all metal. Nylocks came later. http://en.wikipedia.org/wiki/Distorted_thread_locknut Zs have several self-locking nuts, like the transmission cross member mounting bolt nuts, the mustache bar nuts and the exhaust flange nuts. They thread on easy until the last few threads. In general, they're re-usable. The exhaust nuts and studs tend to weld themselves together though, and either break or come out as one piece. Quote Link to comment Share on other sites More sharing options...
rossman Posted February 29, 2012 Share Posted February 29, 2012 (edited) You need all metal self-locking nuts. These nuts are very nice and compact. The are reduced hex allowing the use of a smaller tool thus making installation easier. Edited February 29, 2012 by rossman Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted February 29, 2012 Share Posted February 29, 2012 Also wouldn't hurt to throw on a lock washer. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 29, 2012 Share Posted February 29, 2012 You need all metal self-locking nuts. These nuts are very nice and compact. The are reduced hex allowing the use of a smaller tool thus making installation easier. Thanks for clarifying. I was speaking historically, in general, not in terms of Nissan's use of lock nuts. Nylock nylon would just melt away and burn if used on the exhaust manifold. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted February 29, 2012 Author Share Posted February 29, 2012 Also wouldn't hurt to throw on a lock washer. Blu, In that heat I expect the spring value of the steel to be cooked out pretty quickly. This is a very hot spot on the engine. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted February 29, 2012 Author Share Posted February 29, 2012 Nylock nylon would just melt away and burn if used on the exhaust manifold. Yes, rather. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted February 29, 2012 Author Share Posted February 29, 2012 You need all metal self-locking nuts. These nuts are very nice and compact. The are reduced hex allowing the use of a smaller tool thus making installation easier. Do I understand you to write that what I am looking for is a 8mm x 1mm? 'Cause I can certainly dash out and grab a few of those! Quote Link to comment Share on other sites More sharing options...
rossman Posted February 29, 2012 Share Posted February 29, 2012 Do I understand you to write that what I am looking for is a 8mm x 1mm? 'Cause I can certainly dash out and grab a few of those! I'm not sure of the tread pitch, my GUESS is M8 x 1.25 but you better stick a thread gauge on it to verify. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted February 29, 2012 Author Share Posted February 29, 2012 I'm not sure of the tread pitch, my GUESS is M8 x 1.25 but you better stick a thread gauge on it to verify. Indeed. I have a pair of Ztherapy throttle bodies coming and want to do all the work in one hit. Quote Link to comment Share on other sites More sharing options...
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