Confirmation on where to seam weld before i start

[Wedge]

Hi guys just wanting to make sure that i have this right I made some red lines where im going to be seam welding the front . Please let me know if their are places where i should not weld and if their are places i forgot

thank you

[johnc]

Hi guys just wanting to make sure that i have this right I made some red lines where im going to be seam welding the front . Please let me know if their are places where i should not weld and if their are places i forgot

thank you

 

 

That's fine. Also focus on the seams around the TC rod mount and if you can get inside the cowl weld the seams in there.

[Wedge]

Thank you very much John ! I'll post pictures of the finish product

Edited July 29, 2010 by Wedge

[Tony D]

At the firewall to floor juncture, making a 'c channel' with flanges to bridge the stock lap joint will help reinforce it as well... but that may not be legal for racing. For a street car you can do it, but racing usually has limitations so check the rules.

 

Datsun was better than US Manufacturers in moving that joint back from the firewall/floor junction.

[LLave]

On the seams? I doubt you can do much harm unless you way over heat or burn through. Some will question how effective stitching up the seams are at all.

[Wedge]

Thanks Tony D , finally the machine we rented didnt work out it was gas powered SMAW machine and the power was alternating to much so it stuck the rod or it burnt through . On 1/16 steel plate it worked nice but on the datsuns 1/32 it didnt . Ill have to get a MIG next time .

[Tony D]

At the factory, in the day, they used Oxy-Acetelyene and it seemed to work fine...

[Boy from Oz]

Here is something you may wish to consider. It was my intention to weld every seam on the car but the chap I got to come and do it offered a pretty good reason not to do so. He has been involved in the preparation of race cars for 40 years so I figured he had some experience on such matters.

 

In much the same way as rollcages have been adapted to serve a duel purpose, seam welding should try to emulate those same goals - crash protection and structural rigidity. That said, there is no need to weld seams which do not bear suspension forces or engine torque loads. By stiffening other areas you are reducing the impact attenuation properties which soften the deceleration if you hit something (or something hits you) and very importantly it allows any damaged panels to be repaired or replaced. If you have an overly rigid shell you don't know where it will give. Have you ever noticed cars that have had a tap in the back but the whole boot area retains it shape and the car folds around the rear window area.

 

I wouldn't be welding the radiator surround or anything forward of the strut towers. Likewise I woudn't weld the rear frame rails rearward of the moustache bar cross-member.

Edited August 6, 2010 by Boy from Oz

[Wedge]

^ Thanks for the advice Boy from OZ,so you just welded everything I outlined except front radiatior supports and the frame rails .In your first picture I dont recognize where this is on the Z it looks like the frame rails but im not sure .

 

The reason why im doing this is beause I was told by a Z guy I met that the RB26 swap im doing would absolutly need some reinforcements to prevent twisting of the front end ... I am a little doubtfull since V8 guys dont seem to be doing seam welding but I told myself what the heck it doesnt hurt to make it more rigid .Since the car will be street driven 90% of its time ,their is no race track within 300km for my place, their is no need to go overkill either.

 

And Tony D can you show me a picture or just a simple drawing of what you are talking about the C channel from floor to firewall .

Edited August 6, 2010 by Wedge

[johnc]

Please remember that loads into the chassis from the suspension are far greater then loads into the chassis from engine torque. A 125hp 240Z that road races on 8" wide slicks will see a lot of benefit from seam welding. A 500hp 240Z that drives on the street with 240 treadwear tires will see much less benefit from seam welding.

[Boy from Oz]

I agree with johnc about the greater importance of suspension loads and even though I’ve undertaken seam welding I’m skeptical of its worth. I think braces across the strut towers both front and rear is probably all that is needed.

 

I have undertaken a complete rotisserie build for an LS1 installation mainly to address rust and poor repair problems. A front frame rail was in very poor condition and a previous repairer had just welded plates over sections. The floor needed relpacing so the seam welding was really a case of ‘well I’m here I might as well do it’. I do however consider extending the frame rails to the diff cross-member a worthwhile exercise. The first photos were not the completed job and I have in fact stitched the frame rails.

 

I also fitted a 300mm ‘C’ channel over the front rails at the engine mount points to strengthen the area.

[johnc]

Seam welding repeatedly proves its worth with Rally cars. On pre-1973 S30s its worth another 50 lb. in. in spring rate in the front of the car with no other reinforcements. It also help to seam weld the radiator core support if for no other reason then to keep from tearing your aluminum radiator apart. Again, its of less value on 1973 and later S30s but I have customers that run the vintage Safari Rally and all of their S30 cars are seam welded. It helps make the chassis last more then just a few seasons.

[Wedge]

Thanks alot for the clarifications and picture everyone I guess I was being misinformed about the need to stitch weld the hole thing for a street driven 380-400hp RB 280Z . I will however do the shock towers and TC box . Thanks again .