Is there such a thing or would it be benificial at all to have some type of strong alloy tension bolts? Say cromolly or some other strong alloy? Would this help in any way for housing twisting? I have a machined and dowelled 13B, but am wondering if this could be an alternative, or are the tollerances in the bolt holes not that tight of a tollerance to matter?

I allready know I am gonna get the "you don't even need to dowell your block" replies, but I want to know anyway. We run these motors @ 25-30 psi for complete desert seasons in our sand cars, and they take A LOT of hard driving!!!! So they stronger the better.

 

From my knowledge and experience, there has never been a need for better tension bolts. Your best bet is just having your engine dowelled (which, of course, you have already done) because having stronger tension bolts will provide absolutely nothing at all over stock tension bolts. There has been no record of them actually stretching. Remember, there are 18 or so bolts holding the engine together. However, Mazdatrix has actually done a recent experiment with extremely high boost levels in rotary engines and they have found out that under those high pressures, the housings themselves have actually "expanded" or have been "pushed" outwards away from the face of the rotor. In some cases, the rotor faces themselves have actually collapsed!!! So, my friend, tension bolts are the last thing you need to worry about. Your best bet is staying with having your engine dowelled which keeps the block as a whole from actually "twisting" and "expanding". If your worried about the rotor faces themselves, well, you had better find yourself a MUCH bigger turbo and run MUCH higher boost before you have to worry about that!!!

Brian

 

.............unless, of course, you get tension bolts machined that fit PERFECTLY in your block with extremely close tolerances so that they act like DOWELS themselves, but I hardly think that you'll have to worry about that

 

I've never seen a motor requiring stronger tension bolts.
There is a vendor who was selling stronger studs for replacement, but I dunno if they still sell them.
If you're paranoid, the 20B uses thicker tension bolts.


-Ted

 

Thanks for the info. I was just looking for alternatives to dowelling. I'm sure that this motor is gonna be junk at some point and am looking to alternatives of having to rely on someone machining through the motor.

 

Get a stud kit, they do the same thign as dowling,.. i think they come in 2 sizes one you dont have to bore out the stock tension bolt pass thrus and one you do...

 

Here:

http://www.xtremerotaries.com/


They have 13b and 20b kits.

 

Thanks man!!!! That's what I'm talkin' about!!!!!

 

Stronger tension bolts cannot replace tension bolts.
There are certain weak points in the 13B block which cannot be "fixed" with stronger tension bolts.
Specifically, the oil supply fitting on the front iron and then the oil filter pedestal tend to crack.
Tensions bolts cannot strengthen this points - only dowelling can.


-Ted

 

I got the full guru stud kit on my 12a. So much better than dowelling.

 

I like the idea of that stud kit, studs are superior to bolts when it comes to clamping strength....
But the big strength gain isn't from the studs alone, its the way the studs fit through the housings, The only torsional strength in the engine is the two dowels, and where those dowels fit into the irons, is also right where the irons crack.. Those new studs are tight fit in the irons whic spreads the dowels load partially onto the studs, basically its like adding 18 dowels without really removing a ton of material to add more dowels..Its a hell of an idea, I thought someone like ARP would have come up with a kit already, seems its the Ausies thought that are always ahead of the game when it comes to rotary aftermarket..Max

 

^^^^I agree

 

I am using the GURU stud kit in my latest 13B along with their 2 piece centre bearing racing eccentric shaft.

You cant go past the GURU product if you want ultimate fit, finish and function.

 

How difficult is it to get the machining done to the front plate to use the studs? Meaning getting them drilled and tapped. That's the only concern I have and if anyone knows if any machine shop can perform this modification? I really like this setup.

 

Yeah, I would like to know as well

 

If you're able to twist the motor like that, the motor isn't coming apart.


-Ted