Stitch welding seams on a ta22 - worth it?

[bLaCkFoXsA]

Hey all
Just acquired a new mig welder with a bunch of new rolls of wire, and i'm considering going through and stitch welding all the seams on my 22.. I have welded before, though i'm no pro, and I have a qualified welder in the family who can tell me where I go wrong but is not about to do it for me. What I want to know is (opinions or experience, either one) will it be worth the effort and time needed, if so which seams need attention, and how likely am I to somehow destroy what is otherwise a very clean shell?

What can I say, my project's boring at the moment due to lack of funds and I need to do something

[SilverRA23]

If its a road car its not worth the effort.

If its a track car then it would definitely be worth the effort.

[bLaCkFoXsA]

What if It's a combination of the two? It's going to be running an sr20 and pretty stiff suspension

[thechuckster]

then on the road it'll be bloody unpleasant. Stitch weld if you need rigidity in the body (e.g. are turning the car into a track or rally-only vehicle.

[bLaCkFoXsA]

ahhk, probably won't be worth it.. cheers for the info

[J-M kujala]

I have stich weld mine, like ~10mm weld and 25-50mm without (about) Basicly whole engine bay and all "beams" & main joints. dont know was it worth it, but in a track its still to soft chassis. I will use mine in a racing circuit & street.
Was it worth... After sandblasting that was like ~ 6 hour work..
If you gonna do it, be sure the car is in the straight floor, not lifted up from one corner :-)

[Duk]

then on the road it'll be bloody unpleasant. Stitch weld if you need rigidity in the body (e.g. are turning the car into a track or rally-only vehicle.

If making the chassis more rigid makes the car ride worse, then you are doing something very wrong!
With the exception of weight penalty, there is no such thing as a car that is too rigid.
If the car rides crap after increasing the rigidity, then that just shows you how much the chassis was flexing. The suspension is there to deal with bumps, not the chassis!

Case in point. On another car forum I'm on, a guy tells me that his HUGE (something in the order of 3.8 times higher spring rate than standard!!!) increase in front spring rates (torsion bar size increase), still has his car providing a decent ride quality. 6-12 months later, same guy shows pictures of cracks in his car's body work
Guess which part was flexing, the big torsion bars or the floppy chassis???
I would say that this same guy would have hated the ride of his car if his chassis had been braced and seam welded with these springs and especially the standard spec, linear valve, Koni dampers, because the bump harshness would have been transferred to the occupants via the stiffer chassis instead of being dissipated by flexing the chassis.
But with a properly seam welded and braced chassis, spring rates and damper specs could be much better matched to achieve an improvement in chassis balance (handling) while maintaining very good ride quality.

I would suggest applying proper seam welding techniques to any older chassis, but be prepared to then have to do some proper spring and damper tuning to get decent results from the thing. 'Off the shelf' probably won't cut the mustard.

[J-M kujala]

TA22 stich welded chassis is still more flexible than TA12 chassis without. Missing B-pillar and windscreen angle and lenght of the door makes HUGE difference, got TA12 without and TA22 with weldings. I have drive bought with same suspension setup.

Also when test chassis torsion stiffnes, TA12 wins.

I have test it like drive one front wheel to a ramp, (used on car repairs) drive until one wheel raise up at the floor.
So the chassis share weight in a 2 wheel (cross hanging) and then make measurement between wheel arch or marking tape near tha place and straight floor, do the same to a every corner, write them up and re measure when car sits in a floor just line usually, make calculations whats the difference, After stich weld you can measure like this, it wont flex like before. But in my measurements TA12 is still more stiffer, and can feel it in a track.

But cant say is it help and how much, because not use never my celica without stich weldings. But the roof flexing still a lot.

[JadeEstevez]

What about welding up seems on the shock towers and radiator supports before paint, for a cleaner look in the engine bay of a show car? O___o Would that be okay?

[timbosaurus]

So I'm not speaking from experience, but have been reading up a bit because I wanted to do the engine bay on mine while it's bare.

I'll echo some of the things that kinda made sense to me.

Stitch welding forward of the front strut towers is a bit pointless.

Stitch welding part of the car doesn't work... Because you amplify the loads on the non-stitched parts, then they start cracking.

Should be done on a level ground (or jig even), because its not moving once welded.

[JadeEstevez]

Stitch welding forward of the front strut towers is a bit pointless.

Interesting, I can understand why but what if the show car idea as said above? Because I may be doing this =P Sorry for hijacking.

[Duk]

Stitch welding forward of the front strut towers is a bit pointless.

There could be some benefits in stitch welding around the front, remember that the antiroll bar will push and pull against the body.
Even though the twisting force is opposed by the opposite side of the suspension, there is still a vertical force that will be put into the ARB's mounting point on the load side of the car during cornering. With chunky bars, those forces increase.

Stitch welding part of the car doesn't work... Because you amplify the loads on the non-stitched parts, then they start cracking.

The front of a front engined car will have the highest spring rates, the lowest roll centre height and the stiffest antiroll bar. So front of the chassis has to resist the most of the forces the car is subjected too.
By stitch welding the strut towers, there will be more force put into the adjoining parts of the chassis, but by combing multiple parts together more effectively, the net result be an improvement. The firewall for example, is a pretty solid bit of metal. Attaching strut towers and/or inner guard panels more rigidly to the firewall is unlikely to cause cracking elsewhere.
Decently solid strut tower bracing that triangulates either too the centre of the firewall, or even better, cross each other and go to the opposite side A pillar, would add significant strength to the strut towers, rather than some spindly little bit of aluminium tube that goes left to right and is fixed by a single bolt on each side. Solid enough to make a direct left to right brace redundant.
Same for adding triangular bracing inside the front guards, linking the lower part of the A pillar to the strut tower. Holden started doing this at some point in the Commodore range and most people would have seen those 'inner guard braces'. By adding something similar, vertical forces from the front springs will be much better resisted by getting the strong A pillar section and lower box section that the sill panel forms, to help support the strut tower, rather than just the inner guard/engine bay sheet metal.
By helping to transfer the bending and twisting forces more effectively into the already strong parts of the car (the A pillars areas where the door hinges are, the firewall and the lower box section/sill panels), the car will be more rigid.

[timbosaurus]

So it goes to show that what you do, how you do it, and whether it's worth it is so subjective.

My front anti-roll bar is essentially connected straight to the chassis rails, and the cracks i discovered in mine are actually between the firewall and the rest of the car. So what works for me won't necessarily work for you and vice versa.


I'll probably still do my engine bay while it's stripped, because there is no way it'll happen again once I paint and reassemble. I'll do everything along the rails, up the strut towers, the firewall onto the body, and I've already got a triangulated strut brace. If/when the rest of the car get's stripped, I'll continue the rails and link the front half to back half.

[4th surf]

Interesting, I can understand why but what if the show car idea as said above? Because I may be doing this =P Sorry for hijacking.

Then something like sikaflex or a paint over sealant is going to be your friend if you want to also use the car as a daily or occasional drive lest cracking occur or it be relegated to being a "trailer queen". To put it simply you only stitch or seam weld a monocoque bodyshell if it is only to be used for competition use. This is accepted practice to stiffen everything up. Hell in days gone by smash repair would seam or stitch weld new parts on and when you went to buy a used car checking for cracking was a sure sign it had been in a crash. Modern repair under i-car or similar states that the welds on repair must be of a certain type in a certain location on manufacturers specs. Same also applied to 4wd bodyshells even with a separate chassis

[JadeEstevez]

^ Yes but if you were using a TiG, Wouldn't the welds be more flexible anyways?