Project 300ZX [7] - More work in progress

More updates on the work that's being done on the Z!

I had mentioned that the front bumper was cracked. It turns out that the lower section has very wide vents and the actual piece of bumper between the center vent and the side vents is kind of slim, and it supports the whole lower portion of the bumper. In the following frontal view maybe you can get what I mean.

The bumper goes from the lower front portion of the wheel arches, then horizontally towards the front and then up to meet the headlights, so it's a big piece of fiberglass-reinforced plastic.
Below the black portion holding the turn signals and foglights there is a black stripe. That is actually just a groove with a black stripe sticker on it; the bumper is a single piece. Those slotted vents on the sides lead to the intercoolers, one on each side and each feeding one turbo and then the air from each of them reaches half of the cylinders. This is a completely split intake, split exhaust car. Although the aftermarket cone air filter is a single one, replacing the twin airboxes it originally had. The center vent feeds the oil cooler, the radiator, and used to cool also the A/C heat exchanger but that's gone. There are also two fans, one big one behind the radiator (looks just like those big old belt-driven ones), and one smaller one in the front. With such a cramped engine bay (because of the very low hood line), you need all the cooling you can get.

So anyway, those two sections between the side vents and the center vent support quite a bit of weight because besides the bumper, the splash guard rests on it so it needs support too. In the next two pictures you can see the cracked one (the right of the car, left when looking straight on the front) and the good one:

With blind trust in my handyman skills, I set out to repair it and to do that, the whole bumper would have to be removed from the car.

Tools

I researched a little on the internets and found out you need a socket wrench for the job. Mine was crappy and not even a proper wrench but one of those screwdrivers with ratcheting action. Which I destroyed when I rebuilt the air compressor on my other car. Off to Lowe's and I got a nice set of the cheapo brand called... what's its name again? Task Force. 7 dollars for a metric set, 1/4" drive with 4mm to 13mm bits plus torx, hex and regular phillips and flat bits. 24 pieces in all. Even came with a nice storage box. But then I also needed an extension and none came with the set so I had to get a standalone one. Just the 1/4" drive, 6"long extension from a better brand cost me 5 dollars more. Anyway for 12 bucks I think it's a pretty sweet deal.

Removing the bumper

There are a lot of screws, nuts and bolts holding this thing securely to the rest of the car, and some of them are a little hard to get to, but I went for it with the confidence that only ignorance can give you. I didn't document the whole procedure because others before me have done it... I stand on the shoulders of giants. Suffice to say that there are some 30 screws, nuts or bolts and that it takes about an hour to get it out. The wrench was absolutely necessary and the 6" extension was spot on.

So we will jump magically from the early stages of removing the turn signals...

... to having the whole thing off the car:

So now for some more details on the status of the underside of the bumper:

WTF? What was the deal with the previous owners? They had a love for climbing on high curbs or something?

And the backside. The yellowish tint is typical of fiberglass:

While I figured out how to repair the cracked part, my eyes landed on that black section that hold the foglights and turn signals, and saw that it had been painted but now it was all faded and cracked, and guess what?

Of course, off to plastidip it like there's no tomorrow!
So I took out my painter's tape, and then also I finally found a use to the ton of paper I get everyday in the form of promotional material from supermarkets, credit unions, farmer's markets and whatnot! Masking the white parts of the bumper, of course. But seriously, in this country an enormous amount of paper is wasted daily with this material that I would guess most people throw away without even looking at them.

So here is that paper put to good use:

Same ol' same ol', 4 coats of plasti dip, nice and smooth and this is the result:

Great stuff.

So now for the final bit: repairing the damage. As it turns out, they had previously tried to repair it. There was a lot of clear RTV silicone in there (sure, like if silicone would hold weight, what were they thinking?). And there was a strip of metal glued with silicone as well that seemed pretty solid so I left it there.
The thing is, only by joining the edges you would never get enough strength with any adhesive to hold the weight and also the torsion and shock from the ocasional kiss to the curb or those fucking concrete logs on parking spots that supposedly keep you from bumping into that big wall right in front of you that it's oh so hard to see, right?

I played a little with my trusty old "StrongStik" that I used on the windshield cowl, but it was easily defeated. Not strong enough to hold everything rigidly in place, and not flexible enough to at least go with the flow and bend. So I had to bring out the big guns. Just by the sight of my JB Weld the bumper started shaking and apologizing. But I would have none of that. It had it coming.

I decided to join the edges with my "la gotita" (one type of instant glue) and hold them together with masking tape just for a few minutes while the Loctite-lookalike glue hardened.

I reckoned that gluing the edge, plus wrapping everything in JB weld would not be enough on the long run; I would need something to hold that weight real good and have the adhesives just prevent torsion and traction movements. I needed a "reinforced" weld, a rebar of sorts. So I thought of holding on to the piece of metal that was already there with a wire, and then run that wire up, securing the other end wherever I could safely anchor. I found a black plastic structure that sits on a horizontal edge of the upper bumper, perfect for supporting weight. I made a hole in it by heating the wire, and passed it straight through, with a nice wire "knot". Finally I J-B Welded the shit out of it.

In the picture to the left you can see the anchored wire, with the not on the upper end and the lower end wrapping around the lower edge of the metal strip, that square piece in the center. You can already see a horizontal strip of JB weld along another section of the fracture line.

Then it was just a matter of liberally applying the weld over the whole contraption, and also on the front side where I tried to mold it as much as I could so it won't stick out so much after that part gets painted. Hopefully it wil kind of blend in.

So my solution has yet to be proven, because I'm still waiting for the weld to cure and solidify properly. That silicone-glued metal strip is I guess the weakest link. I may reinforce that as well.

The final question is: do I put this thing back on the car? The paint job would be much simpler with the bumper off I guess, but there are two problems: 1) it could be a while before I do the paint job, and 2) I would guess that it's not legal to drive the car without its bumper, both because of the missing turn signals, and for low-speed crash compliance... California, you know...

So I'll give it some thought and report back. Till then, so long!