I forgot to mention, that I will check my oil temp sender and gauge. But I have no

reason to

believe they are inaccurate. It indicates exactly 160F during a long descent and on the
ground taxiing back to the hangar after flight. This is the temperature Mazda specs for

the

oil cooler thermostat, I believe. If I am in error somebody please let me know. If my

oil

temp gauge happens to be off by 20F at 230F indication, then problem solved!

Perry

How are the duct pressure measurements coming? Can you use some more help this coming
weekend?

Paul Lamar

Perry Mick wrote:

Are you going to be back up here this weekend? I sealed the exit duct a
little better. I'm now getting big suction at the rear again, but it is
not equal across the length of the oil cooler. I saw 9" of suction
yesterday at the rear but it drops to very little at the front. When the
louvers were in there it was more equal accross the length of the cooler.

It appears now that the oil cooler is getting good airflow so the high oil temp must have

some other cause.

Perry Mick

I could if you think I can help. I'll bring my Mavica.
Hard to say about putting the louvers in. My guess is the front of the
exit scoop is too close too the back side of the oil cooler.

Have you tried the pressure tap on the strake surface just behind
the oil cooler exit duct out let?

I think I have a self contained thermocouple
gage around here with a remote meter read out we might be able to use.
We could tape the thermocouple to the oil fittings with red RTV tape.
Yes I do. Here is a picture. I used it in the early 70's to
take the  temperature distribution on race car tires.

Unfortunately the probe cable is only three feet long.

Does anybody in the area have a spare CHT gage and thermocouple
they could loan us? I also have the EGT gage out of my Cessna as
I replaced it with a scanner. No thermocouple for that however.

Have you tested the oil cooler sensor by boiling it in water?

BTW I am not clear on something.
Are you using the oil thermostat in the oil cooler?

Paul Lamar

Yes I am using the oil thermostat. I only removed it briefly, but
didn't like the fact that oil temp would run too cool on long
descents. It makes no difference on the "hot" side.

There is some evidence that my oil temp gauge is indeed in error.
I always thought the oil thermostat was 160F, but that must be
because that is what my gauge told me. The '86 Mazda shop manual
says "oil cooler relief temperature 140-149F".

Even though it's been a source of frustration, hopefully that
is all it is. If it had to be in error, I'm glad it was on the
conservative side. It forced me to build probably the best
possible inlet and exit ducting for my configuration.

So I will be checking that darn thing in the next day or two,
and hopefully there is an adjustment to set it correctly.

Hold off on plans to come up this weekend, the wife may have
other plans. Are you going to Arlington? It is the following
weekend.

Perry

OK. We would also probably have a problem with Mikey. Our baby sitters
are probably out of town.

Take a hot plate to the hangar and stick the sensor in boiling water.
A coffee cup heater might also work.

Paul Lamar
 
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