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High CHT and Oil temp

BobCollins(AA)

Well Known Member
I have 24hrs flown so far in phase one and after sealing all the baffles and trying to plug the areas where the air could escape my CHT is still high during climb. Also my oil temp is high 210 during pretty much all the time when OAT is in the 70s. I am using Van's oil cooler for the IO360 which is the engine on my airplane, the oil cooler is mounted on the firewall with a 3" scat directing air over it. Any suggestions?
I wonder if the EZ Cowl Flaps from AntiSplat would help?
 
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Bob,
What is your Cyl Temp.
You might not be done breaking in the engine. Have you been running above 75 percent on all your breakin flights.

Don't get in a rush to get the mineral oil out... it does not hurt anything.
How often have you changed the oil and filter since the first flight

What speed are you climbing at. Try climbing out at 120 once you get above the immediate ground trash.

I have the same similar set up... ended up putting a cowl flap on by Anti splat.
The best single investment with the biggest improvement. I only put one on.
I could not keep my Cyl Temp below 380
Now they don't even get there at a 90 kt climb. in 80 degree weather.
Jack

Jack
 
Thanks for the answer Jack
I have 24hrs on the hobb and changed oil at 12 hrs and still using mineral
I have been running at 75%+ all the time
I will probably invest on the cowl flap
Should I get two or one is sufficient
 
One vs two would likely depend on your location and typical temps. My first impression, before reading Jack's response was that you need more airflow behind the engine and the cowl flap would do that for you.
 
1. Can you verify that your ignition timing is on the base map and no higher than a mag might be?

2. I am currently circling the baffles, and notice there a LOT of areas for air to pass through holes and not go through fins. To understand how much air this might be - - take your shop vac, set it to blow, then close off the end but leave a 1/2" dia hole. You will be amazed at how much air that will be. Yes, the pressure is more like 25" of water, not 13" but it is still amazing.

3. Do you have the vans oil cooler cover or a more airflow friendly one? An inlet ring, rather than the squared off hole, in the baffle will increase airflow by 30% for the same plenum pressure.

4. Do you have a curved exit air ramp from the base of the firewall up into the lower cowl?

5. Does your engine have piston oil jets?
 
Bob,
I started out by putting louvers in the bottom of the cowling. but that did not help at all.
I installed one cowl flap and put the little switch right next to the throttle between the throttle and the prop control. It is a really small toggle switch and fits nicely there and you can flip it closed with your finger.

One cowl flap did it for me. I painted it one day and installed it the next. about 2 inches infront of the firewall duez line. or if you have the piano hinge it will be easy to measure. it was easy to make it 90 degrees to that line.
I know some folks have installed 2 just for looks. I just took the attitude if one works fine if not I'll install another and parallel the wires.

it calls for a small circuit breaker. I installed a thermo breaker 1/3 amp and it works well. or a very small fuse and that can be inline. The wires are like No 28 really little.

Also take your cowling off and check the timing. a couple degrees one way or the other can have an effect.
Have you looked at y our plugs since the first hour?
I had to clean my injectors in Hoppie no 9 gun cleaner in about 15 hours.
could not believe one little bit of trash in one made the engine run so rough.

Jack
 
1. Can you verify that your ignition timing is on the base map and no higher than a mag might be?

2. I am currently circling the baffles, and notice there a LOT of areas for air to pass through holes and not go through fins. To understand how much air this might be - - take your shop vac, set it to blow, then close off the end but leave a 1/2" dia hole. You will be amazed at how much air that will be. Yes, the pressure is more like 25" of water, not 13" but it is still amazing.

3. Do you have the vans oil cooler cover or a more airflow friendly one? An inlet ring, rather than the squared off hole, in the baffle will increase airflow by 30% for the same plenum pressure.

4. Do you have a curved exit air ramp from the base of the firewall up into the lower cowl?

5. Does your engine have piston oil jets?

Hi Bill
Where can I get the more airflow friendly oil cooler cover?
I do have the piston oil jets
Bob
 
Hi Bill
Where can I get the more airflow friendly oil cooler cover?
I do have the piston oil jets
Bob

Hmmm - I will look, there are some with nice diffusers made from fiberglass. I decided against a remote cooler so don't have links, but i have seen links here.

Regarding the cooler, is it the Niagara 20002 cooler? If so, it is likely that is not going to be adequate. I can not say definitively, but this is the standard cooler for engines without jets. Many pilot/builders have said that it was too cool and use shutters, so maybe? A trumpet on the inlet maybe 4.5" dia with a radius down to the 3" will increase the air flow. It really does not have to be fancy just a .75" inlet radius would work. Both of these are easy and there is a slightly larger cooler that will fit with little modification, if it gets that far.

Lower oil temps will help lower CHT too.

Edit: Here is a link for cooler plenums. Did you seal the ends of the vans cover to to the cooler? Leaks there too.
 
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1. Can you verify that your ignition timing is on the base map and no higher than a mag might be?
...
5. Does your engine have piston oil jets?
The timing is a big one! Is your IO-360 an angle valve or parallel valve engine and do you have high compression pistons installed?

If Parallel valve engine, make sure the jumper is in place. This forces the P-mag to the "A" curve which starts at 26*. If you have an angle valve or high compression pistons, you will want to install either one of our EICommanders or use the Emag EICAD program to set in a negative offset on the P-mags to help with timing. (Check your PM's.)

If you have the oil squirters installed, you are removing cylinder temps with oil and your oil temps will run high.
 
cooling

I always had high oil temps and cylinder temps on my RV7A. Changed to a better cooler to help oil temps. Still had high cylinder temps. I installed one antisplat cowl flap and I keep the temps down on climb and level off and shut the cowl flap. It has worked great for me. Its harder to cool things down after a climb. My 2 cents worth
 
Today I am getting two EZ Cowls that I will install on the airplane and I will post the results after my next flight.
 
After installing two anti splat electric cowl flaps I finally manage to reduce the CHT by 30 degrees and the oil temp by 15degrees.
 
All the reading I have done has the best FW mounted oil cooler installation with 4" scat.
Is your cooler mounted vertical or horizontal? If vertical, the inlet should be at the bottom.

The ramps on the cowling inlet, are the ends sealed up such that they cannot be a bypass source?
 
After installing two anti splat electric cowl flaps I finally manage to reduce the CHT by 30 degrees and the oil temp by 15degrees.

Great to hear your issue is resolved. With timing advance, and piston jets, this is probably a lower cost way to go as opposed to wrestling with a new cooler installation!
 
CHT high - Oil temp low

seems to be different flying either an injected or a carbureted engine, is it?

Since the installation of a G3X Touch panel in our flying RV 9a O320 FP we can see all these phantastic numbers as CHTs a.s.o. We didn't know before that CHTs on this engine are pretty high in climb (450 F) and during high speed cruise (400+). Only the oiltemp remains low (160-180 F) in the cruise as it did before. Louvers or EZ cowl flaps from AntiSplat would lower CHTs what would be appreciated. But this way oil temps probably would be lower as well, what is contrary to what is beeing needed. :rolleyes:

Any ideas ?
 
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seems to be different flying either an injected or a carbureted engine, is it?

Since the installation of a G3X Touch panel in our flying RV 9a O320 FP we can see all these phantastic numbers as CHTs a.s.o. We didn't know before that CHTs on this engine are pretty high in climb (450 F) and during high speed cruise (400+). Only the oiltemp remains low (160-180 F) in the cruise as it did before. Louvers or EZ cowl flaps from AntiSplat would lower CHTs what would be appreciated. But this way oil temps probably would be lower as well, what is contrary to what is beeing needed. :rolleyes:

Any ideas ?

Add the cowl flaps or improve your baffles to lower CHTs. Then use aluminum tape to cover part of your oil cooler. In summer my oil cooler is 1/3 blocked. In winter I will probably need to block more of it.
 
Bob,
I am glad to hear the cowl flaps work well. I thought you would be pleased. Just had a nice trip to Kitty Hawk... and had a blessing on the wind last Friday 55 kts directly on the tail... and behold... on the return Sunday I had no wind. Same day Friday the 13. that Cirrus deployed his chute in North Carolina after an engine failure, what the pilot said. He is from PDK. so I will find out what happen. They had a video of it after it was on the ground and the chute inflated again and flipped it over on its back.... you can Google it.


It sure was nice to see a speed of 258 on the GS.



Jack
 
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flying RV9a

Add the cowl flaps or improve your baffles to lower CHTs. Then use aluminum tape to cover part of your oil cooler. In summer my oil cooler is 1/3 blocked. In winter I will probably need to block more of it.

Kurt,
thanks, baffle seals are redone, no leaks, even the washer at the baffle behind cyl.3 was installed which remarkably lowered the #3s CHT. Now #2 is the hottest. Van's oil shutter is a handy device which is easily beeing added and controlled from the panel.
If we are flying 75% on a hot day we will get 400+ CHT on #1,2 & 3. But who would like to fly the cruise whith opened cowl flaps? Thats the problem. :confused:
 
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