rsicard Posted November 23, 2013 Share Posted November 23, 2013 The trick to not twisting the chassis is to tack weld the rear sections in first (both sides) while shooting a last down the chassis to make sure they point toward the center of the front rail structure at the TC rod mount. Then tack weld the front sections in place (both sides) again using the laser for alignment. Then weld the front and rear sections together. Now you can do the full stich/seam welding of the frame rails to the car, alternating sides of the car, front to back, and inner/outer edges of the rails for each weld. If you get the rails welded together straight while tacked to the car, the stich/seam welding will not affect the chassis alignment if you alternate where you weld. The won't overpower the rocker panels, closed doors, or the roof structure. John: What is the method to use to check for any chassis twisting knowing the amount of experience you have with these cars? Quote Link to comment Share on other sites More sharing options...
rsicard Posted November 23, 2013 Share Posted November 23, 2013 The trick to not twisting the chassis is to tack weld the rear sections in first (both sides) while shooting a last down the chassis to make sure they point toward the center of the front rail structure at the TC rod mount. Then tack weld the front sections in place (both sides) again using the laser for alignment. Then weld the front and rear sections together. Now you can do the full stich/seam welding of the frame rails to the car, alternating sides of the car, front to back, and inner/outer edges of the rails for each weld. If you get the rails welded together straight while tacked to the car, the stich/seam welding will not affect the chassis alignment if you alternate where you weld. The won't overpower the rocker panels, closed doors, or the roof structure. John: More to the story. It appears my 240Z was in an accident where the right front was damaged. It now appears to lean to the right a small amount. Is there a way to correct for this? Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 23, 2013 Share Posted November 23, 2013 With the right surface prep an automotive adhesive might be better than welding or bolting, at least for portions of the new rails. Especially considering all of the surface area available, and stress distribution. One company's web site. There are others. Might have to register to see details. http://www.lord.com/products-and-solutions/adhesives.xml Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 24, 2013 Share Posted November 24, 2013 Once upon a time frame checking a Z in SoCal was $575, including the first pull. That was putting it on the frame machine and checking all dimensions, determining if there was a plane of misalignment (or more than one) and making one corrective pull along with remeasurement after relaxation. If the thing tore apart during the pull....it was on you. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted November 25, 2013 Share Posted November 25, 2013 http://www.chiefautomotive.com/pulling/titan.asp For those members that would like to learn about frame/unibody correction. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted November 26, 2013 Share Posted November 26, 2013 ^If the floors are not rusty, I don't see why they wouldn't be able to have the rails welded properly. The stock sheet metal is around 20 gauge, and the bad dog rails are I believe 18 or 16 gauge. If you start on the bad dog rail and weld to the floor you can greatly diminish your chance of blowing through. Bolts and washers would be a way to do it, and it would work, but it wouldn't be ideal, and I think it is important that we don't put out those ideas, as they can be taken incorrectly very easily. Imagine if someone went out and used cheap hardware, one big bump and all the hardware could snap, not something you would want to be credited with the idea for. The floors are not as structural as the roof or the rockers, but the frame rail is. And as the frame rail attaches to the floor it in turn is structural. Not to mention it also supports the seat mounts which are really important. Even though the seat mounts are welded to the side of the transmission tunnel and the rocker, it still is welded to the floor as well. That and it helps support the transmission tunnel in place which holds the transmission, cut out both floors and you can bend the transmission tunnel quite a bit. johnc: That's a pretty good hint, I always underestimate the laser level. In the interest of discussion, could I ask if you choose to cap the bent/rusting rail when you did them in the past? Or do you prefer to cut out the old rotting rail? If you cut out the rail, do you leave the floor portion of it on top as in just cutting out the sides? Or do you cut out the top and patch the floor? I've seen a few done, and I usually see either a cap, or a full floor and rail replacement, I'm kind of curious what decides which route you would do. Quote Link to comment Share on other sites More sharing options...
Xnke Posted November 30, 2013 Share Posted November 30, 2013 The floors ARE a signifigant structural component of the unibody. You are wrong, rsicard. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 1, 2013 Share Posted December 1, 2013 The floors are structural in the context of their support for the trans tunnel - which is a structural part of the car. But on their own you dont really need then except as something to support the seats and keep your feet from dragging on the ground. Quote Link to comment Share on other sites More sharing options...
Xnke Posted December 1, 2013 Share Posted December 1, 2013 Sure...Cut out your floor pans on a stock car and set the car on the ground. Now shut the doors. The floors are a major structure of the car. Cut them out and those doors are NOT going to shut right. Quote Link to comment Share on other sites More sharing options...
9rider Posted December 2, 2013 Author Share Posted December 2, 2013 Guys, I am trying to weld the frame rail and not going to cut any holes on my floor pans or trunk or rocker panel or roof. Those parts are fine in my Z. I live in snow area whereas will be salt on road so I don't think I will screw drive the frame rail to the floor pan. Thanks guy. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 2, 2013 Share Posted December 2, 2013 "Sure...Cut out your floor pans on a stock car and set the car on the ground. Now shut the doors." I have, dozens of times. Not an issue. The doors shut the same way as when the car came into the shop. And welding in new pans does not improve door alignment. Quote Link to comment Share on other sites More sharing options...
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