heavy85 Posted December 22, 2004 Share Posted December 22, 2004 As many cars have been, mine has been subjected to countless errant jackings. Although there is virtually no rust the entire underbody - virtually every square inch by the looks of it has at one time or another been used as a jacking point. The floors / frame rails can be relaced (thinking along the lines of subframe connectors anyway) and that's pretty obvious what to do, but what about the seam where the floor / inner / outer rockers meet. What I'm referring to is the very bottom of the rocker where the three panels come together and for a lip - mine is squashed down in several spots. I'm afraid if I try to bend the lip(s) back out they will crack (at least did on my old GTI when I tried it) and it's just one of those things that altough not structural it just bugs me and I can't see an easy solution. Any ideas? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
jkube Posted December 22, 2004 Share Posted December 22, 2004 Heavy85 I noticed the same thing on all the zcars I've restored. I also remember when I was a kid working at the local Datsun dealership (washing these cars) that even when they were brand new, I was told not to jack the cars up at the rockers becuase they were very weak there. Now I am restoring a few of these cars and I see there is an inner sheet metal support piece located at the door post. It it sandwiched between the inner and outer rocker panels. I have found that this panel rusts away first leaving little strength in the rocker to lift the car. What I've started doing was installing a 14ga steel metal piece ( 6" wide with flanges) as a replacement. It protudes slightly beyond the lower lip of the rocker so that a jack will contact this support piece rather than the rocker panel, and it is welded to the top of the rocker as well. This way all the wieght of the car is supported at the door post when you jack up the car If you decide to change out the rockers I would suggest taking the time to do the same. You'll be happy that you did. Jeff Quote Link to comment Share on other sites More sharing options...
heavy85 Posted December 22, 2004 Author Share Posted December 22, 2004 Jeff - I think I understand but do you have any pics of what you are describing? If I understand right you are actually removing the outer rocker and putting in a new piece behind it (the piece that's sandwhiched between the inner and out - I've seen the three layers of metal in the squashed lip on my car) then putting on a new rocker? Since mine aren't rusted out I was not wanting to replace the whole rockers but I can't see a better way around it. For me its really just that the lips (all three) are squashed. I wonder how much rigidity your fix would add to the rockers and thus the chassis in general especially if you were to extend this piece back instead of just under the door post .... hmmm Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Hugh Posted December 22, 2004 Share Posted December 22, 2004 So where are the safest jack points? (sorry to sound like an idiot... but this is my first Z) Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted December 22, 2004 Share Posted December 22, 2004 I may get corrected here, but I've always jacked mine up by either the center of the front crossmember in front, or by the rear end in the back, just forward of the diff cover. Jack stands can be placed under the front crossmember as well, and on the rear subframe just ahead of the rear tires. My car has sat on jackstands like this for many moons..... Mike Quote Link to comment Share on other sites More sharing options...
jkube Posted December 22, 2004 Share Posted December 22, 2004 Heavy85 I see your delima. The solution I had suggested is only if you are going to replace the rockers. I can only think of this for your situation: Try to bend back the flattened flange so it looks as original as possible. You're worried about the metal cracking. that is a possibility, but I think that if does its only because the metal is getting pretty rusty and thin. For these you may to have a new section welded in, or if the metal still looks good the cracks can be welded together. Fabricate a 16 gage steel L-shaped piece about 6-8" long ( 3/4 " flanges) Use sheet metal and form it into an L-shape. Dont take preformed angle iron. It just doest seem to work right. Maybe the metal is too thick Weld it behind the rocker flange and on the floor. What this will do is give you 4 layers of metal on the flange, and also spreads out some of the load over the floor area. I've use dthis before on a race car and it worked well Its similar to a weld pad on a roll cage, where the tubes meet the floor panels. Some of the undercoating will have to be removed from the floor area so the welding can be done. Just recoate the are once its finished. You wont see the add in piece from the side of the car. I only have a picture of my zcar with the rocker off. I somehow never took a picture of the support flange that I made. http://www.execulink.com/~jkube/Brians240z/Oct04pics/000_0918%20copy.JPG The piece should be postioned just under the door post. I've tried to point to the area where it goes. Anyways, hope this helps Jeff PS - Ztard- You are not wrong. The places you've picked are the same ones I've always used. The only time I use the rockers is at a lapping day when I have to change tires or do some quick work on the brakes. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 23, 2004 Share Posted December 23, 2004 Yikes.. rockers to jack up a vehicle?!?!?! I know.. they are SUPOSED to be the jack ponts, but I to was told (at a dealership I worked at) NOT to use them even on brand new cars. As for Z's, I have found the front x-member or the flat spot just behind the T/C rod 'box' is pretty strong. it was the only thing left to jack up on in my 75 280 when I got it.. And the rear, yah I used the diff (in FRONT of the cover, on the cast part of the unit) for a while, but I now have subframe conectors I use. 2x2" 3/16 square tube fron the T/C mounts back and up to the rear subframe, welded all along the way.. I can now jack my car up with ONE little jack from the center of the car (roughly the middle of the door.. in about 12") and the whole side comes up at once. As long as I get it 'balanced' in the middle ind you.. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted December 23, 2004 Share Posted December 23, 2004 Once you have sub frame connectors installed you have all kinds of jack points Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted December 23, 2004 Share Posted December 23, 2004 Can someone please explain a little bit more about subframe connectors (particularly for a 280ZX)? Does anyone have pics of what it looks like? I take it, that it's for chassis stiffening, but what kind of work does this entail to install? Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 24, 2004 Share Posted December 24, 2004 Well from personal expiriance, a ZX is a little... tricky compared to the earlier Z's.. the front/rear subframes don't line up quite the same (in line w/eachother) but it's doable. Basicaly, it's a lot of work no matter what you do.. but planing/measuring, and CLEANING of the rust/ect (prior to welding anything) is most important.. Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted December 24, 2004 Share Posted December 24, 2004 So are sub frame supports for repairing of a rusted or weak frame/underbody, or is it a performance thing? I was kind of imagining it as a bunch of crossbars welded to the rail frames like a roll cage or something. Quote Link to comment Share on other sites More sharing options...
260DET Posted December 24, 2004 Share Posted December 24, 2004 Run a length of RHS right along under the sill/rocker, parallel with and welded to the lip that protudes along the bottom. Of course it should be attached additionally to just welding it to the lip but basically thats it. Can be bent and extended forward to the tension rod pickup points as well, ideally it would be just part of other complimentary body stiffening work. I used approx 50x25mm RHS ( Rectangular Hollow Section) and jack under it anywhere. Very handy when changing to the race wheels, find the right point and both wheels on one side come up Quote Link to comment Share on other sites More sharing options...
heavy85 Posted December 24, 2004 Author Share Posted December 24, 2004 260DET - I've never seen frame connectors all the way out at that lip like you describe. All the one's I've seen (just do a seach on these forums and you will come up with a bunch) were extensions of the front frame rails all the way to the back but nothing going out to the sides. And you used 1 x 2" (25 x 50 mm) where it seems most have used 1 x 3 or even 2 x 3". Something to think about there ... a picture of your overall chassis stiffening scheme would be nice. Cameron Quote Link to comment Share on other sites More sharing options...
Guest DiZeased_240 Posted December 24, 2004 Share Posted December 24, 2004 HeatRaveR - Go to the link below and at the bottom of the page you will see some subframe connectors made by Pete Paraska. I know that this is for a 240z but you should be able to adapt the basics for a ZX. http://alteredz.com/structuralmods.htm The connectors are for structural rigidity and allow for less chassis flex, which when properly installed should provide better handling. I am not familar with the ZX so maybe someone here with more knowledge of that model can chime in and let you know if the connectors are beneficial to your car. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 24, 2004 Share Posted December 24, 2004 I think the subframe conector is definatly a performance thing, but can ALSO be a part of the 'repairing the rusted floor boards' aspect of Z cars.. heck, anything as old as these cars really.. I've seen a few cars with the subframe 'extending' out to the rockers in some way.. I think the member here named DOT (V12 Jag in a 240z) did something like this. The rockers are actually 'boxed' for aditional strength and to resist flex. (He was originally intending to install a big block V8 I believe..) I would say that yes, the zx could benifit from conectors, as it is a unibody rear wheel drive car.. it really depends on how much power you're making though. IMO if the car is esentialy rust free, and the drivetrain fairly stock, there would be no need for a subframe conector setup. If you plan to up the power (turbo/V8/?) or do a lot of racing though, I'd consider it. Quote Link to comment Share on other sites More sharing options...
Sven Posted January 3, 2005 Share Posted January 3, 2005 There is a person or company on the east coast selling a frame rail reinforcing kit, and "jacking rails" to beef up the rockers. In my great windows crash I lost my bookmark to that site. I've been searching for a week now. Does anyone know what site I'm talking about? I'd really like to pick these up. They were @ $150 as I recall. Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted January 5, 2005 Share Posted January 5, 2005 Wow, if you find out, be sure to post it up! Quote Link to comment Share on other sites More sharing options...
Sven Posted February 5, 2005 Share Posted February 5, 2005 Well HeatRaveR, I found the site! It was less than I remembered, too. It seems like a good option for those who aren't really repairing damage, but just beefing it up a bit. I would like to see if the frame rail caps extend the whole way back, though. (click on Products) http://www.baddogparts.com/ Quote Link to comment Share on other sites More sharing options...
cameron Posted February 5, 2005 Share Posted February 5, 2005 I'm in the mid of putting subframe contectors into my car using the info from Paraska, Owen, and even tim240z. There is a lot of good info out there ,but the key is finding it. For future Hybrider's I'm going to try to break it all down step by step and also take a crazy amount of pics to help people . I should be done in about a week and when I am ill post. Cam~ Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted February 5, 2005 Share Posted February 5, 2005 Hey thanks for finding it Sven! I'd almost forgotten about this! I just hope the stuff they sell can be made to fit on a 280ZX. And cameron, I can't wait to see the pics and info you come up with! Quote Link to comment Share on other sites More sharing options...
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