240z SCCA vintage race car, restoration

[Dat73z]

Not a race car guy but I've worked t a bodyshop and we had some racecars come through. 

 

If you don't care about the surface finish I'd neutralize the rust and epoxy coat it. Topcoat for UV protection with minimal single stage coverage for weight savings is what we did for racecars. Also easy to touch up. 

 

If you care more you could always use some stranded filler, etc. 

[AydinZ71]

@Dat73z ahh interesting! So when did you choose stranded filler over standard light-weight filler? I already have a ton of 2K white epoxy so my plan was to put the filler directly on the exposed metal, scruff the surrounding finish with a DA sander, feather the filler into the surrounding finish, seal it with the white epoxy, base coat, then clear coat. What are your thoughts? I already bought 2K urethane clear so that’s what I have on-hand. My base coat is silver, which usually works as a single coat on a white base. I learned why the epoxy can’t be bare… it’s too porous. Soaks stains right up. Instead of wet sanding the urethane, I was just gonna buff it with compound and leave the dust and peaks as they are. 

[Dat73z]

I was thinking you had some areas with pinholes, etc. maybe ok metal but not cut out and patched. Generally I would use stranded filler for any areas with gouges or pinholes, areas which require reinforcement. But best practice is to cut out and replace those areas, dolly, or pull them out as good as possible. You don't really want to be layering on the body filler thick on any area, just a skim coat which mostly gets block off. 

 

Your prep work sounds about right. Personally I'd go single stage non-metallic fleet color for easy match when things inevitably need touch up on a racecar. But since you already have the base/clear I'd stick with it. I think nowadays people prefer to epoxy to seal then filler over that. Whatever you do absolutely 100% follow the mfg instructions for prep, time, compatibility, etc. 

 

Your prep work will dictate the outcome. You can easily spend weeks guide coating and blocking the whole car multiple times over

 

It's probably been 15 years since I did any serious bodywork. I was working on the mechanic side and moved over to help prep whole cars, repair rust and collision damage when things got slow

[AydinZ71]

Ahh I see! Here let me show you what I’m working with. Gouges are too broad of a describing by me. These are areas where rust had come through, or the finish had cracked. Took them down to bare metal. Ideally I’d like to keep the existing filler in place and patch up to it, feather it. It’s a lot of work to take the exterior down to bare metal and build the filler back up. It is clear the body had some accident damage in the past so it’s there for a reason. 
 

thanks for the tip on applying the sealer o to the bare metal before filler. 10-4! 
 

i have zero body work experience. Here is a pic of what I am used to painting. That is the silly experience I got from understanding how paints differ. I chose a generic silver because it covers so easily, and with such little paint. You make a much better point about matching.  
 

Please do let me know how you would tackle these missing patches if it would differ from my new plan. Epoxy, filler, base, clear 

[Dat73z]

On the 1/4 panels with the exposed seam I'd use stranded filler. For the other areas you'll be ok using regular filler. Ideally you'd take that all down and rework the metal but I can understand why you wouldn't want to do that. Make sure you follow the mfg specs for sanding grits and prep exactly

[AydinZ71]

@Dat73z appreciate it! That helps a bunch. 

[AydinZ71]

Removed all the body leading. Not clear if this was factory or from a previous repair. Will do some welding to bind the seams, the apply short-stranded fiberglass filler to fill the gap. 
 

Took a DA sander to existing finish. Lots of body work ahead. 

[clarkspeed]

That is a lot of freaking filler. Tough decision. Ideally you would take out the filler, hammer back to something not so drastic, then re-apply. I always shoot for filler less than 1/8" thick when welding in patches like you are. But those are big areas.  I have done a lot of body work but I am no metal expert.  I am not convinced I could caress all that to a better position. And filling big areas is not easy. If you are not a pro it can take many hours to get a decent finish.

 

On the other hand, if the filler has not cracked or chunked off you can assume the panel is "stable" and not flexing around when being driven. And if no rust is present, the panels were prepped well before filler applied. In that case, yes just keep going with filler. If you start hammering to get a better surface it will start cracking up. Keep in mind you are building a race car. Most are loaded with filler these days. 

[AydinZ71]

@clarkspeed thanks man. Yep! That’s the idea… the car had been stored for 20yrs with this finish (and raced before that) so I assume if it’s stable now it will remain so. I removed the finish anywhere I saw cracking.

 

speaking of body work, got started on some of the few body panel areas that need replacing. First stop is the gas door. PO just used the door and welded into the recess. This created a 1/8-3/16” gap that was filled. Naturally, it expanded/contracted over time and cracked through. I removed it entirely and put in a replacement sheet. Hammered off-dolly with a torch to bend and straighten it out when complete. Not much warping and it’s pretty straight! Now onto to the rest of the rear quarter panel. 
 

hey, do you apply DTM primer before you use filler, or do you apply filler straight on bare metal? 

Edited May 7, 2022 by AydinZ71

[clarkspeed]

Someone may correct me, but I have applied over metal, primer, and more primer, and fiberglass. I have never had any issues. As long as clean, dry, and not dusty. But the more you apply on top of, the more you depend on the substraight quality.  I usually clean with a wax and grease remover and allow to flash before applying.

[Dat73z]

I'm prepping some pieces (louvered inspection lids, front grille, etc.) to shoot some epoxy today over bare metal. I've removed the rust and dolly'd it all out as straight as I can get. I'm going to try the strategy of epoxy over bare metal, filler within 24 hours, primer and guide coat blocking over that, thin coat of sealer e.g. epoxy, then single stage on top. In the past I've always done filler over bare metal then epoxy and everything over that but figured I'd change it up. 

 

At the end of the day, imo you just want to ensure all of your work is sealed and you get a combination of both mechanical and chemical adhesion. Which is why following the mfg instructions for cure/coat times is important. 

[AydinZ71]

Thanks @clarkspeed, @Dat73z

 

I’m leaning towards just applying filler over bare metal. I’m going to hit it with 80-grit on a DA sander to rough it up, then clean with acetone and let flash like you said Clark. 
depending on how straight it is, I may or may not use polyester primer on top of the filler. If not, il go straight to epoxy, block sand one more time, then base then clear. I will only wet sand the clear where there is dust or particles, then buff with compound. Oh… easy enough. Only another 2-3Mo 😂😂

 

On the interior I’m just spraying epoxy, base before the 3-day epoxy cure is up, then clear on top.

 

im noodling the idea of painting my cowl and hood semigloss black. Just to cut back a bit on the glare. The rest of the car will be silver, and the tracks down here are really bright (desert). 

[rossman]

In my experience, the metal will rust under the filler if you don't first seal the metal with epoxy paint. This exact situation was occurring with the hood I'm restoring on my build page - rusty metal under the filler. Is it a real problem? I don't know for sure. There was no sign of rust from the outside...but it was definitely there, and the reason I prefer to put epoxy down first, then filler.

[AydinZ71]

22 hours ago, rossman said:

In my experience, the metal will rust under the filler if you don't first seal the metal with epoxy paint. This exact situation was occurring with the hood I'm restoring on my build page - rusty metal under the filler. Is it a real problem? I don't know for sure. There was no sign of rust from the outside...but it was definitely there, and the reason I prefer to put epoxy down first, then filler.

If you apply epoxy on metal than apply filler you really have nothing to lose. That is definitely the safe option. I was doing more reading and apparently only some filler is designated as a “DTM” (direct-to-metal), so I guess it all depends on the specific brand/model of filler. I’m reading really good things about eastwoods aluminum filler to replace the leaded seam filler I removed. That looks to be a DTM type and is more flexible than fiberglass filler but still as resistant to cracking. I’m going to start with that and confirm the rest of the materials I am working with are DTM or il put a layer of epoxy down.

 

im only hesitating for two reasons. One: weight. Sounds silly, but if you pick up your can of primer, paint, etc. it isn’t light. It’s really hard to believe you can add that much weight to a car but it really is. It’s just spread out so thin and so wide you can’t tell how much you are actually adding. Two: hassle. Prepping, mixing, and cleaning the spray can for epoxy creates a lot of waste, consumables, and takes a lot of time. as everyone keeps reminding me, it’s a race car. As long as the filler and finish does not crack through the paint or separate from the steel, I’m happy  

 

I don’t think I would attempt all this myself if I wanted a great finish on a street car. I’m as Novice as it gets 😂
 

 

 

[AydinZ71]

Hey all. Mind sharing those links to the folks who sell used racing tires (on facebook I believe)? I need to mount a set so I can check the clearance on the fender flares. I have 15" steelies. 

 

We can run cantilevered slicks but limited to a 15X7" wheel. Greg recommends a 245X45X15

Silly question for a complete novice, but am I gonna have trouble getting a shop to want to mount them? 

 

PS: these are the "right" Marugen Shokai flares yeah? I see a lot of discussion about getting the "special" for the added thickness.

 

https://www.rhdjapan.com/marugen-shoukai-zg-type-special-over-fenders-s30-s31.html

Edited May 10, 2022 by AydinZ71

[clarkspeed]

I have used usedracingtire.com.  I think John Borget sell them also. I used another, but can't remember name. Not sure who would be best on those cantilevers. 

 

I'm not sure what bodywork you are running. Greg has the Subtle Z kit from ztrix. Those tires have an incredible 9" tread width. If you have any space left over, push out the rims with wheel spacers. I'm running 1.5" on the tube car.

[AydinZ71]

Thanks @clarkspeed! Yep, 9” wide is the one! I confirmed with Greg after cross referencing with the Hoosier website. It’s the 245/560R15. Comes in MS and M compounds. Usedracingtire.com has them so il grab a set and get them mounted. Seemed silly to prep for paint without having the wheel clearance confirmed. 
 

my fenders are still OEM so il need some kind of a flare to fit those 9” meats. I know we can run FRP fenders front and back, but I just really want to get her on the road now. My street car has MSA flares the PO put on, so I could take and look and see how easy they would be to recreate in 20-gauge sheet metal. Otherwise il go with those Marugen ones.

 

[jhm]

Have had nothing but good experiences with usedracingtires.com, that Clark mentioned, and usdrrt on eBay (https://www.ebay.com/str/racetiresusdrrt?_trksid=p2047675.m3561.l2563). 

 

USDRRT always had a good selection of nice-condition cantilever slicks at really good prices; but I haven't bought from him in a while so am not familiar with his current inventory.  He always seemed to have a lot of SM tires, so that might suit your needs nicely.

[AydinZ71]

@jhm thanks John!! I found a pair for a reasonable price on the eBay site you shared and got them on order. Many thanks!! Now to noodle a flare option and get it all mounted before I finish bodywork  

 

dunno what I’d do without this community. Thanks all

Edited May 10, 2022 by AydinZ71

[clarkspeed]

This community is not what it used to be, but the flame keeps burning.  Maybe not as many replies as you might have gotten in the past, but also not as many assholes. Again, all of is that follow you recognize this is a project you are taking the time to make it right and it's not going to disappear unfinished. And keep in mind you could probably message most any other member for advice if you needed.