What Temps are Normal?

bluemaule · #1 10-23-2011, 03:31 PM

For an RV-7 with a Superior O-360, what would be considered normal operating temps? I manage the fuel flow to run about 360 degrees CHT - #3 is the hottest, and am wondering what EGTs I should see... around 1300?

Thanks for your help!

RV10inOz · #2 10-23-2011, 03:44 PM

Here we go

Absolute values of EGT are almost meaningless. They are best used a relative indicator of things changing. Unfortunately people think of egt like they do oil temp.

Nothing wrong with 360 cht but I would say most RV owners are well into the low 300's

As an example at 20LOP up high around 300-320f. Yesterday at high power settings down low, 40lop I had 300-314F.

It all depends. What is your fuel management strategy? If those temps you get were at 20-40LOP I would say you need to sort the cooling air flow out. Not that it is really bad but it is not optimal.

DB

PS I note it is a carby engine.....and I can get some of them LOP quite happily.

rv9av8tr · #3 10-23-2011, 03:44 PM

EGT absolute values are relative to many variables. "Normal" for one plane can be different for someone else.

woodmanrog · #4 10-24-2011, 07:53 AM

We regularly run at 2400 rpm, 21.5MAP, LOP and see cyl head temps averaging 350 degrees. We have no problem running up to 1450 on EGT's if there is no engine stumble being too leaned out. 0360 carburated w/ FP prop.

Greg Arehart · #5 10-24-2011, 09:49 AM

Blue,

Welcome to VAF. A couple points for general reference (as others have noted, there is quite a bit of variability in both parameters):

I run a Superior IO360 in my 9 and CHTs vary with OAT. Typical summer day at 65 degrees OAT, 8000 ft DA, I see around 340-350 on CHT, lower if throttled back. As noted, EGTs are only relative. Mine are mounted about 6" below the cylinder (not optimal, I know) and run around 1450 peak. At low altitude, I sometimes see them over 1500 at peak.

cheers,
greg

bluemaule · #6 10-24-2011, 08:28 PM

OK, this is helpful... so I'm not going to melt anything if my EGTs run up to 1450 then...

I have a fair amount of variation with the CHTs... 1 runs at 318, 2 at 338, 3 at 358 and I forgot where 4 is, but I think its about 320... this is at 3500' at 10.7 gph and 2300 rpm... my MP gauge is inop at the moment due to fuel vapor hitting the sensor... I need to get a longer hose, to create a P-trap for fuel vapor from the head to the sensor... EGTs are in the 1300 range... OAT 55 degrees... similar temps at 5500'...

I would like to get the engine injected and then balance the injectors... most of my time is in Twin Comanches and an older Debonair, with injected engines and less variation in temps than this particular carb set-up.

Greg Arehart · #7 10-24-2011, 09:54 PM

And, for the record, my CHTs can vary a lot depending on altitude, mixture, etc. That includes variation between cylinders - at some settings, the CHTs are all very close but at other settings, the CHTs can vary by >50 degrees. And I have an injected engine. [one day I'm going to the AFP seminar and have the injectors balanced....]

greg