I’m definitely open to all opinions about slicing the hat off, and re attaching…..

       pictures are of a parts car, with the severed tower head.   

I try to minimize cutting and welding long sections whenever possible. Looks like there are about 40 spots that would need to be cut to r&r the entire tower. May take a bit longer, but would be my preference. 

16 hours ago, bluez said:

I try to minimize cutting and welding long sections  May take a bit longer, but would be my preference. 

      Looking at this chart, that may or may not be applicable, it would seem a properly butt welded/ground smooth joint retains 65-75% of its original strength??

Given the critically of the shock tower, and stresses of suspension, I’d go with plug welding the entire tower over butt welding the upper and lower pieces. Just my 2 cents..

13 hours ago, bluez said:

Given the critically of the shock tower, and stresses of suspension, I’d go with plug welding the entire tower over butt welding the upper and lower pieces. Just my 2 cents..

Agree. Those weld failure numbers appear to be premised on the joining of thick panels ('plate'), where lateral alignment of the joined edges isn't terribly critical.  For thin automotive sheet metal, it will be difficult to achieve good panel alignment along the entire length of the seam.  Even a brief segment with poor alignment will become the weak point that invites failure.  There's also the potential for low-level burn-through, again resulting in weak point(s).

Those published failure numbers are also premised on a steady separation load ('pull').  The weld in the shock tower will be taking variable loads (combination of spring load and shock absorber loads) that include the potential for big peaks if/when the spring bottoms out (the load curve will be high-amplitude and brief in duration, so quite demanding for the structure).

Edited June 5, 2024Jun 5 by Namerow

     Before abandoning the original metal work, I’m heating/dolly the metal to try and get back to original shape, first run through, smoothed out virtually all of the “marks” in the inner fender…..   fortunately, I have access to a nice “tip of inner fender, “?    The section that is adjacent to headlight “scoop”.

Looks like I’ve found a nice doner peice for the left side inner fender extension?  Where both bumper and headlight buckets attach.

   Will continue to for now avoiding the entire front clip replacement

Progress finally being made on 51, up on rotisserie with new rails, floors, front clip, rear valance, dog legs, sections roof, and roof rail replaced, repaired.  3 weeks in with a couple of retired body men, that are definitely up to the task!!

Early fenders inspection lid tabs are slightly different with metal versus plastic clips. 
     I’m sure most know of this, but I simply had not noticed that and other differences in “early 69-72”?    Fenders, nos fenders will have to be made right, but definitely another  3-4 steps to take for each fender to be right….”look” right.

8 hours ago, dspillman said:

Early fenders inspection lid tabs are slightly different with metal versus plastic clips. 
     I’m sure most know of this, but I simply had not noticed that and other differences in “early 69-72”?    Fenders, nos fenders will have to be made right, but definitely another  3-4 steps to take for each fender to be right….”look” right.

Does anyone know when the plastic inspection lid clips were phased out? Date wise?

Reason I ask is that HS30 0004 has build date features in line with 1969 production HLS30s such as the bonnet (or hood as you'd call it in North America) without the corner support brackets where the hood meets the windscreen cowl panel/inspection lids and the solid rear plastic panel in the boot (no tail lamp bulb access covers).

I've got photos of the above attributes attached, and I can't find them now, but I'm certain HS30 0004 had the plastic fender inspection lid clips too. (I'll try and dig the photo out if I can find it).

I'm fairly certain HS30 0004 started production in 1969 or early 70, but may have been put on pause whilst other things happened at the factory as @HS30-H points out here.

https://www.viczcar.com/forums/topic/36375-1969-240z-hs30-00048-destroyed-seeking-advice/?do=findComment&comment=246026

Quote

'HS30-00048' would not have been made in 1969. It is certain that 'HS30-00001', 'HS30-00002' and 'HS30-00003' were manufactured in 1969 (factory data proves it) and possibly 'HS30-00004' too, but production of 'HS30' prefixed bodies stopped thereabouts and didn't restart until several months later.

In my experience to date, I haven't seen other HS30 (AU) market cars with the plastic clips on the inspection lids yet. Hence why I'm wondering when the plastic clips changed.

My own car HS30 00051 had the early Nissan 2400 OHC valve cover, which I know was sort of phased out around July 1970 and many other early AU market 240z's had the 2400 OHC valve cover, but they stopped somewhere between HS30 00100 and HS30 00149.

I guess my question is this: are the plastic inspection lid clips considered a 1969 production date feature?