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Oil Cooler Mod works!

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yankee-flyer

Well Known Member
During the CI last November I followed all the posted information and moved my oil radiator about an inch forward. Naturally there's been no way to see if that did anything until yesterday.

OAT at runup 87 F, grass strip, 2 adults and 10 gallons fuel. Off the ground in less than 1000 ft (previous airplane was an AA-1, no WAY that would have happened), climbed at 75 Kt IAS to 4250 IA (DA about 5500). Last year the oil temp would have been at the top of the yellow arc or just into the red by 3500 IA-- yesterday it just hit the bottom of the yellow arc and dropped back to 220 deg as soon as we leveled out and got into cruise mode.

All of you in the build process be sure you have at least in inch between the back of the oil radiator and the closest point of the muffler. Lots of variables in how the muffler is fitted. how the lower cowl is trimmed and how the oil cooler duct is trimmed. It's a LOT easier to get that right the first time than it is to go back and do it later.

MANY thanks to those who figured out the problem, engineered the fix, and posted all the info and photos. This group is great!

Wayne 120241.143WM, 186 hours
 
Here in Phoenix that mod would be nice. In summer I end up climbing to 2500 AGL and letting the oil cool from 236 to 228 before climbing the next 2000 FT to repeat the process until I get to my cruising altitude. I also operate at about 14 Gal initial fuel load to get extra margin unless I need to go somewhere. My takeoff DA is usually about 3500 FT.
 
Ceramic coating on muffler

Just throwing this out...
Now that Eagle's Nest -3 is flying and we have a good base line for OAT/oil temps, we're considering a test - an alternative if you will to modifying the cowl in flying aircraft - ceramic coating on the muffler. EN-3 has 3/4" clearance and on 90 degree days we run at the top of the yellow. Will probably wait until after OSH to coat the muffler and will report our findings. On Eagle's Nest -10, our second build at Clear Springs HS starting this Fall , we'll probably modify the cowl. What ya think?
 
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Ernie, someone out in forum land has tried the ceramic coating and I can't remember what the result was. It seems that 1 inch is the magic number. Any closer and it's still a bit hot and further away creates some pretty long warm up times in the winter. The cost of the mod is very minimal, only a few bucks and it is known to work. Maybe someone will chime in with knowledge on the coating.
 
Oil cooler

We also did the mod at last condition inspection (December) and it has worked well. We have enough space between the cooler and muffler that I can get my hand easily in that space. It has worked out well. On a warm day I did a 75kt climb from sea level to 5500 ft. It just got into the yellow range and then started going back down when the air cooled outside.

Great mod.

Richard
 
How About An Exhaust Wrap

Has anyone tried an exhaust wrap? There is a 1/4" thick product that will handle up to 1800 degrees continuous. The manufacturer touts that this product will direct the heat out the tailpipe, where it is suppose to go, rather than radiating the heat into the engine compartment. Just a thought!!
Tom
 
Answer - yes - -

No way of knowing how much good it is doing, but seems to be helping. Forgot to take picture when I did it.
 
Hi, my name is Mike in northern Ca. and am running high oil temps with my RV7. I've got a Sam James cowling, and am just starting to investigate what to do. What is the Oil Cooler Mod you mentioned? Thanks! Mike
 
skycloudster said:
Hi, my name is Mike in northern Ca. and am running high oil temps with my RV7. I've got a Sam James cowling, and am just starting to investigate what to do. What is the Oil Cooler Mod you mentioned? Thanks! Mike
Click to expand...

Mike, I don't think this thread will help you, but good luck. Check out this previous thread on the subject. Pete was good enough to take pictures.
http://www.vansairforce.com/community/showthread.php?t=89532

Here is another thread on this subject. As you can see, a lot has been written on this subject.

http://www.vansairforce.com/community/showthread.php?t=88612
 
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Hey Dave

Hey Dave. You may have missed it, but I sent you a pm. Hope to hear back from you. Also, from everything that I have read, you are the oil temp reduction expert. So, what are your thoughts about trying a thermal wrap on the muffler. My cowl is already painted, any I hate to cut into it. But if I have to, I will. I'm just so sure that I am going to have to do something with so small of an air gap. Thanks.
Tom
 
todehnal said:
Hey Dave. You may have missed it, but I sent you a pm. Hope to hear back from you. Also, from everything that I have read, you are the oil temp reduction expert. So, what are your thoughts about trying a thermal wrap on the muffler. My cowl is already painted, any I hate to cut into it. But if I have to, I will. I'm just so sure that I am going to have to do something with so small of an air gap. Thanks.
Tom
Click to expand...

If you have not received the emails (2), you might want to supply another address. I have no experience with the wrap, but personally view it as a band-aid. With only 1/4" gap, I think your temps will be very high.
 
Can you overheat the exhause pipes?

todehnal said:
Has anyone tried an exhaust wrap? There is a 1/4" thick product that will handle up to 1800 degrees continuous. The manufacturer touts that this product will direct the heat out the tailpipe, where it is suppose to go, rather than radiating the heat into the engine compartment. Just a thought!!
Tom
Click to expand...

We have to be careful with heat muffs to keep air flowing or the exhaust pipe will overheat. Wrapping the exhaust pipe might also overheat it.
 
Too Bad

Too bad that the 'rules' of LSA don't allow the 'manufacturer' (Van's in this case), to change small but significant changes to the 'kit' as those who are flying the product (RV-12) find an improvement such as this one.

Another improvement to the kit in my opinion, would be the utilization of the Muehler sp? gas tank gauge. Too bad that I'll have to do these mods after certification - I'd really like to do these during the build.
 
Ed,

Before you go to the expense and work of installing a gage you might want to try sounding the tank with a piece of nylon brake line. It's stiff enough to give a good reading and flexible enough to get around the bend in the filler line.

Rich
 
jim skala said:
We have to be careful with heat muffs to keep air flowing or the exhaust pipe will overheat. Wrapping the exhaust pipe might also overheat it.
Click to expand...

Thanks for your thoughts Jim. I considered the muffler surface temp increase by wrapping it, but I'm hearing EGT temps only in the 1100 to 1200 degree range for these engines, and it's a very large muffler. Lyc. O360s will run more in the 1400 degree range without exhaust issues. I'm not sure that it is much of a concern here. Sure wish that someone had some real experience with this idea. By the way. I would not be wrapping the exhaust pipes, nor the ends of the muffler, just the cylinder wall area.

Tom
 
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Vans sent one guy a "letter" about the Moeller fuel gauge. The point was to install the hole in the fuel tank with the nut plates, sealant, etc, then cover it with a gasket and a bolted-down plate. What you have done is to repair the hole. Later, drop in the gauge and bolt it down. That's what I did, no problem, your mileage may vary.
 
The proximity of the muffler and oil cooler affects oil cooling in two ways.
1. Radiant heat from the muffler warms the oil cooler.
2. The muffler location hinders air flowing out of the oil cooler.
Of these two, I think that air flow through the oil cooler has the greater affect. Increasing the distance between the muffler and oil cooler will reduce the radiation heat absorbed by the oil cooler and will also allow more air to flow out of the oil cooler. It is too bad that the fix requires working with fiberglass. :)
Joe Gores
 
I'll Do The Mod

Good stuff Joe! I'm going to do the mod, and it's not that I mind working the fiberglass, as much as I do messing up my nice paint job. Oh well.........

Tom
 
Post Mod Touch-up Painting

Hey Dave, after you did your mod, did you have to do any touch-up painting on the outside of the cowl, or just inside of the mouth opening?

Tom
 
INside, and Joe has it right

The only re-painting necessary after completing the oil duct mod is inside the air scoop opening. Not too bad and I did my touch-up work with an air-brush.

What I can remember from my long-ago Heat Transfer courses says that Joe has it right. I believe the high temps come from the muffler blocking the airflow through the radiator, not from the heat of the muffler being radiated forward. If that's the case, wrapping the muffler will make things worse since that will increase the diameter of the obstruction and further reduce clearance. Get that cooler as far from the muffler as you can-- in my case about 3/4 to 1" was all I could get because of the routing of the oil hoses. There seems to be some wiggle room when attaching the exhaust pipes for the first time, too-- get the muffler as far back as you can, After a year and a half, I couldn't move my muffler.

Wayne 120241/143WM
 
Made The Cut

Thanks Wayne,
I did the surgery yesterday, repositioned the oil cooler mounting area forward, about an inch, and glassed it in. I will re-route the hoses if I have to. It went well so far. The instruction sheet from Dave12, and the pictures posted by Pete were a great help. I appreciate the tip on the air brush idea. After I get the glass work done, and have trial fitted the cowling with the oil cooler in place, I will try my hand at air brushing.
 
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