RebekahsZ Posted May 24, 2013 Share Posted May 24, 2013 I'm trying to get ready for a day of road race instruction with cobramatt. Going thru car tightening loose bolts and checking things out. I have auto crossed car three times and gone to the drags twice. So far, Ive found de-torqued lug nuts, a loose gland nut, and almost every nut throughout the rear suspension subframe. Driveshaft bolts were good, still gotta check axles. Gotta check TC rods-Matt like curb hopping. Haven't found any NEW chassis cracks. Quote Link to comment Share on other sites More sharing options...
Zfan1 Posted May 24, 2013 Share Posted May 24, 2013 I welded in a cage and it stiffened it up measurably! My car has been a V8 swap since 1980 and has hundreds of time slips with no bending or twisting....yet Quote Link to comment Share on other sites More sharing options...
socorob Posted May 24, 2013 Share Posted May 24, 2013 did y'all do any spot or stitch welding to the seams before the engine swap? i'm curious because I'm planning an LS swap into mine and i spent the last couple evenings putting extra spot welds all over every seam in the interior. I was planning on doing the same underneath once I get the car raised some. I'm still on the fence about to rollbar or not to rollbar. Do you think if everything is stitched up and with baddog rails it will be ok? Quote Link to comment Share on other sites More sharing options...
frank280zx Posted May 24, 2013 Share Posted May 24, 2013 On my race car wich is fully built i hav eto loctide the bolts down to say in there intended place.. slicks or sticky tires do that to a rear subframe. But indeed welding in a cage or halfcage and seemwelding makes any car allot stiffer! Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted May 24, 2013 Share Posted May 24, 2013 My car is ripping the frame rails by the transmission mount .... put it on the list! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 24, 2013 Author Share Posted May 24, 2013 (edited) I only have loose bolts and no torn metal, but if you have carnage related to your LS swap, throw up a pic! There are several other "carnage" threads out there, so this is not intended to suplant those.To answer and earlier question, I haven't done any seam welding. This winter's plans include a 6-point bar to connect from the rear strut towers to the footwell. My car flexes the most when jacking it up-it is noticeable. Not sure if that has anything to do with having an LS-motor. You can really tell when you open and close the doors when car is on jackstands and comparing that with how well they close when on the ground on the tires. There are jackstand locations that cause more flex than others. Edited May 24, 2013 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
Dans toy Posted May 24, 2013 Share Posted May 24, 2013 I've always had concern for the central part of the car on all of my unibody projects. As traction improves its my opinion that you will find the weaknesses in the car. Stock Z's seem to hold up better than others. Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 24, 2013 Share Posted May 24, 2013 It is fairly easy to stiffen up the rear portion of the unibody with round tubing and roll cage. It is going to take a lot more intelligent effort to stiffen the mid and front of the unibody. As far as SUNNYZs situation, a torque arm can be fabricated from the transmission to the rear differential to absorb some or most of the torque of the engine/trans combination and less to the integral frame rails. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 24, 2013 Author Share Posted May 24, 2013 I'm starting to see the merits of the spring steel tranny crossmember that JCI makes. Perhaps that flexibility will insulate my chassis a bit. I think all of us would be wise to use a frequent inspection schedule to inspect every fastener in the suspension and driveline in order to avoid major repairs. I'm a big advocate of an inspection aid called Torque Seal. It is made by Organic Products and sold cheap on-line by Parts Geek. The postage is more than the product but don't order more than a couple of tubes-it has a pretty short shelf life in a hot summer garage. You use torque seal to mark a fastener so that you can just do a visual inspection to spot de-torqued fasteners. It is like wax-if the wax is cracked, get out the torque wrench. If it is still "sealed" rock on. I spotted my loose gland nut thanks to this stuff. We used it in aviation maintenance on the Army. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted May 24, 2013 Share Posted May 24, 2013 I'm trying to get ready for a day of road race instruction with cobramatt. Going thru car tightening loose bolts and checking things out. I have auto crossed car three times and gone to the drags twice. So far, Ive found de-torqued lug nuts, a loose gland nut, and almost every nut throughout the rear suspension subframe. Driveshaft bolts were good, still gotta check axles. Gotta check TC rods-Matt like curb hopping. Haven't found any NEW chassis cracks. I have experienced quite of few of the same problems you are seeing and am at a much lower power level than your car. I periodically put it up on the lift and re tighten everything. I've safety wired a few things just so I wouldn't loose a fastener if it did come loose that far. I mainly see my axle bolts come loose which is scary and the last time I put some red loctite on them so we shall see. Some day i'll spring for CV's but not this week. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 24, 2013 Author Share Posted May 24, 2013 When I dragged my car with a L24 the stock axles needed tightening after every trip. And there were always a few that were loose. Always at the end near the hub. Quote Link to comment Share on other sites More sharing options...
socorob Posted May 24, 2013 Share Posted May 24, 2013 I guess the torque arm you are talking about would be like the backbone ala miata. Some of them had an arm that went from the trans to the diff. Wonder how easily one of those could be modified for the Z? http://www.miataturbo.net/attachments/general-miata-chat-9/60327d1353449479-need-help-purchase-decision-miata-chassis-5k85s35j83id3nc3hac9nc5dd3e18e1c8150e-jpg It would stiffen it up a lot but would wreak all kinds of havoc on trying to get dual exhaust down there. It's hard to see in the pic above But you get the idea. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 25, 2013 Author Share Posted May 25, 2013 I never get wheel hop at the drag strip on slicks (maybe because the car just hooks and goes!) but I got wheel hop at the start of the autocross on street tires and I just got a bunch of wheel hop on Hoosier R6s leaving a car show tonight. I get off it as soon as I feel it, but that can't be too good for the old girl! Quote Link to comment Share on other sites More sharing options...
Zfan1 Posted May 25, 2013 Share Posted May 25, 2013 Seam welded, 6 point with door bars, welded in, no floor board placement, directly to kick panels. Also loctite blue or red bolts in most places. I have dozens of 9 and 10 second passes with zero twisting other than a front diff. mount that got turned into a pretzel...lol Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 25, 2013 Share Posted May 25, 2013 After every track weekend I would recommend checking all suspension, drivetrain and brake bolt/nut. Get into the habit and you won't get surprised! Mike Quote Link to comment Share on other sites More sharing options...
heavy85 Posted May 26, 2013 Share Posted May 26, 2013 After every track weekend I would recommend checking all suspension, drivetrain and brake bolt/nut. Get into the habit and you won't get surprised! Mike This has prevented a lot of issues as you often find little issues and can fix before they become a problem. This has also resulted in zero DNFs in about 40 track days. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 26, 2013 Share Posted May 26, 2013 (edited) The bolts becoming loose overtime because of engine torque is a myth to me. We do not tighten every bolts on ZR1, GTR, Ferrari's (maybe not Ferrari's ), etc. whereas they've got torque. Lack of unibody stiffness is not a reason to explain either why bolts get loose. Most likely, bolts were not torqued properly. Reasons could be many: bolts already stretched a little, thread contaminated (rust, dust), improper bolt quality, etc. If you reuse bolts, this is probably the reason. I used also to retorque bolts (stock units), I've replaced them all with new bolts, clean threads, get them torqued properly. They never get loose now. Checking bolts after every event, as Mike is suggesting, is not a bad idea though. Our car are like prototypes since we all mess up with them in every way. Edited May 26, 2013 by Lazeum Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted May 26, 2013 Share Posted May 26, 2013 The bolts becoming loose overtime because of engine torque is a myth to me. We do not tighten every bolts on ZR1, GTR, Ferrari's (maybe not Ferrari's ), etc. whereas they've got torque. Lack of unibody stiffness is not a reason to explain either why bolts get loose. Most likely, bolts were not torqued properly. Reasons could be many: bolts already stretched a little, thread contaminated (rust, dust), improper bolt quality, etc. If you reuse bolts, this is probably the reason. I used also to retorque bolts (stock units), I've replaced them all with new bolts, clean threads, get them torqued properly. They never get loose now. Checking bolts after every event, as Mike is suggesting, is not a bad idea though. Our car are like prototypes since we all mess up with them in every way. Maybe it has something to do with the time / space continuum over here in the states............. Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 26, 2013 Share Posted May 26, 2013 Use fine thread bolts and clinched self locking nuts. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 26, 2013 Author Share Posted May 26, 2013 Finished going thru everything. TC rods were fine, but the bolts connecting the outer CV to the companion flange accepted some turning to get them back to 55# with a crows foot. I went ahead and took them on up to 60# then put thread seal on them. I'm gonna start blue locktiting all these bolts in the future. Surprisingly, the JTR headers have stayed torqued just fine. Quote Link to comment Share on other sites More sharing options...
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