240z SCCA vintage race car, restoration

[AydinZ71]

While I’m at it, here are some progress picks. After months of searching for the “perfect” lightweight headlights, I landed on these motorcycle PIAA projectors. They weren’t cheap, but the reviews were great. Planning to mount them somewhere in the rad intake area. Not sure about too many night races but it’s warm enough out here to track the car in winter, so lights help with the early sundown.

 

Finished the body work on the rear valence and drivers rear quarter panel. Sealed and primed. Moving on to the rockers and doors, before finishing at the fenders. 
 

machine shop has started on the 3.1L block with the Kameari internals. This shop is expensive but their main business is race engines. Happy to pay for the experience, since I don’t have an intuition on what is critical and what is not. 

[Exposed]

great progress, how are you mounting your new lights?

[AydinZ71]

They come with little foot-mounting tabs with a pivot point to adjust the angle. I have a general idea of it going somewhere in the rad intake. That whole area is custom so it shouldn’t be difficult to a fabricate a mount for it. 

[clarkspeed]

Nice door hinges!

[AydinZ71]

Hi all! Seeking some advice from our racer community. Clark, Jon, John, Cary, and the like. 
 

Stuck with those 9.92” (252mm) S130 vented front rotors from EP rules, and looking for a rear brake kit. Rotor must be smaller than the OEM fronts (272mm) I was going to pull the trigger on the  T3 rear micro brake conversion (265mm) but Mr. EP Greg thinks the rears will be too big relative to the fronts. That would cause my bias (Tilton mechanical) to skew too far to the front making adjustment more difficult. Makes sense to me. I also don’t know what rotor T3 uses which concerns me about replacements. 

Any thoughts on a rear brake kit that will balance well with the teeny 252mm fronts? I see a lot of brackets and I do for converting the rear calipers to 240sx or Maxima, but not clear what the right rotor spec (car, size) w works with those. 
 

many thanks!

 

 

[JMortensen]

510 guys swap in S130 struts all the time. The strut is shorter so it's like sectioning and the S130 brakes are an upgrade. You should be able to run any comparable S130 rear disc upgrade. I've seen Dynalite calipers used on 510s. Would probably have to make a bracket. 

[AydinZ71]

@JMortensen I would go with s130 rear brakes, especially if I can swap the caliper for a lightweight willwood unit. Unfortunately, I can’t swap the whole strut as we have to keep OEM hubs. Not really sure how anyone would know, but better safe than sorry. We have a lot more options in the rear since car never came with rear disks, but we are super limited in the front  

[JMortensen]

Don't use the S130 brakes. Use the rotors, maybe, but not the calipers. You're upgrading the front, right? If so, just go to a 510 vendor like www.ermishracing.com and see what they do for the rear, and then do what it takes to make it work.

I had the early 79-81 S130 brakes on my car using a ZQuip bracket (no longer in business) and the caliper was HUGE and heavy and the pads were tiny and overheated easily and came off in chunks. The early rotor also has a really deep hat, so that makes the rotor heavier.

I'd look for something that uses the 82-83 rotor. I think there is a setup that uses that later rotor and a 240SX caliper with a maxima bracket, but I'm trying to remember details from the 90s so don't quote me.

[JMortensen]

Early ZX caliper: 

Late ZX:

[AydinZ71]

Thank you Jon! Gosh so much misinformation out there. I was told the calipers were the same for all ZX, so this is really helpful. Attached is my spec line.

 

As you can see, I’m stuck on the 252 vented fronts and a ZX caliper, but which ZX caliper is open (so definitely will be using the later year). 
 

for the rear, because OEM was drum the EP rules are a bit looser. We are allowed to swap out drums for disks, and the spec line (attached) doesn’t limit this ability. The rear rotor has to be smaller than OEM front (272mm), and we are allowed to use alluminum calipers. 
 

Therefore, what I pick for the rear just need to balance well with the 252 vented ZX fronts so the  bias (Tilton mechanical screw, seperate masters) is not too-far too the front at the get-go.

 

ideally a 2-piston willwood rear caliper and an OEM S130 rear disk would be ideal. A kit to get the caliper on would be helpful and keep me from wasting more time on fab. 

Edited February 27, 2023 by AydinZ71

[JMortensen]

Yeah, I'd bet a 510 guy would know what rear to use with stock fronts. Tube80z has some 510 experience. I'm sure Ermish would have the answer. Gary Savage on FB too.  

[calZ]

Everything from the usual suspects I find doesn't fit under the 272mm, but there may be something out there other than the T3 kit. If you decide to go with the Maxima calipers and Z31 rotors, I believe I have a setup and live in LA. Would be happy to sell them to you. 

[AydinZ71]

Thanks Jon and CalZ,

 

Yep, so I did more research. It appears the MSA does sell a rear kit that uses the 280zx later year rotor and a maxima caliper. That will work, but I would be losing-out on the Willwood 2-pot weight savings. Since it is sprung weight, this isnt ideal.

 

MilkFab also makes one using the older ZX rear rotor/caliper. 

 

https://milkfab-engineering.com/shop/ols/products/s130-turbo-disk-brake-kit-datsun-240z-slash-260z-slash-280z

 

Since the hat height on the later ZX and Z31 rotors is the same (dia different), I could buy a bracket from silvermine for example designed for the larger rotor and just re-drill holes for the smaller rotor and use a small willwood. That assumes there is enough "meat" on the bracket. If not, I'll have to fab my own. 

[AydinZ71]

PS: Jon, how are you Johnny-on-the-spot (no pun intended) with those ZX caliper pictures? That is incredible. You must have a library of stuff at your finger tips. I forget specs constantly haha. You must be very organized

[JMortensen]

Googled it, came up at an auto parts site. Can't remember which one. I thought the pics were pretty good. I think they're pretty accurate with the sizing, must be a fixture they use and then stick one part under the camera, click, next part, click.

The pads in the later one are bigger, and that gigantic steel piece that holds the pads on the early one really is that big in comparison. Weird caliper. Has dual pistons, one fits inside the other and the push away from each other, sliding the big clamshell thingy and applying the brakes. Stupid design.

All of the ZX calipers are failure prone. Ebrake is the issue.

[AydinZ71]

Thanks jon. You are a resourceful dude. Took me several tries just to confirm the critical specs on rotors.

 

so here is the solution I have cooking:

using Silvermine rear willwood 2-piston caliper brackets. They were adapted to the 11.4” Z31 rotor. Later S130 is the same hat height and width, but 10.16”. Il have to drill two new holes closer to the hub to accommodate the difference. And voila, I have a small 2-pot 1.5Lb caliper paired with the right dia. Rotor. The his combo should compliment the tiny 9.92” vented fronts.

 

il have to take a closer look at the caliper bracket. I might save some cash by just making it myself from 1/4”-3/8” 6061. 

[AydinZ71]

It’s been a while since I made any updates so might as well attach some pics  

[clarkspeed]

Love the pic of your kids holding bumper 😀

[AydinZ71]

11 hours ago, clarkspeed said:

Love the pic of your kids holding bumper 😀

Thanks Clark! Literally the first time I have let them “help” in a long time haha. It’s usually dust, toxic paint, etc. and I don’t have PPE small enough for them 😂

[jhm]

Good thing you've decided against the S130 calipers, Aydin.  I had looked into that option a couple years ago (along the lines of what Terry Oxendale did with his car), and I swear those calipers were NLA anywhere!  New, used, reman, etc....I looked for a couple months and found nothing available.  You might have had better luck this year, on the west coast, but it appears to be a moot point for you now.  I think you'll be much happier overall with the Wilwoods.

 

I like your custom front air dam!  Looks very IMSA-like.  Put a thick rubber skirt along the bottom edge to give a good seal with track surface and still be flexible/survivable.  Making the unit yourself means you won't have to spend the $ to replace it when you inevitably destroy it in the future.  (Speaking from personal experience, of course).  😜