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240zJJR

RWB Jeff - 1970 Datsun 240z - Build

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2 hours ago, 240zJJR said:

I am using the complete unibody. I will be removing the frame rails from the front and carrying a full frame from front to back. I will also be tying in the cage for extra strength.

 

My car had to be clipped in front of the strut towers due to a previous hack repair job.  We discovered that the frame rails had been covered with body filler to hide the wrinkles so new frame rails were in order too.  We removed the frame rails and replaced them with 2 1/2" x 2 1/2" square tube which was close in size to the factory ones and then took 1x3 tube steel under the floors and tied them to the rear factory subframe.  The 1x3's add a fair amount of strength and give you some much needed jack points instead of the factory ones that are always crushed.  The challenge was mating the 1x3 & 2 1/2" tube together at the base of the firewall.  I believe that structurally it's sound but not the prettiest joint.  You have to be under the car to see it.  We removed the factory core support and put in a simple bolted one but I know it's weaker torsionally than the factory unit.  I never finished the car and it's tucked away in storage right now but when I get back to it I'm probably going to go with a braced welded in unit.  Here are some pics to see what was done and just food for thought.

 

image021.jpgimage027.jpgimage029.jpg  

Added a plate as a gusset and TC bucket tie in.

TC%20Tie%20In.jpg

I did media blast every square inch and apply some good epoxy primer before the body work started.  Should have done that before the metal work.

primed.jpg

Engine compartment all smoothed out and ready for color. 

Core%20Support%201.jpg

 

Edited by Jeff

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On 11/5/2018 at 3:29 PM, Jeff said:

 

My car had to be clipped in front of the strut towers due to a previous hack repair job.  We discovered that the frame rails had been covered with body filler to hide the wrinkles so new frame rails were in order too.  We removed the frame rails and replaced them with 2 1/2" x 2 1/2" square tube which was close in size to the factory ones and then took 1x3 tube steel under the floors and tied them to the rear factory subframe.  The 1x3's add a fair amount of strength and give you some much needed jack points instead of the factory ones that are always crushed.  The challenge was mating the 1x3 & 2 1/2" tube together at the base of the firewall.  I believe that structurally it's sound but not the prettiest joint.  You have to be under the car to see it.  We removed the factory core support and put in a simple bolted one but I know it's weaker torsionally than the factory unit.  I never finished the car and it's tucked away in storage right now but when I get back to it I'm probably going to go with a braced welded in unit.  Here are some pics to see what was done and just food for thought.

 

 

Ahhhh, thank you Jeff. This was my exact plan. I have been looking at your build and many others. I am actually starting on it this week. My first thing is to brace the engine bay and the inside of the car so i have no movement. I was going to put it back on the rotisserie, start with new floor pans and rails. I will then take it off the rotisserie to level the car and start on the front rails.

 

I have been trying to find pictures on bracing the whole car before I start... Engine bay i om ok with...just need to figure out how to brace the interior properly.

 

Jeff

Edited by 240zJJR

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If this is going to be a street car, you may want to rethink a full cage, there's a number of posts on here on why a full cage in a street car is dangerous. 74_5.0L_Z built a cage without a pillar/roof bars when he rebuilt his Z with a tube frame, and would be a good example of how to stiffen and reinforce the car without the issues of a full cage.

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On 11/6/2018 at 3:55 PM, 240zJJR said:

Ahhhh, thank you Jeff. This was my exact plan. I have been looking at your build and many others. I am actually starting on it this week. My first thing is to brace the engine bay and the inside of the car so i have no movement. I was going to put it back on the rotisserie, start with new floor pans and rails. I will then take it off the rotisserie to level the car and start on the front rails.

 

I did the front frame rails first with it on the ground and no bracing.  We hung doors, fenders and hood back on it and everything lined up great, no worries.  I then put it on the rotisserie, put the 1x3 frame rails in, cut out the floors & replaced one side at the time.  Did all of that without any bracing and I paid a big price.  The body shop was pretty far into it before they hung the fenders and hood again only to discover that the front of the drivers frame rail was 1 1/2" higher than the passenger side.  It had to be put on a frame table and pulled back into shape but the good news is I now know it's square and straight.  That was a costly lesson, so yes make sure you brace yours well.  I would cross brace the interior from the front edge of the inner rocker to the opposite strut tower but hopefully someone that has actually done it will chime in.   

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30 minutes ago, Jeff said:

 

I did the front frame rails first with it on the ground and no bracing.  We hung doors, fenders and hood back on it and everything lined up great, no worries.  I then put it on the rotisserie, put the 1x3 frame rails in, cut out the floors & replaced one side at the time.  Did all of that without any bracing and I paid a big price.  The body shop was pretty far into it before they hung the fenders and hood again only to discover that the front of the drivers frame rail was 1 1/2" higher than the passenger side.  It had to be put on a frame table and pulled back into shape but the good news is I now know it's square and straight.  That was a costly lesson, so yes make sure you brace yours well.  I would cross brace the interior from the front edge of the inner rocker to the opposite strut tower but hopefully someone that has actually done it will chime in.   

This is what I did to the inside of the body so far . Bracing the engine bay tonight. Want to install custom oil pan as well before I pull the motor one last time before all my metal work!!!

 

 

B93D7DFC-0A9B-4E80-85F1-97B5E8B62199.jpeg

76E1B107-2D50-412E-8511-80E6B8BCB765.jpeg

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