Ed Cesnalis Posted October 30, 2013 Report Posted October 30, 2013 I know this has been discussed by my searches fail to find it. As my CHT to Oil Temp differential grows I tend to believe my CHT and doubt my Oil Temp even more. Oil now runs 40F hotter than CHT. This morning's flight was below freezing temps with one strip of tape across the bottom, not quite end to end. On the ground CHT was 30F higher than Oil Temp but by the time I was leaving the pattern oil was 35F higher than CHT. I was climbing slowly at 12,000' and Oil Temp got to 250F and CHT to 210. Level I went down to 235 and 190. My confirming thermometer gets here in a week which will have to go in the oil tank but if it is cooler than my Oil Temp gauge I will know the gauge is high. What is your differential?
Anticept Posted October 30, 2013 Report Posted October 30, 2013 You should probably specify that you do not have a thermostat. My aircraft, oil is usually cooler than CHT. I'll look later and report back.
chanik Posted October 30, 2013 Report Posted October 30, 2013 Unless there is a fire burning in the engine cowl, it is pretty much impossible for oil to be hotter than CHT
Ed Cesnalis Posted October 30, 2013 Author Report Posted October 30, 2013 Unless there is a fire burning in the engine cowl, it is pretty much impossible for oil to be hotter than CHT Kurt, please explain why
Ed Cesnalis Posted October 30, 2013 Author Report Posted October 30, 2013 I think in our CT world we use gauges that are labeled CHT when they are actually measuring coolant temperature. The CHT idiot light for a Corvair was set to 475F CHT and coolant temps are in different ranges. Roger, I'm on my 3rd set of hoses and a recent inspection also been there done that on the coolers. The one thing I haven't done is confirm the high oil readings. After that I can look at my oil hoses again. The digital thermometer confirmation was your idea too.
Ed Cesnalis Posted October 30, 2013 Author Report Posted October 30, 2013 The CHT only reads metal temp out on the edge of the heads. It is not in contact with any coolant. Thanks for the correction. Interesting that my CHT remains so cool. We spent a day flushing and blowing out the coolers to perfect condition and they remain clean.
Jacques Posted October 30, 2013 Report Posted October 30, 2013 which cylinder head do you take the CHT reading ? #3 or # 1 or both .. if so ..are they the same ?
Jacques Posted October 31, 2013 Report Posted October 31, 2013 I should have taken a picture of the hose that comes out of the cooler on the top right and back to the oil pump, but I forgot. here we go Roger took that picture while visiting you remember the reason for the head removal..?
Jacques Posted October 31, 2013 Report Posted October 31, 2013 sure 2 and 3 of course the head removal was for a tie wrap the plane wasn't yours but 537..
Runtoeat Posted October 31, 2013 Report Posted October 31, 2013 Roger, instead of replacing with longer hoses, would installing a spring inside the current oil hoses keep these from kinking - similar to what is done with coolant hoses?
FastEddieB Posted October 31, 2013 Report Posted October 31, 2013 As an option to an internal spring... ...in the past I've taken a piece of slightly larger diameter hose, slit it, slid it over the problematic kink-prone area and ty-wrapped it in place. Mostly done it on garden hoses, but I don't see a reason why it might not work here.
207WF Posted November 16, 2013 Report Posted November 16, 2013 It is not uncommon for me to see 195-200 CHT and 235-240 on the oil, similar spread as Ed is seeing. WF
suntheman Posted June 3, 2014 Report Posted June 3, 2014 The Dynon's are #2 & #3 CHT. My CHT's within 10F of each other. Is it normal roger? How much differential be tolerated? Dhony
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