12.7 mm stud kit review dowl pinning
 

Just got my oversized stud kit today since I cracked my s5 rear iron dowl land last month after 2 years of 400+ rwhp fun.

This is the xtreme rotories oversized kit through mazdatrix for $481


After a solid month of finding everything stud and pinned related this was the best choice for my application. I read that engines CAN run high power just fine without this however, logic would tell me that you keep building the broken parts better it will only make a better engine in the long run.

Anyway, I was a little disturbed by the kit,

No allen heads to screw them in, cut threads instead of rolled, all bolts same with them all being "E" bolt length(no wonder you can't use stock flywheel), o rings look too big and to top it off..... zero instructions in the box.

Don't get me wrong, I'm glad it was available and I am sure it will work but, WTF.
I Guess I can measure the studs tread patern and size to be taped on front plate, guess at some torque specs and use my fingers to screw them in far enough or cut a flathead grove in the end( I have to guess at that too).

To be fair I have not called either place yet for instructions.

Oh well. The kit is here and I'll have to modify it to work right-good thing I'm creative....

Keep you updated as the install goes forward.

Scott

Agreed with everything, except...

I dunno if you ever had experience with installing studs, but there is no torque spec on them!
They are all supposed to be "finger tight".
So arguing about some fasteners to install them right is moot.
Having some kinda special fastener to install them would tempt people to crank them down - big no-no.

The reason being that if you torque them in, you induce a (downwards) force on the threads.
Upon full installation with the nut at the other end, the additional (upwards)torque cancel each other out, and now you can get a stud that has zero force on it and full relaxed with no tension / compression!
There's a chance the stud could back out and loosen if this was the case!!!
This is why studs should never be torque down.


-Ted

Good info Reted.
I was not refering to the studs being torqued though...just the nut. I would like the top to still have a means of screwing it in and removing them later.

So far -so good. Lot of time taping these holes by hand.
I felt like spending my money on a new floor drill press and reamers and do it myself as I love to have new tools.
I highly recommend a machine shop as cnc machine would smoke my butt.

Must get drill press dead straight, line up the hole, clamp it all down, change bit for tap, then get a few turns on the tap and then do it all over again 18 times.
They are all coming out straight so far.

Next is a jig for the holes in the housings....

Can you take some pictures of how you lined/clamped everything up ? Also, take some pictures of the process ?

no?

Missing my micro sd card adapter..I am collecting pictures though.
My test holes are tight enough for suction lOl .503-.505" on the .500" studs.

I'm not sure if .2 mm is a better idea as a little rust could make my gaps too close,

Anybody know if 4140 Chrome moly rusts at all?

I am finding that the studs are not all threaded 100% dead center, the shanks are perfect though. I'd imagine a little play in the theads is normal and will mold it's self under pressure to some degree.

Drilling for taps.

More pics...

Taping on drill press.
Making Jig.
Drilled first housing and test fit/measure. .08mm clearance...very tight.

You may notice some ajustable bars under the drill press that I made....holds that extra weight to keep it straight.

more

All ready to go.

Pics of ports with light behind...Happy Halloween.

nice, more pics

I have some of my hairy butt....?

Up and running grand so far. No leaks like I was expecting from the studs.

Running 8 psi on 200 miles for now. Few 120 mph pulls have gone good.

Um wow! I couldn't find a single thing correct about that! I'd elaborate but it would save someone the effort from doing their homework. Then again, I only deal with engineering crap like this on a daily basis at work so what do I know?

I understand what RETED is saying. If the end of the stud hits the bottom of the hole or the unthreaded ledge it will resist moving any further/stretch the theads and want to reverse or back out as it goes through it's heat cycles form this stored energy. This could reduce the tension a little bit.
I think it would take some xtream over torquing to back out any distance for a 10" rod though.

Anyway , I have 100 psi comp #'s after 200 miles

300 Miles and 15psi....

That sucks, what happened.

I'm leaving rubber, that's what.

Any updates. I'm "interested" in using the 12.7mm stud kit for my FD. I might get the stronger OEM sized studs from Mazdatrix but it's still up in the air. LMK what your thoughts are about everything and if you would have done anything different. Thanks!

Still going...

When installing studs, it is important to only hand tighten the ends when first threading them into the housings and then torque the nuts to the proper specifications. By only torquing the bolts by the nut end the whole bolt is able to stretch during the process. If the end is tightened before the nut is put on, when tightening the nut afterwards the bolt does not stretch (at all/as much) as before as it has already been pre-tightend at one end. This can lead to loss of tension/leaking during operation when the engine goes through thermal cycles.

This is the explanation that rotarygod was alluding too but did not give (whether he knew it or not is up for debate). However an engineer should always back up his point with logical reasoning, I hope this has been sufficient. http://www.multipleimageuploader.com...tudinstall.png

http://www.multipleimageuploader.com...tudinstall.png

Correct diagram