Low CHTs in Winter temps

[N729LS]

Living in AZ, I have worked hard to get good cooling in my -8. Clean airflow, good baffling, running LOP, etc. Now that I am traveling more, I find the opposite problem. At altitude (10.5K ?2K) in cooler winter temps, I find that my CHTs are getting too low , like <280? in cruise, and even less in the descents.
I can keep the oil temps OK by blocking air flow to the cooler, but with my rear-baffle-mounted oil cooler, that makes the CHTs even lower, since that flow now goes through the engine.
Of course, running ROP does make the engine somewhat warmer, but costs me 2 gal/hour for a 10 knot delta, and reduces range. That's what I'm doing for now, but I am wondering if others, especially those that live in colder climes, have similar problems and if they have developed any solutions?
Thanks,
Andy

[spatsch]

Not sure I understand the problem. Why are you worried about low CHTs? I understand the water burn off issue with low oil temperatures but never heard somebody explain why a lower CHT (200-300) would be bad for anything.

I guess you are wasting airflow and, therefore, speed but that doesn't hurt the engine.

Oliver

[jrs14855]

Close up the outlet some and install a cowl flap.

[JonJay]

Lots of discussions you can search for here, with lots of opinions.
From what I have read, unless you are operating at mid 200?s or below for long periods of time, for hours, pipeline survey, etc... the primary concern - lack of lead scavenging - developing symptoms has historically not been an issue.

[cross]

I built fibreglass plugs that block off about a third of the inlet air and I have a shutter on the oil cooler air. CHT's are still less than 300 degrees but I have not found any low limits from Lycoming other than 200 degrees before take-off. I would prefer to block off outlet air but the outlet area is so congested with four exhaust stacks it would be too complicated.
Chuck Ross rv4 with 1300 hours on engine.

[rocketbob]

Run mogas or TCP.

Cool temps don?t hurt anything.

[Dean Pichon]

My RV-4 (17 years old, 850 hrs) has always had very low CHTs (220-280 depending upon OAT). Just last week I had the cylinders borescoped for the first time. The cylinders, valves, and pistons looked good, but the mechanic pointed out lead deposits that he attributed to my low cylinder head temps. He suggested reducing the size of the airflow exit at the bottom of the cowl. I would like to do this, but will probably try some TCP until I get around to it.

[Red Mtn flyer]

particulate/ condensate scavenging is the issue with 'cold' CHTs, leading to associated wear/ fouling/ etc. Running richer would only exacerbate those issues. While 375F is "ideal" [ok, guys, pick your own number], some variation is inevitable.
If you have an oil temp indication, try partial blocking of the oil cooler first - it's the easiest [which is why Cessna and others used to build 'cold weather kits' that way].

[Robert Anglin]

We run an old 210 that used to go up to the high country for a few years.
Cessna had a baffle kit for it that we could put on to restrict the area of the intake air. It was just held in place by a number of screws around the opening. That along with Cowl flaps worked very well. We have thought of making fiberglass plugs that would go into the air inlets for our 8 but it seems to do well in both summer and winter conditions. We have had it up to FL-18 at around 10* F and it still does not get all that cold, we just keep some power in on the way down to keep the engine from flash cooling.
Just an idea we have not tried on an RV, just yet.
Yours, R.E.A. III # 80888

[Canadian_JOY]

A local -8A owner made some aluminum plates to partially cover the inlets. He just held them in place with clecos. He indicated they worked well in our consistently-cold winter temperatures. That is, until the clecos came out. No harm done, but his plates disappeared!