A tale of two Z's - NA vs Turbo

[calZ]

I don't think I've ever seen a billet, CNC-machined backplate before. That's show car stuff

[MONZTER]

Finally finished both L&R of the new rear Backing plates for the NA car.  These are adapters that allow me to use a Z31 parking brake system and z31 rotor with Z32 aluminum 2 piston calipers and bolt it all on to a stock 240z strut.  Yep it all works.  For fun I took some pics of the machining steps to show what it took to make them from billet and finish them up.

 

This is the first operation that mills the side to mount all the parking brake shoes and hardware.  Comes out of a 8"x8.5"x2" thick piece of billet.

 

 

Some detail of the surface machining and stepover of the cutting tool to make for a smooth finish

 

 

After the first operation is complete the part needs to be flipped and held to machine the backside.  I made a simple fixture plate that held the part by registered with 3 mounting holes and a single center screw to hold it down.  This is the fixture plate.

 

 

And this is the part after the first OP held tot he fixture plate ready to machine the second OP

 

 

This is the part after the second aoperation is complete.  About 2 hours of run time.  You could go faster, but I wanted small step-over lines so it would not need any hand finishing

 

 

After washing it and prepping it for a Alodine finish, here is the part as machined

 

 

Final finish is a 5 second dip in the Alodine which gives it a goldish iridescent finish, then I sprayed it with a clear Cerakote to keep it looking good and easy cleaning

 

And this is the final part.  Next need to make a few small parts and the parking brake cable

 

 

 

 

 

[jhm]

That's some beautiful jewelry!!!  Really impressive work there.  👍👍

[MONZTER]

Here are some final assembly pics of the NA car Rear brakes.

 

I had to take the OEM Z31 backing plate and cut the spot rivets holding this parking brake cable guide on.  I then had to shorten it and weld on a new front mounting point.  I ground the welds all nice so it looked OEM and then replated it in Yellow Zink.  In the second picture you can see where I press fit in some stainless steel rivots, just sitting proud of the surface.  This is where the "feet" on the parking brake shoes hit, and a little dab of grease should keep them smooth and quiet without worry of wear on the aliminum

 

 

 

I next had to make a custom boss that will screw in to the new backing plate.  This is the pivot and load point for the parking brake shoes.  So I turned it out of 4140 steel, Yellow Zink plated it and threaded it into the backing plate with Red Loctite.

 

 

Then I could re-assemble the stub axle and companion flange.  These parts came out nice with a Zink plating on all the mating surfaces and powder-coating everywhere else.  They should stay nice for a while.

 

 

 

You can see the mounting bolts for the new backing pates.

 

 

This is what the caliper looks like mounted with the Z-31 rotor

 

 

Installed the parking brake shoes, springs, adjusters, ect.  All fit up just like OEM

 

 

 

Some final shots of the plates all assembled.  I think  they came out looking cool, kinda morphing from the struts hub shape to the mounting ears of the calipers.  The look will be very clean IMO

 

 

 

Edited September 28, 2023 by MONZTER

[MONZTER]

Been busy working on the body of the NA car.  Overall in really good original paint condition.  But of course the common areas still need to be replaces even in a low mile California car.  So I got busy cutting and welding.

 

The KF parts are really nice but I only want to replace as much metal as trulely needed, so instead of just replacing the entire part, I grafted in what I need to keep it as original as possible.  Here are some pics of the first dogleg

 

What is hiding inside you ask

 

 

Surprise

 

 

cut it all out

 

 

start fitting  rebuilding from the inside out as how it was originally done

 

 

 

 

 

 

 

Blast it all clean and start TIG welding

 

 

 

 

 

Edited April 18 by MONZTER

[MONZTER]

I dont want any filler, so I fit each part perfectly with a butt joint, dolly it out where possible, then grind it flat and smooth for an original fit.  before any welding I prime all parts on the back side and pinch points with weld-thru primer

 

the arc and inner rocker are new in this picture

 

 

then the rear of the rocker, putting back the spot welds in the OEM position

 

 

Some more primer to look super clean and blend in tot he original rocker which was perfect everywhere else

 

 

 

Finally fit the outer skin and tig it in small steps so no warping

 

 

Some more smoothing of the welds and original spotweld locations used

 

 

 

Just a small skim coat of filler on the upper weld seem, but making sure to leave all the factory spot welds to show through the paint.

 

Other side is the same, so on to the front fender next

 

 

[Leon]

Threads like these are what makes HybridZ special. Bravo! How did you develop your welding and metalworking skills?

[madkaw]

Are you fill welding with silicon bronze ? 

[MONZTER]

19 hours ago, Leon said:

Threads like these are what makes HybridZ special. Bravo! How did you develop your welding and metalworking skills?

I miss the old days of the forums.  I would not call it a skill, but just some practice over the years and figuring out what works, and what not to do, usually the hard way.  So dont be afraid to try and practice if you enjoy this sort of thing.  Its not great work, but good enough to satify myself.  I have a friend who welds, he has talant

[MONZTER]

4 hours ago, madkaw said:

Are you fill welding with silicon bronze ? 

No, Just ER70S-2, works well with the tig and low amperage, so no distortion from overheating or cracking metal like it MIG.  On headers I would use silicone bronze to weld the primaries to the flanges.The heat cycling needs the ductility of the silicon bronze, but on a body panel I dont thinkit is necessary unless you were trying to flame weld and minimize warping.

[madkaw]

10 hours ago, MONZTER said:

No, Just ER70S-2, works well with the tig and low amperage, so no distortion from overheating or cracking metal like it MIG.  On headers I would use silicone bronze to weld the primaries to the flanges.The heat cycling needs the ductility of the silicon bronze, but on a body panel I dont thinkit is necessary unless you were trying to flame weld and minimize warping.

I assumed you were MIGing .  My body shop friend recommended to fill with silicon bronze because it takes less heat . 

[MONZTER]

Here are pics of the front rocker panel and front fender work.  All the same concept of only removing what was necessay and trying to keep it as original as possible with little to no filler.

 

All original paint and never worked.  Looks pretty good

 

 

 

Whats hidden

 

 

After blating with crushed glass

 

 

Cut out the old, you can see the inside of the rocker was perfect and clean.  the rust comes from the overlap of the inner fender and the front rocker.  The cowl drain dumps back here and it just fills with wet dirt

 

 

 

I bought a KF Fab full rocker and only used the small pc to repalce the area.  The fit is really good on these parts

 

 

TIG welded it back in.  Carefully only 1/4" at a time jumping around with an air quench.  Some quick grinding of the weld bead and it blends in perfect so it doesnt even look repaired.

 

 

[MONZTER]

Then on to the front fender, Inner and lower.

 

 

Another KF Fab part fitted in and TIG welded

 

Cleaned up the weld beads and spot welded it back to the lower fender return

 

 

Same deal on the lower fender.  lots of small tack welds to keep it fron warping and small welds.  I kept the original lower flange of the fender so the fit would not change.  It cleaned up nicely with some blasting, and will keep the original fit and look of the fender

 

 

For TIG the metal needs to be perfectly clean forpretty welds, but the overlap of the inner fender made this difficult, but they will look fine when ground back.

 

 

A grinder, a file and a shrinking disk got it straight.  A skim coat of filler will probably be needed to make it perfect as I cant get behing the repair to dolly it out perfect.

 

 

The Hatch slam is up next

Edited May 4 by MONZTER

[Leon]

Amazing work! I definitely don't have the time and patience for this, at least not now, but maybe give it a decade or two when the kids are older and hopefully work is not so consuming.  Reminds me of the absolutely entrancing my mechanics 240Z resto videos on YT. I salute the people who have taken the time to get this good at metalwork.

 

 

 

[MONZTER]

Last bit of body work was the hatch slam.  I did not replace it entirely.  After getting a Tabco replacement and then a classic fab replacement, I decided mine was not bad enough to justify changing the entire part out and reducing the originality as the replacement parts are not a 100%

 

The original paint

 

Drilling out the tack welds

 

After drilling out the spot welds and cutting part of it away, I blasted the undelay of framing.  There was some corrosion deepen than I liked so I cut it out and patched it.  Then ground it back and sprayed it with a weld through primer

 

 

 

Next I removed the rest of the panel, blasted it and replaced the little bit of rusted metal.  Tig welded it and ground it flat along with some dolly work to make it flat after welding

 

I then tig welded the old spot weld location and ground them flat so it looked like a new panel again.

 

All the underserface of the rebuilt hatch slam got coated in weldthrough primer.  I then applied a weld through seam sealer.

 

 

I used the old pc of metal to mark the exact location of the original tack welds

 

Final to tack weld it in.  Looks great and factory original in my opinion

 

[MONZTER]

Back to work on the Z Turbo car and taking a break on the NA car after finishing up the body work.  Time to dry fit the rear suspension for the Turbo Car.

 

Designed and built my own control arms and rear support years and years ago, finally fitting it up.  They are 4130 seamless Chromoly that I polished welded then clear powder coated.

 

Here are the rear control arms.  I stuck with the standard urethane mounting bushing fror the inner front pivot location, but used really nice Teflon lined Aurora rod ends everywhere else.

 

 

 

I had some 6-4 titanium bar drops and plate, so I was feeling creative and made all the big control arm bolts from the titanium

 

 

 

 

 

 

 

Here it is all installed with the brakes and custom parking brake cable as well as custom CV axles, Diff mount and front mount

 

 

 

 

This is a custom front diff mount with a double hump for the duel exhaust that will fit in very nicely.  The Diff is an R-200 with 3.70 gears and a Quaife Limited slip.  Can remember where the diff cover was from, but I think it was a Nismo part.

 

 

I bent up my own sway bars from StressProof steel and made two point adjustment links for the end.  

 

 

I machined some mounts with solid Teflon busings for the sway bars, similar tot he 280z placement, front mount style

 

 

The bar is sitting too low and will hit the duel exhaust pipes so I need to remake the mounts and raise the bar higher in the chassis.

 

Thats it for now, on to the front suspension and crossmenber next.

 

Let me know if any questions, clarifications or more pics.

 

Busy Summer.

 

Edited August 20 by MONZTER

[madkaw]

Pure art ! 
 

duals ?

[MONZTER]

Duals, oops just a typo, duel exhaust pipes like original, thanks

[Exposed]

great quality fabrication in this build, enjoying the build journey

[Zetsaz]

Those rear control arms are works of art