Spaced 280ZX calipers for vented rotors?

[Boy from Oz]

I see that 280ZX calipers are a popular disc brake conversion on early Zs. They appear to be limited to use with solid rotors (I think) around 10mm thick. Are they two-piece calipers that could have a 10mm spacer inserted (dowlled in necessary to avoid movement and drilled if necessary to make sure no brake fluid galleries were cut off) making them suitable for use with vented rotors?

 

Or are they a floating type making all this academic?

[blueovalz]

The ZX calipers are for the ZX rotors, which are vented. The caliper is a "floating" design, but that shouldn't make this subject academic.

[Boy from Oz]

The brake catalogues here in Oz suggest that rear rotors for the 280 ZX are solid and 10mm thick. You may have different versions in the US. I was hoping to use 300ZX rotors on the rear of my 240Z (as per the front) with modified 280ZX calipers because of the handbrake (ebrake) capability and for uniformity.

 

Has anyone ever spaced calipers for a wider rotor. I have concerns about issues like to coefficient of expansion of different materials and thus whether the whole concept is essentially flawed.

[blueovalz]

Ohhhhh, I saw nothing about rear calipers and assumed (my bad) the front calipers were the subject of discussion. The concept of inserting a spacer is no different than several manufactures do. But the 280ZX rear calipers cannot be modified as such. I successfully use 280ZX front calipers on the rear of my car with front Maxima rotors (vented), but my set-up, with a good proportioning valve allowed this. What could be done is take the OEM front Z caliper, insert a spacer, and use it in the rear, but then you'd have no emergency brake, which basically negates your desire for the emergency brake. Being a rear caliper mounting bracket must be fabricated anyway, why don't you go ahead and use the 300ZX rear calipers then?

[JMortensen]

So you're talking rear calipers then. It's a floating caliper, so you'd need longer pins. I also don't think the main clamp part of the caliper that goes across the top would be long enough. It's sized so that the caliper has just enough room to fit the rotor and the pads in there.

 

To answer your question though, Wilwood makes some calipers that are the same for the .38, .81, and 1.25" rotor widths. The only difference is a 1/2" spacer is added for the .81, and two are added for the 1.25" rotors. This only works on a fixed caliper, and won't work on a sliding single piston like the 280ZX has.

[Boy from Oz]

Sorry about not specifying rear brakes and thanks for the comments so far. If, as is said, other suppliers use spacers then they may not be an issue and it might work. My problem now is what calipers could I modify. Making a support bracket is not a problem for me, it's finding split calipers that are smaller than the Toyota 4x4 that will be on the front (for balance reasons - though I will use a proportioning valve) and will adapt to the ebrake cables on a 240Z. Would the Maxima (I think known as Skylines R31 & R32 down here) be suitable?

[JMortensen]

I don't think you're going to find a fixed caliper that works as an ebrake. If you look at the ebrake calipers, the lever you pull with the cable pushes on ONE piston. If you have a 2 piston or 4 piston fixed caliper, you won't be able to push both or all of the pistons, because you only have one cable per side.

 

You NEED a sliding caliper with an ebrake that fits a vented rotor. You might check older Subarus. They had the ebrake on the front calipers and I think they had vented rotors up there too. I had some a LONG time ago and there were some clearance issues with the strut, but I was trying to put the caliper on a small rotor. If you upped the size of the rotor it might work.

[Boy from Oz]

I'm now thinking of installing a separate ebrake caliper set-up on each rear rotor. They are a much smaller caliper and some are two-piece allowing you to space them to your rotor thickness. They could be mounted at 180 degrees from the hydraulic calipers without restricting heat dissipation too much. There are a few kits available from Hotrod shops. It means a bit of work making the support bracket/s but should allow me to use the vented rear rotors. Again any crtique of this concept would be much appreciated.

[zed240au]

if u want rear caliper with e brake in the caliper on vented discs one that does this is series 4 mazda rx7 vented discs and calipers with ebrake been running them on my rx4 rally car number years now work fine

only trouble we has the e brake pulling on over bigger jumps on dirt rallies and some sealed rallies we ended disconnecting the ebrake got the hydraulic ebrake as well any way just coonect the cable one for rego issues

for normal road work they work great and u can get decent pads for them too

[Boy from Oz]

The RX7 looks like a good set up to overcome the ebrake issue but I'm a bit concerned that the piston area is too small to satisify the vehicle modification rules down here. The rules say you need to match the brakes on a production vehicle with similar power to weight ratio, e.g. Dodge Viper or a Ferrari 360.

 

BTW there is a set of RX7 vented rotor rear calipers on e-bay starting at $9.99US if anyone is interested. My wrecker quoted me $90US each, today!

[JMortensen]

How about a Vette PBR caliper?

[Nismo280zEd]

I'm now thinking of installing a separate ebrake caliper set-up on each rear rotor. They are a much smaller caliper and some are two-piece allowing you to space them to your rotor thickness. They could be mounted at 180 degrees from the hydraulic calipers without restricting heat dissipation too much. There are a few kits available from Hotrod shops. It means a bit of work making the support bracket/s but should allow me to use the vented rear rotors. Again any crtique of this concept would be much appreciated.

 

 

I believe porsche does this... the rear brakes your foot uses are different from the rear brakes your e brake uses.

 

-Ed