However, I still maintain that  if we are going to categorize systems as such then there are (should be)  specific perameters and specific values to be assoicated with a system that mades the dividing line between the marginal and the "safe" system.  And I   would like to be made aware of them.

 

You don't need specific parameters to improve something. I agree, it's nice to have them. The world is chock full of greys, very few black and white, good and bad.

 

 

 

 

If I put the "Red Bars" at 220 and 240F and only hit 200 and 210F on take off would my system now be no longer marginal?      Of course, not, we both know where the red bar is at does not necessarily mean anything about how close or far from the margin you may be.  So what does? 

 

There is undoubtedly some heat related conditions as reflected in oil/coolant  temperature limits which if exceeded will unquivocably cause damage to the rotary.  But, What are they?  Where can we find them? and do we understand under what conditions they occur?  For what duration must they exist for damage to occur - instanteous, 30 seconds? five minutes?

 

Good questions. They suddenly become insignificant if you can just improve your cooling to the point that you don't exceed automobile temps. I'd measure temps in car, then use that for my limits.

 

The ONLY thing I have ever found on rotary temp limits was that published by Racing Beat in their early 1980s technical catalog. Even in there they describe  temperature limits with cavets. 

 

 For instance they give a coolant temp limit of 185F - then they state that if the temperature increase  rises slowly engine damage is not likely to happen even if their stated limited was exceeded by 15 F (this brings up up to 200F)  on the other hand if the temperature rise was quick due to a broken hose, lost fan belt, etc, then engine damage is likely.    So In this case there was a 15F difference in the point engine damage was likely to happen - depending on the conditions.

 

 Keep in mind that these were describing the older 13B blocks - changes have been made in the castings for the housings since then to improve cooling (mainly due to the addition of turbochargers which considerably increased the heat they had to get rid of). Do they necessary change any temp limits - don't know (but I suspect so). 

 

Furthermore what kind of damage would exceeding the cooling margins likely bring.  Well, the first item  likely to fail experience has shown is the stock coolant "O" rings around the combustion chambers .  The orginal stock "O" rings had the look and feel of thick rubber bands.  They did not look like they would take much heat abuse (and apparently did not)  and they are what keep the combustion gases and coolant separated - so would not be too suprising for them to fail first. 

 

  The rotary racing crowd first took action and started using TES "O" rings which showed much more resistance to overheating.  Now, most of us no longer use the stock coolant "O" rings at all but instead use the Teflon Encoated Silicon TES "O" rings with much higher temperature capability. 

 

So does this mean we can safely exceed 200F maybe so, maybe no.  My bet is if the stock O ring was first point of failure then switching "O" rings moved the temp limit for "O" rings beyond 240F.  But, even if I were correct, we don't know for certain what the next component to fail might be?  Perhaps it fails at 210F.  In that case, the 400F coolant "O" rings don't buy us much 0r perhaps the next failure items is at 230F. If that were the case the the change of Coolant "O" rings buy us a nicely increased margin.  I simply do not know. 

 

Sorry to take up so much windage, but my point is we need to better know the failure mechanisms and their limits before we can accurately assess a "marginal" system.  If a system repeated operates and exceeds the "marginal" limits we set and continues to operate without failure mean the system is extrodinary, the operator is lucky?(don't you just love that word).   0r does it means the margin assessment limits might be too low or perhaps that we do not understand the failure mechanism.

 

In any case, Al.  My viewpoint is your motivation is right on the money, couldn't agree more - if I see something I personally feel could cause damage or particularly harm, I would speak out on it.  That I may take issue with you on some points does not in any way mean I don't appreaciate and respect your viewpoint.  I think such debate does more to simulate thinking that any dogmatic statement.  There is no doubt in my mind that after such a debate someone, somewhere has the light bulb come on (sometimes its even mine {:>).

 

By the way, did you have any luck finding clams?

 

Always enjoy my exchanges with you Ed. You are quite open minded.

I went clamming 2 days last month. Got 1 clam each day. Went clamming this time and got my limit (15) in half hour. Ended up with 45 clams. Although the two dinner parties since have drained stocks. Fun  to share them with friends.

 

So I agree, near impossible to know what time and high temp are a genuine issue. However, since there are hundreds of thousands of hours on the auto's, you know if you meet those limits, you are guaranteed to be ok. I'd stick thermometer in oil and coolant of arizona RX vehicle. Then declare those peaks to be my genuine limits. I assume those arizona peaks don't cause warranty issues for Mazda.

 

regards

-al wick