madmanadam Posted June 18, 2002 Share Posted June 18, 2002 Hello, everyone Been driving the car alott with the new poly bushings and notice sqweeking noise. Sounds like it is coming from the mustache bar. What should the torque be on the mustach bar? The car handles great, hugs the road. I have a little viberation at 70 due to I welded the rear mount soild, but other wise all is smooth. Up to 900 miles on the new motor. Summer is here and this will be the first summer that the car will not be apart. This is a great site and thanks for the help I have received here. Take it zeasy and keep on zeeing. _adam Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 18, 2002 Share Posted June 18, 2002 Could be several things. If your concern is the two stud nuts that hold the differential to the mustache bar, then I can only offer a good guess at about 50-55 ft/lbs of torque (remember, the studs are set in aluminum). I assume from your statement of a welded rear mount that this means the bar is welded where the bushings normally go. Did you insure that the bar was fully flat against the differntial before welding it in place (with the differential in it's correct location)? If not, then some movement may be taking place, metal-to-metal, causing the squeeking noise. Worst case: Bar has cracked and you are hearing the metal rubbing at the crack. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 18, 2002 Share Posted June 18, 2002 If a demented lad were to build a solid rear mustache bar out of pipe or rectangular tubing, what sort of thickness would be required of pipe to do the job (plus a right foot overkill factor)? Anyone hazard a guess? If the mustache bars are problematic and its going to be solid anyway... Regards, Lone Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 18, 2002 Share Posted June 18, 2002 Ron Tyler made an Aluminum replacement for the mustache bar and rear hangers for the control arms. It bolts to the 4 bolts holes in the subframe for the down-hanger plates and also to the studs that hold the mustache bar on the ends. I don't know the details of the design though. I'd think a 1.5" or 2" piece of black sched 40 pipe would be plenty, but I'd probably just use flat plate (1/4" thick) and some welded on brackets to go to the studs that bolt into the body that hold the M-bar. You could just remove the studs (they unscrew) and put bolts in instead. AL would be cool, though, for weight savings. I just don't have a TIG setup. I guess I could AL braze it together (Got some neat AL brazing rods from a guy off ebay - they work with MAP gas) and then have someone do the TIGing for me. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 18, 2002 Share Posted June 18, 2002 I'm not sure any thickness is appropriate with a "rear only" solid set-up. IMveryHO, if you use a very rigid rear only solid mount, then you have forced the weak link to go elsewhere (perhaps the aluminum diff cover?). And this goes for a solid front only mount too. My thoughts on this is either they both be solid or both be flexible, but not mixed. If one side is allowed to flex (poly or otherwise), then movement allowed by the flex mount is passed to the solid mount. With enough movement, frequency, and time, the solid mount will fail (327 knows) or the material around it will (sheet metal). Is there a material that will not fatique under repeated stesses and flexing that can be used as a solid mount? Perhaps part of the wing of a B52?. Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 18, 2002 Share Posted June 18, 2002 Terry, a steel structure can be designed for infinite fatigue life, but AL cannot, although it can have a very long fatigue life if the correct materials and design is used. I agree that both ends should be either solid or cushioned. Personally, I think even a drag car can have soft mounted diffs, if they are done correctly (FORGET the stock Nissan front mount!). I've been in a few Z's with a solid front mount and the noise in them was incredibly annoying. I'm sure if you had a pristine Diff it would be quieter, but those are rare. For a drage only car, MO is that solid is fine, but for a street car, I'd only want cushioned mounting of everything. An above the diff rubber front mount like Ron Tyler (and I) have is one solution for the front, while Simon DeGroot and others have done it differently (ScottieGNZ, etc.) As for the rear, you could easily design an M-bar replacement that is very strong, and still used rubber or Urethane cushions between the unibody subframe and the new part. Just sandwich it between a "foot" on the new M-bar and that member, with a cushion between the "foot" and the bolt head/washer. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 18, 2002 Share Posted June 18, 2002 Here is my solid mounting system currently on the car Quote Link to comment Share on other sites More sharing options...
madmanadam Posted June 18, 2002 Author Share Posted June 18, 2002 Sorry for the comfusion, The soild mount that I'm talking about is the front mount of the lsd, not the mustache bar. The car justs sqweeks when going slow, bumps, when up to speed 60-70 no sqweek. or I should say I cant hear nothing but air flying by, no top. What would be the benifit to making the mustache bar soild? I have replaced all busings with MSD stuff. Oh by the way the Toyota 4x4 brakes work great, had someone pull on in front of me and the car stoped on a dime, boy was I happy. Will i ever be done with this toy, nope always changing. Thanks -Adam Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 18, 2002 Share Posted June 18, 2002 The tightening torque on the differential mounting front member which holds the front of the rear A Arm suspension in place should be 33 to 44 foot #'s Lay a little grease to the sqeakers Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 18, 2002 Share Posted June 18, 2002 I should have said that both mounts would indeed be solid if I were to do that, thats a given, just like using a solid tranny mount, must use solid engine mounts. If I ever get the exhaust sorted and quiet enough perhaps the noise would be annoying, I've never riden in a Z with a hard mounted rear. I have to get a R200 mustache bar anyway, maybe I'll look it over, or maybe some pipe with bushings pressed in the end and it just being a sturdier mustache bar replacement I was really just trying to improve the strengh of it if another one ended up being broken I've heard of a few of them doing it and didn't know if its a common breakage or not. *shrug* Regards, Lone Quote Link to comment Share on other sites More sharing options...
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