Chasis Welding on a S13 coupe

[Big Zee]

hey there, first off, I have the idea's in my head, but want to know specific information before I sink money into the car. The ultimate plan for this car is to be a Street Legal car and Track ready car, with the only real thing needed to be swtich once on the track is the tires.

first off, I bought it as a bare shell. it is a 1989 Nissan Silvia. trim level ? I do not know, haven't thought of reading the badge on the door yet. although I have had it for 3 years now.

I want to clean it up, and found a bit of rust, mostly surface, but 2 spots inside the cab by the door have eaten through, and so I have decided, as it is a shell, I'll have all the rust that has to be cut out and replaced done, and surface rust taken care of. once that is done, I want to have the car weld reinforced.

My question is, Is it better to Stitch weld the entire car, or seam weld it. and Yes, it will be all over the entire car as it is a bare shell, and everything is showing. Although the Interior won't be as much as the engine bay.

I'm not posting this to be a newb of any sort I have done a bit of research into it, where as the stitch will hold better as it has more holding joints, and the seamweld will be a full combing joint, but the heat stress on the metal with the seamweld would be greater then that of a stitch and may cause warpage.

I'm pretty sure Stitch welding will be the better option, but if anyone knows for a fact which one is the best option please let me know :).

ps, here's a pic of what I get to work with.
http://i43.photobucket.com/albums/e374/BigZee1/more%20240%20pics/Silvia%20Pics/DSCF1406.jpg

[redsx13]

i would stitch weld, thats what mine is...

http://i279.photobucket.com/albums/kk141/redsx13/llll010.jpg

http://i279.photobucket.com/albums/kk141/redsx13/DSC01664.gif

[Big Zee]

Redsx13, you have such a nice engine bay. I am very jealous haha. and thank you for the reply and undercarriage pic. looking at it makes me think Stitch is the way to go and thats what I'll have done :).

Thank you.

[redsx13]

Redsx13, you have such a nice engine bay. I am very jealous haha. and thank you for the reply and undercarriage pic. looking at it makes me think Stitch is the way to go and thats what I'll have done :).


Thanks, now all i have to do is figure out my terrible idle.

O, btw, if you don’t have the car acid dipped or sand blasted make sure you grind off as much paint off the welding area as you can. It will work even better if you grind the paint off both sides. if you don’t, you are going to have some shitty welds! o, and while you are in there, you can fill up the random holes in the engine bay, and pull off all the bs brackets (battery tray, stock air box...)

[Mx_Eva]

You want to stitch weld the chassis. Unless you have a giant jig for the entire car.

Seam welding is only found in racing where they have a framing they put the car in during such activities. Reason being, seamwelding can cause too much deformation of the original chassis shape. Without a jig to hold the body in place you will distort your frame.

http://www.free-build-it-info.com/images/jig_chassis.jpg

And being that your car isn't a tube frame...it'll be even bigger than this.

[redsx13]

You want to stitch weld the chassis. Unless you have a giant jig for the entire car.

Seam welding is only found in racing where they have a framing they put the car in during such activities. Reason being, seamwelding can cause too much deformation of the original chassis shape. Without a jig to hold the body in place you will distort your frame.

http://www.free-build-it-info.com/images/jig_chassis.jpg

And being that your car isn't a tube frame...it'll be even bigger than this.

that is very true, our cars are made out of very thin sheet metal and it doesn't take much to distort them.

Although, I have seen it done on 240's w/o a jig. mainly for auto x. people who do this use a 2 on 2 off technique where they only weld two inches, two inches apart. This process causes minimal distortion, and has been used by many reputable race shops.

[kalypso123]

good to know

[Big Zee]

Thanks, now all i have to do is figure out my terrible idle.

O, btw, if you don’t have the car acid dipped or sand blasted make sure you grind off as much paint off the welding area as you can. It will work even better if you grind the paint off both sides. if you don’t, you are going to have some shitty welds! o, and while you are in there, you can fill up the random holes in the engine bay, and pull off all the bs brackets (battery tray, stock air box...)

good call I didn't think about that at all about getting it acid dipped or sanblated. It's going to be sandblasted I think....prolly cheaper and it'll take all that hitthe last guy missed off :)

thanks for the help guys soon as I get it done I'll get some pics up :)

ps. that cage looks pretty intense haha

[Dousan_PG]

i wouldnt sandblast
that sand is everywhere and abitch to get out
alex p was doing that w/ his SC for FD
said he'd go acid dip for sure next time

anyways
spot welding is great, my car is all welded up

here's flyberts S13

http://i2.photobucket.com/albums/y9/dousan_pg/FLYBERT/IMG_1706.jpg

i took more pics but they are on my other computer.

[PoorMans180SX]

Yeah sandblasting is good if you have a rotisserie.

If you go acid dip, just make sure you get a guarantee that all the acid is neutralized, otherwise it will eat through the paint.

[Jonnie Fraz]

Here is what we did on my buddys S13.
http://mestiso.net/photogallery/240/CIMG2867.jpg

And on my buddies S14
http://i10.photobucket.com/albums/a126/345ikadizzle/240sx%20Build/StichWeldandPaint002.jpg

This is more skip welding than stich. Weld an inch skip an inch...ect

[Gription]

What you could do is stitch weld everything, then go back and connect the welds with very short seam welds. My friend welded my hood this way and there was no warping whatsoever. This is how I plan on doing my chassis.

[PoorMans180SX]

So you're saying eventually laying a full seam-weld along the seams? I see a couple problems with this:

1. It's way too much work.
2. I doubt there is much gain over stitch welding
3. If you ever crash, you will never be able to repair anything

[drifter_for_life06]

stitch FTW. We did this on my old works drift 350z (the Sikky/JE Import Performance 350). Works great, and all we did was sandblast it. Took a DA with a grinding wheel and tore off some of that tar in some spots, but other than that just the sand blasting worked pretty damn good.

[Z33dori]

we are starting to stitch our cars...

here is a lil clip from my buddy's car...

http://c2.ac-images.myspacecdn.com/images02/11/l_4c2c7e862c654b69a9b9bd341a8e5acd.jpg

[drifter_for_life06]

that shock tower looks like its seen some hammer abuse :(

[Z33dori]

it has.... the car was wrecked before my buddy bought it.

[udon!]

bumping an old ass thread.

is it a bad idea to stich weld in only certain parts of the chassis so i dont have to remove the engine?

(i.e. just strut towers and fender area, interior floor, rear hatch area?)

[Jonnie Fraz]

If you are good enough you don't have to remove the motor...lol. The more you can do the better, but if you don't want to pull the motor do as much as you can. Do your best to get the car level before doing it, because if your chassis is flexed and you weld it that way it will stay all flexed.

[BIGGJERRYC]

is stitch welding the seams on these cars noticeable? is it a noticeable gain in rigidity?

or.. what is the point for welding the seams?

[lester7c]

bump
@bigjerry, they say that stitch weld reinforces the chassis frame especially old cars. pros pls confirm.

@topic, will the Hobart 140 spot welder do the job for an entire s13 chassis reinforcement? TIA

[Croustibat]

Bumping a 3 y.o. thread to answer the last post. Wow.