[vex]

Originally Posted by glenrx7

Nothing over 8k, here is the deal my man. It being harder is the issue. If you have a hardened piece of metal you need to temper it in order for it to be able to have "memory" with out memory it will bend and stay that way. Tempering will soften it in comparison to a non tempered hardened shaft.

Harder metals have a higher tensile resistance but a lower ductile fracture point: more likely to break than to bend--but this isn't always true depending on what metal is used, hence why I asked if you had the specific steel name on hand.

Spring back of a shaft would not stop damage to the bearings though--Will it reduce the problem; sure. Will it be the end all be all of failure. I don't see it. By bending the shaft in the first place that means in unequal force was applied to the two different combustion chambers at one ignition event (assuming balanced shaft). That would dictate to me that the flame front propagation produced more force directly perpendicular to the lobe than the other ignition events. Since the RX8 shaft has material removed from the lobe that would cause an "abnormal" ignition event cause the probable deformation. Further running the engine then increased the problem and eventual destruction.

Look, I dont want to brag or try and make my self look great or anything like that I try and stay humble, to help you out let me give you a little background info.

I was trained to build the top racing rotary engines by Paul Yaw of Yawpower. I built all the engines that came out of his shop for the last 6years or so. Paul moved on to motec and injectors so no more engines, He helped Tom and I start azrotaryrockets.

We are also "sponsored" if you will by Mazda, i act as tech support for there rotary team and motor sports team.....

After coming from Yaw Mazda came with us, they send us project and customers, so I would say we know a little about this subject.

So take my word or dont ...I was aiming to help thats all....Good luck.

Wasn't aiming to discredit you, but I don't see the shaft as being the problem but a symptom of an underlying cause. Was the event spontaneous or did it occur at a specific location during a pull? For instance were the HP/Trq curve climbing as the other runs then all of a sudden stopped climbing as previous pulls had become? Or did it occur after a run that was normal, then never pulled the same? I ask because the timing events may have dictated the cause of failure.

Originally Posted by glenrx7

Ok, well some of your logic is flawed. The rx8 is an na engine with a low combustion pressure putting less stress on the shaft. You increase combustion pressure and you increase forces on the shaft. So for the sake of argument lets jump into black and white for a second. Combustion pressure basically aquates to torque, if you increase it the tourque will increase increasing the force aplied to the rotor, bearing and shaft. So with boost you increase combustion pressure. So with out the turbo you have less force on the shaft even at 9k.......Not to mention the torque on a renisis is well we all know that ./


Now if the shaft is bent .006 it is out of :mazdaspec" by .0045.


The shaft being bent .006 at one point of the shaft would give you a diameter of .012 meaning the shaft is digging .006 all the way around pushing the rotor out of place destroying the bearing etc.

I'm doing a little digging on it because I would find it peculiar that the shaft itself would spontaneously become out of spec.

I'm not sure where this data comes from originally but it might become useful in this discussion. The original website is: http://www.rotaryeng.net/Rotar-v-Piston.html

If we assume that to be an NA style 13B then I don't see the Turbo variations being order of magnitudes bigger (where the NA reads 170 kg/cm^2, the turbo will not read 1700 kg/cm^2).

Originally Posted by glenrx7

Let me also say that i am not sure what torque rate you would have to exceed to bend this shaft but I know 300+ and you are going to be in trouble I doubt chadwick is anywhere near that..


I hope this all does not sound defensive I am about as articulate as a 3 year old on acid that lots there mommy....That s why I do not teach.

It's not defensive. If I'm coming off accusatory I apologize, but I think the problem is before the bend of the shaft.