JMortensen Posted July 4, 2006 Author Share Posted July 4, 2006 I guess this crossmember stuff fits in this thread pretty good. Didn't feel like it warranted a whole new thread. Anyway, I finished up my front crossmember mods. This ties into the TC rod mod a bit. The crossmember is slotted for pivot height adjustment, the rack is moved back about 7/8" for Ackerman, the stock rack mounts are gone, no more bushings. Had to clearance the crossmember for room for the pinion housing, filled in that area with a piece of pipe. Installed the crossmember, double checked everything, then took the plunge. I stitch welded the crossmember to the frame rails and welded some supports from the crossmember to the TC brackets, making the crossmember into a K member. I also stitched the crossmember seams while I was at it. I'm hoping this front end should be pretty stiff... Link to comment Share on other sites More sharing options...
BWRex Posted July 12, 2006 Share Posted July 12, 2006 Very nice.What is bolted just inside the trans tunnel?Metal plate?Exaust clearance ok? Link to comment Share on other sites More sharing options...
JMortensen Posted July 12, 2006 Author Share Posted July 12, 2006 That is my scattershield that I half-assed together after buying the 12 lb AZC flywheel. It's 2 pieces of 1/8" plate that were bent to match the tunnel shape (poorly) and then stitch welded together, and bolted to the floor. Link to comment Share on other sites More sharing options...
z-ya Posted January 23, 2007 Share Posted January 23, 2007 Jon, Your electric bill must be through the freakin' roof! Nice work!! Link to comment Share on other sites More sharing options...
JMortensen Posted January 23, 2007 Author Share Posted January 23, 2007 Nah, takes me YEARS to do this crap, so I have the bill spreads out... Thanks, though! Link to comment Share on other sites More sharing options...
auxilary Posted January 23, 2007 Share Posted January 23, 2007 DUDE! you welded the crossmember on backwards! just kidding Link to comment Share on other sites More sharing options...
JMortensen Posted January 23, 2007 Author Share Posted January 23, 2007 That would SUCK!!! Link to comment Share on other sites More sharing options...
The Rototiller Posted February 7, 2007 Share Posted February 7, 2007 i installed my mad dog frame rails. i had them make me an uncut front section so i could fab a better fit. jmortensen, looks like you stitch welded your rails on. i stitch welded mine on too, then went back and filled in the gaps so it formed a weld bead down the whole length of the rail. i know that might not have been the optimal route to go, but it looked like crud could have easily gotten into those gaps and caused more rust troubles down the road..... should i have just left them stitch welded? Link to comment Share on other sites More sharing options...
JMortensen Posted February 7, 2007 Author Share Posted February 7, 2007 I figure that the stockers were just spot welded, so I didn't get too obsessed with sealing the seam. Speaking of which, if I were to seal the seam, I would use seam sealer instead of welding the whole thing. Besides, mine aren't sealed up against the floor in back either... I don't think you really hurt anything, but I think stitching is theoretically stiffer than seam welding. Link to comment Share on other sites More sharing options...
Rebird Posted February 15, 2007 Share Posted February 15, 2007 wow jon, this is a great thread and thanks for inspiring me (and i'm sure 100 other guys) to get off the computer and get busy!! thanks for documenting the project, very informative with great pics!! A+ Link to comment Share on other sites More sharing options...
jonnymrp Posted April 8, 2007 Share Posted April 8, 2007 im just put my front end together for the first time last weeked and got the car on its owne weight for the first time in a year. this is mt take n the sloted tc box. http://album.hybridz.org/showgallery.php?cat=500&ppuser=12917 jon... let me know what you guys think. Link to comment Share on other sites More sharing options...
JMortensen Posted April 8, 2007 Author Share Posted April 8, 2007 The bracketry looks nice but it appears you've drastically shortened the TC rod. This is not a good thing because it makes the caster sweep really bad. Ideally you'd like the TC rod and the control arm to be as long as possible. That would minimize the geometry change. Two ideas to fix the caster issue would be to either relocate the bracket and use a longer turnbuckle or make the control arm into an A arm instead of a control arm and a TC rod. Link to comment Share on other sites More sharing options...
jonnymrp Posted April 9, 2007 Share Posted April 9, 2007 ya i agree. after seeing it all together i think i prolly end up rebuild the arms. it never clued in to me up to the point when i was welding the arms up that with the 240sx rear it is a couple inches wider in the back. so im going to end up makeing new longer arms to match the width in the rear. and i agree the tc arm looks to short but i think it looks shortter than it is. because it mounts to the control arm ferther in board. and the amount of frame behind the "tc box". im no expert but whats a bad castor sweep. my understanding is that once set with this desighn castor would be the same no matter what the static legnth of the arm. jon... Link to comment Share on other sites More sharing options...
jonnymrp Posted April 9, 2007 Share Posted April 9, 2007 i had a shower and thought about for a bit i get what you were saying about castor change. prety much what im going to have to do is rebuild every thing. but one of the next things i want to do i get the car to my work and put it on the rack and do a alignment just so i can see if the dang thing will go straight. this set up will do enough for test porposes. ive sloted the kmember that very nicely gets rid of bump steer but it also raises the front rool center quite a bit. i think once i get my engine test fit im goign to make a k member that adjusts the control arm height but also can move the rack up down forward and backward. for a truely adjustable front end. Link to comment Share on other sites More sharing options...
WizardBlack Posted August 23, 2007 Share Posted August 23, 2007 Jon, would you be able to update all the images, or just repost the finalized stuff, etc. for this sticky? Also, another (probably stupid) question; If you go through the trouble to make a new T/C rod mounting point and fab your own T/C rods, why not simply fab another point like the subframe mount for the lower control arm and make it a standard control arm with two mounting points like the rear lower control arm? This avoids the whole caster issue cause by the arc the T/C rod sweeps since both chassis side pivoting points would have precisely the same pivot axis. Link to comment Share on other sites More sharing options...
JMortensen Posted August 23, 2007 Author Share Posted August 23, 2007 I don't see a control arm as an advantage vs an LCA and TC setup. You can't lengthen the control arm in that type of setup, and when the caster angles get extreme the arm starts to point forward, which makes it act differently than an arm that is perpendicular to the center line of the car (the reaction to this is discussed at the very beginning of this thread). It would also eliminate or at least make much more difficult the ability to add in adjustable anti-dive and front roll center. The potential benefits would be tire clearance and possibly weight and strength, but above and beyond that if there are any I'm not aware of them, and I'm not really worried about the weight or strength of the pieces as I've modified them. Floor with stock rails cut off: Pulling floor to SFC with sheet metal screws. Also shows custom piece Bad Dog and roostmonkey made for me: Stitching the SFC's to the floor: Cut the entire TC bucket and the supporting frame structure off: The seat bracket lined up with the SFC perfectly: Weird shaped hole cut into top of new TC box to line it up with bottom of frame rail: TC box setting on frame rail: Shot shows the now slotted TC rod box, forward gusset, the modified Bad Dog SFC connecting to the TC box, and the support from the box to the rocker tip. Angle iron gusset on top of TC box Mocking up the TC rod angle to make sure the rod didn't hit the box through the suspension travel. Link to comment Share on other sites More sharing options...
JMortensen Posted November 25, 2007 Author Share Posted November 25, 2007 Believe it or not there is a new development on this project. I never did make my new TC rods previously. I ordered up some turnbuckles and they were too long, then I just used the old rods on the car to move it to the new house. So now that I'm about to paint the undercarriage I finally decided to make new TC rods. Got a new turnbuckle, a 3/8" clevis and a piece of 3/8 x 1 bar stock and went to work. Based on info from another thread I tried to make the TC rod point directly at the ball joint. This is supposed to load the rod itself better (straighter). I think I did a pretty good job at aiming the rod, but now the piece of bar stock is pretty long and I'm thinking that in itself might be a weakness. I guess I'm considering drilling a new hole closer to the control arm, even if it loads the bar a little bit off dead center. I remember Cary talking about cars on slicks bending the stock TC rod at the bend. I would imagine mine is a little stronger at this joint than a stocker, but I'm not sure I want to take chances here. Thoughts? Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted November 26, 2007 Share Posted November 26, 2007 Jon, The design will work if you redo the plate on the control arm such that it also captures the outboard bolt on the ball joint. The current design places that bar in bending when you apply the brakes. The other issue that you may encounter is the tire rubbing the T/C rod when turned fully to the left or right. As you know, I had an issue with my T/C rod a couple of years ago. As part of putting my car back together, I reengineered my T/C rods similar to what you have. The plate that I use on top of the control arms uses the same two bolts as the stock T/C rod. A third hole in the plate lies on the line drawn between the rear-most bolt on the plate and the T/C pivot on the frame. I'll have to borrow a camera, so that I can post a picture. Link to comment Share on other sites More sharing options...
JMortensen Posted November 26, 2007 Author Share Posted November 26, 2007 How about welding on a tab like this? Seems like it makes the TC rod connection double shear which was something Cary had mentioned, and it also gives another load path for the rod to the control arm. The tab has a slight bend to it in order to hit right on the edge of the control arm, but I don't think that would be too much of a problem... Link to comment Share on other sites More sharing options...
JMortensen Posted November 26, 2007 Author Share Posted November 26, 2007 Well I went ahead and welded tabs on both arms. There is also a reinforcing plate on the arm underneath which stops about 1/8" from the edge of the arm, I welded the gap up so that there is a solid 1/8" thick or thicker piece of metal from the TC rod all the way across the top of the control arm. This just looked like such a naturally good solution that I figured what the hell... Link to comment Share on other sites More sharing options...
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