Datsun Roadster Forum-311s.org

This is a continuing post but I decided to start again because the subject has morphed. LOL
Subject: Altima vented 4 bolt rotors 280mm X 22mm
Here are some pictures of my machined hubs.
Hub centric diameter (wheel side) cut to 73.1 mm.


5 mm cut from the rotor mounting surface.


Mounting bolts need washers or shorter bolts (watch out for the bolts bottoming out on the hub)
The inside centering hole of the rotor needs to be cut to 2.993 inches (clean and measure your hub)

This is all work in progress and things could change. and they did. LOL
These are Volvo 240D Girling Vented calipers. You don't need to change the bracket.
All that is needed is a spacer or washers to center the rotor.

looking good so far... how was the hub machining done? could it be done on a brake lathe?

fixitman04 wrote:looking good so far... how was the hub machining done? could it be done on a brake lathe?

I took it in to a machine shop that I trust. I would think it could be done with a brake lathe. It would be necessary to go very slowly because its an interrupted cut and the bit could catch if you go too deep. I paid 1.7 hours

That's very cool. Would taking a bit more off the hubs make it work without caliper spacers?

I think you could go 6 mm off the hub and still have room for the wheel stud heads. There is another thing to take into account. By moving the caliper in (spacer) you gain clearance between the Rim face and the caliper. I test fit my 14 Libra wheels and they just barely clear. The VTO wheel have lots more clearance. The 40-60 thou. I need to space the caliper will give additional clearance. I make a 1 piece spacer, it makes assembly much much easier.

Out of curiosity, what's the diameter of the Altima rotors?

st3ph3nm wrote:Out of curiosity, what's the diameter of the Altima rotors?

They are 280 X 22

I tried to crop these but I don't know what happened.

Im surprised you found anyone in Cal. to do any cutting on brake related parts. Everyone is so sue happy in that state. Ya I lived there off and on for 30 yrs. You got er done so thats good. The local Napa didnt want to turn the rotors on my roadster cause they said they were throw aways. Cause they werent vented. I had to go home and get the darn book to show them they werent under cut and they could cut them. Go figure.

Rich

The guy I used has been doing it for ever....

He did the machine work on a U20 for me in the 70's and several since than. He commented that he doesn't see many of them these days...Had a nice long talk about my SDS EFI....

Beside they were machined to my spec.

WOW, if you don't have to do much to mount the caliper you have solved a lot of the problems upgrading to a vented disc! The machine work is minimal to say the least. As I recall, all I did on my maxima rotors (which may very well be the same) was to reduce the outside diameter a bit, cut the rotor thickness down to match the spec for the 4Runner caliper, and hone out the center of the rotor so the Roadster hub would fit over it (instead of modifying the hub)... as I recall there was a clear "lip" of material on the rotor where the hub would fit through that was easy to remove with a grinding stone and a drill without having to worry about it being centered (because the lip edge was clear if that makes sense... it guided your work on how much to remove).

The hard part of the 4Runner conversion has been the need to modify the caliper mount... it was really a custom job. If the Volvo vented caliper bolts up to a Roadster mount that would be awesome and a VERY easy modification to our brakes. Great work!!! Really excited to see how this comes out.

fj20spl311 wrote:I think you could go 6 mm off the hub and still have room for the wheel stud heads. There is another thing to take into account. By moving the caliper in (spacer) you gain clearance between the Rim face and the caliper. I test fit my 14 Libra wheels and they just barely clear. The VTO wheel have lots more clearance. The 40-60 thou. I need to space the caliper will give additional clearance. I make a 1 piece spacer, it makes assembly much much easier.

The caliper hitting the wheel can be an issue. I have to run a very thin wheel spacer to fit my 6 spoke 280zx wheels or the caliper hits inside the wheel on the spokes.

Gregs672000 wrote:

fj20spl311 wrote:I think you could go 6 mm off the hub and still have room for the wheel stud heads. There is another thing to take into account. By moving the caliper in (spacer) you gain clearance between the Rim face and the caliper. I test fit my 14 Libra wheels and they just barely clear. The VTO wheel have lots more clearance. The 40-60 thou. I need to space the caliper will give additional clearance. I make a 1 piece spacer, it makes assembly much much easier.

The caliper hitting the wheel can be an issue. I have to run a very thin wheel spacer to fit my 6 spoke 280zx wheels or the caliper hits inside the wheel on the spokes.

I went with 5 mm because that puts the rotor's inside face very close to the stock location. I have not measured everything yet, but there is clearance between the rotor and the bracket to move the rotor in 2 mm (3 mm hub cut). I also am planning on trying other (larger) rotors (350Z???).

Hi, I am new to this thread but interested in this conversion. Do you have part numbers or year and model for the rotors and calipers? Was something machined in the very first picture view? My understanding is the machining was all done to one side of the hub i.e. faced 5 mm and the one diameter turned.

Jack Maskell wrote:Hi, I am new to this thread but interested in this conversion. Do you have part numbers or year and model for the rotors and calipers? Was something machined in the very first picture view? My understanding is the machining was all done to one side of the hub i.e. faced 5 mm and the one diameter turned.

I had the "hub centric diameter" turned down while I was there. One of the problems with aftermarket wheels is there hub center hole is not large enough to clear the roadster hub (76mm)
I went to a more standard size of 73 mm.

The rotors are 4 Bolt Nissan Altima (lile 93-2001) you can also use the 280mm x 22mm 5 bolt rotors but you will need to drill them for 4 bolt. (use a piece of tubing to protect the threads and use the hub as a drill guide....Just bolt the rotor on with one bolt and drill three. Rotors are about $25-30 each.

THe calipers are Volvo Girling 240 (70s-80s) series vented rotor. There are 4 calipers used on the 240 series. Ate and Girling, vented and solid. search the wiki and the forum for the necessary changes to use Volvo Girling calipers. Calipers are < $100 pair.

23yrRebuild found a great article on modifying the caliper so you don't need to use a manifold or 2 to 1 union.

If you are going to use drum brakes I would suggest an adjustable proportioning valve because the smaller piston area shifts the brake balance towards the rear. You can also use "better" pads to shift the braking back towards the front.