The Murphy Builders Site

I have an oil filter installed in line with the oil cooler. Just go to
your local VW specialty shop and get an oil filter bracket for a bug. The
filter holds almost a litre of oil so the increased capacity will help too.
Drew Dalgleish

-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of
Drew Dalgleish
Sent: Sunday, July 20, 2003 9:17 PM
To: murphy-rebel@dcsol.com
Subject: Re: The fun of temps


At 11:11 PM 7/20/2003 -0400, you wrote:

Hi all, just thought I'd finally drop a

line to all on the fun and games
I've been having.

I have had similar problems to Walter

as far as oil temps are
concerned, and as we are both running very
similar setups, 0-320's with
150hp conical mnts. and Bobp's beloved speed
cowl. I am still running the
warp drive prop with a dampner. I've watched
carefully along with trying
stuff of my own, so here goes.

When on the wheels the oil temp was

not a concern, cht's were.
Opening the bottom of the cowl up and
cleaning up the exit around the
firewall flange, adding a 1" lip to the
front/ bottom of the opening,and a
learning curve on the readings you want from
a thermocouple under the
sparkplug cured that.(See the archives for
those details.

Once I began the float flying, I began

to have to pay close attention
to the oil temps. It actually was kind of a
slow increase, not a " you did
this and this happened" sort of thing. I
really noticed it last year on the
way to and back from the big "OSH" last
year, and it was evident on the
long climb for altitude over the big water.
It was a very hot time last
year, and I figured that had an impact. Now
this year. Most of my flying is
vey short hops, lake to lake for sunset,
stopping to harrass friends and
the like. Lake ops were fine. I began to
notice if I cruised at 2450rpm for
more than 1/2 hr the temps would begin to
rise. Were talking in the 215f
range, and even with slowing rpm's and
running the mix fat it would not
cool. A couple of times i streched my stops
to allow for some cooling
before I departed. Doing multiple tkof's and
landings didn't seem to cause
the temp to rise as much but it would rise.

So I went and tried somthing different.

My longeze buddies have found a
bilge blower that they were using to try and
move heat up to ther toes.
Nice 3" dia and explosion proof. I took me
about 45 min to adapt it to my
setup. The result was I had no problems with
short hops and on the lake it
was never above the 190f it had been on the
wheels. So I took it for a nice
long ride of about 1.5hr with a long climb.
The result? The long climb
temps were worse! Now do give me a little
credit, I had some suspisions
that the fan blades and motor could block
the tube, but what the heck it is
and experimental.

Now during the installation I had fired

up the fan on the ground and I
noticed that I really got alot of air
bleeding by the shroud to cooler
space and I had siliconed the gaps shut
then, stopping the blow by. I
really didn't think it was that much but it
was to much none the less.

So with those results the creative

juices began to go(read I was
forgetting to keep it simple). Maybe a
shroud to get the airflow closer to
the cowl outlet. Maybe with a cowl flap!
Maybe I need to open the cowl
more. and so on. Enough of the long winded speach.

I removed the blower. I found a little

better routing for the scat
tube. And I took some advice and pulled the
vernotherm for checking. Seems
the eze's have been having the same oil temp
problems on long climbs and
found that to be a culprit. Well I did find
some carbon junk around the
vernotherm and some signs of it not seating
properly, so I cleaned it very
well and reinstalled it, figuring I'd get
the right poop on dimensions if
the problem persisted. I am not running an
oil filter YET, but I will be
soon although I now feel one should remove
the vernotherm and clean it
with the oil change too.

Results? well, the air temps have been

cooler here,75f or so, but my
first flight had the temps at 175f! Barley a
budge on a 1/2 hr climb!
Almost to cool! I think I'm looking forward
to a much warmer day to give it
a try! That will probably be on the way to
OSH again!

Theory? Keep the scat tube arch as clean

and smooth as possible. Close
all holes and gaps around the shroud to
cooler. Make sure your vernotherm
is operating correctly and completly. KEEP
IT SIMPLE!

Well that's my disortation for now. Next

time it will be on the STOL
kit. Hope this was fun reading, KEEP AT
It,it is worth it! Curt N97MR


Hi Curt
I had similar problems with my oil temps
until one of the local mechanics
told me about the experiments they'd done on
a pitts special. The only oil
cooler location that worked for them was to
mount directly to the rear
baffle. I mounted my undersized antique
brass cooler from a ? in the same
place and ended up with acceptable temps
while on wheels. I also wrapped my
exhaust with ceramic header tape which also
lowered my oil temp. When I
mounted my plane on floats I changed the oil
cooler to a proper sized one
and now even on the hottest days of the year
the highest I've seen is 185
degrees.
I have an oil filter installed in line
with the oil cooler. Just go to
your local VW specialty shop and get an oil
filter bracket for a bug. The
filter holds almost a litre of oil so the
increased capacity will help too.
Drew Dalgleish




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