http://www.xtremerotaries.com/main2/...large/stud.jpg



http://www.xtremerotaries.com/



I want!

nice

I think this could be easily duplicated... I'm not going to pay $400 aus for some friggin bolts... I have a local machine shop that I could have them drill and tap my front iron and whatever else needs machining..

" High strength stud kit eliminates the need for doweling the engine block.



All studs act as dowels which massively increases torsionial strength 70%. Rotor housing deflection reduced - increases apex seal life. Less material machined from housings and plates than with doweling, reducing the possibility of cracking.



High boost engine expansion reduced.



Studs are less prone to stretching under high boost applications. More accurate tensioning of engine.



Less chance of bolt breakage. High quality 12-point nuts rated at 180,000 PSI tensile strength. Studs manufactured from 4140 chrome moly, heat treated, centreless ground and black oxided.



Engine must be accurately drilled reamed & tapped to give 0.1mm clearance.



Standard replacement 13B kits available with no modifications.



20B kits available soon. "



Wow... They aren't playing around!

i donno how good this is though, in terms of strength for teh engine. i think u want it to twist some

I'd be REAL interested in seeing some practical testing data of these things.



B

Why would you want your engine to twist some? Whats the reasoning behind that. The way i look at it is, if the engine is flexing you are losing clearances that are supose to be maintained. This will cause increased ware.

Similar to how you don't want your chassis to flex.

But i could be wrong.

It would seem to be a pain to assembly, you will have the thread the stud through the engine and then tighten the nut. I know with some studs, they are suppose to he hand tight and then the nut is tighthen. What are the chances of the stud getting loose after some time. And what about the harmonic vibrations of the solid studs. I remember reading that a dab of silicone on the stock bolts prevent the vibrations. I would think that this stud is the same size all the way through, it would have more harmonic vibration than the stock bolts.

Considering that's $14 AUS more than what Mazdatrix wants for a set of stock bolts that's pretty cheap. I doubt you can get them made yourself for that unless someone cuts you a huge deal.



I think it will cost that much again to have all the machining done to make them fit.



I think it's pretty interesting though. https://www.nopistons.com/forums/pub..._DIR#>/dry.png

thats pretty interesting, I too would like to see some testing to find out what kind of difference it really makes.

Yea I relized the price was pretty good after all the process they have them go through too.

i want to know how they got the 70% figure. looks beefy though.

FYI



There is also good info on Rx7Club about these. Here.

theoretically yes, but the engine is at various different temps (ie it expands and contracts) so you need to give it a little freedom to move around. the idea behind the clearances cold, is so that they go away when the motor heats up, but not to the point where things bind

how important is this mod anyways?



wont you blow an apex seal before you twist the engine

No, not necessarily.



B

Someone should call up ARP and have them make a stud kit for the 13b. Would probably come out substantially cheaper than the aussie counterparts.

if i remember right arp was thinking about coming out something for our engines but i don't know if they decided on it.

we would have to show a definate intrest in order to get ARP to design a kit. I have thought about contacting them, but to do the R & D for this kit, they would need a market of more than just 5 people, if you could get 100 intrested in such a product, or show there was a market for them, they might be more inclined to produce such a kit.

Looks pretty interesting. Hey count me in as one in need of an ARP stud kit.

check here

there are 2 reasons i can think of why theres a gap on the stock bolts.



1. the dowel pins are designed to take that side to side load and not the tension bolts, they are meant to clamp the whole mess together.



b. if they were tighter they have a chance of rusting in there, making engine dissasembly like removing the cylinder head from a tr7....

Have you ever seen 10A tension bolts? They're very thin. Even early 12A bolts are thinner than later 12A bolts.

hmm i never really looked at em

very good points,,, amp- good link, ha

did i date myself with the tr7 comment?

no it shows extensive experience and good taste in cars... https://www.nopistons.com/forums/pub...#>/biggrin.png

not a big fan of the tr7

http://www.brochures.fsnet.co.uk/tr7.jpg



instead of having 2 rows of vertical head studs like every single car even made except the tr7 it had one row at an angle. so when the head gasket blows (note thats not an if) you have to pull the studs out of the block which wouldnt be so bad except that they rust to the head.

LOL,



this is typical British Leyland, trying to save money.



I remember working on a Triumph Dolomite Sprint, that instead of normal bolts the engine was assembled with "Allen" type bolts, it was an extreme pain in the ass.



I had only owned Morris/Austin/Leyland/Rover vehicles before I got an RX-7 and when I did I found it soooooo easy to work on in comparison.



No raw knuckles anymore.





That being said I still have a Mini Cooper S sitting in the garage waiting for me to get enthused enough about rebuilding it.

i have a tr3, theres nothing in the world easier to work on then a mazda https://www.nopistons.com/forums/pub...#>/biggrin.png

my engine builder had one of those in the other day i was laughing at that and the bicycle chain they call a timing chain .. some funky ****

Will you ever replace the boinger with a rotary? You know, *when* it breaks? Then you can be rotary only, like me. https://www.nopistons.com/forums/pub...#>/biggrin.png