Looking around Mazdatrix and I found these. I will be getting em soon for my build. http://www.mazdatrix.com/studkit.htm



http://www.mazdatrix.com/pictures/b-engprt/stud.jpg

Nice





I wonder if the torque value should be changed..

looks like the extremerotaries kit

they do not have the ribbed OEM tension section in the middle... As far as I remember those were an upgrade within Mazda itself as well.

Damn looks like you will finally be able to put 13B rotors in a 12Amotor https://www.nopistons.com/forums/pub...#>/biggrin.png

looks like it'd be a bitch to tilt the center plate when you put the engine together.

I would think so, they should come with a spec I hope.









I wonder if the front plate needs to be re-threaded with larger diameter?

Does anyone know if there is a kit like this for the 20B ?

Should be the same as any other engine build. The studs probably get installed last, or at least after the center housing is laid on.

Correct. You install them after you got the center housing on. They can be a bitch to get in the first time https://www.nopistons.com/forums/pub...DIR#>/wink.png

so... if you have to install them after you build half the engine, and remove them to tear the engine down.... they are really just bolts without heads on them. Other than them being oversized,,, what is the benefit here?

Yes, but having a harder and denser fastener works just like the ribbed section.

There are two ways to look at it.



Primarily in this instance, the studs are also acting as locating dowels. (Machining is required) Instead of two dowels, there would be 19-20 dowels. The benefit for the effort is somewhat debatable, but let it be known that Mazda determined that part of the reason for chattermarks in the chrome is partly because the rotor housing itself would oscillate.



Ordinarily, studs are used because they are more predictable than bolts. The torque stretches the bolt or stud, but the act of torquing a bolt also twists the bolt since the area you're torquing is so far away from where that torque is acting, the threads. Additionally, the bolt is threading into what can we can consider to be a old cast iron nut. The threads can gall or pull out on occasion. (I have never experienced it on a rotary, yet, but it gets depressingly common on certain popular engine blocks from the 1980s after a few head torquings) Using a stud helps this, since it is threaded in under no load, and the nut that applies the load is nice and hardened just like the stud.



I would worry about how well the studs can stretch to accomodate the aluminum housings, or if they will get crushed the first time the engine gets a little too hot. Probably not a problem for drag use.

You make a good point here, and its something to consider. But to me the benefits seem to be greater than the downfalls at this point.

Im pretty sure that Gurumotorsports has put some research into this mod.

The bolts is a pretty tight fit and will follow the engines heatrange, using the proper steel and it will not cause a problem with engine expansion.

One of the key benefits to s stud system is where the tension of the bolts is located. When you have a simple bolt system like stock, all of the stress of tightening them is located only at the threaded end with relatively lieelt stress throughout the bolts. With a stud system, you are splitting this stress in half between both sides, even if you torqued everything down the same. Instead of all of the rotational forces of tightening them down being all located at the front iron, half of the force is now also on the nut end. The bolts are stressed far less than they were before and more evenly over a larger area. It is even between the front and rear housings. This means you can apply more torque to tightening them down without worrying about stripping out a housing or breaking a bolt at the far end.

This is an e-mail I recieved from mazdatrix So, it seems machiening is a little more extensive than I thought for the oversized studs... But there must be an easier way to line up the holes.

And what flywheel should be used with it? (FD engine)?



Both standard and oversized kit require a non- OEM flywheel

Im assuming any one using an auto counterweight.

Well if you don't want to go that route; I sell a stock diameter stud kit for $325 shipped...

Yes but didn't your studs have something insane for the torque compaired to the ones that Mazdatrix is quoting?

ARP is making oversized stud kits,



they are in the development stage now...

Where did you hear this? I've been emailing them for over a year to see if they would do this and never get a reply. Also the fact that they have a RX7 on their import page made me wonder why they haven't made them yet. Do you know if they will also make a standard kit?

they are the X-treme rotaries from australia's kits.

Yes, this set is the Guru Motorsport stud kit originally sold by X-Treme Rotaries.



The studs are 12.7mm diameter, so they will require quite a lot of machining to fit.



I'm still using them to.. =)

If anyone wants the machining or the studs I am set up to do it. Machining is done on a CNC I have it set up for both 2 and 3 rotor apps.





-S-

Where are you located?

Chicago.