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From: <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: high oil pressure and coolers
Date: Sun, 12 Sep 2004 12:37:00 -0400
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Rusty, I wouldn't put too much stock in the fact that my cooler sprung a leak.  I am pretty sure that the cause was poor mounting and not over pressure problems.  And at least the leak came on slowly.  My new one has about 10 hours now and my cowl is dryer than ever.  I have redone my mounting system and would not fly if I didn't think that it was going to work.  I even think my old cooler may have had a small leak right from the start (that's why it was so cheap on e-bay).

I haven't been following this thread.  I'm sure you know that vibration isolation is paramount for durability of these coolers.

BTW, Setrab makes a high durability line of coolers that may work better.

Here is on supplier:
http://www.capa.com.au/setrab_com.htm
website says: "If the STD is the most flexible oil cooler then COM is the most durable. The COM unit is designed to meet extreme working conditions regarding vibrations and oil pressure."

Mine is the STD.  If it springs a leak again I will go to the COM.

Dave Leonard


> >  
> > I'm really concerned about the evap core in the current installation.  
> > First, it just failed, as did Dave's Setrab (rated up to 232 psi).  
> > How many other non-Mazda oil coolers have failed? 
> >  
> > In my case, I have other causes for concern.  My oil goes from the 
> > engine, to the evap core, to a Peterson inline filter, back to the 
> > engine.  Along the way, I do a couple restrictive things.  First, 
> > I start at AN12, then change to AN10 at the outlet of the filter.  
> > That probably causes some restriction, but perhaps not as much as the 
> > oil filter itself.  The Peterson filter is a stainless mesh filter, 
> > which normally comes with a 60 micron screen.  I was concerned about 
> > that being too big, and changed to a 45 micron screen.  This will 
> > certainly be more restrictive, but the Peterson filters are very high 
> > flow to start with, so maybe this isn't an issue.  Nevertheless, I'm 
> > concerned that I've caused enough restriction to make the oil outlet 
> > pressure stay near it's 157 psi limit at high rpms.  
> >  
> > The next problem is not knowing what the evap core can handle.  The 
> > more I've thought about it, the more I don't think the evap core 
> > routinely sees pressures over 90-100 psi in the car.  I also worry 
> > that pressure pulses in gas are far more forgiving than they will be 
> > with liquid.  Who knows if there are pulses in the oil pressure that 
> > even exceed the 232 psi rating of the Setrab.  Anyone know what the 
> > stock Mazda coolers are rated for.      
> >   
> > I'm probably not going to fly again, until I have a pressure gauge on 
> > the oil outlet of the engine, so I can read what pressure the evap 
> > core is seeing.   The VDO senders seem to skip from 150 psi, to 350 
> > psi, so there isn't a great choice.  I'm even considering not flying 
> > the evap core oil cooler again regardless.  I already know it isn't 
> > going to work well enough for my current power level, so why take a 
> > chance. 
> >  
> > Has anyone checked the pressure out of the engine?  What do you guys 
> > think about all this?
> >  
> > Thanks,
> > Rusty (this is why I needed another plane)
> >  
> >  
> 
> 
>