Hi Gordon. I hope I'm not too late with this suggestion. It is "cheap and
cheerful"
as the saying goes and furthermore it works! The oil temperature came down
by 20C, without moving anything or cutting holes.
I have a Classic which was converted to a tri-gear and then later had the 80hp
engine replaced with the ULS 100hp. Immediately I experienced the same cooling
problems as you describe, but I didn't want to rush into moving the oil cooler
nor to start cutting holes in the lower cowling, in case such experimenting
didn't work.
At first I made a little scoop which sat above the left radiator and ducted air
coming through the gap between the top of the radiator and the opening in the
cowling, intending to increase cold air flow down into the gap between the
radiator
and the oil cooler. This little arrangement was a failure, but got me thinking
harder.
The real problem turns out to be that after air has passed through the
relatively
widely spaced cooling fins in the radiator, it then struggles to pass through
the tightly spaced cooling fins of the oil cooler. So it takes the easier route
and spills around the sides of the oil cooler. The answer for me was to seal
the 20ish mm gap between radiator and cooler, giving the air no choice but
to pass through the cooler.
Off to Halfords I went and bought a car exhaust repair bandage, which is a strip
of aluminium tape about 50 or 60 mm wide and sticky on one side. I then folded
it over lengthwise to make the tape narrower but still the same length, with
the sticky side outwards. This narrower strip of tape was slightly wider than
the gap and I easily used it to wrap all around the gap between radiator and
cooler, sticking to the cooler and touching the fins of the radiator.
Job done! I live and fly in Aberdeenshire where it's a miracle if we ever see an
OAT above 20C, so I won't claim that my fix is the answer to your prayers. But
I'd be surprised if my solution doesn't drop your oil temperature noticeably.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457551#457551
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