P

prkaye

Well Known Member
My first flight was this evening. With the exception of a problem of high CHTs, the engine ran smoothly and the airplane performed nicely.
Photos:
http://www.c-func.com/album.html
Video:
http://www.youtube.com/watch?v=JA3v69GY2j4

Now, the CHTs are concerning me. Here's the data:

Overhauled O-320D2A from AeroSport with new ECI cylinders. The engine was run-in for about 1.5 hours at aerosport, and my initial ground runs did not take more than 0.1 hours total. Fixed pitch catto prop.
Flew at about 1500ASL (~1000 AGL) for about 1 hour. It was quite warm outside. Ran full-rich the whole time.
Oil pressure and temperature steady at about 70 and 212-215 respectively.
With power around 2300RPM, the CHTS were all very close in the 425 range. Whenever I ran it at 2400RPM or higher, the CHTs on all the back to cylinders crept up to around 430. Manifold Pressure was about 29".
If I powered back below 2300RPM, the CHTs would fall off to around 405.
I had wheelpants and leg fairings off and was only making about 120-130 kts.
I didn't like the high CHTs but I felt it was important to keep the power up for hte break-in. So I ran it with the CHTs in the 420s, and when the temps crept much over 430, I powered back to cool them back down closer to 400, and then increased power again until the CHTs crept up over 430 again. I ran like this for a total of about 1 hr.
Questions:
1) Should I be worried?
2) What should I do?
 
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too slow for the power settings...

congratulations on first flight! even with a well sealed plenum i suspect that you are just not getting enough airflow to cool the engine at 120-130 knots for those sustained power settings.
 
Congrats!!!!!!!!!!!!

Good for you-----:D

You are still breaking in the engine, temps are going to run a bit high.

Are you leaning it now, or still running full rich??
 
Congratulations!

IMO 410-420F may be expected during the initial few hours. My experience is that the ECI Nickel Carbide cylinders run hot, and especially hot during break in.

Do whatever you can to keep the airspeed up - including climbing out at 100-110+ knots. I would also fly in the early morning / late afternoon when it?s cooler.

Early in my test phase I got things quite hot doing slow flight. When the power is back and things are getting hot you need to remember to get the power on and increase airspeed... not so easy when nervous about the temps. You're running at a fairly high power setting, so that may not be too much of a problem.

You don't say if you have electronic ignition, but regardless do check your timing is correct and not advanced too much during the break in. Also, it may be wise to confirm the fuel flow is adequate. Does the mixture arm go all the way to full rich and are you flowing sufficient fuel on takeoff? For a 360 it should be about 60l/h. I?m not sure for the 320.

At about 5-10 hours you should see a very marked decrease in CHT. Once that occurs you should have a better idea if you have a hot engine or the break-in is making heat.

One other comment is that your MAP seems high. Have a look at the Lycoming manual and you will find that is a more than 75% power if the gauge is accurate.

Richard
 
Congrats on the first flight Phil!

I personally have never don the research on the "leave the wheel pants off so that the engine will work harder to break it in" school of thought, but my sense is that if you just fly the engine hard per the various recommended break-in procedures, it will do what it needs to do. I would NOT want to have a lack of cooling during this timeframe, and 120 knots is not going to do an optimum job. I flew with full fairings from day one, and the engine broke in just fine - and yes, I flew pretty fast for those first couple of hours.

Breaking in the engine properly is an important consideration for a long service life, and once you have ascertained that airplane flies fine, I'd put it very high on the Phase 1 list. I'd be concerned with flying that slowly while the engine is generating more than normal waste heat during break-in.

Paul
 
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Sounds normal to me. I've broken in two sets now. Keep flying it hard if you can, and don't panic at early 420 cht.
 
Congratulations on this milestone! How wide was your RV Grin?:D

Regarding the hotter cylinders, I spoke with Cory at Aerosport yesterday about one hot cylinder I have (runs between 430 and 440) on my new Aerosport engine in my -4, I have 14 hours on it now. One rule of thumb he mentioned was that the danger zone was where the EGT and the CHT added together was 1850 or higher. That is when you are likely to start burning exhaust valves. Mine is running under 1800 so he thought I was not in any danger of damaging the engine, but the CHT should be lower.

He did mention that the EGTs should be run about 100 rich of peak for coolness. In my case that puts it right about the Lycoming spec of 1275.
 
I am for putting your fairings back on and letting her rip...
I broke mine in during August heat and had no issues with temps. It was pretty rough down low at those speeds, though...
 
Awesome and congrats! I've been following your progress, great job!

Don't sweat the CHT's. You can go back and read all my ramblings about mine when I first flew. It took about 25-30 hours before my oil and CHT's settled down. It still runs hot at high power settings (75%). Keep it wide open throttle in the climb and it'll really cool things down. There's a temptation to back off a bit because of red line fears. Still your temps look good to me. Right now your senses are heightened because of the mystery of the "test flying". You'll learn to ignore more and more of your indications as you comfortable. Just think of all the planes out there that have no CHT or EGT gauges. They never seem to run hot!
 
Thansk guys, your comments make me feel a little better about the temps.

How wide was your RV Grin?
Click to expand...

Actually not very wide. I was so focussed on the temps and concerned with tryign to keep them down while at the same time running the engine hard fro break-in, that I didn't really get to enjoy the flight.
There was also a weird feeling of disconnect... it was just like flying usually is, there was no strong association between the thing I was flying yesterday and the thing I spent four years building. Not what I expected it to be like.... almost anti-climactic. I went to bed feeling deflated, worried that my temps indicated a serious problem or that I might have done some damage to the engine at those temps.

I will definately put the pants and fairings on for the next flight (not till mid next week), and probably wait for a day when it's not so warm out. I'll also goup a bunch more High-temp RTV around my baffling to seal any places that might be air leaks.
 
First, congratulations are in order.
I removed my front cylinder dams to help lower cht (ECI cylinders) then used aluminum tape for the first 100 hours to even out the chts. My chts are very sensitive to anything I do to the intake area. Did a bunch of experimenting with this .:eek:
My chts settled down at about 50 hrs (415 F max in climb).:)
bjaahg.jpg
 
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RE:Congrats and go get that grin!!!!!

Hi Phil

I am running a iox-360 eci titan engine on my RV7A.....so a bit different but.

I have had the same feeling as you described. After alot of calles, info gathering, data gathering.............I noted

that after a year of flying what used to take 12 to 13 GPH to keep the cht's in line with ECi recommendations (400 to 435) (now I know the real world says 380) now only takes 9.5 to 10.5..........:D

The engine is broken in now or is very close to it (85 on the hobbs) and is a real joy to fly. I have completed the first inspection and all is good......

I finally got the RV Grin at about 60 hours when I took a close look at my numbers and realized that all wass well!!!!!!!!!

I think most of us RV builder want that perfect machine even with regards to those things that we have a hard time controlling. These engine have a personality all their own. Some hot some cool some a bit faster than others so..............go get that RV Grin.:D

Frank @ 1L8 ...Flying and Tracken....(MT-RTG)


prkaye said:
Thansk guys, your comments make me feel a little better about the temps.



Actually not very wide. I was so focussed on the temps and concerned with tryign to keep them down while at the same time running the engine hard fro break-in, that I didn't really get to enjoy the flight.
There was also a weird feeling of disconnect... it was just like flying usually is, there was no strong association between the thing I was flying yesterday and the thing I spent four years building. Not what I expected it to be like.... almost anti-climactic. I went to bed feeling deflated, worried that my temps indicated a serious problem or that I might have done some damage to the engine at those temps.

I will definately put the pants and fairings on for the next flight (not till mid next week), and probably wait for a day when it's not so warm out. I'll also goup a bunch more High-temp RTV around my baffling to seal any places that might be air leaks.
Click to expand...
 
Good going, Phil. Beautiful plane and a great landing. ...nose gear coming down ever so smoothly. Sweet!
 
First flight temps

Great job! I know the feeling.... just made my first flight last weekend!

I've not had any problems with CHT or OT.... BUT I installed exit louvers in the bottom of my cowl to help with cooling. (http://www.mykitlog.com/users/display_log.php?user=n539rv&project=161&category=3629&log=90985&row=16

I had heard from several folks that high CHT's were something of a common problem and that putting in these louvers really helped. I've not flown without them yet, but I can say I have great cooling.

With 91 Deg OAT, 82% power (3500'; full throttle and prop set at 2400 RPM), w/ EGT's around 1300 (125 Rich of Peak), my CHT's are stable at 398 to 375 and oil temp at 182. With only the nose pant installed, I'm getting IAS of 152 MPH and TAS 172 MPH.

Also, right at 30 min into the first flight, my CHT's all dropped about 40 DegF.
 
Page 3-11 of Lycoming Operator's Manual:

"Max CHT: 500 degree F. At Bayonet location - For maximum service life of the engine, maintain cylinder head temperatures between 150 degree F and 435 degree F during continuous operation."

I am on my second set of cylinders (ECi SB). I have followed the ECi run-in/break-in procedures. Initially my CHTs would go beyond 435 degree F during climb out even at 100 kts. I usually level off for it to cool down below 400 degree F before climbing again. It takes many hours (50+ hrs according to ECi) for the cylinders to break in. Eventually temperatures all settle down. http://www.eci.aero/pdf/BreakInInstructions.pdf

I know a lot of people have better cooling and low CHTs. I feel okay as long as I am operating within the limits set in the Operator's Manual.
 
problem maybe found

Well, a week after my first flight and I finally got out to take the cowls off and do an inspection. I think I may have found a cause of my high CHTs (and slightly high OT). After removing the top cowl, one section of the top rubber baffle seals in the #4 cyl was turned out instead of in. This was a relatively small section of material, but I suspect this could still have a measurable impact on temps. Now, I cannot be certain that hte material did not get flipped-out during the act of removing the upper cowl, but I removed it pretty carefully, so it's at least a good bet. I also added a tonne (couple tubes) of red RTV all over the place, particularly around the front of the inlet ramps where were some major gaps between the edges of the ramps and the engine case. I also added the RTV around the back and sides, and anywhere I could find holes. I also taped-up the cabin heat exit on the aft baffle (that feeds air to the heat muff) - I don't need cabin heat in the summer. I also removed some flashing between some of my cylinder cooling fins (it wasn't a huge amount, but some definately visible chunks).
I'm hoping to get up again on Monday morning, and hoping that all these improvements bring my CHTs down under 400.
The bad news is that my homemade restrictor fitting for my manifold pressure port was blocked, and so I actually had no MP reading on first flight. I therefore do not know if I was developing sufficient power to facilitate break-in. I was only runnign 2300-2400RPM, and so I may have compromised break-in during this first hour :( I just hope the glazing isn't too severe.
 
Phil,

I found that my rubber would flip back....if it was too wide.. Sounds backwards to what you might think but after I cut it back about 1/2" it stopped doing that. Just don't make it too short.

I also riveted the corner together with the side piece and this might have helped as well.


Push that black knob all the way in, climb till you see 75% power on that EMS and hang on!!!!
 
update -2nd flight

Update. I did my 2nd flight this morning. Looks like my baffling improvements have helped. My CHTs were noticeably better. My oil temps were also better. Still a bit high, but hopefully they should continue to come down as I get a few hours on the engine.
When running WOT (~2650RPM on a FP) the hottest cylidner was only about 421. When runnign about 80-90% power (~2500-2600RPM, ~27"MP (FP prop)) I was seeing under 400 on cylinders 1 and 3, under 410 on the others. Throttling back to around 75% power the temps all dipped below 400. Oil temp pretty stable around 196. With still under 5 hours on the engine including the run-in at Aero-sport, these seem reasonable.
The ambient temp was considerably lower than first flight, but I think at least some of the temp improvement must be due to my baffle improvements.
At least now I can feel relaxed about flying it hard without worrying about damaging or compromising break-in.
 
That is great news Phil. Those CHTs look pretty good.

The OAT was a lot cooler this morning than it would have been when you did the first flight, so that will have caused a significant percentage of the CHT and oil temp drop you saw. Depending on how the engine temperatures and OATs go, you may need to do much of your testing in the morning until the engine gets a bit broken in and its temperatures start to come down.
 
prkaye said:
....... I also taped-up the cabin heat exit on the aft baffle (that feeds air to the heat muff) - I don't need cabin heat in the summer. ......
Click to expand...

I think you need to maintain some airflow thru your heat muff to prevent it from overheating.
 
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