Good catch ED. After looking at the first of the two pictures again, it appears that the line in question feeds into the oil filter adapter block, thereby bypassing the oil filter and half of the oil cooler. My guess is that its purpose was to keep air from being trapped in the top of the oil cooler. Of course, you pointed out a couple of other things it may be doing as well. While it may not completely solve his oil temp problems, removing & plugging the line should bring his oil temps down by at least a few degrees. It shouldn't be too difficult to test that theory.
Mark St.
On 7/5/07, Ed Anderson <eanderson@carolina.rr.com> wrote:
Good catch, Buly.
Both oil fittings (in and out) are on the same end of the oil cooler if its
a stock Mazda RX-7 Oil cooler. I see what Buly means - there is also
appears to be an AN-8 hose out the other (top) end of the oil cooler. You
do not mention this hose in your description of your oil system.
I guess that could be unique to the Cosmo oil cooler (if that is what you
are using) not having seen one myself, but the small top hose looks like
an add-on to the oil cooler core.
However, the bottom line is -- IF your oil line to your oil filter and the
hose out of the top of the oil cooler to your block do provide a parallel
path for the oil to return to the block , then I can see two things
resulting - neither very good:
1. The top hose (one next to prop flange) on the cooler would appear to
permit oil to leave the cooler after only passing through one or two rows of
the cooler - therefore not loosing very much heat to the air. So 20-30% (or
more) of your oil may not be flowing through all rows of the cooler. IF
true then that would make a major difference in oil temps and no amount of
air flow through the cooler will really help much.
2. Some of your oil will not be flowing through your oil filter and you will
therefore have some "dirty" oil flowing through your cooler and returning
directly to the engine.
If this is a Cosmo oil cooler for a 3 rotor, then Buly is correct, it should
have no problem cooling a two rotor.
So its possible that the combination of some oil by-passing the cooler (If
indeed that is the case) and insufficient cooling air through the oil cooler
could both be playing a part in your high oil temps.
So exactly how is your oil system set up? What is the purpose of the hose
coming out of the top of the oil cooler(end closest to the prop flange)?
Ed
----- Original Message -----
From: "Bulent Aliev" <atlasyts@bellsouth.net
>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, July 04, 2007 9:40 PM
Subject: [FlyRotary] Re: [Fwd: [Fwd: RV-7A Cooling]]
> Dennis,
> I used the same oil cooler on my Cosmo 13B and it was cooling too much in
> flight 137F at cruise.
> I see one thing you have done that disturbs me. The oil line tapped at
> the high end of the oil cooler going into the oil filter adapter plate..
> By doing this, great percentage of the oil is bypassing the oil cooler
> core and going back into the block.
> If it was me I'll block this outlet, and turn the oil cooler around, so
> the oil gets in and out at the higher end. This will prevent an air lock
> at the high end.
> Buly
> On Jul 4, 2007, at 6:44 PM, Dennis Haverlah wrote:
>
>>
>>
>>
>> Flew my RV yesterday with OAT of 83 deg F - should have cooled really
>> well - No Joy!! The water was OK but the oil cooling just does not
>> appear to cool any better after all the duct/air flow improvements. The
>> wedge oil pan did not help either- I guess I did not have oil foaming
>> after all. My oil level in the wedge pan is 3/4 inch below the 1/2 inch
>> aluminum mounting plate. Now I'm wondering if my oil system is too flow
>> restrictive. My oil pressure only reaches 85 psi when the oil is cool
>> and when I'm flying it goes to the lower 60's. Oil pressure is measured
>> on the adaptor plate where the oil returnes to the engine.
>>
>> My oil system is as follows: I come out of the normal oil outlet - (I
>> have not tapped the lower galley and plumbed the oil outlet there) -
>> with an An - 10 line to the Mazda (89?) oil cooler. After the oil
>> cooler, I use An-8 hose from the oil radiator to an aftermarket oil
>> filter housing with the K&N HP 1002 oil filter. From the oil filter I
>> use An-8 hose to go to the adaptor block on the enigne. Two pictures of
>> the oil system are attached. The attached pictures are early pictures
>> before the wiring etc. was in flight ready condition.
>>
>> The oil cooler is clean and I've removed and checked the oil by- pass
>> thermostat in hot water - it opened at or below 160 Deg F. Anyone know
>> of an easy and accurate way to determine if it is working properlly -
>> maybe check temps. at both ends of the oil radiator as the engine and
>> oil heats up. Also, is there an easy way to remove the oil thermostat
>> and seal the bypass hole?
>>
>> <003_3 (Small).JPG>
>> <011_11 (Small).JPG>
>> --
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