welding the seams?

[grannyknot]

When I get the Z stripped down to bare metal would there be any advantage to welding all the seams while they are exposed? I thought it might make the car a little stiffer, maybe squeak and rattle less

or would I just be wasting time?

Thanks,

Chris

[d240zx2]

You would likely be trapping unseen rust that would eventually cause a lot of problems. The only way I would consider doing this is if the car was COMPLETELY disassembled, then put back. I mean you would have to take all body panels, floor panels, etc. apart...bust the spot welds, clean, POR, then reweld. BTW, do you have a body jig? You'd need it.

[grannyknot]

I'm thinking of having the body dipped, the whole shell is submerged in a bath of boiling caustic acid. I'm told that nothing escapes it.

[olzed]

Everwhere you weld is another place for rust to start between the panels.

I'm not a fan of dipping either. I know of two zeds that rusted away after acid dipping.

.

Edited September 5, 2012 by olzed

[Zed Head]

I think that the acid bath will make the whole car a spot for rust to start. You would have to do the acid bath, do the welding, do another acid batch to re-clean everything, then do a dip in E-coat or rust-proof coating of some kind. Could get very expensive.

I've seen a thread or two on another site about stitch-welding the seams after extensive media blasting and even then there is lots of smoke and contaminated welds. Sounded like a real pain.

Might be more effective to add some of the typical body/frame bracing first and maybe some selective welding. Hybridz has a lot more to look at, since they have a racing tilt over there.

[John Coffey]

A lot of ignorance in this thread. Seam welding is a long time racer trick to reinforce the chassis and the S30 benefits from it and even brand new, off the assembly line cars are stripped and seam welded. Its a lot of work to get the seam areas clean enough to properly do the seam welding and the car needs to be pretty much stripped bare (including the wiring harness). I've seam welded five S30s, none of them were street cars. IMHO, it not worth the time or effort for a street car, plus the seams on the car now have 1" welds spaced 1" a part - everywhere. Some people feel it looks bad. Go on HybridZ.org and search - there are a number of threads with pictures showing the process.

[26th-Z]

Read about electrolytic rust removal. http://www.classiczcars.com/forums/thread16506.html I understand the comments about acid dipping your car and I agree. Acid dipping is not a good idea.

[Zed Head]

A lot of ignorance in this thread. Seam welding is a long time racer trick to reinforce the chassis and the S30 benefits from it and even brand new, off the assembly line cars are stripped and seam welded. Its a lot of work to get the seam areas clean enough to properly do the seam welding and the car needs to be pretty much stripped bare (including the wiring harness). I've seam welded five S30s, none of them were street cars. IMHO, it not worth the time or effort for a street car, plus the seams on the car now have 1" welds spaced 1" a part - everywhere. Some people feel it looks bad. Go on HybridZ.org and search - there are a number of threads with pictures showing the process.

I don't claim to be non-ignorant. Feel free to pick out the specific points if I'm one of the purveyors of bad information, on the welding, the acid bath, or the need to re-coat the body. Or the difficulty in getting things clean enough.

I'm seeing two messages (or one big one) in your post. Basically, that it's only worth doing for a race car, a waste of time for a street car.

Shed some more light please. Thanks.

p.s. The OP is just trying to make the car feel firmer and less noisy. Any thoughts on the first things you would do to stiffen the chassis? My car creaks in the headliner area, in the back, if I get diagonal wheels unloaded, like when coming off a ramped, humped, driveway at an angle. I assume it's the body torquing a little but I don't know what to do to stiffen it up diagonally.

[John Coffey]

I'm not pointing fingers at anyone in this thread. Having done it there are a lot of aspects to it that are not mentioned and that's where I'm saying there is ignorance. Seam welding will increase torsional rigidity within the limits of the original design. Will it be enough to eliminate creaks and groans, probably not. What seam welding does is improve the chassis ability to handle its designed loads. There's always a loss when going from the design board to production. While the S30 chassis may have been designed to absorb X Nm of torsional load on paper, when the chassis finally rolled off the assembly lines that number is now > X (i.e: maybe Hoji had a bad day on the spot welder when your car was made.) Does this difference matter on a street driven car? IMHO, no. A race car will see 1G lateral and under braking 9 or 10 times per lap (every 90 seconds) and spend at least 5 hours doing that each race weekend. A street car may see 1G lateral once per month and that's if the car is setup correctly.

Less involved and less expensive chassis stiffening is more appropriate for a street car. Roll bar, welded in subframe connectors, strut tower braces, etc.

[26th-Z]

I'm going to suggest that the 'creaking' is not coming from the chassis. Take all the interior finish panels out (which may involve buying those danged rivets) and reinstall them with a caulk / pad / sealant at the attachment points and the seams. My experience has been that those old plastic interior panels move, rattle, and creak. Give them some padding and I'll bet your car will be a lot quieter.

[olzed]

A lot of ignorance in this thread. Seam welding is a long time racer trick to reinforce the chassis and the S30 benefits from it ant not worth the time or effort for a street car,.

I believe we are just trying to give some sensible advice to a member here. He did not say it was a track car, so I assumed it was a street car.

Most, if not all of us would know full well why a car body is seam welded. Still doesn't make it a clever idea for a street car IMHO. The car has survived 40 years

withought the seams welded. We also all know these cars are prone to rust, so why seam weld and risk creating more.

[John Coffey]

We also all know these cars are prone to rust, so why seam weld and risk creating more.

The process of getting a car ready for seam welding will reveal all the rust that's in the chassis and that all needs to be fixed before any seam welding begins (if not, what's the point of seam welding the car?) Seam welding itself does not create rust. And a proper seam welding job finishes with all the seams sprayed with a good high zinc primer and sealed with 3M or Wurth body seam sealer. The car should end up even more rust free and rust resistant then when the seam welding process started.