ConVerTT

240z - fabbing new front rails

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So I decided to fab up some new front rails for the Z..  What is the worst that can happen, right? (Answer: waste some time, buy a proper set from a vendor).  So why not?

Step 1 ūüėÄ

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Step 2 - Pretty much committed now ....

 

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Step 3 - make a pattern and a cheap test piece from some leftover 20 ga

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Step 4 -  game time ...18 ga

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Step 5 - bend them up....  

This was way harder than it looks.  My cheapo metal brake was at capacity, and several teeth had to be removed, inserted and realigned in order to make all the bends.  But it seemed to work.  

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Step 6 - test fit

 

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Still a lot to do, (weld in the bend, all the internal bracing, new crossmember brackets, all the nuts, TC rod supports) but so far so good!

 

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 And the jig is working perfectly.  I should have done this years ago....

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6 minutes ago, grannyknot said:

I guess you are an expert spot weld driller by now,  big project.

Sawzall actually.  The inner panel was pretty rusty too so I am going to re-skin about 2 inches.

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Oh - and a must buy tool ... easier and more accurate than a tape measure, less crawling around.  $30 on Amazon....

 

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Edited by ConVerTT
Typo

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Got a chance to weld up some crossmember brackets.  They are 14 ga.

 

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Also ‚Äúmade‚ÄĚ the sway bar braces. ¬†Basically 3/4 of a 2.5 x 2.5 x 1/8 square tube....easy peasy ūüėܬ†

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And test fitting everything ....

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Should have a completed rail in a few more days!

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On 1/27/2019 at 7:36 PM, ConVerTT said:

And the jig is working perfectly.  I should have done this years ago....

Does this mean that you've done the same kind of work on other Z's in the past?

And tell us a bit more about that 'jig'.  Is it a jig (i.e. being used for alignment) or just a support frame?  Are you actually supporting the front of the car through the shock towers?

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This all looks vaguely familiar...!

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2 hours ago, Namerow said:

Does this mean that you've done the same kind of work on other Z's in the past?

And tell us a bit more about that 'jig'.  Is it a jig (i.e. being used for alignment) or just a support frame?  Are you actually supporting the front of the car through the shock towers?

LOL - no.  I did the floors years ago, and then the car just sat for a couple of years....

The jig was built to factory dimensions, not to this car. ¬†I posted about the build in my other¬†thread ‚Äú240z gets jiggy‚ÄĚ. (Can you link to another thread here? ¬†Not sure how to do it). ¬†Anyways, the jig supports the car at all the factory drivetrain and suspension points and under the floor rails. ¬†If the car is out of alignment you can pull it pack in for sure. ¬†The front is partially¬†supported by the strut tower. ¬†It would be almost entirely if I had cut out both rails at the same time. ¬†The next support point is the transmission mount.

its very rigid.  Car did not budge when I cut the rail.

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1 hour ago, wheee! said:

This all looks vaguely familiar...!

Haha for sure ūüėČ. ¬† I gotta post some pics - my wife is getting sick of the daily updates.¬†Am¬†I about 18 months behind you, give or take? ¬†Maybe more. ¬†Old red has been sitting for quite a while....

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5 hours ago, ConVerTT said:

its very rigid.  Car did not budge when I cut the rail.

That's not the first time I've heard this.  Same goes for replacing the floors, it would seem. The caveat seems to be that you only do one side at a time.

What I find interesting is that I've also heard comments that the Z's front structure is surprisingly 'soft' (have a look at how Elliott000 tweaked the front end of his Z back into alignment).  It would appear that the softness is only in torsion/twist.  In beam strength, it seems that the Z is pretty stout.  A lot of that is probably down to the front upper structure created by the 'horns' that extend from the shock towers back to the firewall and door pillars.

BTW, I like your 'jig' concept.  I had completely missed your earlier thread.  Lots of good details there. 

More questions for you:

  1. You say, "If the car is out of alignment you can pull it back in for sure."  How would this be accomplished?
     
  2. How did you get the car up onto the jig?
     
  3. What's the covering material used on your shop floor?

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12 hours ago, Namerow said:

 

More questions for you:

  1. You say, "If the car is out of alignment you can pull it back in for sure."  How would this be accomplished?
     
  2. How did you get the car up onto the jig?
     
  3. What's the covering material used on your shop floor?

Sure.  So with the front rail and the rad support out, I could push/pull the horn side to side a few mm by hand easily (except for the strut support holding it it place). If it was out of alignment, I could easily be re-aligned.

The legs of the jig are bolted to the car, and to the long longitudinal rails.  So the jig gets assembled / dissambled under the car while the car is on jacks.

The floor is epoxy installed by the previous owner.  It is slowly being destroyed by all the metal work ....

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Hey guys!  Got the inner fender skin patch fabbed and fitted.  Almost there!

 

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Starting to to look like a rail ūüėÄūüėÄūüėÄ

Edited by ConVerTT
Typo
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I don't know how much of your original frame rail was left but the area I have circled in red has few layers of support webbing and gusset plates inside to stiffen that area, will you reuse the original T/C rod boxes?

The new rail looks very accurate. ūüĎć

 

triangle area.jpg

Edited by grannyknot

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15 hours ago, grannyknot said:

I don't know how much of your original frame rail was left but the area I have circled in red has few layers of support webbing and gusset plates inside to stiffen that area, will you reuse the original T/C rod boxes?

The new rail looks very accurate. ūüĎć

 

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Thanks!  So the factory rail did have a gusset over the outer skin.  It is badly rusted out so it is hard to say what guage it was.  I plan on making a replacement from either 18 ga or 14 ga once the inner skin is in place.  The TC rod boxes are in great shape, likely due to the heavy white paint coat from the PO.  I am going to bead blast them for closer inspection but they seem reusable.

Question for you:  I don’t see any drain holes at all on the original rail?  It seems that the the intersection of the front rail, floor rail and firewall is is fantastic water trap once it gets wet.  Did they come like that from the factory?

Edited by ConVerTT
Many typos

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I think that if you just weld in some triangulated baffles into that circled area you should be  good but actually @wheee! just did his last year so he should have a good idea of the configuration  that is in there.

6 hours ago, ConVerTT said:

It seems that the the intersection of the front rail, floor rail and firewall is is fantastic water trap once it gets wet.

An excellent water trap!  Which is why they are eaten away so often,  I can't say that I have ever seen a pristine frame rail to know if it had a drain hole or not, maybe one of our members from Arizona could tell us.

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31 minutes ago, grannyknot said:

I think that if you just weld in some triangulated baffles into that circled area you should be  good but actually @wheee! just did his last year so he should have a good idea of the configuration  that is in there.

An excellent water trap!  Which is why they are eaten away so often,  I can't say that I have ever seen a pristine frame rail to know if it had a drain hole or not, maybe one of our members from Arizona could tell us.

Haha thanks!   So I know Mark and he is only three hours away.  Been bugging him all afternoon via text about his rails and his  drainage setup..  He had a lot of good suggestions and I have a couple of thoughts too.  Definitely adding some type of drainage path though.  Good thing everything is just clamped in right now ....

Edited by ConVerTT
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Yup, been burning up the data with pics of my install etc. Kent is on track with what I did, he is just going to have to modify the setup he has a now a little to achieve the same type of drainage.

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Well its been a few days.  The rails are pretty much done.  Time to get ready to weld so ....AIRCRAFT STRIPPER time!  Yay!

Personally I prefer chemical to mechanical stripping.  Wear a respirator.

First pass ...

 

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I always ‚Äúbag‚ÄĚ the panel after a generous application, especially on vertical panels. ¬†Keeps everything wet a bit longer and cuts down the fumes ....

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Good start, but looks like it will need a looks like it will need a second pass....

 

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Much better after a second pass...

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Panel looks pretty clean.  Rusty at the firewall and under the rad support as expected...

 

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So while I was waiting, I thought I would try the stripper on the undercoat in the fender well.  I have been told that it will NOT work on undercoat ....189DD783-7EEF-4464-9907-12E01BAC98DF.jpeg

...but it sure did!  Softened it right up so that I could scrape it off with a putty knife ...

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Finnished it up with WD40 on a rag and a wire wheel on some of the stubborn stuff.  Tomorrow we weld!  Cheers all!

Edited by ConVerTT
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Paint stripper for undercoating.  That's a worthwhile discovery.  Certainly a lot safer than using a torch and probably more effective than a heat gun. Undercoating removal is a miserable-but-unavoidable job, so anything that eases the pain and improves the result is worth knowing about. 

I wonder whether the stripper approach will work with the applied-with-a-brush-from-a-can parts store-type undercoating that was inflicted on so many cars from this era by their owners.  That stuff is just diluted asphalt.

I'm impressed by how well you managed to contain all of the paint and undercoating gunk/debris.  Almost makes the job look easy (although I'm pretty sure it wasn't).

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9 hours ago, ConVerTT said:

Personally I prefer chemical to mechanical stripping.  Wear a respirator.

I agree it certainly is the fastest but it also comes with the danger of the stripping chemicals hiding in the seams and crevises  then seeping out after the new paint is on causing breaks in the paint, then the rust starts all over again (ask me how I know).  A small fine wire brush and an air gun along the seams helps a lot removing the last of the stripper.

Looking good,  I really like your plastic sheet trough under the work area, I'm going to try that next time.

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14 hours ago, Namerow said:

Paint stripper for undercoating.  That's a worthwhile discovery.  Certainly a lot safer than using a torch and probably more effective than a heat gun. Undercoating removal is a miserable-but-unavoidable job, so anything that eases the pain and improves the result is worth knowing about. 

I wonder whether the stripper approach will work with the applied-with-a-brush-from-a-can parts store-type undercoating that was inflicted on so many cars from this era by their owners.  That stuff is just diluted asphalt.

I'm impressed by how well you managed to contain all of the paint and undercoating gunk/debris.  Almost makes the job look easy (although I'm pretty sure it wasn't).

Thanks!

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