Forums/Z31P/z31-performance-upgrade-forums suspension-chassis-and-brakes/Molitor's Frame Rebuild
Imported from Z31Performance.com Forums{{#if:1artworkz| — original post by 1artworkz}}{{#if:2009-07-10 22:06:58|, posted 2009-07-10 22:06:58}}{{#if:23| · 23 post{{#ifeq:23|1||s}}}}{{#if:/Z31performance_archive/forum/z31-performance-upgrade-forums/suspension-chassis-and-brakes/7875-molitor-s-frame-rebuild.html|
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1artworkz: (2009-07-10 22:06:58)
Well, I finally got around to up dating my frame rebuild page.
http://home.comcast.net/~gwmolitor/frame_repair.html
I now understand from another Z31 owner that the factory frame rails are
no longer available so this might be one way to fix those nasty "cancer"
issues.
[archived image: underbody-back.jpg]
vagabond: (2009-07-10 23:06:36)
Re: Molitor's Frame Rebuild
Sweet! Thnak's Gary. I'm getting a quote this fall for Frame Rail repair.
zmech: (2009-07-11 00:50:23)
Re: Molitor's Frame Rebuild
0
sporklift: (2009-07-11 01:37:16)
Re: Molitor's Frame Rebuild
That is some serious work. The foam to fill in the rails and seal them is simply awesome. I hope I can get this serious with my Z some day. Amazing.
SATAN: (2009-07-11 06:46:49)
Re: Molitor's Frame Rebuild
It's when you go this far with a car that you can never let it go, simply because nobody will ever appreciate, or can even fathom exactly how much work went into it.
Chrisw_2003: (2009-07-11 07:14:32)
Re: Molitor's Frame Rebuild
so where does the flux capacitor go? im sure your planning on doing some time travel at some point with that much work into it [archived image: biggrin.png]
Smn2k7: (2009-07-18 17:24:06)
Re: Molitor's Frame Rebuild
That is absolutely outstanding. And with the epoxy and detail of the work, you honestly can't tell it wasn't designed that way from the factory. Just beautiful, as your work always is.
Volgrath: (2009-07-18 19:13:32)
Re: Molitor's Frame Rebuild
I understood that the 300zx was a unibody?
OK, I'll stop being a dick. Hence forth I will try my best to stop making stupid posts in threads such as my "chinese rods out of U235" in serious threads.
Honestly, Nicely done. What SATAN says is true though, no one else (except maybe someone that is a Z31 freak like us, or maybe another TRUE car guy, the kind that can appreciate the love between man and the steel beasts) will truely appreciate the work going into it. Though I honestly love it. Just wish that color was a flat black.
New 2 Z: (2009-07-18 19:25:59)
Re: Molitor's Frame Rebuild
great info right here.
I'm gonna do this later on when i do the 240Z rear suspension swap
New 2 Z: (2009-07-18 19:26:43)
Re: Molitor's Frame Rebuild
quoted for the plain and simple truth.
Matt89: (2009-11-17 22:43:29)
Re: Molitor's Frame Rebuild
Gary, i love what you have done with the car so far. I have been planning a frame rail project of my own. Going to cut out my rails like you have except replace them with thicker rectangular stock. When i cage the car the tubing will be welded through the floor pan directly to these rails.
240Z rear suspension??? Oh god… :-?
AeLadyZ: (2009-11-20 18:06:22)
Re: Molitor's Frame Rebuild
Ok Mister…what are you trying to hide with the "Painted Undercoating Look"? :lol:
- I can fully understand why you went the way you did, but really, with that much time into it, and for what you have planned for it...... "You didn't even LOCK the undercarriage frame work with a for the front and rear subframes".
- I'm sorry Gary, But with the amount of effort you put fourth, having been here and done that, seen first hand what the improvements were…you really should have followed what I had posted my results were(I know you asked me)…the ties alone make a huge difference in the feel of the car…which means that the design is improved and weakness in this area ELIMINATED. I know you chose to foam fill the channels vs. my method of using 1/8" plate and angle steel to re-enforce the front and rear rails....(those differences are prolly neglible), but ugh…Disappointed.
Those with serious track plans, and /or Drag duties…NEED TO LISTEN UP…and follow the advise of those who have done this. Foam filling (potentailly/possibly) or (what I have experience with…)plating the frame rails for stiffening the chassis leads for exceptional results…however, TIE in the subframes with some 1/8" steel and WOW!!!!.....It is almost like the improvements that are had from adding a "8 point cage" all by itself....
I'm, just a Little let down.
Dan :-?
New 2 Z: (2009-11-20 19:15:32)
Re: Molitor's Frame Rebuild
doesn't paint like chip if it hits something too hard?
AeLadyZ: (2009-11-20 19:52:52)
Re: Molitor's Frame Rebuild
Yes, However.....In 3 Years of use and a little over 4500 miles....What you see pictured, still looks "almost" like it did the day I did it. Primary use/mileage is paved roads, and the car is a show/performance build use car.
Quoted from the response....
- I can fully understand why you went the way you did, but really, with that much time into it, and for what you have planned for it......
1artworkz: (2009-11-20 20:56:27)
Re: Molitor's Frame Rebuild
Dan; your work on that car has always impressed me. I really like the clean look of the under-body
without the undercoating. That look is a real show winner.
These are the reasons I chose to do it this way … RUST was my primary focus.
⢠Replace and streghten rusted frame rails with heavier gauge steel and structural foam.
⢠Seal all areas of potential water entry into frame rails with moisture-cure elastomeric sealant.
⢠Add to the factory sound deadening and apply a hard protective coating to approximate factory color.
When I started this project I considered adding the you used. However, after consulting a structural
engineer (Z31.com member), his opinion was, the added little to the over all stiffness or rigidity of
the frame members when considering the unitized body as a whole.
AeLadyZ: (2009-11-20 21:23:20)
Re: Molitor's Frame Rebuild
When I started this project I considered adding the you used. However, after consulting a structural
engineer (Z31.com member), his opinion was, the added little to the over all stiffness or rigidity of
the frame members when considering the unitized body as a whole.
hehe…
I am really sorry....but. It's a Damn Shame!
The cars are weakest here. I couldn't believe it, wouldn't believe it if I hadn't done it and drove it hard to feel the improvements myself. The more equal squalt of the chassis is obvious in turning and straight line abuse.
- IF the car I built was my own, the only other thing I would have done differently would be to build a tie for between the two front strut towers to the firewall, as the "feeling" now that sticks out with this modification is movement/flex in the chassis up front under extreme circumstances.
Thanx, for the neutral comment Gary…you are truley seasoned member.
Dan
Z_Karma: (2009-11-21 00:52:52)
Re: Molitor's Frame Rebuild
For me and all the others that may read this, what is this you guys are referring to.?
Both of your guys attention to detail borders on the unhealthy…i like it!
Matt89: (2009-11-21 03:28:42)
Re: Molitor's Frame Rebuild
^^Look at where the rear frame rails end and the front ones start. Dan welded in material to tie these together.
nismopu: (2009-11-21 03:31:37)
Re: Molitor's Frame Rebuild
Mike, look in the two photos. See where gary's rails end and Dans don't ever stop and continue all the way underneath the vehicle? I am sure just by looking at how you did it that it in fact increased rigidity by quite a bit. Honestly, I never realized the frame rails didnt continue further back than that. You think Nissan would've realized the benefits after doing it to their very own s30's in racing trim. Not doubting your friends motor-neering capabilities but its been proven time and time again over at hybridz.org that extending the frame rails full length increased body rigidity incredibly.
Your work on that car is absolutely ASTOUNDING gary and I love looking over your site for new ideas and mods to do to my z. Thanks for taking so many pics and keep on improving! peace.
F/A 300: (2009-11-21 16:46:40)
Re: Molitor's Frame Rebuild
All I can say is WOW!!!! I am have that problem with my car where the rails are bent inwards and I was wondering how to fix it. I just found my way! They both look amazing but my car will be no show piece I'm going for straight performance and rust prevention. I will put the ties in though. AEladyZ do you have a write up for what you did?
AeLadyZ: (2009-11-21 17:44:36)
Re: Molitor's Frame Rebuild
No actual write up, just took my time making a cardboard mock-up of the pieces I needed, and cut them up with a plasma cutter, then welded them in.
-I used a wire wheel and stripped all the oem rubberized undercoating off the frame rails/chassis.
-I then took 1/8" angle and plate steel and re-boxed the frame rails from the downward angled area beginning in the engine bay to the oem rear section just before the gas tank area.
-I did alot of welding and grinding..starting with tack welds, then finishing with 1" welds spaced 1.5" apart through-out.
-I then then sealed everything with seam sealer before painting to keep the elements out and to give the seamless look.
As for the rear ties, I used 1/8" 1x3 tubing and full welded it to the chassis and overlapped a section of 1/8" plate to full weld and lock these sections together.
-If you look closely, you'll see the next weak area was in the rear where the rear differential mounts.....see the 1/8" plate steel "T" sections fully welded to the oem frame rails.
- I didn't bother boxing the rear section of the oem subframe because there is already sufficient layering of steel here from the factory.
Careless: (2009-11-23 15:13:28)
Re: Molitor's Frame Rebuild
I think both Dan and Gary did an exceptional job, but it looks as though the sections of plate steel that Dan welded in would help, and it's not like it would have been a big downer if it DIDN'T help, seeing as the don't look like they would get in the way, nor are they very hard to make. A grinding wheel and some spare time on weekends would have made that a good choice.
However, I'm sure this can be solved easily without much worry. Gary, I think you should perhaps find some steel dowel that you can thread on one end with a nice large bolt size, drill the frame out near where dan made his modifications and slot the dowel into the hole and weld it there, then drill some small holes on the side to inject more structural foam.
Having bolt holes would allow you to tie in many more places to some "torque boxes" or chassis/frame endings while allowing you to improve on the design by continuously changing the stiffness and geometry of the frame connectors that would bolt to these welded holes.
I think that would be a fair solution and would require minimal welding, grinding, and re-finishing.
Plus, It would stand out more as a chassis improvement with huge powder coated bars hanging off the car :-D
Excellent work guys. The Z31 forums have some dedicated individuals when it comes to ground-up restos.
tlmaniac: (2009-11-27 14:53:46)
Re: Molitor's Frame Rebuild
i just have one question where did you source your foam for teh injection?