General Info wanted about temps

[n502pd]

I would like to hear from some flyers with the AeroVee engine, and get a smattering of Cylinder head temps, EGT temps, oil temps, and exhaust stack color. I want to see if what I have is appropriate:
cruise flight,2900-3000rpm, 2500 ft, 115+/-mph, OAT about 80 deg, CHT 250-290, EGT 1050-1150, oil temp 170- 185 (estimated) oil press 65. Cowl exit enlarged 25%, very tight baffeling seals to the extent it can take two to install cowling. TT on engine is 3.9 hrs. Stack color is a med gray using 100 LL. Leaned to about 3/4 in out. I feel I am pretty close to what I want, and can richen or lean to my needs. Stack color darkens when I dont lean, but I wish to have the option to richen up if needed. I do have an oversized bottom oil cooler installed for Tx heat.

Thanks for any input!

PS--vacation from 8/13-8/29 and no interweb!

[MichaelFarley56]

Hi Joe,

This is just my two cents so take it for what it's worth, but with CHTs that cool you can probably lean your mixture or lean your needle valve just a little to save fuel. Given your air temps, those CHTs are incredibly low but if you have tight baffle seals and an enlarged bottom exit area, that makes sense.

I will normally see CHTs range from 290-350 with EGTs around 1250 or so.

What rpms do you get when you run your engine at wide open throttle? Remember, you're still breaking in those cylinders so don't be afraid to run the engine hard for a while.

Sounds like she's running great!

[n502pd]

Your 2 cents is certianly worth more than that face value!!! I do understand that I can lean a bit more, and I do when cruising around the airport, but I like the fact that I do have more fuel to feed the beast if needed for some yet unforeseen reason durring break in. I wanted to get others thoughts anyway. And egts do show more lean is available. Just another thing to investigate as to how much. I did a high speed...yellow arc/140+ mph ..shallow dive at WOT and saw over 335o rpms, and throttled back as its still new. No flutter...that was the test. I had it leaned a bit at that time. I feel it could have gone more. Standard non turbo prop. I also took special attention durring the engine build to break away any flashing from casting between fins and any .other place it showed up, on the heads.

Thanks for the input!
Keep the bottom side down...mostly!!s

[radfordc]

Joe, your numbers look great! Remember, you don't want to baby the engine too much during breakin. It's OK to run wide open for a period of time if you can do so and keep the temps in the green.

[mike.smith]

I would like to hear from some flyers with the AeroVee engine, and get a smattering of Cylinder head temps, EGT temps, oil temps, and exhaust stack color. I want to see if what I have is appropriate:
cruise flight,2900-3000rpm, 2500 ft, 115+/-mph, OAT about 80 deg, CHT 250-290, EGT 1050-1150, oil temp 170- 185 (estimated) oil press 65. Cowl exit enlarged 25%, very tight baffeling seals to the extent it can take two to install cowling. TT on engine is 3.9 hrs. Stack color is a med gray using 100 LL. Leaned to about 3/4 in out. I feel I am pretty close to what I want, and can richen or lean to my needs. Stack color darkens when I dont lean, but I wish to have the option to richen up if needed. I do have an oversized bottom oil cooler installed for Tx heat.

For break-in those numbers are awesome. I would run WOT per the break in recommendations, and just make sure you don't go over 390 on the CHTs (my personal high end) if you're pushing the engine hard. My numbers after 270 hours are very similar to your current numbers, but my CHTs in those OAT's would be more like 290 for the coolest, and 340 for the hottest (#3 for me) when running at 3,000 rpm.

[n502pd]

Thanks for the encouragment! I think I am on the correct path with my observations, and wont baby it at all. a side note, after the high speed test was initiated, about half way thru the pass the engine picked up some rpm and seemed to run 'easier', if that can be imagined! maybe that was a good thing to do?! It and I survived in good shape, and nothing fell off!!!

[wlarson861]

In the first 50 hours if you have cht's below 375f I would revisit the tuning as it is probably way too rich. pull a few plugs and see if they are carbonizing . Most new aerovees are lucky to stay under 390 in the first 20 hours, especially in a long hot day climb. Also as stated above run the engine pretty hard to make sure the rings seat well.

[gammaxy]

In the first 50 hours if you have cht's below 375f I would revisit the tuning as it is probably way too rich.

His measurements appear to have been made at a low power setting (2900-3000 rpm at 115 mph). In this case, I don't think his temperatures are unusual.

It only takes about 55 horsepower to fly a Sonex at that speed so there's much less heat to deal with.

Joe, flying extended distances at wide open throttle until the temperatures and airspeeds stabilize will help collect the necessary data to further tune the aeroinjector (if needed), secondary ignition, and cooling, and will probably help with break-in. I initially tuned my aeroinjector a bit lean and only noticed once in WOT cruise flight at over 135mph when the rpms were high and I got an occasional "miss" due to being too lean despite being full rich. As the fixed-pitch propeller unloads and rpms increase, the engine generates more power and demands more fuel, but you can't recreate that scenario and allow the engine to develop maximum power without the 135mph wind.

[n502pd]

That is very interesting, Chris! I will try to leave it at wot next time I fly, probably in a couple of weeks as I will be out of country for a while The short time I did open to wot, I got some roughness, which I cleared immediately by leaning a bit. It ran smoothe afterwards. I have pulled the bottom plugs and they were very clean. Now, in my own defence, I have built engines for other things and have not really babied them, but I dont want to have pieces with part numbers on them to come out, so to speak! I therefore sort of cringe about WOT for long periods on a 4 hour engine. But 3500 rpms isnt really that high! I shall endevor to continue!:))

[mike.smith]

Thanks for the encouragment! I think I am on the correct path with my observations, and wont baby it at all. a side note, after the high speed test was initiated, about half way thru the pass the engine picked up some rpm and seemed to run 'easier', if that can be imagined! maybe that was a good thing to do?! It and I survived in good shape, and nothing fell off!!!

My engine always runs better after I've been flying for 20 or 30 minutes or so.