My 'Coupe has a C-85 with approximately 1400 hrs SMOH, swinging a 7146 prop. Here in western Nevada I generally cruise at 6 -7,000' MSL and this time of year 85 F is not unusual at those altitudes. My temperatures for cruise at that altitude and temperature generally fall in the 190-200 F for oil temp and 190-200 degrees Centigrade (375-392 F) for cylinder head temp. My definition of "cruise" may be different than others. Some folks "cruise" at 2500 RPM indicating 110 MPH or more. Some folks "cruise" at other RPMs indicating something else. I generally cruise at about 2300 RPM indicating 85-90 MPH.
I concur with Kevin1 about what the manuals say; my Ercoupe Flight Manual and Continental Overhaul Manual: max cylinder head temp 540 F; max cylinder barrel/base temp 300 F; max oil inlet temp 225 F for the C-85. For the C-75 the max cylinder head temp is 550 F. Another consideration is how many hours on the engine? Is it "tight" or "loose?" Has it normally run at 425 and 200, or has it been running with lower temperatures recently? If you recently got the Coupe, what does the previous owner say it "normally" indicated? I've been fortunate to learn and begin to understand some mechanical things during my many years as a diesel truck and equipment mechanic and quite a few years in military aviation maintenance. Though I do have an A&P certificate, I am not sure I am a "real" airplane mechanic. I do have almost 5,000 hours as a flight engineer on C-141 jet transports and they do have a lot of round temperature and pressure indicators (analog & digital) and even vertical tape indicators that I was always trying to understand what they were trying to tell me. The important thing to me about indicators and gauges is not how accurate they indicate, but what they indicate. What are they trying to tell me? If they have been indicating within certain acceptable parameters, good enough, but when those normal indications change, then I know that gauge or instrument is trying to tell me something! I try to remember gauges and instruments are just one step above a warning light; they can tell me something is going wrong before it is bad versus something is wrong and bad (idiot light)! JMHO. Aim High! Speaking of Aim High. I flew UP to South Lake Tahoe today and got 78H up to 10,500' MSL (11,900' density altitude), still climbing at 150 fpm at 85 mph IAS! 55 F IOAT, 195 F oil temp, 200 C cylinder head temp. Takeoff roll from KTVL with the young son and his camping gear, 14 gals of gas, and my fat **s, grossing 1350lbs was just short of 2000 feet, but with 8,500' DA, climb out was at 200 fpm! Good thing we take off to the north out over the lake. I am pleased with 78H's performance! Fly Safe! Willie N3378H '46 415D @ 1NV1 http://www.airnav.com/airport/1NV1 <http://www.airnav.com/airport/1NV1> --- In [email protected], "kgassert" <[EMAIL PROTECTED]> wrote: > > Ideal oil temp is 180, that is what it takes to remove the water. My > A&C operators manual states max oil temp is 225 and max CHT is 540 > for the C85. > > Kevin1 > > --- In [email protected], "Al Demarzo" noshitoal@ > wrote: > > > > Absolutely not! 425 is waaaay too hot and you're on the verge of > doing damage. 400 should be the max before you need to take action. > Not sure about 200 but I would like to see it a bit cooler. > > > > That being said, how accurate is your CHT gauge and what type of > probes are you using? Basically you need to carefully check the > conditions of your engine baffling, that's all you have to cool your > engine. Always make sure it's in top shape. > > > > Get into AVWEB and search for John Deakin's articles (Pelican's > Perch). John has been able to communicate all the proven data about > temps very well. > > > > Al DeMarzo > > Visit the Ercoupe Swap Page > > Free, Easy and No Membership Required > > http://www.ercoupeowners.com/swap/swapbook.htm > > > > > > > > ----- Original Message ----- > > From: fwellman@ > > To: Ercoupe Tech > > Sent: Friday, July 18, 2008 3:26 PM > > Subject: [ercoupe-tech] Temperatures > > > > > > With an Outside Air Temperature of 85 degrees, what is a > reasonable cylinder head and oil temperatre reading at cruise speed? > > > > Mine are about 425 and 200 respectively. Is that normal? > > > > Thanks, > > Fred > > >
