Oil Temperatures

[Ross Richardson]

I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
prop.

My oil temperatures are always low. I pulled the probe and place in in a
can of oil heated to 180 degrees and had a calibrated thermometer beside
it. I marked the meter in the plane so I know where this temperature is.
Even in the summer I cannot reach that temperature. I have the oil
cooler mounted on the back of the rear baffle on the port side of the
aircraft. It has run cool with the old engine and two years ago I
installed a factory overhauled engine. Any ideas why it stays so low.

Ross

[john smith]

Ross Richardson wrote:
> I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
> prop.
> My oil temperatures are always low. I pulled the probe and place in in a
> can of oil heated to 180 degrees and had a calibrated thermometer beside
> it. I marked the meter in the plane so I know where this temperature is.
> Even in the summer I cannot reach that temperature. I have the oil
> cooler mounted on the back of the rear baffle on the port side of the
> aircraft. It has run cool with the old engine and two years ago I
> installed a factory overhauled engine. Any ideas why it stays so low.


Where in the engine are you measuring the temperature?

[Darrel Toepfer]

Ross Richardson wrote:

> I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
> prop.

Hi Ross, can you give any details on who did and how much the
conversion cost?

We have this same airframe with the original O-300D and fixed pitch.

Thanks...

[Ross Richardson]

The probe goes into the Lycoming spin on oil filter adapter.

Ross

john smith wrote:
>
> Ross Richardson wrote:
> > I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
> > prop.
> > My oil temperatures are always low. I pulled the probe and place in in a
> > can of oil heated to 180 degrees and had a calibrated thermometer beside
> > it. I marked the meter in the plane so I know where this temperature is.
> > Even in the summer I cannot reach that temperature. I have the oil
> > cooler mounted on the back of the rear baffle on the port side of the
> > aircraft. It has run cool with the old engine and two years ago I
> > installed a factory overhauled engine. Any ideas why it stays so low.
>
> Where in the engine are you measuring the temperature?

[Ross Richardson]

The plane came with the conversion. Really makes a C-172 fly. I have the
Bush (aka Avcon or Doyn) conversion. No support from Bush of Udall, KS;
I tried when I needed some information when I purchased the airplane.
Airplains and Penn-Yann also do conversions.

Pluses:

much better climb, somewhat more speed

Minuses:

This airframe does not allow (to what I can find) for a gross weight
increase

you still have 36 usable gallons in the tank and therefore shorter legs
if you push the engine. I usually fly at 60% and try to maintain a 4
hour no reserve burn. I plan for 2.5 hours, though.

Ross

Darrel Toepfer wrote:
>
> Ross Richardson wrote:
>
> > I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
> > prop.
>
> Hi Ross, can you give any details on who did and how much the
> conversion cost?
>
> We have this same airframe with the original O-300D and fixed pitch.
>
> Thanks...

[Darrel Toepfer]

Ross Richardson wrote:

> The plane came with the conversion. Really makes a C-172 fly. I have the
> Bush (aka Avcon or Doyn) conversion. No support from Bush of Udall, KS;
> I tried when I needed some information when I purchased the airplane.
> Airplains and Penn-Yann also do conversions.
>
> Pluses:
> much better climb, somewhat more speed
>
> Minuses:
> This airframe does not allow (to what I can find) for a gross weight
> increase
>
> you still have 36 usable gallons in the tank and therefore shorter legs
> if you push the engine. I usually fly at 60% and try to maintain a 4
> hour no reserve burn. I plan for 2.5 hours, though.

Thanks... Sofar we've replaced the wingtips with STOL versions and
its helped with takeoff and climb performance. Haven't cruised with
them yet (just finished it yesterday), but cruise performance before the
change was less than we had hoped for...

They helped the cruise performance of our C152...

[john smith]

Ross Richardson wrote:
> The probe goes into the Lycoming spin on oil filter adapter.

So long as the temperature of the oil returning from the engine is
around 230(?) degrees F, I wouldn't be too concerned. If it isn't
getting over 210, I would wonder if it was getting to all the places it
is supposed to get to.

[Mike Noel]

As a cross check, you might try checking the sump oil temp immediately after
flying by dipping a long thermometer into the dipstick tube.
I have an O-360 A4A in my Archer with a very small oil cooler near the
bottom of the firewall. My problem until lately was too high an oil temp in
summer. At annual I asked my mechanic to check the vernatherm. He told me
it was OK. A bit later I pulled the vernatherm to look at it and saw the
seat on the plunger was not hitting the seat in the oil filter adapter
squarely. I had another mechanic install a new vernatherm and resurface the
filter adapter seat. The engine temperatures now look OK on summer
climb-outs.
I can't imagine my engine running too cold in the summer even with the
vernatherm stuck closed and routing all of the oil through the cooler. But
if it was stuck closed and the OAT was cool and I was running at 60% power,
it might happen.

Here is an interesting discussion of the factors affecting engine oil temp:

http://www.sacskyranch.com/eng18.htm
--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html
"Ross Richardson" > wrote in message
...
> I have a Cessna 172F with the Lycoming O-360 conversion and a C/S speed
> prop.
>
> My oil temperatures are always low. I pulled the probe and place in in a
> can of oil heated to 180 degrees and had a calibrated thermometer beside
> it. I marked the meter in the plane so I know where this temperature is.
> Even in the summer I cannot reach that temperature. I have the oil
> cooler mounted on the back of the rear baffle on the port side of the
> aircraft. It has run cool with the old engine and two years ago I
> installed a factory overhauled engine. Any ideas why it stays so low.
>
> Ross

[Newps]

230 is way too high on a regular basis for oil going to the cooler much
less returning to the engine from the cooler. The generally accepted
number is 180 degrees at the point where most of us are getting our
readings from.



john smith wrote:
> Ross Richardson wrote:
>
>> The probe goes into the Lycoming spin on oil filter adapter.
>
>
> So long as the temperature of the oil returning from the engine is
> around 230(?) degrees F, I wouldn't be too concerned. If it isn't
> getting over 210, I would wonder if it was getting to all the places it
> is supposed to get to.
>

[[email protected]]

Ross

I have a 172M with an O320E2D @1700 hrs TTSN with the same oil filter
system that likewise is cold blooded. My guess is that ours has very
little blowby as the oil also stays clean for many hours after a
change. It has been run mostly on MoGas, so the contamination load on
the oil is low. Does your oil stay clean unusually long too?

Have you tried covering part or all of the oil cooler?

Ours does not have a Vernatherm element installed in the oil filter
adapter - only a plug. Does yours?

My guess is you have a very good break-in. I don't think it is
something to worry about.

The justification for having the oil run above 180 degF though, is
that the dew point of the combustion products is about 180 degF.

[Ross Richardson]

The oil does stay clean between oil changes. I change around 40 hours. I
have about 200 hours on this factory overhauled O-360 engine. I have to
run 100LL in it. I add a quart about every 13 hours. I am going to play
with a winterization plate this winter. I believe the Piper Arrow that
has the same engine configuration has a winterization plate that has
about a inch and a quarter diameter hole in the middle. That seems too
small though.

Ross

" wrote:
>
> Ross
>
> I have a 172M with an O320E2D @1700 hrs TTSN with the same oil filter
> system that likewise is cold blooded. My guess is that ours has very
> little blowby as the oil also stays clean for many hours after a
> change. It has been run mostly on MoGas, so the contamination load on
> the oil is low. Does your oil stay clean unusually long too?
>
> Have you tried covering part or all of the oil cooler?
>
> Ours does not have a Vernatherm element installed in the oil filter
> adapter - only a plug. Does yours?
>
> My guess is you have a very good break-in. I don't think it is
> something to worry about.
>
> The justification for having the oil run above 180 degF though, is
> that the dew point of the combustion products is about 180 degF.

[john smith]

Newps wrote:
> 230 is way too high on a regular basis for oil going to the cooler much
> less returning to the engine from the cooler. The generally accepted
> number is 180 degrees at the point where most of us are getting our
> readings from.

My understanding was 180 in the sump with a 50 degree F increase in the
engine (hence the 230). Maybe I understand it wrong. Doesn't the engine
manual give the specifics?

[[email protected]]

Let me guess - your oil gets gray due to lead sludge, rather than
coffee colored like my 172. You probably have a very tight solid air
baffle system with little gap developing under air pressure loads, the
engine cooling fins are clean, and the alignment of the casting molds
for the heads happened to be very good at the Lycoming factory. All
good things that make for good cooling, and a good piston ring
break-in.

Your oil consumption is higher than mine but acceptable of course. I
get about 30 hours to a quart, and see no increase in consumption
despite the high time. I cruise at lower power settings and try to
keep the cooling system in perfect order.

We bought the airplane when it was new so I'm the only pilot. My
primary concern now is when to major it as a matter of principle. I
doubt I could get back to the present smoothness and oil consumption
even after a major, so barring any changes, I'm still inclined to
leave it alone. Lycoming says to major every 12 years, which would
have put me halfway thru a second major. But really, taken care of,
they seem to run almost forever.

I covered the oil cooler air inlet last winter to get some semblance
of warmth. When the cover was left (forgotten) last spring, it got
warm (but just upper green) fast. Otherwise it usually only can get
to the bottom of the "L" of "oil temp" on the Cessna gage.

I also feel Cessna has a superior baffling system for their Lycomings,
compared to Piper, and especially to Grumman.