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Through the course of my bare metal rebuild I've gained a greater appreciation for what makes a unibody strong (or weak) and I'm wondering what if any seam/stitch welding and or additional plate reinforcements would be prudent upgrades for a street car. I plan on running stock dimension tires and at least to start with I'm running all stock suspension (with the addition of stock-like Koni-Reds). In other words, my goal is making the chassis more responsive, enjoyable and durable, not to prepare it for 215 tires and 200bhp.

I'm getting pretty good at MIG welding and fabrication, but I don't want to do anything that could damage the chassis - for instance put too much heat into the susp/ mounting points and wonk it out of alignment.

Any advice? Might be that this is barking up the wrong tree, but this seems like the right time to ask the question.
 

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What ShadeTree said.

Seam welding on a street car is a very bad idea: it can prevent the body from deforming in the way it was designed to in the event of a collision, increasing the risk of injury to occupants.

This is not really a concern in a race car, where you are presumably adding other substantial life safety equipment, and therefore not too concerned with original crumple zones.
 

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...Seam welding on a street car is a very bad idea: it can prevent the body from deforming in the way it was designed to in the event of a collision, increasing the risk of injury to occupants....
Well, maybe not. These cars were designed in the days before finite element analysis and validation crash testing. Also, given their age, it is likely the spot welds are weakened from low-cycle fatigue. The body is as likely to be much weaker than originally designed as it is to become too stiff from seam welding.

In addition, there are a number of areas that were noticeably weak in the early ('64-66 Alfas) that the company improved in later models. The front cross member was made of heavier gauge steel in later years, as were most of the front inner panels. Alfa even provided details on how to replace the early (two-bolt) cross member with a later version (four-bolt) that includes fully seam welding the new unit.

And we all know of the weakness in the steering box (and idler arm) mounting that has lead to many reinforcements.

Given that Alfa even recommends reinforcement in the front areas, I'd happily go ahead if you are confident in your skills. If you do the seams in short segments, you will not have any warping issues.

Robert
 

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i agree with robert. The idea of a crush zone didn't really exist (As we think of it today) when these cars were built. design work would have been done in the early 60's for these cars. most cars still didn't have seat belts at this point.

the first "crush zone" was the 5 mph bumper..in 1972. it's job was to protect things like the headlights.

stiffen up the trunk area where all that weight is hanging, reinforce the steering box. beyond that, it'll probably make no diff. in a street car.
 

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If we're talking safety, personally, I'd leave it alone. Even if the stock welds have weakened over the years, the deformation of the front end will act as a crumple zone. Modern cars are designed to absord energy rather than have it transmitted to the cabin. If you seam weld the engine bay area, you're doing just the opposite. Unless the entire cabin area is also seam welded, the cabin will be the weakest area and the first to deform in an accident.
 

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If we're talking safety, Failure of the front spot welds, loosening the cross member, or cracking in the steering box mounts are more likely to CAUSE in an accident. That's much worse than issues of front or compartment deforming in a crash. Especially since a crash that risks deforming the passenger compartment may not be survivable at all!!

This stuff is foolish commentary - these cars are not crash engineered; guessing how they might react in an undefined crash is just idle blather and poppycock!

KEY: Alfa strengthened the front end in later models. Making yours stronger cannot be wrong !!!!!!!

Robert
 

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Actually, I beg to differ on the subject of crumple zones. The following is an excerpt from a historical timeline on the Alfa Romeo corporate website:

"The Giulia was the first to adopt a crumple-zone body and feature a five-speed gearbox."

If you've ever seen a GTV that got hit hard in the rear, it will be obvious that there are crumple zones designed into the car.

Another touchpoint: Andrew (on this forum) has mentioned in other threads that he actually has some factory advertising literature on the Giulia Sedan and it's crumple zones, so not only was Alfa designing them into the cars at that point, but they even thought it was important enough to advertise it.
 

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rkirkpatrick is right. Alfa Romeo, along with Mercedes Benz, Citroen and Rover were designing crumple zones well before it was fashionable,commonplace, or mandatory. I have literature indicating this fact, as obviously rkirkpatrick has. Alfa was amongst a small group of manufacturers whose engineers seemed on a mission to produce a "better" car simply almost as an intellectual exercise rather than the purely commercially driven (and ultimately more successful) manufacturers. Certainly with frontal or rear impact the zones appear to work quite well although because of the infancy of this aspect of design the zones would not work as effectively as a modern obviously.
I`m for seam welding the passenger cell, especially along the sill to floor area but would leave the front and rear segments alone. I have done this to my Giulia Ti and the increase in torsional stiffness is noticeable.
 

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Excerpt from Road & Track, July 1967:

"Crash! The entrance of our Alfa Romeo Giulia Sprint GTV was undeniably dramatic. The scene: A fog-smothered coast highway intersection, where the Alfa waited apprehensively before a red signal, surrounded by darkness and things that go bump in the night. The heavy: An on-coming full-size native sedan, secure in self knowledge and pride of home turf. The action: Predictable and disastrous. Nuccio Bertone would have wept.
Taken squarely up the back by two tons at 30 mph the rear seat bodywork was crushed, but with superb progressive reluctance: to such good effect that our driver emerged physically unharmed, though with a bombed-out psyche. Crumpling extended forward to the front of the rear wheel well, popping loose the rear window and distorting the rear vent frames. Surprisingly, however, the doors could be opened after the collision, and even the chassis and rear axle geometry remained undistorted. All of which rounds out to high marks indeed for the craftsmen of Milano, plus a concomitant hint to the legislators of Washington that there may be even more to automotive safety than lap belts and hazard lights."

And then some ;)
 

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Sorry to awaken such old thread, but if we leave the trunk area - how about the chassie parts underneath the car? Would it do any difference in handling to weld 1" welds and leave 2" in between? The front should benifit from this, since all performance upgrades includes a beafty anti-roll bar.

Just curious about the real benifit of seam welding a chassi/body.
 

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Most of these cars have had their floors or chassis rails replaced and therefore these areas are now seam welded and as not part of the collapsible zone all good. I intend to seam weld my front cross member (inch on inch off) and my floors and chassis rails have been but that will be all.

My car will be a street car with standard power but I do plan to do regularity track events with her just for fun.
Pete
 

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And if they have not had the floors and rails replaced..?
Then they will have the original spot welded panels... Personally I agree with Robert (Pete & Richard) as above and intend to seam weld. I have already found spot welds during my restoration that can be separated with minimal force.

60sRacer said:
<snip>..... Also, given their age, it is likely the spot welds are weakened from low-cycle fatigue.
 

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Jema, I would strongly suggest seam welding the passenger cell area of your car. The benefits outweigh any negatives I can think of.
 

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Does anyone have some photos of their cars floor stitch / seam welded? Having a hard time visualizing how to do this. From underneath the car, or from inside also?
What about the rear? No stitching or seaming? (That would make sense since you would benifit from more rigidity in the front in these cars?)

I borrowed a photo from google, is this what I should strive for?
 

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Pancho has some great pictures in his rebuild/resto thread, I'll add the link later.
 

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That photo is how it is done. I also did all joins inside of the cabin too in my Giulia Ti. Essentially the passenger cell/tub is where you want the added strength for both increased torsional strength and increased protection. The front and rear portions shouldn`t be altered too much for a road car as it is these that are your energy absorbing parts and if in good condition are more than adequate for a road car providing you don`t go silly with tyre sizing. These structures are designed for soft well controlled suspension and limited grip (controllable slide) Increase the firmness of the suspension too much or the grip too much and you load the structure beyond what was originally intended.
 

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Hi

Do you have photos of your steering shaft inside the cabin. It not looks standard or is it special version?

Juha

 
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