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  #21  
Old 09-08-2020, 11:22 PM
czechsix's Avatar
czechsix czechsix is offline
 
Join Date: Mar 2006
Location: Spring Hill, KS
Posts: 376
Default 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...
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RV-8A N2D #80583 - built/flew/sold
RV-14A #140017 - wings complete, empacone in progress...
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  #22  
Old 09-09-2020, 12:27 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,494
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Quote:
Originally Posted by czechsix View Post
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.
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Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - Flying
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  #23  
Old 09-09-2020, 07:55 AM
ShortSnorter ShortSnorter is offline
 
Join Date: Dec 2013
Location: NOLA
Posts: 270
Default

Quote:
Originally Posted by czechsix View Post
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.
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  #24  
Old 09-09-2020, 10:00 PM
theduff theduff is offline
 
Join Date: Jan 2012
Location: Fallbrook Calif.
Posts: 309
Default 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 !
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  #25  
Old 09-10-2020, 07:42 AM
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DanH DanH is offline
 
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Location: 08A
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Quote:
Originally Posted by theduff View Post
..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.

Quote:
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.
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  #26  
Old 09-10-2020, 08:11 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by theduff View Post
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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Last edited by lr172 : 09-10-2020 at 08:16 AM.
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  #27  
Old 09-10-2020, 12:07 PM
theduff theduff is offline
 
Join Date: Jan 2012
Location: Fallbrook Calif.
Posts: 309
Default 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.
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  #28  
Old 09-10-2020, 12:23 PM
theduff theduff is offline
 
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Location: Fallbrook Calif.
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Default Red line oil temp

Quote:
Originally Posted by lr172 View Post
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 ?
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  #29  
Old 09-10-2020, 01:40 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by theduff View Post
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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Last edited by lr172 : 09-10-2020 at 02:06 PM.
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  #30  
Old 09-10-2020, 02:01 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,494
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Quote:
Originally Posted by theduff View Post
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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Last edited by Bavafa : 09-10-2020 at 02:03 PM.
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