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High Oil Temps----Problem Solved

Bruce

Well Known Member
Friend
After 1 year and 111 hours WE finally solved my high oil temp problem.

Here is my setup first.

ECi-IO-360
James Cowl
James Plenum
Vetterman 4 pipe
7--A

After much debating my test flight after annual my OT was 230*.
Had to get it fixed because it was only 95* OAT so we put our heads
together and made the final decisions on the plane.

1st---Cut lower tunnel on the lower cowl and extend down 2.5 inches.
This would give me 35 sq inches more of exit air.

Cut, Reglassed and sanded.

2nd---Remove the brackets holding the lower cowl halves together.

3rd---take 2 pieces of .050, couple of platenuts to hold the two cowl halves
together. Put on the forward nose gear cutout cover in place and then
put the upper nose gear fairing on.



Test fly---------185* WOW

Thanks to Glider,Rooster and Woody for all the help and knowledge.

Boomer
 
Looking for cooler temps

Great news, Bruce. Sounds like I might benefit from similar surgery. Got any pictures to share? It would make the big cut a little less stressful. ;)

I've tried to clean up everything I can on top but there is so much "junk" in the way of the exit, it seems like a good place to look next.

ECi-IO-320
Van's Cooler
James Cowl
James Plenum
Vetterman crossover
9--A
 
Russ,

I will try to load some pics.

Pretty easy cut. Leave about 1 inch of the top exit tunnel and
then cut about 12 inches forward. Put some blocks to hold the
2.5 inches and then glass with the cowl on. I cut it on the plane
and then glassed it in.

Pretty happy about the results and did not cost much.
 


Uploaded with ImageShack.us

Here is the before pic.

Note the flow marks on the oil on the bottom of the plane.
There are swirl marks going back into the cowl.
On the new setup these marks are gone.

There is a tuft film somewhere on the sight that shows the air
going back into the cowl on an A model.
 
Thanks...

Your "before" picture looks way too much like my "now" picture - even down to the oil swirl patterns! I take it the louvres weren't as effective as the added exit air opening (or are they still in use)?
 
Well I am glad that you have fixed it.
Looking at the picture I have to ask the following:

What effect will the hole in front of the gear leg have - can it increase the bottom cowl pressure and lessen the pressure differential and therefore also the cooling?

The four pipes coming out - what effect will this have on the cooling as it surely reduces the outlet area. I guess that is why you have lowered the tunnel part.
 
Along those same lines...

......The four pipes coming out - what effect will this have on the cooling as it surely reduces the outlet area. I guess that is why you have lowered the tunnel part.

I wonder if the four-into-one exhaust helps the cooling since it's only one pipe instead of the usual two...even less restriction for the exiting air.

Best,
 


Uploaded with ImageShack.us

Here is the 2.5 inch cut. Cut all the way forward till you can pull
down and glass.

I will get a pic of the back as soon as I go back to the 140* hangar
and get one:D


Oil Cooler is SW 8607 --??

Janekom---
I have not covered the louvers and test flown it that way yet.
The cover on the front of the nose gear blocked the exit flow that
was going down the nose gear leg and out the bottom on top of
the nose gear fairing. Some have seen this and that is pushing
the air out the front. I am trying to get ALL the air going out
the back of the cowl.

The 4 pipe took up a lot of space. Some of them are level and mine
are slightly stacked. Flat might have been better but it is what it is.
All of the 35 inches of exit air came below the exhaust pipes.
I took it to within 1/2 inch above the pipes. Wanted the exit air to keep
pushing the exhaust gases.
 


Front Gear Leg cover---Before






Look all the way to the front on this one and then the forward gear leg hole.



You can compare this to the other one I posted on the before for the
side view.

You can see that I cleaned up the whole area around the nose gear.
Note that you can see the filter housing in the nose of the cowl. You
can also see why I plugged the hole for the front nose gear fairing.

As of speed that Rocket was talking about I will have to see in
the future. I hope I did not lose too much speed. Still very aerodynamic
but will have to see on the cooling drag portion of it. I was a concern
but the temps were a bigger concern.:eek:
 
Ok,

Here is the side view before and after.

And don't send me a note about having to sand
any of this. Test flown and parked after 200 miler.



After






Before
 
So Bruce, the louvers didn't help your temp situation at all? Or did they help a little bit, but not enough?
 
Would be handy if the pics were still there though.

My latest status - changed the cooler to a 10-row and installed a rough diffuser, it dropped cruise temps to 210 but I still hit 235-240 in extended climbs. I'm spilling enough air off the left side of the plenum that now my 2 and 4 cylinders are running about 40F hotter than they were, so I'm obviously moving more air but now I've got widely spread CHT's. I pulled filter adapter and vernatherm, all measurements check out with a micrometer, I installed a new vernatherm this morning with no difference in temps.

My cowl is a Sam James long cowl, and was originally cut to meet the firewall everywhere but the exit tunnel. The exit tunnel actually extends back to the original length of the virgin cowl right now today, about 1" aft of the firewall. I'm going to trim this flush with the firewall and reseal the edge and test fly that, I know it will increase the exit airflow (and likely increase my drag too) but I've got to improve the cooling. I may end up angling that cut forward another inch later on, but first cut will be straight and flush with the firewall.

I'm also going to do some fiberglass surgery on my plenum to improve my intakes, they are not ideal right now and I know I'm generating some turbulence on the inlets, and I know that's not a good thing. Right now I have several "not good things" working against me and the trick is knowing (or guessing) which one is the biggest offender. I'm certainly not an expert on airflows in this type of environment, I'll admit I didn't have a **** clue walking in, but I'm learning fast.

Interestingly, I still think my #4 cylinder is not broken in - on a cold start this morning in the 50's that cylinder head temp reached 125 about the time the others were upper 80's, indicating quite a bit more friction, and this has been the case on each start over the last several hours. It's also definitely the hottest at high power, followed closely by #2. I have 12.5 hours on the engine now at this point.
 
Last edited:
Greg,
Pics gone and can't get back.

Do you still have the front dams on 1 & 3?
I saw that on your web page.
Only make one change at a time , fly, evaluate.
Can use aluminum tape after removal to steady cht's.

Remove dams will lower your cht's.
 
Yes, the inlet dams are unchanged from the pics on my build site.

Next step is cutting the cowl exit even with the firewall and flying that, and I'm going to insulate my FWF fuel delivery line as well. It works fine with 100LL but running 91 premium auto fuel (with the higher vapor pressure) it absorbs too much heat during low power operatings (lower fuel flow, more time spent in the line picking up heat) and has a tendency to flash into vapor between the servo and the injectors where the pressure drops.

I'm going to do both of those things this week and fly again this coming weekend, then the next step is going to be a lengthy one - plenum inlet fiberglass surgery. It needs to be cleaned up anyway, even if it's not one of the major contributing causes (though I believe it is), it's going to change. I think cutting the exit opening wider is going to be my major contributor.
 
Vapor Issue

Hi Greg,

Ref your fuel vapor issue--another way of reducing this is to increase the "head pressure" by going down in injector restrictor size. I believe the stock injector restrictors for the 180 hp Lyc (or clone) are 028. I went down to 024 and reduced about 80% of my issue (stumbling on low power approaches and stumbling when taxing in after a flight in hot conditions). Don Rivera of AFP did the calculations for me and said I could go all the way down to 023 and still have sufficient flow for up to (speaking from memory here) 185hp.

Cheers,

db
 
Hi Greg,

Ref your fuel vapor issue--another way of reducing this is to increase the "head pressure" by going down in injector restrictor size. I believe the stock injector restrictors for the 180 hp Lyc (or clone) are 028. I went down to 024 and reduced about 80% of my issue (stumbling on low power approaches and stumbling when taxing in after a flight in hot conditions). Don Rivera of AFP did the calculations for me and said I could go all the way down to 023 and still have sufficient flow for up to (speaking from memory here) 185hp.

Cheers,

db

Now THAT is definitely an interesting piece of information, and I'll follow up on it, thanks!
 
Hey Greg, let us know what you find out on the injector size issue. I could definitely use a little love in the hot fuel flash department as well.
 
Hey Greg,

Have you considered going to a cowl flap? ASA makes that really trick electrically actuated one...you could open it during climbs to lower temps. Maybe a last resort after other options are exhausted, but another arrow in the quiver...
 
Hey Greg,

Have you considered going to a cowl flap? ASA makes that really trick electrically actuated one...you could open it during climbs to lower temps. Maybe a last resort after other options are exhausted, but another arrow in the quiver...

Ready to order that one if I can't solve it another way - my primary goal was to accomplish the cooling without adding drag, but cowl flaps are always the nuclear option.
 
Ready to order that one if I can't solve it another way - my primary goal was to accomplish the cooling without adding drag, but cowl flaps are always the nuclear option.

Hi Greg, I'm not sure you posted it already, but a good measurement of upper and lower cowl pressures with a digital manometer (vs airspeed) would greatly help the to quantify the effects of possible solutions.

If the upper is low then the inlet diffuser is controlling, if the lower is high then the exit is restricted.
 
Have you tried 'exit ramps' at the bottom of the firewall? I know it will be a bit harder to do with a nose wheel strut, but might be worth the effort before you start with cowl surgery.

Charlie
 
... I'm going to insulate my FWF fuel delivery line as well. It works fine with 100LL but running 91 premium auto fuel (with the higher vapor pressure) it absorbs too much heat during low power operatings (lower fuel flow, more time spent in the line picking up heat) and has a tendency to flash into vapor between the servo and the injectors where the pressure drops...

Please do that before you next flight.

This thread explains why that is so important.
 
Please do that before you next flight.

This thread explains why that is so important.

Heh, funny you should post that, I read that old thread about a week ago. Yes, I'm very aware of the dangers posed by hot fuel flashing into vapor in the lines. Until I am absolutely sure it is resolved I'll be doing all my landings and takeoffs with 100LL and using the high-vapor pressure fuel only for cruise. The time that I really pushed it for the previous tests I was at KBPG with their very long runway, it gives me plenty options for a low-altitude engine failure on takeoff, I'll continue to do my testing there.
 
Fly safe my friend!

What really got me were the extended flights at low speeds. The low fuel flow and low cooling air did me in.

The good news was that the insulation solved the problem.
 
Yes, the inlet dams are unchanged from the pics on my build site.

Next step is cutting the cowl exit even with the firewall and flying that, and I'm going to insulate my FWF fuel delivery line as well. It works fine with 100LL but running 91 premium auto fuel (with the higher vapor pressure) it absorbs too much heat during low power operatings (lower fuel flow, more time spent in the line picking up heat) and has a tendency to flash into vapor between the servo and the injectors where the pressure drops.

I'm going to do both of those things this week and fly again this coming weekend, then the next step is going to be a lengthy one - plenum inlet fiberglass surgery. It needs to be cleaned up anyway, even if it's not one of the major contributing causes (though I believe it is), it's going to change. I think cutting the exit opening wider is going to be my major contributor.

Greg,
I see something is working.
How is it going in phase 1???

Boomer
 
Phase I is going good so far - just not enough time to fly, I've only got 17 hours on it so far. I did a fair bit of "cleanup" on the fiberglass of the inlets, and ended up hacking on my lower cowl exit to open it up 1" forward of the firewall. Now my temps in cruise are very nice indeed, I've lost a couple knots of top end speed from the additional drag, and I'm still seeing high temps on climb unless I run just slobbering rich.

My left side (#2 and #4) run warmer than the right, due to the oil cooler air spilling off that side and the fact that my left side air inlet is not aligned correctly between the plenum and cowl opening, with the result that the neoprene connector between them is wrinkled and buckled slightly, producing some drag there and cutting down on the inlet flow on that side. I'll have to cut that left plenum inlet and reglass it slightly lower and slightly inboard to solve that problem, and I think I'm going to install the Anti-Splat Aero electric cowl flap to enable me to dump large volumes of air out of the lower cowl for climb, and add back about half of the exit area I cut off the lower cowl exit previously to see if I can get those couple knots of top-end speed back without raising the cruise temps. That's going to be a bit of a balancing act, but the nice part is that it's just fiberglass - you can hack it off and redo it any time you want.

Believe it or not, I may end up with a 13-row oil cooler on this airplane. I'm having no real problems keeping the CHT's in check, but with the piston squirters on this engine I'm just dumping huge amounts of heat into the oil at full power. I just changed from mineral oil for break-in to Phillips XC standard 20-50, I'll fly for a bit with that and see if it affects anything before jumping off the bridge on the oil cooler.
 
Piston squirters... What a great idea. Seems like you are now like porsche. Air and oil cooled

It wasn't intentional, I wouldn't have done it by choice. I bought a used engine from a Reno race-engine builder and he had installed them, I didn't realize they were in place until it was flying.
 
Greg
I have an O-360 ECi with squirters. Last summer when I flew my plane for the first time I was getting high oil & CHT temps as well. Oil cooler was a Stewart Warner 8406R, firewall mounted with a 4" duct. Also had a very nicely formed fiberglass plenum on the cooler. I did all the things to help mitigate the problem: baffle seal leaks, air dam trimming, etc. The next thing I did was install the Antisplat cowl flap on left side (just under where the oil cooler is mounted). CHTs came down some but didn't help the oil temps much. So, I bit the bullet & got a 10611R cooler from Pacific. It's an Aero Classic which is now made by Pacific Coolers...or a sister company maybe. It had the same bolt pattern & same length as the 8406R; just more (11) rows. I did have to fabricate a new fiberglass plenum for the 4" duct.
Since the install, rarely do I see oil temps over 200*. Back in September when it was still pretty warm here in Abilene, I had a 96* OAT day and never saw oil temps past 193*.
I still have hotter #1 & #2 CHTs, but I still need to do some more air dam trimming.
 
My left side (#2 and #4) run warmer than the right, due to the oil cooler air spilling off that side..

Probably not. One of my cooling experiments was to take oil cooler air from the rear baffle wall behind #4, and in a different iteration, ducting it from just inside the cowl inlet...i.e. no air "stolen" near #4. CHT did not change.

...and the fact that my left side air inlet is not aligned correctly between the plenum and cowl opening, with the result that the neoprene connector between them is wrinkled and buckled slightly, producing some drag there and cutting down on the inlet flow on that side.

More likely. Perhaps not drag in the usual sense, but pressure loss. Velocity wasted in flow separation and turbulence does not result in plenum pressure rise. Pressure moves air through the fins.

...I bit the bullet & got a 10611R cooler from Pacific... Since the install, rarely do I see oil temps over 200*. Back in September when it was still pretty warm here in Abilene, I had a 96* OAT day and never saw oil temps past 193*.

Same here with the 390. The small coolers seem to be fine with squirters if the owner is happy with 200F+ on a regular basis, but nothing but a large cooler will bring happiness if you want temps under 200F in the hot parts of the world.
 
Same here with the 390. The small coolers seem to be fine with squirters if the owner is happy with 200F+ on a regular basis, but nothing but a large cooler will bring happiness if you want temps under 200F in the hot parts of the world.

I can hold 200-205 oil temp now at 60%-65% cruise, I was hoping for 190-195. I can still get it up to 230 pretty quick on a Vy climb at full power though, that's what has my attention right now.
 
My buddy's RV-8 with ECI Titan IO-360 that has piston squirters sure has nice CHTs (typically 350-365 even in TX summer heat) but we ended up installing an expensive SW oil cooler to get the oil temps under control. We had a 13 row cooler on it for a short while but that one worked a little too good and mounted on the rear cyl 4 baffle, it rubbed the engine mount and the fiberglass cowl too. A 13 row cooler firewall mounted with an adjustable butterfly valve to vary the airflow into the cooler would've worked fantastic but we didn't have the room, or willpower to do that, so it got the SW10599 on the baffle instead.
 
Photos

It seems like every time there is a photo shared on this website, its gone. I?m looking for the before and after trimming pics of the cowl for cooling. Image Shack doesn?t have them. Why do pics not work very well for very long on VansAF? And.. does anyone have any pics with a successful trimming for high cht? Thx
[email protected] if you do.
 
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