Vented rotor conversion
by: Stephen Moffett, initial and editing notes by Bob Hanvey
Obviously there are several approaches to front and rear brake upgrades. The following are two of the most common. I am merely linking the original writeup about upgrading your front brakes. It was written by Craig Marcho long ago. It involves a direct bolt on of the Toyota 4 piston caliper to the existing stock Z rotor. Many people have done this upgrade and are very happy. That link is Stop that Z! The following is similar, but utilizes a vented front rotor. My notes are in ( ) with ed. preceding my comments.
This was a post to the "big" list,(IZCC, see link on link page),
by Stephen Moffett about his conversion from the stock solid rotors
on his 77 280Z to a vented setup. As he clearly states below, he, nor
I, can in any way take any responsibility for any gains, losses, or
general screwups that may happen. You may see a increase in braking
capability, you may not. Stephen has had great luck with it. Others have not.
It really depends on driving style, current brake condition, and a number
of other unmeasureable factors. These type of modifications are always the subject
of hot debate on the mailing lists. Many people use the stock brakes in racing
and have no problems, pushing the limits beyond what you and I may drive.
Others have toasted the stock brakes in short order. As always, it is a
personal decision, just as putting a 3.1 or a v8 in our meek Z's is.
In the end, it comes down to you. What do you want? If it is worth it to you, then
by all means, go for it. If you are unsure, keep researching. If at all possible, find
someone who has done the mod, and ask them, or, if they like you a whole lot,
see if you can drive it!
As we are both stating, done incorrectly, the results can be disasterous. Don't
attempt this unless you are sure you know what you are doing!
(Do any of us ever know what we are doing?)
I had some of the discussions from the list and was going to put them on another page but I have misplaced those comments. If you are looking at doing the conversion, you
really need to check on message boards and mailing lists for opinions/experiences on different setups. Read it all, it's worth it.
Also, many people have had a fair amount of confusion about which calipers to use, etc...
so I posted the different years, what they are, etc... It also includes some part numbers posted by someone on the mailing list.
Ok, enough on that, here is what Stephen posted:
I've decided to go ahead and just post the conversion here first. It's
going to be short so if you have any questions feel free to e-mail.
----------------------------------------------------------
*!*DISCLAIMER*!*
My car:
'77 280z
original strut assemblies w/ KYB struts (new)
completely rebuilt front-end
15x7 Fast Wheels w/ 225-50-15 Falken tires (my rims have 3.75" backspacing)
'88 Toyota 4x4 (4-Runner) brake calipers
'84 Nissan 300zx rotors
steel braided brake lines
This is the car that I did the conversion on, it works and I've been
driving around like this for approx. 5 months w/ no problems (knock on
wood).
Everything that I write was measured according to my car, things could
differ for yours.
I'm putting this disclaimer in here to say that I assume no responsibility
for the outcome of anyone's finished product.
If there is any bad info. in this post please let me know, or someone
correct me.
----------------------------------------------------
Alright,
YOU MUST DO THIS FIRST (if you haven't already). Go out and get front
brake calipers for an '88 Toyota 4-Runner.
Go through the process of fitting these onto your car FIRST. They will fit
on without any modifications (except cutting the heat shield, and actually
you might as well take this heat/dust shield OFF, because you probably
won't be able to use it with these rotors!)
AFTER you have gotten these calipers to fit, that is - they clear
EVERYTHING (i.e. struts, wheels, tires...etc.) Now you can go buy your
nice new '84 Nissan 300zx front rotors.
These rotors look just like the Z's except that the "hat" section where the
hub bolts to, is shorter, therefore you will need a spacer to go in between
the hub and the rotor.
The hub I used was the original one on my '77 280z.
(ed note-several sources list different heights for hat section during the run of
the Z's, ie 70-78, bottom line, measure yours).
The way that I measured to see what size spacer I needed was to just
measure the difference between the "hats" of the two rotors ('77 compared
to the '84). This difference when I measured it was .5 of an inch. This
lead me to believe that this was an exact difference ( I mean that Nissan
made these exactly .5" different). It may for some strange reason be
different on your car (as far as position relative to the caliper mounting
bolts or something) - take measurements and find out exactly what size
spacer you need.
You can make this spacer however you want to and out of whatever material
you want.
I chose to design the spacer on Auto CAD, just a 2-D drawing that I made
into a .dxf file-type so that it could be cut using a CNC water-jet router.
I had a friend cut this for me out of .5" mild steel (I don't have any
money, so you can certainly make this out of whatever material you think
will withstand the shock, heat, etc.). This mild steel is a little heavy
for me, but it was more than strong enough for the application).
***I still have the Auto CAD file of the spacer (like I said it's not that
big of a deal), but anyway, if anyone wants the file I will send it to
them.
Or if anyone wants me to make the spacer for them I will do this.
(ed again-Stephen's e-mail is at the bottom)
After you have obtained this spacer you are practically done!! :) Just
reassemble putting the spacer in between the rotor and the hub.
OH YEAH, I ALMOST FORGOT!! You will need to buy new bolts to secure the
rotor-spacer-hub assembly together. You can take the original bolts to the
store and just get the next size LONGER. I couldn't find the size of the
bolt that I used (I had it written down) I believe they were 40mm long,
they fit perfectly, they use all the threads in the hub and don't stick out
at all. These were obtained at Pep Boys, they are a metric grade 10.9.
Get some new lock washers too.
Completely assemble the rotor-spacer-hub assembly back on the car (like I
said earlier I couldn't keep the hear/dust shield on...you may find
differently).
Now try to install the calipers without the pads.......anything....any
sparks....did the car thank you?...mine didn't either.
You may find that you need to shim the calipers a bit. By this I mean that
the rotor needs to fit right in the middle of the groove/track of the
calipers (i.e. if the pads were installed the rotor needs to fit right
between them). For some reason it may not fit perfectly. If you need to
shim, just get very thin washers (good strong ones though) and put them
between the caliper and the caliper mounting piece that is welded to the
strut assembly. Make sure to put the same amount of shim at both of the
caliper bolts so that the calipers stay straight.
Reconnect everything else, bleed brakes, and you're off.
There's been a lot of talk about adding a proportioning/bias valve to the
system...IMHO it is necessary for 100% completion. I haven't added this
yet, but I would be grateful in someone would send me one...come
on....there only ~$30....alright just kidding!!
You can view a pic of the finished product by clicking here, but I forwarn you, until I can edit it, it is a 215K file.
Vented Rotor finished product
I hope everyone is satisfied with the results, I have been.
Any questions? Let me know and I'll try to help.
Stephen Moffett
[email protected]
Mechanical Engineering student at the University of Texas
'77 280z (turbo) intercooled
Programmable EFI
etc.....
...still working on the $80 short-throw shifter kit...almost there!
(ed-his address may no longer be any good. This was written three + years ago)
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