Has anyone installed the Xtreme Rotaries stud kit and if so we need your help.

We're (Gotham Racing) putting my 20B back together and we've hit a snag with the Xtreme Rotaries stud kit. We took the irons and housings to a CNC machine shop that does Ken from RX7.com's race cars and the drilled out the holes. When test reassembling the engine, some of the studs slide in easily and some don't. We could probably use a rubber mallet to get the trouble studs to slide in but we're worried about the effect on the engine.

Has anyone had this issue and what should be done? Also, the instructions say to drill and ream each hole. Is this done separately on each iron and housing ro do you stack the engine components together and the ream the hole?

Finally, the studs are 12.7mm and clearance is supposed to be 0.2mm. This means the reamer should be 12.9 mm right?

Thanks so much for the help!

 

Can you peer down the holes and verify that they are lined up perfectly? I didn't use the oversize kit, so I didn't need to have my housings machined.

 

Hard to tell. Looks good but then the studs don't go in easily.

 

I'm not expert, but what I would do is stack the plates one and a time and try the holes which don't seem to be fitting right (i.e. put one plate on top of the front housing and try one or two of the problem studs.. If they are ok there, stack the next one and try them again, etc). You might be able to narrow it down to one housing which may need a little massaging.

 

David
Check your PM's.

 

Does not sound like the machine shop machined the block correctly..

 

Um, you can't just enlarge every hole, unless you're compensating for deviation?
There's a significant difference between all the holes, and this kinda stuff should be done on a CNC with repeatable performance using set-up dies so the housings are always milled precisely the same.

What's the directions for these things?


-Ted

 

David

A freind of mine has the 12.7mm kit for his 13b, and i remember when we put it together not all the studs whent straight trough. We had to use a rubber mallet to get some of them all the way in.

Don't think u should be too worried about it. It might just be the housings beeing sliglty moved on the dowels compeard to when the holes got drilled on the cnc.

There is way more slack on the stock Tension bolts so don't worry if u hafto give a few of them a slight crak with a rubber mallet to get them in.

Make sure the the studs go easy into the thick plate tho. It's a pain to screw them in by hand if there is any kind of dirt in there.

But if the studs don't go in with a soft hit from a rubber mallet then there is something wrong.

Keeep up the good work man. The engine is going to be so good now with the right seals, and the engine built the right way.

JT

 

Thanks for all of the responses. We followed the directions from Rohan/Xtreme Rotaries to have the parts machined but we think the CNC shop didn't ream the parts so we're back over their now to have this done. From what we've gathered, we can have each part individually reamed.

Once this gets accomplished, we should be good to go. I'll keep you posted.

 

Good deal David. While I'm sure smacking them with a rubber mallet hammer would have produced results, IMO, that's not something I would want to do in that situation. I would prefer that they all slide in without effort.

 

David, sounds like the machine shop didn't indicate each part correctly. A precision CNC is only great in the hands of a precision machinst. With ~.008" clearance, all studs should go in easily, if all holes were indicated properly.

 

Final update: If you have read my posts in my other thread about my conversion, we got the stud kit to work. Had to go back thru each hole and gently enlarge them. After speaking to Rohan from Xtreme Rotaries, did this with a hand reamer and the studs now slide in. They should slide in with anti-seize on them and be a little tight. The whacking them in with a rubber mallet idea is not a good one because the metal needs area to expand when it gets hot and if they are too tight, they can crack your irons.

Final note, the machine shop guy also screwed us by radiusing the edges of each hole. They were supposed to be flat as the washers have a radius on them and the supplied stud o-rings didn't fill the doubled space properly, giving us a coolant leak. Had to pull the engine and replace the o rings with ones that were twice the thickness. I suppose we could have flipped the washers around but we didn't want to do this.

All of this from a shop in Dallas that supposedly already had a template for the 3 rotor. We used the shop recommended by Ken from RX7.com racing. He's had good luck with them, we didn't.

 

David, what's the name of the shop? No use protecting the guilty.

In my experience machinists are only *slightly* more dependable than welders and fabricators

 

Don't know the name, Gotham would though. You have connections there, right? I only know it as the shop that Ken uses for his race stuff.

 

Glad to heard you got everything worked out David.