Evening All
Think Automotive sent me a drawing of the oil stat with some hand
written annotations. As well as the temperature figures they clearly
marked flow from and to the engine and flow to and from the oil cooler.
On the diagram if you hold the stat so that the 2 screws that hold it
together have their heads at the top, then turn it so that the higher
pipe it to the right. Now the right hand pipes are engine and the left
had pair the cooler. Looking at the diagram the other way round would
have oil pressure pushing up the diaphragm and potentially opening the
stat. I will send a TIF of the diagram off forum.
Regards
Pete
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Richard
Holder
Sent: 24 January 2006 18:04
Subject: Europa-List: Oil Thermostat
Hi team
I am reporting back after further investigation.
To Nigel Graham, the crankcase pressure does return the
oil to the oil tank. Wierd but it does work. However the
oil cooler is NOT in that return. The oil cooler is
between the oil tank and the oil pump, which SUCKS from
the tank, through the cooler. The oil thermostat provides
a by-pass of the cooler - and indeed as the cooler
provides significant restriction to the sucking the
by-pass might well provide MORE oil to the pump. If the
thermostat failed closed then there would be plenty of
oil, but it would get hot rapidly.
I reported on Sunday about my experience. My oil went to
95 in a climb to 2500 feet and then down to 60 in the
cruise on a very cold (2 C) day. Neither was what I was
expecting and so today I ripped the thermostat out,
dropping only a small amount of oil on the hanger floor :-)
I checked the installation and I was happy I had done it
right.
So I brought the wax-stat home and put it in a saucepan on
the AGA. Eventually I found a Celsius thermometer and
tried it. Then I put an elastic band on it to provide a
return spring force. It worked exactly as I expected -
opening at about 73 and being fully open at 80. As per spec.
So I did some thinking, and drew it past Simon Nash who
has part-installed his. We decided that it is likely that
the sealing of the ports in the thermostat has been
compromised by the required drilling out of the ports to
10 mm. If in the hot position the disk that seals off the
by-pass doesn't quite block it off then oil will prefer to
go the by-pass route and not go via the cooler.
I have a "cunning plan" to check on this and I will report
back soon after it is installed and tested. It should
prove the problem of heating up too much in the climb. The
cruise coldness may be a by-product, but I can live with
that for now as it was a VERY cold day when I test flew
it, and I had no baffles whatsoever on the radiators.
In the mean-time - I would recommend anyone who has bought
one of these thermostats to avoid drilling out the ports
until I report back. Or if you have done two ports then
DON'T do the other two.
Another lateral thought - does anyone know if oil coolers
ever have a required direction of flow ?
Richard Holder, who can envisage installation, and then a
further removal and re-installation. In the brrrrrrrr cold !
G-OWWW, High Cross
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20/01/2006
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20/01/2006
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