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Oil Temps too High

kdedmunds

Active Member
I have flown my RV14 for close to 50 hours. Most of that time has been in the winter when temps were a little cooler. On an aggressive climb i would get oil temperatures in the 220s but leveling out I would get back to 180s and could lean the fuel injected IO 390 to about 10 gal per hour. Now Im climbing at 300 ft/min to reach altitude and forget leaning at all. I can keep the temps in the high 190's running the engine at full rich but as soon as I lean I start climbing in temperature. The oil cooler is standard for the engine and I know there are 14's out there that are running with oil temps just fine. Any suggestions?
 
Did you seal your baffle so no air is escaping? There are a number of areas that need filled with RTV.
 
Hi Ed,
For a better comparison with other 14s, perhaps a bit more info would be useful. What are the OAT for those temps and what is the target altitude?

As a reference, my temps have also gone up a fair amount than during the winter time but not nearly as high as you are reporting.
On my last cross country trip, I was able to climb to 12000 ft from sea level at 700-800 fpm with the OAT of 86 but my temp got as high as 212. During slow flight (practice approach) I easily see temps in the 200+ range but if I speed up to the normal cruise speed, it comes back down quickly. My cruise speed temps are in the 185 range unless I am high up and cooler temps.
As mentioned above, make sure all baffles are sealed well including the oil cooler.
I miss my oil temp during the winter time.
 
I really don't think there is anything wrong with those temps. Hitting 220 or so in the climb in the summer is fine, especially since you are getting back into the 180's in cruise. Make sure the quantity is at 6 qts.
I saw the same thing with the factory demos, and the first time I saw it climbing above 210 I was a little concerned, but then I started experimenting with full power climbs to 10K' in the Atlanta summer heat and noticed it cooled right back down very quickly, so I quit being concerned about it. I also think as you get more time on the engine they will come down some as well.

Vic
 
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The IO-390 operator's manual is clear. For maximum engine life, the desired oil temperature is 185F.

No one, including the staff at Vans, would consider this performance acceptable:

Now I'm climbing at 300 ft/min to reach altitude and forget leaning at all. I can keep the temps in the high 190's running the engine at full rich but as soon as I lean I start climbing in temperature.

There is something wrong. Happy to help, but we'll need more information, photos, etc. ID the ignition system and timing, and post a few photos with the upper cowl removed.
 
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Inlets?

I know the 14 has a wider fuselage, so the cowling is from a different mold to allow it to fit - but are the inlets also reworked to allow for the larger engine? If all the other recommended checks and fixes are done, and the temps still are not what they should be - it could be time to add a set of (non-patented) Dan Horton Inlets - sure fixed all temp problems for me!:)

Yes, the plane should be able to climb at ~130KIAS all the way to cruise altitude with no problems.
 
Like Dan said, you have problem(s) to investigate. With a stock setup you should have lower temps. I'd start by looking for obvious stuff, like a blockage in the air going to the cooler. Leave a rag in the oil cooler plenum?

Side note - I have used the Airflow Systems 2006X cooler in two airplanes and recommend them over the one Van's provides in their Firewall Forward kit.

Carl
 
From my Lycoming manual
"Oil Temperature: The maximum permissible oil temperature is 235?F (118?C). For maximum engine life, the desired oil temperature should be maintained between 165?F (73.8?C) and 200?F (93.3?C) in level-flight cruise conditions."

In checking with other RV14 drivers, temps in the 210 range in the steady climb and 185-195 during cruise has been the common temp.
 
During development of the RV-14 (and the FWF kit specifically), flight testing was done in relatively hot temps (90-95 F.) by doing a take-off from 160 ft MSL and climbing to 10K feet at Vy (best rate) for the entire climb, with the aircraft ballasted to gross weight.

The highest peak oil temp I recall was just over 220F. This would occur at some point during the climb and the temp would begin to drop before reaching 10K feet.

Keep in mind that this was a climb to 10K feet using best rate of climb speed for the entire climb. This is not a typical operation mode. Using a cruise climb airspeed has a very small impact on ROC but a very large impact on cooling. If traveling cross country it also gets you down the road more quickly and provides for a higher overall miles per gallon on a cross country trip.
I personally cruise climb (and descend) at 500 FPM unless there are terrain constants.

New engines will tend to run a bit hotter in oil temp. Some engines will have temps continue to reduce further going out beyond 50 hrs, but in this case I would be searching for issues that would be allowing air leakage from the baffle system.
 
The engine does have 250 hours. I bought the plane didn't build it. Last Thursday I was cruising at 6500ft with an OAT of 73. Full rich the oil temps showed 198. I leaned to 10.5 gal per hour and the temps started climbing slowly. I went back to full rich at 215. I will check for leaks as well as air blockage on the oil filter.
 
The engine does have 250 hours. I bought the plane didn't build it. Last Thursday I was cruising at 6500ft with an OAT of 73. Full rich the oil temps showed 198. I leaned to 10.5 gal per hour and the temps started climbing slowly. I went back to full rich at 215. I will check for leaks as well as air blockage on the oil filter.

In that case the engine should be well broken in and not a factor.

As already mentioned, info about other details about the airplane might be relevant.
In particular, what type of ignition system it has and depending on that, what ignition timing profile is being used.
 
High Oil Temp - RV-14 - Break In Flights

I would like to join in on this thread. I have flown my RV-14 twice now and am concerned about high oil temp. IO-390 (1.8 hours), vans oil cooler, dual e-mags. I have the following indications:

OIL TEMP 220-225
74% power, MAP 24.2, RPM 2490, Oil PSI 72
CHTs(1,2,3,4) - 349, 339, 329, 324
EGTs (1,2,3,4) - 1210, 1190, 1230, 1230.
Mixture- Full Rich
4500' MSL, 67F OAT

Baffles have been checked by experienced RV builders and they say they look good. All holes filled with RTV and tight fitting. No cowling mods.

Should i be concerned at this point in break in with oil temps in the 220's? Others i have talked to seem to think this is high even for a new engine. I haven't tested the Garmin oil temp sensor, but i plan on doing that.

Other thoughts or comments would be appreciated.

Thanks
 
At 1.8hrs it's too soon to worry about the temp as long as it is within limits for the IO 390 which is 235 degrees F. Shallower climb or more speed and they should go down some but more time on the engine will cool things as well. As a general rule, most -14s that I know run low CHTs and high oil temps vs other RV models.


I would like to join in on this thread. I have flown my RV-14 twice now and am concerned about high oil temp. IO-390 (1.8 hours), vans oil cooler, dual e-mags. I have the following indications:

OIL TEMP 220-225
74% power, MAP 24.2, RPM 2490, Oil PSI 72
CHTs(1,2,3,4) - 349, 339, 329, 324
EGTs (1,2,3,4) - 1210, 1190, 1230, 1230.
Mixture- Full Rich
4500' MSL, 67F OAT

Baffles have been checked by experienced RV builders and they say they look good. All holes filled with RTV and tight fitting. No cowling mods.

Should i be concerned at this point in break in with oil temps in the 220's? Others i have talked to seem to think this is high even for a new engine. I haven't tested the Garmin oil temp sensor, but i plan on doing that.

Other thoughts or comments would be appreciated.

Thanks
 
Rob,

As your CHTs look good, I’d guess you have the engine timed right and jumper in on the pMags.

For now I would get more hours on the engine and monitor the trend.

As I posted before, I’m a fan of the Airflow Systems coolers over the stock coolers Van’s includes in their FWF kit.

Carl
 
Rob,

As your CHTs look good, I’d guess you have the engine timed right and jumper in on the pMags.

For now I would get more hours on the engine and monitor the trend.

As I posted before, I’m a fan of the Airflow Systems coolers over the stock coolers Van’s includes in their FWF kit.

Carl

Ditto on the Airflow Systems or Real-Deal SW/Meggitt/Troy OC's.

Subjectively and objectively, the oil coolers with the "smooth" end-tanks perform better than their finned - clone - cousins...

I think DanC posted something about this difference some 16-odd years ago...


B
 
Carl, perhaps the one you helped build was an early kit, The FWF parts list from my 2017 shipment shows this.
OIL COOLER 2006X RV-14 13 ROW
And the Vans website shows that part number and description as an Airflow Systems 2006X.
 
My CHT and oil temps were high for a long time until I replaced my Vernatherm. My understanding is that Vernatherms do not get checked during overhauls. My hangar neighbor had a similar issue and found two washers under the vernatherm so it never seated. Just something to check.
 
My CHT and oil temps were high for a long time until I replaced my Vernatherm. My understanding is that Vernatherms do not get checked during overhauls. My hangar neighbor had a similar issue and found two washers under the vernatherm so it never seated. Just something to check.

Vernatherms are actually replacement items at overhaul - but I agree that too many people don’t understand that you only use the hard washer supplied, and nothing else....
 
New 5" SCAT tube

Not sure if Van's has the parts available yet, but in their announcement about the new IO-390-EXP119 they said one of the changes that would be included in all FWF kits going forward (regardless of which engine you choose) will be a larger 5" SCAT tube along with the corresponding aft right baffle and oil cooler shroud fittings where the tube connects on each end. That should flow more air through your oil cooler with corresponding drop in oil temps. Give the mothership a call...
 
Not sure if Van's has the parts available yet, but in their announcement about the new IO-390-EXP119 they said one of the changes that would be included in all FWF kits going forward (regardless of which engine you choose) will be a larger 5" SCAT tube along with the corresponding aft right baffle and oil cooler shroud fittings where the tube connects on each end. That should flow more air through your oil cooler with corresponding drop in oil temps. Give the mothership a call...

although mine seem to be a normal temp for the RV14A, I am very much interested and planning on installing it on mine.
 
Not sure if Van's has the parts available yet, but in their announcement about the new IO-390-EXP119 they said one of the changes that would be included in all FWF kits going forward (regardless of which engine you choose) will be a larger 5" SCAT tube along with the corresponding aft right baffle and oil cooler shroud fittings where the tube connects on each end. That should flow more air through your oil cooler with corresponding drop in oil temps. Give the mothership a call...

My baffle kit was backordered since June and shipped about a week and a half ago. The right right rear baffle was in fact the new 5" model (CB-00015A vs CB00015). Included were the new, larger, attachement hardware and SCAT tubing.
 
Angle Valve Engine Oil Temps

Just a thought as I’ve battled oil temps as well. Most of you know by now that the angle valve engines employ piston cooling nozzles that spray a mist of oil on the bottom side of the piston to cool it. This elevates the oil temperature by 20* in my experience thus the larger coolers that are employed on these engines but generally CHTs stay in check. Think Porsche with 16 quarts of oil and no radiator, oil cooled not just air cooled.
In the Lycoming manual it lists the oil outlet temperature as 190*-210* for ALL their engines. Thanks to DanH’s diagram I can now see that where the temp probe is located on the oil filter adapter is indeed the oil outlet. Now they list the oil inlet temp ( pre oil cooler) as 165*-230*. The 165* is when the vernatherm opens and allows oil to flow to the cooler and 230* seems pretty universal as where mineral oil starts breaking down and losing its ability to lubricate. People get these 2 sets of numbers confused all the time as I often hear 230* used as a redline. This is a mistake if your temp probe is located in the usual location ie post cooler.

Now on the other end I hear pilots bragging that thier oil temps are only 175*-180*. That’s too cold. I believe you need 190* min. to burn off the moisture. With that being said it would seem you would need someway of regulating airflow to keep the temps in that narrow 20* band. If your flying from snow to desert it would seem a shutter would be the obvious solution. I would consider these cruise numbers with short excursions out side the band OK in climb etc.
My two cents and worth about that much !
 
..Now they list the oil inlet temp ( pre oil cooler) as 165*-230*. The 165* is when the vernatherm opens and allows oil to flow to the cooler ....

No.

The vernatherm is retracted when cold, meaning the cooler bypass passage is open. Some oil flows through the cooler, while some flows through the bypass.

When the oil is hot, the vernatherm extends, closing the bypass, forcing all flow to route through the cooler.

Note hot or cold, there is always flow through the cooler.

Now on the other end I hear pilots bragging that thier oil temps are only 175*-180*. That’s too cold. I believe you need 190* min. to burn off the moisture.

Sorry, no basis for your belief.
 
Now they list the oil inlet temp ( pre oil cooler) as 165*-230*. The 165* is when the vernatherm opens and allows oil to flow to the cooler and 230* seems pretty universal as where mineral oil starts breaking down and losing its ability to lubricate.

From my research (inluding a phone call to a Philips Engineer), modern oils begin to oxidize (i.e. break down) significantly at 250-260 degrees. Yes, increasingly higher temps below that level will moderately reduce the life of the oil, but do not create immediate problems with the oil's lubricating properties, unlike what happens at the 250-260 critical temp.

Because of the measurement location, we know that oil in the sump is warmer than the oil measured by the sensor (at least at temps above 200). How much higher seems unproven, but I have seen people here speculate on 20*. Can't remember if that was based on actual measurements. Therefore 230-240, as measured in a lyc, seems like a good and safe redline temp for our engines.

Larry
 
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Lycoming min oil temp spec.

“now on the other end I hear pilots bragging about their oil temps are only 175*-180*. That’s too cold. I believe you need 190* min to burn off the moisture”
DanH “Sorry no basis for your belief”

I will defer to DanH here as I’ve read his work on air oil separators.

“However, there is no shortage of information about exhaust gas constituents , including water content, and the dewpoint calculations can be borrowed from flue gas engineering. The resulting dewpoint appears to be between 125° and 145° F.”
If the dew point calculations are correct the moisture will burn off at much lower temperature than Lycoming specs for the oil temp operating range on their engines but yet they do specify a min oil temp of 190*. I believe Lycoming have established this min temp for sound engineering purposes. I would ask DanH what His thoughts are on the matter.
 
Red line oil temp

Because of the measurement location, we know that oil in the sump is warmer than the oil measured by the sensor (at least at temps above 200). How much higher seems unproven, but I have seen people here speculate on 20*. Can't remember if that was based on actual measurements. Therefore 230-240, as measured in a lyc, seems like a good and safe redline temp for our engines.

Larry

Again referring to the Lycoming manual they spec 230* as max pre-cooler temp with post cooler being 210*. That would seem to indicate the 20* you’ve speculated is about right. I would just get back to my point that if your measuring oil temp in the standard location and you get a reading of 240* you are 30* over redline !! With the oil temp pre-cooler being in the neighborhood of 260* !!

Again I know DanH has measured the temp delta pre-cooler vs post-cooler. Could you share your results ?
 
Again referring to the Lycoming manual they spec 230* as max pre-cooler temp with post cooler being 210*.


I have not seen that reference in the manual, but I don't understand how one could realistically measure "pre-cooler termperature" on a stock lycoming engine with stock lycoming parts. Once the vernatherm is closed (implies the temp is above 185, in normal situations), the oil temp sensor port is downstream from the oil cooler. There is really no place to install another temp sensor, other than fabricating one that would fit an NPT thread.

Numerous Lycoming operating manuals list redline oil temp as 235 and the only real place to measure that temp is post-cooler (this is where Lyc provides you with a place to measure it), therefore the 235 essentially has to be post-cooler redline temp. Lyc can't be providing you with a location to measure the oil temp post-cooler, yet giving you a not exceed temp based upon a pre-cooler measurement. That would be like the govt issuing speed limits based upon RPM (no standardized correlation between RPM and MPH).

Larry
 
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Again referring to the Lycoming manual they spec 230* as max pre-cooler temp with post cooler being 210*. That would seem to indicate the 20* you’ve speculated is about right. I would just get back to my point that if your measuring oil temp in the standard location and you get a reading of 240* you are 30* over redline !! With the oil temp pre-cooler being in the neighborhood of 260* !!

Again I know DanH has measured the temp delta pre-cooler vs post-cooler. Could you share your results ?

Considering the fact that Lycoming knows where the oil temp sensor is located, it begs the question why they did not account and adjusted the max oil temp in their manual if in fact oil will lose all its lubrication properties at 235F.

Or is it possible that they recommend this max oil temp based on location that is being measured and that 235 is not the temp that oil will lose its lubrication properties. My manual for the IO390 does not have any info about post or pre oil cooler temp. It only indicate that the max (red line) is 235 and for maximum life it is recommended to keep between 180-200F
 
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If the dew point calculations are correct the moisture will burn off at much lower temperature than Lycoming specs for the oil temp operating range on their engines but yet they do specify a min oil temp of 190*.

They do? Show us the document.
 
Table 9-1 Engine Run-In Test Limits

I don’t subscribe to a photo hosting site so can’t use the embedded image hosting feature.
I’m getting my info from the Lycoming Overhaul Manual Section 9.

I can email a screenshot of the page to someone who has a photo hosting site but I suspect DanH has this manual and is coaxing me to the cheese ready to spring the trap !
 
Inlet Temperature?

RV8JD posts an excerpt from an IO-360’s operating manual which gives the max oil temperature as 245* but that brings me back to my original point:
Isn’t Inlet Temperature pre-oil cooler ? If That is not the case then my whole point falls on its face.
When I run engines on the test cell we have probes monitoring both inlet and outlet temps. Lycoming is always specific about temp limits being Inlet temps. So is the probe mounted in the oil filter adapter reading oil outlet temp or inlet temp ? I think it’s reading oil outlet temp. ie post cooler but the point made about publishing oil temps that are not monitored in the standard probe location is well taken.
 
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I’m getting my info from the Lycoming Overhaul Manual Section 9.

No trap. Always interesting to see what folks dig out of Lycoming and Continental documents.

You're evidently referring to Table 9-1, attached. It's a list of preferred conditions for run-in on a test stand.

Isn’t Inlet Temperature pre-oil cooler ? If That is not the case then my whole point falls on its face.

Pretty sure inlet and outlet, in the context of Table 9-1, refer to test cell external oiling, per SB113, also attached.

When I run engines on the test cell we have probes monitoring both inlet and outlet temps.

Cool. Where are they installed?
 

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I can email a screenshot of the page to someone who has a photo hosting site but I suspect DanH has this manual and is coaxing me to the cheese ready to spring the trap !

Nah, I've spent just enough time with Dan to know he doesn't bite and IS old enough to kindly give you a shoulder nudge away from the deep end if you'll budge. Good conversation!
 
This example snippet is from the Lyc (I)O-360 Operator's Manual. The Desired and Maximum temps are specified as oil inlet temps.

i-HmLh3QS-N.jpg

So, what is "oil inlet temperature?" This is an operators manual, so geared towards pilots and mechanics, not just overhaul shops and dyno operators (I understand that they have access to inlet and outlet temps). I think I understand what they meant by this phrase, but the average pilot and mechanic have access to only one temperature reading on their engine (post-cooler). Shame on Lycoming if they provided a specification that doesn't align with the reading taken at the spot that they provided and specified for measuring oil temp. I don't see how you can specify an inlet temperature max, yet only design and account for a method of measuring outlet temp. How is it helpful to know the max inlet temp, when I have no means to measure or display the inlet temp.

I am still not convinced that inlet temp means pre-cooler, though it probably does, given that oil coolers are not required and when left out, the stock measuring location will read what would match a pre-cooler reading.

In the end, if there is about a 20* delta from the sump to post cooler, I still don't believe that 245 will create many issues if the time spent there is limited. I would be concerned over any significant time running at that temp.

Larry
 
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Inlet vs Outlet Temp

Larry your concerns mirror mine. The last thing I want to do is mislead anybody. In that regard I have talked to 2 of the sharpest Lycoming guys I know and they aren’t sure how Lycoming defines inlet vs outlet temp either. I’ve called Lycoming Factory Support and they didn’t know ! They said they would run it by engineering and get back to me. I’ve also left a message with the Lycoming field rep. Between all of that a definitive answer should be forthcoming.
DanH refers to an obsolete SB that discusses a dry sump test rig that heats and cools the oil for oil consumption runs Which may be the basis for the oil outlet temps. If that’s the case we need to come up with an award for obscure knowledge here on VAF ! Rest assured since I opened this can of worms I will get the definitive answer.
 
Obscure? Hardly. The run-in chart is page 9-2. SB113 is referenced in the first paragraph on page 9-3.

When I run engines on the test cell we have probes monitoring both inlet and outlet temps.

So where are you locating the temperature probes?
 
Oil Temp Probes

Obscure? Hardly. The run-in chart is page 9-2. SB113 is referenced in the first paragraph on page 9-3.



So where are you locating the temperature probes?

Snap goes the trap !!

Obscure as in printed in 1945 and revised in 55. The test cell operator that I work with hadn’t ever heard of the dry sump rig and the one tech I talked to at Lycoming hadn’t heard of it either but I’ve got inquiries out to older tech reps.

As an aside some of the old guard are turning in retirement packages related to the Covid disruption. Going to be a shame to loose their vast body of knowledge and experience.

In frustration I watched videos of Lycoming’s test cell and couldn’t see the dry sump rig utilized there either. I haven’t spoke to anyone yet who has seen/used one but I haven’t quit trying.

On the issue of temp probes I was reminded by my friend who runs the test cell that as set up it runs 2 oil pressure probes (to determine interior leakage) and only runs multiple probes on oil temp when there chasing cooling issues which was the case with one of the 0-360’s I built.Then it’s set up with a probe near the filter canister which would be the traditional location and then an additional probe measuring oil temp on the inlet line to the cooler and sometimes a third immediately after the cooler. He shared some info on one of the tests with a 9 row cooler. They were only seeing 12* delta across the cooler with a flow rate of 7-8 Gallons per minute. We also tested changing the max oil pressure from 90 psi to 70 psi and found that lowered oil temps by approximately 15* !! I had forgot about that. They use a manometer to measure airflow as well but don’t recall the pressure drop.
So until I get a response from Lycoming I can’t definitively say what the oil inlet vs outlet temp is referring too. I’ve made enough assumptions and when your self taught you can be in an information vacuum but interestingly those that do this as a full time profession don’t know either at least so far.

Now, DanH sounds like you know more than your sharing so please come clean.
 
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...and only runs multiple probes on oil temp when there chasing cooling issues...

Ok, usual probe in the filter adapter location plus, sometimes, one in the line to the cooler.

He shared some info on one of the tests with a 9 row cooler. They were only seeing 12* delta across the cooler with a flow rate of 7-8 quarts per minute.

Gallons per minute, unless the vernatherm was cold/retracted.

...I hear pilots bragging that thier oil temps are only 175*-180*. That’s too cold. I believe you need 190* min. to burn off the moisture.

Which returns us to topic. Table 9-1 doesn't address water, and anyway, water will evaporate at room temperature. Forget in and out.

The key variation with temperature is vapor pressure, 464 mb at 175F vs 645 mb at 190F, a 28% increase. It's not insignificant, so no one is wrong in thinking the higher temperature boosts the evaporation rate of water emulsified in oil, or liquid water clinging to parts.

However, note it's a change in rate of evaporation. Water evaporates (changes phase from liquid to gas) just fine at 175F. It merely takes a little longer to transition a given quantity of water as compared to 190F. So if the goal is getting all the cold engine's condensed water into vapor and out the breather, a pilot with 175F oil temp needs to fly a few more minutes.

It's good work if you can get it ;)
 
It's worth knowing that the dew point of gasoline exhaust (at stoichiometric) is about 127F. Meaning, until the oil temp passes above that temperature, water is condensing onto the oil from the bypass gases. Any oil temperature in the guts of the engine that is above that approximate temperature is driving water out, and, of course as Dan and others have mentioned, it is then only a matter of rate and time. And, water in oil doesn't instantly rot your engine out; rather, as in so many things, concentration and time are big variables. I do not know the chemistry of all of this, but I'm guessing it's quite well known.
 
Edit: Nevermind the below. I studied an accessory housing more carefully and my takeaway at the bottom is incorrect. The temp sender does measure what goes into the engine after cooling. My vernatherm must be leaking substantially to get the engine inlet temp so close to cooler inlet, and could explain why such a big deltaT in the cooler inlet/outlet.


With all this confusion as to oil temp measurement [looks like me included!] , I figured it would be a good idea to get out the bluetooth temp probes and actually characterize what my engine's doing in flight (angle-valve 360). I placed probes on the inlet and outlet of the (SW 10599) cooler and monitored what the oil temp reading on my EFIS was. At 2000' and 150 KIAS at 2200 rpm and OAT 81F, flew 2 different days and got:

205F oil cooler inlet, 185 outlet, and 200 EFIS-indicated (which is probably within acceptable range of the Garmin-supplied thermistor).
First flight I got 201/174/196 indicated, but was playing around with cowl flap settings on both days.

So the takeaway is the oil temp sender sees sump-temperature oil before it goes to the cooler [NO]. The cooler drops 20-25F deg depending on cowl flap setting.
 
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205F oil cooler inlet, 185 outlet, and 200 EFIS-indicated (which is probably within acceptable range of the Garmin-supplied thermistor).
First flight I got 201/174/196 indicated, but was playing around with cowl flap settings on both days.

So the takeaway is the oil temp sender sees sump-temperature oil before it goes to the cooler. The cooler drops 20-25F deg depending on cowl flap setting.


The likely explanation is your vernatherm isn't sealing the bypass hole.
 
The Definitive Answer !!

Below my correspondence with Lycoming:

Hello,
In section 9 of Lycoming’s Overhaul Manual for Direct Drive Engines, there is a Table 9-1 titled Engine Run-In Test Limits. In that table you give 2 sets of values for Oil Temperatures, Oil Inlet Temp and Oil Outlet Temp. I can not find any reference to define their difference. Is the temp probe located in different positions for each ? I’m ASSUMING oil inlet temp is pre oil cooler and oil outlet temp is post cooler but haven’t found anything in the record to document this definition. Any help ie reference that would clarify this would be most appreciated.

Thanks for your help
David Duffer
Duffmiester Airmotive


Hello David,

Table 9-1 Engine Run-in Test Limits is based off of a test stand that Lycoming at one time recommended using in a now obsolete publication. For anywhere but a large shop that does engineering r&d work it would have been overkill have the stand they specified. The oil inlet temp reading would be taken off the accessory case where oil temp is normally read. The oil out temp would be taken from the oil exiting the engine, the closest you would be able to come to this would be by reading the temperature of the oil in the sump, if using a normal test stand.

Thank you,

Brandon Dildine

Field Service Technical Representative
Lycoming Engines, an unincorporated operating division of Avco Corporation


I made an erroneous assumption based on DanH's oil flow schematic and Lycoming's reference to two oil temperature values. My sincere apology for the mis-information.
I find it illustrative that table 9-1 is based off of a 1945 test stand defined in a "now obsolete publication" ( SB #113) and yet it is still carried in the current versions of Lycoming's Overhaul Manual. Not sure how to explain that. In my opinion they should drop the "oil inlet" label from their oil temp limits in current literature to avoid the confusion.
 
So. to clarify, by inlet, they mean inlet into to the filter/distribution structure and not the cooler? That was what I read from that note and makes sense to me, as I expected the 245 max to be based upon a measurement at that std temp measurement location.

Good to have the mystery solved.

Larry
 
In my opinion they should drop the "oil inlet" label from their oil temp limits in current literature to avoid the confusion.

I suspect that the "oil inlet" term is ignored by just about everyone but you and a few others. No one else has seen that test rig and could not comprehend what the term "inlet" could mean, as there is not apparent "outlet" that could reference any different reading. I know that I ignored it; I saw it, but could make no sense of it's reason for being there. At least until this thread showed the test rig details.

Larry
 
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I monitor the oil temps in three spots. The sump, the cooler output and the filter adaptor. I see oil temps in the sump run ~ 230 to ~ 245f. Temps at the cooler output run ~ 185f and temps at the filter adaptor run ~ 180 to ~ 220f depending of flight and OAT. I've replace the adaptor and vernatherm a few times. I run a 13 row Harrison, NACA scoop ducted to the cooler. Injected O-360 10:1, dual EI's no squirters. The odd part is I used to use a VM1000 and my oil temp at the filter adaptor read lower then with the new MGL iEFIS and Westech sensor. I've tried 2 sensors to make sure it's right. There's a theory that the sensor length could have an effect on the oil temp reading, reading closer to the sump oil temp and less at the cooler return temp which are close to each other in the adaptor.

Good reading here: https://vansairforce.com/community/showthread.php?t=45548
 
I monitor the oil temps in three spots. The sump, the cooler output and the filter adaptor. I see oil temps in the sump run ~ 230 to ~ 245f. Temps at the cooler output run ~ 185f and temps at the filter adaptor run ~ 180 to ~ 220f depending of flight and OAT. I've replace the adaptor and vernatherm a few times. I run a 13 row Harrison, NACA scoop ducted to the cooler. Injected O-360 10:1, dual EI's no squirters. The odd part is I used to use a VM1000 and my oil temp at the filter adaptor read lower then with the new MGL iEFIS and Westech sensor. I've tried 2 sensors to make sure it's right. There's a theory that the sensor length could have an effect on the oil temp reading, reading closer to the sump oil temp and less at the cooler return temp which are close to each other in the adaptor.

Good reading here: https://vansairforce.com/community/showthread.php?t=45548

What kind of sensor are you using to read the oil temp at the sump?

I tried to compare my oil temp at the sump to the oil temp reported by the sensor and consistently got lower oil temp at the sump. My procedure was to run the engine with the cowl off and get a sample of oil quickly right after shut down at different temp. At all different oil temp, I was getting a lower temp measuring the actual oil (about 2 oz) drained from my quick drain.

I have tested my oil temp prob and it is pretty accurate within 2-3F
 
What kind of sensor are you using to read the oil temp at the sump?

I tried to compare my oil temp at the sump to the oil temp reported by the sensor and consistently got lower oil temp at the sump. My procedure was to run the engine with the cowl off and get a sample of oil quickly right after shut down at different temp. At all different oil temp, I was getting a lower temp measuring the actual oil (about 2 oz) drained from my quick drain.

I have tested my oil temp prob and it is pretty accurate within 2-3F


The iEFIS allows for multiple sensors to be displayed on the screens. One of the default sensors in the setup are Westech temp sensors. I installed a sensor at the oil screen, it's a low part of the sump and reads the oil before it goes to the pump. I believe it's a good spot to measure the hot oil in the sump. I'm sure an analog oil temp gauge and sensor installed at this same point would give accurate reading.
 
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