High Oil temp

[jatkins]

I have gotten my 1952 C-170B ser 20292 CF-HER , flying again after 5 years and 2 months ( but who is counting ).
It has a "O" time SMOH O-300D engine. She flies straight and level hands off and the stall horn is even spot on.

The only issue is the oil temp. I have almost 3 hours on HER, the OAT is around 20 c , here in southern Ontario.
Today I flew about 20 miles notrh @ 3500ft and then back to the airport, and the oil temp indicates about 1/4 inch from the red line. Any suggestions / recommendations ? I have searched High oil temp, and see lots of talk about the blast tubes ?
I am runnning with 6 1/2 qts of aeroshell 100 mineral oil. I am aware that the oil temp probes have 2 slightly differance
flanges at the bulb , and they are not interchangeable.I saw lots of people recommending testing the temp probe , are these a high failure item.

Lastly I do have an F & N ol filters adapter.

[jrenwick]

You could go a couple of different ways on this. One: since Cessna didn't put any numbers on the oil temperature gauge, they seem to be saying that oil temperature varies a lot, and as long as it's below 225 degrees F (the red line, according to the AFM), it's OK. Nobody knows what temperature 1/4" below the red line is, but it's in the green, so be happy! You could stick the probe in boiling water to be reasonably sure the gauge isn't whacked, and then you'd have one reference point fairly close to the red line. Once you believe the red line is reasonably accurate, then it becomes a job of managing your oil temperature during climbs to keep it below the line.

The other approach is to add an electronic gauge. I did that, and I find the oil temperature warms up to anywhere from 140 in a Minnesota winter to 195 or so clawing for altitude over the high plain north of Denver in July. All of those temperatures are fine, except that I'd like to see 180 or better all the time, and I just can't get it to warm up that much in the winter.

You'll probably have similar results in Canada. Right now, you seem to be heating the oil enough to remove most of the condensed water, and that's a good thing.

[GAHorn]

jatkins, did you red my article about high oil temps in The 170 News, (Vol 40) 1st Qtr 2008 issue?
It answers your questions.

[Bruce Fenstermacher]

Well 1/4 below the red line seems about right to me. In fact some might say your oil temp seems a bit low if you where in Texas.

Remember your engine is not broken in yet and will run a bit on the hot side till it is so under the same conditions in a few hours you may see it 5/16" below the red line.

I'm not saying that you shouldn't be sure your guage is reading correctly and that you shouldn't make sure the blast tubes are pointed correctly.

[jatkins]

Thanks to ALL for responding.

N9149A ,
I will confirm my blast tubes are correct and adjust . I am concerned that in the hot weather the temp will become unmanageable. What sort of time would the engine start to loosen up and possible cool down some ? 15 hours ?

George ,
I did go back and re read the high oil temp article. I had missed the change in the new oil temp limit as now being 240 vrs 225. I have a 225 guage installed. I have a Scott guage with numbers on it , 100 to 250, which I just tested, in boiling water and it went to 210.
It has the flat mounting surface on it. I seem to recall my engine adapter , has a conical flange.
Any idea of where I can get the correct adapter to go into the engine , that will take this guage with the flat flange ?
Also what the part number might be ? I want to go ahead and install this guage as it has much better markings on it
( numbers ).

In the mean time I am going to look very closely at the blast tubes,inspect for any exhaust leaks , and then fly it again this evening.

jrenwick ,
My temp gets to the middle of the green by the time I get to 1000 agl ( 1500 ASL ) and by the time I get to 3000 ASL or so climbing at 80 IAS it is 80% up into the green arch. If i level off and cruise at 2450 RPM for 10 min it gets to 1/4 inch from red , so then in fear of having a problem or doing damage to my engine, I head back to the airport and land.

I really doubt I could get it to more the 4500 ASL which would be 4000 AGL without the temp getting into the red ???
I am certian I am heating the oil enough to get all the moisture out of it ! !


Also I am at 6 1/2 qts of oil , should I put it up to 7 or 7 1/2 qts ?


Thanks ALL Again John

[jrenwick]

Jatkins,

8 quarts of oil in the sump will absorb more heat than 6, so it should cause the temperature to rise more slowly during a climb. That might allow a longer climb without overheating the oil. For breakin, I think I'd fill it right up to 8.

You didn't mention what power setting and airspeed you're using for climb, and of course those things will influence oil temperatures (and cylinder head temperatures!). I like to throttle back a little for extended climbs, and keep the airspeed up (even if I have to tell ATC that I can't maintain 500FPM ).

Do you have a CHT gauge? If you think the engine is running too hot, that would be a really interesting data point to have. I have CHT on all 6. #2 is always the hottest, at about 360-380 degrees in the cooler weather we're having now.

[GAHorn]

Whomever supplied your Scott gauge to you should be capable of providing the correct adaptor for it. (And they should happily do so without charge.)

The recommended climb power setting for the standard engine/prop is FULL THROTTLE, not partial power. The carburetor on this engine has a fuel enrichment circuit to provide additional cooling during full throttle climbs. Reduced power climbs will INCREASE heat which must be absorbed by the engine oil.

[jatkins]

Yup ! FULL throttle, and of course Full Rich mixture.

No idea where this Scott oil temp guage came from ?
I traded my old panel cover and some other stuff ?
I was looking at Spruce ,...OIL TEMP BULB ADAPTER #95527
looks like it might be the item ? any idea ?

John

[Bruce Fenstermacher]

John, 15 hours should be enough to break in the engine and see a slight reduction in heat from the first start.

You can run your engine all day long at 225 degrees or 240 degrees with straight 50 weight (100w) with out hurting it. If I landed every time my oil temperature got within a 1/4 inch of 225 I'd never be flying. I run 50 weight so when it gets to 225 I start to monitor the temperature a little closer.

Be sure all is working as it should which your engine seems to be and go fly and stop worrying.

Like George said or intended to say. The oil phrobe and the adapter are a matched set and sold together. You won't know for sure if the Spruce adapter wiill work till you get it and try it. You may however call them and ask them to look at it and discribe it to you before they send it.

[GAHorn]

You may have to obtain one of each, and select the properly fitted one after close inspection. (The actual PN may be the same for both, unfortunately.

[jatkins]

I will call and see IF I can explain it over the phone to Spruce, or if not order both like you suggest .
I am going to head over to the hangar shortly to prefflight HER , and take HER out again, as tomorrow I go to British Columbia for the weekend and California, for most of next week with out HER !

[jrenwick]

....The recommended climb power setting for the standard engine/prop is FULL THROTTLE, not partial power. The carburetor on this engine has a fuel enrichment circuit to provide additional cooling during full throttle climbs. Reduced power climbs will INCREASE heat which must be absorbed by the engine oil.

Oops! Thanks, George!

John

[jatkins]

I spoke with AC Spruce , they gave my Rochcesters phone # 972-241-2161, customer service seemed very helpful and will call me back to confirm the inside flange , flat or conical. The new part number is now 0044-00571.
vrs the old one 44-0024 which AC Spruce still uses.

Parts Pacific , 310-900-0440 and the adapter part number 95527 they sent me a drawing ( dated 9-27-56 ) it looks like the correct part .
I attempted to attach it but seems the file is too large

[GAHorn]

Based upon the date of the drawing, it must be the OLD OBSOLETE part dwg.

[jatkins]

That part number from Parts Pacific , is still used by them and by AC Spruce pn 95527 ,
it is a Steward Warner drawing.