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    Body Shell Fatigue/Structural Issue - Gemini, so any ex-Gemini Racers please chime in

    Fellas,

    In another PF thread I asked a question about fatigue and how many of you had come across it - ive only really seen and or heard about it in excessively lowered and abused Commodores before so didnt think that it may actually be the cause of my steering issues. Had a poke around last night and its not looking too good for the old girl :cry: Bare with me here, this is going to be fucking long winded.

    Recap on the issues im experiencing [apologies for the wall of text]:

    Issue is really hard to describe and really strange. Theres no consistency to it either - sometimes its really bad, other times its like nothing was ever wrong. Majority of the symptoms and or logic point to something mechanical being wrong with the front end, but then there are other symptoms which cant be caused by the front that have me scratching my head. Bare with me here....I know what i feel while im driving, but not sure how to translate that into a language people can understand.

    Symptoms are as follows:

    -Giant clunk when rolling down a driveway on the brake. Say for eg Im parked in my parents driveway which is right on the 1.5 over 5 council guideline limit. Jump in car, foot on brake, handbrake down and release brake and/or apply brake more while its rolling, results in a loud clang/springy sounding noise coming from the front. Doesnt always do it. My thoughts were the front springs werent quite seated but there is no evidence or witness marks on the spring seats to say that this is the case. On bad days, it knocks from the front over short, sharp bumps.

    -Steering randomly binds - occasionally I cant get the full amount of lock, its like its hit the stops but its still a full rotation off of where it should be lock-to-lock. Ive hopped out at the time and had a look, and theres no reason I can see of whats stopping it - steering coupling looks fine, swaybar isnt tensioned stupidly or anything like that. There is a mark indicating the swaybar has rubbed the sump at some point but at time of sticking my head under there, it wasnt touching.

    -Steering effort is inconsistent; some days its noticeably stiffer and or harder. When its working fine the steering is really light and crisp, when it plays up it feels a bit imprecise and its noticeably heavier through the wheel

    -Car randomly pulls with camber on the road either side. Could drive the same stretch back to back and itll do it sometimes, it wont others. Feels like it sways a bit at speed in a straight line, sort of like its wandering along the road. At times it even feels like its crabbing from the rear. But if you work the wheel sharply left-right-left-right at say 60kmh it feels perfect - tied down, firm and does exactly what you do through the wheel.

    When i first started noticing the wandering and inconsistency i thought maybe it needs an alignment but it has me baffled - doesnt explain why the problem is intermittent, varying steering effort or why it clunks loudly and makes noise. Thought maybe it was mechanical but again that doesnt explain why it comes and goes - a failed bush in the panhard rod for eg would explain some symptoms but not others.

    The following in the car are less than 30k old:

    -Balljoints upper and lower
    -Front bushes upper and lower; replaced with Superpro
    -Steering rack ends and tie rod ends
    -Steering rack to column coupling
    -Swaybar links and bushes front and rear
    -Shocks all round
    -Tyres [Khumo KU33], not showing any real camber wear although rears show some scrubbing from locker

    The only things i didnt change were the rack bushes and rear control arm bushes. Ive got both of these, will be fitting them when the car comes off the road shortly for its 9th rebuild. Ive had it up on stands and couldnt find anything out of place. Seriously contemplating getting someone to do a road worthy check on it just to see if they can isolate anything wrong with the front end.
    Another two symptoms i forgot to add yesterday

    - there are times when it looks like one wheel has more camber than the other, although tyres are wearing well on the edges

    - Sometimes the steering will not center; if you turn the steering, say 5deg, as you would if you were negotiating a lane change or a really really small bend, you can let go of the steering wheel and it will stay turned 5deg. Does this in both directions

    Given the newness of all the suspension components, and my inability to find something obviously wrong, i decided to have a poke around at the body and I think ive found the problem. My car has had a hard life; its done somewhere close to if not over 400k and was originally a country car. When I got it, it got treated like most 21yr olds treat their cars; i drove it hard, it got jumped a few times at speed, turbo motor etc. Its also had a locker for roughly the 10yrs ive owned it.

    Sometime in its life its been hit really hard in the rear and not fixed correctly, noticeable in that it was shorter on one side [door gap to rear arch was way smaller on LHS]. It would also pull left under brakes and lock the left wheel very easily. Anyway, it took considerable effort because it kept springing back when it was released, but was eventually pulled square after it tore some sheet metal. Fixed that, rebuilt the entire car with new suspension and got it on the road. Premature LH locking was gone, not sure if it was suspension that fixed it or pulling it on the rack [wasnt brakes, because replaced them way before that]. And then i walloped a Maxima in front of me at 60kmh, direct hit to the bumper mount which transferred all the force into the inner gaurd. Hit was hard enough to push the drivers side shock tower back 25mm.

    External
    http://www.nick.holdengemini.net/_da...80383df-me.jpg
    RH a pillar seam after accident
    http://www.nick.holdengemini.net/_da...265653c-me.jpg
    Passenger shock tower
    http://www.nick.holdengemini.net/_da...1e6cd02-me.jpg
    Drivers shock tower
    http://www.nick.holdengemini.net/_da...2169628-me.jpg
    Inner gaurd
    http://www.nick.holdengemini.net/_da...88a4187-me.jpg

    That all got fixed, pulled square to +/- 1mm. Car got thrown together in a hurry for my wedding with the intention of rebuilding it aaaaaand 30k and 18months later im still driving it daily. In the meantime its done roughly 4k up the Pacific Hwy, belted through the hunter valley, done the macquarrie pass, done a skidpan day after driving it to and from the even 700km - its even done a track day at wakefield including two big moments where i went off at the fish hook off the curbs at speed etc. Basically, i treat it like shit without intentionally crashing it into things. Its also daily driven through hefty road works [anyone in the north of melb will know how fucked plenty road and cragieburn east road have been the last 2 yrs - it does both daily].

    Yesterday I had a better look at the body. There have been signs for some time that something isnt quite right structurally but ive always put it off as me being paranoid.

    Seam at base of drivers a pillar/plenum/front gaurd. This was redone at paint time - crack has spread and not chip of paint at base of pillar. The paint chip is recent.
    http://www.nick.holdengemini.net/i.p...72406a5-la.jpg

    Seam on passenger side
    http://www.nick.holdengemini.net/i.p...0cf43d2-la.jpg

    These have grown substantially over the last 12mths.

    Crack in a pillar? Look up and left from gaurd bolt
    http://www.nick.holdengemini.net/i.p...4b845f0-la.jpg

    Brace yourselves, this is where it gets ugly.

    Drivers side lower control arm mount


    Close up


    Passenger side lower control arm mount


    Note gap from mount to body. Wifes Gemini for comparisons sake


    Drivers side chassis rail to inner gaurd. Note rail to inner gaurd seam/join is coming apart


    Passenger side chassis rail to inner gaurd. Note rail to inner gaurd seam/join is coming apart. I can fit the metal rule from the square in between the two - and thats roughly 5mm thick


    Passenger side chassis rail to inner gaurd of wifes car for comparisons sake


    no13bcoupe was kind enough to have a look at his Geminis and all are the same as my wifes car, so its pretty apparent that it isnt a figment of my imagination - the car is coming apart at the seams . I managed to get my hands on an old preparation manual used to prep Geminis for the NSW Gemini Rally series and a two things caught my eye:

    Seam weld the front rails, the rear mounting of the bottom wishbone (on the rails), the front shock absorber turret, the front box member under the radiator and the rear parcel shelf braces
    Fit a suspension brace to mount between the lower wishbone rear chassis brackets. This brace passes between sump and gearbox bellhousing. It mounts to the wishbone bolts only
    Based off that it would imply that the old girls have an issue in competition use with the exact areas my car has problems with. I should point out that rust isnt a factor because the car is rust free - impossible you say, but no, it actually doesnt. Either way, cars clearly fucked.

    The question is....how far gone is too far gone? How do you even determine too far gone? Stitch welding the rail to the inner gaurd and doing the same to the lower control arm mounts to body will strengthen whats already there but wont change the stress thats gone through places it shouldnt have - how do you determine if its significantly weakened? Where do I even start?

    My thoughts are that getting the car off the ground should in effect close the gap between the control arm mount and body because unloading the weight off the wheels should stop the arm levering on the mounts, and or driving one wheel up a gutter for eg should exagerate the gap by putting load THROUGH the mount - thoughts?

    The obvious check is to measure the car diagonally from RHR control arm mount to LHF control arm mount and LHR to RHF and see how close measurements are - is there a possibility the car is springing back to post-crash damage as time has gone on, and driving has taken its toll by pounding on areas which were weakened in the crash?

    Is there somewhere it can be taken [ie someone that preps rally cars for eg] that can have a poke around and determine if its weakened or if repairing as outlined in the comp manual will return rigidity?

    My head hurts.

    N-
    1978 Gemini Sedan - Powered by i change my mind every week
    1980 Gemini Sedan
    1992 Land Rover Discovery 200TDI

    #2
    Its a gemini not a Porsche 911 gt3-sr. Drive it or cage it
    Originally posted by 50RTD
    Dave, have you uploaded the data from the carby?

    Comment


      #3
      Check the upper control arm mounts on X member ... I tore the drivers side upper mount off tge x mekber in my gemini series rally car, and most of the time it drove pretty normally but occasionally it'd do odd things. Took ages to track down cos the crack wasnt obvious - and it'd all been welded and plated as per the gemini series manual.

      The x members also bend easily and can lead to the steering coupling fouling on the upright but not at all points in its rotation... Which can give weirdly heavy steering...

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        #4
        The cracks in the A pillar to scuttle join are normal for a car that age. Cars flex, seam sealer tears...

        As for the others, put a pry bar in the gaps and see if any of them move/ are loose/etc. If you find some loose bits, weld them up. It really doesn't look that bad. Commodores end up much worse than that.
        Originally posted by Marlin
        Chickens will slip under water in the cover of darkness like a seal team and FUCK YOU UP.

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          #5
          So. Replace x members weld the seems back and go?

          I've mentioned it before I think the cross member is the problem as well. From time to time i think my coupes one is slighlty bent from previous "adventure" but hasn't really done the damage like what Nicks has.
          Putting the acco track time and general dailying could have helped the seams to split?

          Worth repairing either way. Even if it isn't a Porsche...
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          This is obviously assuming all your AUX outputs are doing something. Ie idle control, and the other does water spray, and the other updates your Instagram automatically etc.

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            #6
            Stick a GoPro underneath and go for a drive

            Comment


              #7
              Originally posted by Dogsballs View Post
              Its a gemini not a Porsche 911 gt3-sr. Drive it or cage it
              This. Any competition use in this thing should mean you at least semi-seam weld it (engine bay, firewall and/or through boot pan). Even caging it through the middle can expose front and rear shell issues unless you stiffen it up. Obviously cage and fully seam welded through the centre is the ideal. Regular road use can tire out an old school car, let alone any race use.

              Originally posted by F3ARED View Post
              Fellas,

              The question is....how far gone is too far gone?

              N-
              This far.

              Untitled by B&E 355, on Flickr

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                #8
                Originally posted by BLO 767 View Post


                This far
                Haha, cortina's loved to do that... bit of extra hp/4 speed/lowered 100% that's the result..

                Bout 2 hours on a hoist to weld it back in.



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                  #9
                  Yep that one was an S2000. Mate of a mate. Surprising amount of track hours on it, on what for all intents and purposes may as well have been full (but still semi) slicks, with as you can see - nothing much else in the form of track prep besides some heavier springs - before that happened. Not pictured of course front spoiler + wing also, for the downforce sodomy.

                  Comment


                    #10
                    Not sure what the relevance behind it not being a 911 is. Cage is not an option, its a street car.

                    Originally posted by rowdytoot View Post
                    Check the upper control arm mounts on X member ... I tore the drivers side upper mount off tge x mekber in my gemini series rally car, and most of the time it drove pretty normally but occasionally it'd do odd things. Took ages to track down cos the crack wasnt obvious - and it'd all been welded and plated as per the gemini series manual.

                    The x members also bend easily and can lead to the steering coupling fouling on the upright but not at all points in its rotation... Which can give weirdly heavy steering...

                    Sent from my G8141 using Tapatalk
                    Checked the upper arm mounts, both the eyelet the tube passes through and the tube itself are fine. The copy of the manual Ive got doesnt say anything about strengthening the upper arm mount though; only strengthening in relation to the upper arm is to seam weld the shock mount.

                    Cross member has a slight bend in it, but its been there forever and hasnt gotten any worse.

                    Originally posted by Faux Forg View Post
                    The cracks in the A pillar to scuttle join are normal for a car that age. Cars flex, seam sealer tears...

                    As for the others, put a pry bar in the gaps and see if any of them move/ are loose/etc. If you find some loose bits, weld them up. It really doesn't look that bad. Commodores end up much worse than that.
                    Gap between chassis rail and inner gaurd is scaring me, moves with fuck all effort. The lower control arm mount gaps are small enough that I cant get anything in there to lever on properly. Really need to get it on a hoist.

                    Originally posted by ls400x View Post
                    Stick a GoPro underneath and go for a drive
                    Not a bad idea, ill see if I can get my hands on a mates.

                    Originally posted by BLO 767 View Post
                    This. Any competition use in this thing should mean you at least semi-seam weld it (engine bay, firewall and/or through boot pan). Even caging it through the middle can expose front and rear shell issues unless you stiffen it up. Obviously cage and fully seam welded through the centre is the ideal. Regular road use can tire out an old school car, let alone any race use.
                    Its a street car that did the occasional track-based activity - the plan was to do a lot more and prep it as per the rally manual but after poking around this weekend I dont think that will happen now.

                    There appear to be two problems at play; one is the rails separating from the inner gaurds/control arm mounts separating from body. Provided the rails havent completely detached, seam welding it should fix it as everyone has pointed out. Whats caused the things to come apart is any ones guess - prang or just old age who knows.

                    The real issue here and I think the main culprit for most of, if not all of, my problems, is that the shell has sprung back on the accident side and is slowly folding in on itself

                    Spent some time with the tape and ran it over this car, my wifes one, and another shell I have at the parents place. No13b also took some photos of his cars for me in the mounting areas/rails to inner gaurds and none had any gaps. Measured the shock tower to firewall lip as I did post-accident and post-repair, and there is now a 15mm difference between drivers side and passenger side. Shock-tower-to-shock-tower is meant to be 893mm according to the factory body manual; its 880mm and the drivers shock tower is visibly sitting higher than the pass side. Measured center of wheels on both sides of the car and there is a 5mm difference in wheelbase. Measured from centre of lower control arm mount FRONT, to the lower control arm mount on the rear end of the car both sides and the same 5mm difference in wheelbase was present. The ONLY dimension I didnt take and I really need a hoist to do it was diagonal between the front and rear. Checked dimensions on the other two cars and both of them are consistent with each other and neither have any variance side-to-side.

                    Shells fucked. I think this is it for the old girl.

                    Thanks for the advice/suggestions.

                    N-
                    1978 Gemini Sedan - Powered by i change my mind every week
                    1980 Gemini Sedan
                    1992 Land Rover Discovery 200TDI

                    Comment


                      #11
                      get it on a jig and get it measured then stitch weld it up nicely. i used to see seams opening regularly on 2.0 turbo vauxhall novas, we jigged them and stitched em. never had issues after that.
                      Originally posted by Marv
                      Only be concerned if that Dunning-Kruger Motorsports bloke is there and goes all Captain Damphands McGigglefingers on you after a couple of lemon squashes....


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                        #12
                        Originally posted by F3ARED View Post
                        Shells fucked. I think this is it for the old girl.
                        Welderup.

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                          #13
                          Yep, another vote for slap it on a rack and weld it back together. I'd clamp and spot weld where it's popped the OEM spotwelds, and then stitch it.
                          I'd absolutely save it.
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                            #14
                            About 15 years ago I had a tg sedan, after having it lowered for a year or so I noticed under the back seat the steel was all cracked from when it would bottom out and the rear diff bump stops would hit the floor.

                            I got it welded up and put it down to the cheap shit steel in them..

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                              #15
                              Originally posted by Sloth View Post
                              get it on a jig and get it measured then stitch weld it up nicely. i used to see seams opening regularly on 2.0 turbo vauxhall novas, we jigged them and stitched em. never had issues after that.
                              Originally posted by Fondles View Post
                              Welderup.
                              Originally posted by Gammaboy View Post
                              Yep, another vote for slap it on a rack and weld it back together. I'd clamp and spot weld where it's popped the OEM spotwelds, and then stitch it.
                              I'd absolutely save it.
                              Even though its already had this damage pulled out and its folding along the exact same lines?

                              I can see how stitching the rails would fix them ever separating from the inner gaurds again, i just cant see how thats going to stop the thing from twisting itself along the same creases again

                              Originally posted by bryan View Post
                              About 15 years ago I had a tg sedan, after having it lowered for a year or so I noticed under the back seat the steel was all cracked from when it would bottom out and the rear diff bump stops would hit the floor.

                              I got it welded up and put it down to the cheap shit steel in them..

                              Ive heard of the rear seat bases cracking; the coupe shell I have at the oldies place the strap that runs vertically from parcel shelf to seat base has broken the weld at the seat base.
                              1978 Gemini Sedan - Powered by i change my mind every week
                              1980 Gemini Sedan
                              1992 Land Rover Discovery 200TDI

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