High Cylinder Head Temperature

dcmarotta

I have a 1980 C-180K with an O-470/U engine. It has a GEM 6-cylinder EGT/CHT gauge in addition to the stock engine instruments. The stock, single cylinder, CHT gauge continuously reads higher than the 6-cylinder GEM, sometimes threatening to pass the red line on the gauge. The GEM reads good temperatures at the same time. I'm certain that the stock gauge is reading too high, but I can't allow a red line even though I suspect the gauge. I've considered disconnecting it, but that doesn't seem right. Any suggestions?

Scott Sherer

Hi, I understand your angst. Your stock sensor/probe and gauge probably haven't had any service since 1980. Perhaps you can solve the problem with a new CHT probe. Probably an inexpensive solution.

Cessnaamphib

I owned a Cessna180K with the exact same engine. And had the same problem. Had difficulty keeping CHT’s below 380, especially #5 cylinder. I bought cowl flap extensions and that solved the problem. I could see it on my 6 cylinder JPI monitor so the change was real and observable. Never would the temps go above 390 even on climb out. I now own a C185 but I kept my cowl flap extensions in case I needed them, but I don’t so they are for sale. Cost me 450$ CDN. Willing to sell for 400$ CDN. Phone 705-232-8301.

Scott Sherer

Thanks for the info!

Cessnaamphib

The 0-470U is a hot engine. Mostly because it redlines at 2400 rpm, I would guess. That doesn’t funnel much air through the cowling. My baffling was always top notch, but still. And mine was on EDO 2790 amphibious floats. I would install my cowl flap extensions in just a few minutes when it warmed up in springtime and remove them in late fall when the air would cool. I live in Northern Ontario.

grwmogrwmo

I have a similar problem with my 1953 180//type A 470. My engine uses a thermocouple under the spark plug. Not a probe.I suspect the 470-u does too, for the original gauge. It is my understanding that the spark plug thermocouple indicates about 50 degrees higher temperature than the probe. The gauge is usually calibrated for this, thus the green is a higher temperature than one using probes. But mine still indicates a higher than desirable temp. I wonder if mine might be like the one above that indicates normal temp with an engine monitor.
My main question is what are cowl flap extensions. I’ve never seen them. Are they available for purchase.

grwmogrwmo

Yes I am interested in purchasing the cowl flap extensions.
870-740-8644
Glen

Cessnaamphib

Call me if you are serious about buying them.
705-232-8301
Marc