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07-26-2011, 07:14 AM
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Join Date: Mar 2005
Location: St. George
Posts: 973
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RE: I will cut
Hi Sonny
Along with an adjustment to the oil pressure regulator adjustment screw (I need an appropriate name for this). I am going to make a forward cut on the lower cowl exitt tunnel and lower it a couple of inchs. Hopefully this will increase the airflow and thus lower the oil temps.
The only down side it get out the paint gun!!!!!!!!!!!!!!!
Frank @ 1L8 ...RV7A... Flying Kinda
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07-26-2011, 08:31 AM
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Join Date: Nov 2006
Location: Cumming, GA
Posts: 610
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oil temp sender
I had oil temp issues. Ultimately in my case, it required replacing the vernatherm and switching to a new 2-wire oil temp probe, which is less sensitive to electrical interference in the system. The vernatherm was marred and probably sticking a bit. As for the probe, I learned about the 2-wire probe because others have had similar issues with the 1-wire. (I found no grounding issues in an exhaustive search, nor did I have any other probes acting up.)
I have AFS-EMS, and they support a couple different 2-wire probes, and they supplied special calibration instructions to use them. Since replacing the vernatherm and switching to the 2-wire probe, my oil temps are rock solid +-187F.
Good luck.
__________________
Don Hall
N517DG - RV7 - Flying!
Ticked Van's Hobbes meter at #6110, 3/7/09
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07-31-2011, 05:16 PM
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Join Date: Nov 2006
Location: Boise, ID
Posts: 1,095
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Update
OK, still trying to pin down the high oil temp issues. The OAT today was about 5 degrees warmer than the last time I flew, and apparently I got my oil temps down a couple degrees. Not great, but at least going in the right direction. I actually peaked at 218 degrees (F), but I was running the engine a little harder and it was a little warmer outside, so I thought I may have made things "better" by trimming the gasket which was blocking my Vernatherm from fully seating.
So, I'm still looking for alternatives because I don't want to cut holes in my cowl for the louvers. My hangar neighbor had an oil filter cooler that he's going to let me borrow to see if that helps. Has anyone used one of these, and do they work? He also mentioned putting a blast tube on the filter. What do you all think?
Last idea for the day...ECI recommends Phillips 20/50 X/C pretty much year 'round. Would going with 100W help oil temps?
Just as an idea of how I was flying today, here's a picture of my EFIS with all of the flight parameters.

__________________
Sonny W
Boise, Idaho
RV-7A Flying!
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07-31-2011, 06:57 PM
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Join Date: Aug 2006
Location: Twin Falls, ID
Posts: 683
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OAT 83 degrees and 197 oil temp. Not all that bad. I'd love mine to run that cool. Cyl head temps are a little high, might look at that. When I run lean of peak my CHTs come down 40 degrees and oil temp 10-15 degrees. Your oil pressure is a touch low 75 would be better. Don
__________________
RV 7 N212MD Flying as of 12/22/2007
Backcountry/TCOW Super Cub flying 03/12/2011
Next project?
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07-31-2011, 07:58 PM
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Join Date: Sep 2009
Location: St. Louis, MO
Posts: 1,788
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How many hours on your engine since new cylinders? New cylinders will run hot for the first 10-20 hours.
To make sure your oil cooler is actually working, I would plug up the inlet air and see what it does to your oil temps.
Do you have a return ground from the engine to the airframe?
Have you calibrated your probe in boiling water?
Just some thoughts....
Your CHTs look a little high, but would be normal for a break in period.....
__________________
Bill Peyton
RV-10 - 1125 hrs
N37CP
First Flight Oct 2012
Aviation Partners, LLC
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07-31-2011, 09:28 PM
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Join Date: Nov 2006
Location: Boise, ID
Posts: 1,095
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Quote:
Originally Posted by yakdriver
OAT 83 degrees and 197 oil temp. Not all that bad. I'd love mine to run that cool. Cyl head temps are a little high, might look at that. When I run lean of peak my CHTs come down 40 degrees and oil temp 10-15 degrees. Your oil pressure is a touch low 75 would be better. Don
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Hey Don, the oil temps are 216 (F). The 197 is the heading!
Trust me, if they were 197, I wouldn't be complaining! Heck, if I could drop them 10 more degrees, I'd be satisfied.
__________________
Sonny W
Boise, Idaho
RV-7A Flying!
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07-31-2011, 09:31 PM
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Join Date: Nov 2006
Location: Boise, ID
Posts: 1,095
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Quote:
Originally Posted by Bill.Peyton
How many hours on your engine since new cylinders? New cylinders will run hot for the first 10-20 hours.
To make sure your oil cooler is actually working, I would plug up the inlet air and see what it does to your oil temps.
Do you have a return ground from the engine to the airframe?
Have you calibrated your probe in boiling water?
Just some thoughts....
Your CHTs look a little high, but would be normal for a break in period.....
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Hi Bill,
The engine has 114 hours. I'm pretty sure the oil cooler is working, but I'm not sure how to prove that without breaking something. Blocking the airflow would put my temps higher than they already are, and I'd rather not go there. The temp sensor isn't an issue...as mentioned in the first post, I tested it last weekend and it's spot on.
__________________
Sonny W
Boise, Idaho
RV-7A Flying!
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08-01-2011, 07:23 PM
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Join Date: Feb 2006
Location: Anywhere, USA
Posts: 1,132
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Quote:
Originally Posted by lostpilot28
Hey Don, the oil temps are 216 (F). The 197 is the heading!
Trust me, if they were 197, I wouldn't be complaining! Heck, if I could drop them 10 more degrees, I'd be satisfied.
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Sonny,
I am running an ECi IO-360 and had some cooling issues BUT. If I had
216 a year ago I would have been Sh***N in high cotton.
I have stabalized mine from 235-240 to 185. Don't worry about the louvers
but look at the exit air. Gave mine 2.5 inches and saw that drop.
James cowl and plenum and now see
295 CHT
1250 EGT
200 OT
all at cruise 8k and then oil drops to 175-185.
Engine has 125 hours on it.
I think your Verni is working, fixing the gasket helped.
I would fly the DOG out of it at 216*
__________________
Bruce (BOOMER) Pauley
Kathy (KAT) Pauley
RV 7A--"MISS MARIE"--- N177WD (SOLD FLYING)72742
VAF #582-----------------EAA LIFETIME MEMBER
EX -KC-135A -------------BOOM OPERATOR #3633
VAN'S FLIGHT------------#6930
See you in OSHKOSH
http://www.mykitlog.com/users/index....ley&project=84
=VAF= 2006-2020 DUES PAID
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08-01-2011, 08:47 PM
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Join Date: Nov 2006
Location: Boise, ID
Posts: 1,095
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Quote:
Originally Posted by Bruce
Sonny,
I am running an ECi IO-360 and had some cooling issues BUT. If I had
216 a year ago I would have been Sh***N in high cotton.
I have stabalized mine from 235-240 to 185. Don't worry about the louvers
but look at the exit air. Gave mine 2.5 inches and saw that drop.
James cowl and plenum and now see
295 CHT
1250 EGT
200 OT
all at cruise 8k and then oil drops to 175-185.
Engine has 125 hours on it.
I think your Verni is working, fixing the gasket helped.
I would fly the DOG out of it at 216*
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Thanks, Bruce...I know that 216 - 220 isn't horrible, but I really want to get it closer to 200 for longevity of the engine. I think you're probably right with the exit air, so I'm probably going to look into trimming that back this weekend. I can't imagine cutting it forward an inch is going to give me that much more exit area (I'm not going to do the math on that!), but I'll take anything at this point.
__________________
Sonny W
Boise, Idaho
RV-7A Flying!
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08-02-2011, 08:25 AM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by lostpilot28
Thanks, Bruce...I know that 216 - 220 isn't horrible, but I really want to get it closer to 200 for longevity of the engine. I think you're probably right with the exit air, so I'm probably going to look into trimming that back this weekend. I can't imagine cutting it forward an inch is going to give me that much more exit area (I'm not going to do the math on that!), but I'll take anything at this point.
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If you interested in engine longevity, you must get those CHT's down. The average shown in the imagine posted is over 400F. That alone will cause high oil temperature. According to engine guru, Mike Busch, 400F should be the red line, not 450. He strongly recommends running at 360 or less for max engine life. At 400F, the cylinders are at 50% strength, according to him.
If you want to get the those temps down, you've got to increase air flow through the engine. There are some who will disagree with that premise but I can state categorically, more air flow improves cooling. This is not rocket science with these simple air cooled engines.
Returning from OSH last Thursday at 8,500' (DA over 11,000) CHT's were 337, 336, 339, 355 respectively. Oil temp was 166 at 75 psi. Engine was LOP about 40F. How come such cool numbers? I have copious amounts of air flowing through the engine. The exit area is about twice the inlet with an enlarged exhaust area and Bonanza styled side vents, and the oil cooler is remote mounted ala RV-10 with a 4" duct feeding air to it.
The image of instruments of your flight at 5,500' reveals that EGT's are running very cool while CHT's are abnormally high - you do have a problem. A rich fuel flow at that altitude should have cooled the cylinders dramatically. Have you tried aggressively leaning the engine? The CHT's will come down running LOP and so will the oil temp.
I would focus on getting more air across the engine. You could have baffle leaks and if that doesn't work, exit area must be increased. Your engine will have a shorter than normal life span running that hot.
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RV-7A...Sold #70374
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