Mailing List flyrotary@lancaironline.net Message #14053
From: Russell Duffy <13brv3@bellsouth.net>
Subject: cooler thoughts
Date: Sat, 18 Dec 2004 11:02:01 -0600
To: Flyrotary List <flyrotary@lancaironline.net>
Message
Greetings,
 
From reading the comments on the list, and from a few offline emails with Leon, I'm convinced that the primary issue is the pressure pulses from the oil pump.  My installation of the oil cooler core was far better than the water cores, in that it wasn't rigidly mounted.  It was also mounted to the engine mount, rather than the moving engine like the water cores are.  The hoses were not under any sort of strain, and should also not have been subject to any significant vibrations. 
 
The problem might simply be that the pulses are hitting high pressures and fatiguing the reasonably flimsy evap cores.  There's also the possibility that the pulses hit a resonant vibration at some point, which causes the failure.  I did have some funny vibrations at times, and was never able to pinpoint the cause.  Either way, I believe I've proven that evap cores are a bad idea as oil coolers. 
 
As for using them for water, I also agree that they have a good track record, and that the operating conditions are much more friendly.  There have been some leaks, but those have been much less severe events, and probably within my risk tolerance limits.  In all likelihood, I'll continue to use them for water on the RV-3, since I have no room for anything else, and since they've been working so well.  I may look into adding some rubber cushioning to their mounting, but that's not as easy as it sounds.   
 
As for the next oil cooler, the leading candidate is of course the stock 2nd gen cooler.  There's also the Mazda racing cooler, which is a similar size.  Both are really expensive new, but I'm willing to pay what it takes to prevent a recurrence of last Sunday's event.  The 3rd gen cooler is a possibility, but I don't think one would be enough, and two take up more space than one of the 2nd gen coolers.   The next problem is having room to put the thing.  I'll do some measuring again today, and see what I can come up with, then go from there.  
 
Cheers,
Rusty (now my heat pump is out of Freon, what else can leak?)
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