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Old 03-02-2021, 07:27 PM
BoydBirchler BoydBirchler is offline
Join Date: Jul 2020
Location: Indianapolis
Posts: 71

RV7 with IO-360/180HP. I take off full throttle and 2700. When I get all obstacles cleared, I reduce RPM to 2500, leaving the throttle full in ( if this hurts the engine, everyone with a fixed prop is in trouble, also the CHT's are cooler).

For cruise I go LOP with 25.8 HG and 2350RPM/7.5 GPH giving 155kts TAS down low, Up high; full throttle, LOP and 2500RPM/8GPH above 8000 giving 165kts TAS.

Last edited by BoydBirchler : 03-02-2021 at 07:31 PM.
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Old 03-03-2021, 12:30 AM
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rv8ch rv8ch is offline
Join Date: Feb 2005
Location: LSGY
Posts: 3,670

Originally Posted by Carl Froehlich View Post

Sorry, but you are dead wrong.

I suggest you watch this Mike Busch video on why valves stick. It provides clear explanation as to why we should strive to maintain CHTs between 350 and 400 degrees.

A couple of slides from this video:

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I'm not clear on one thing - will running CHTs at 300 or 350 make that big of a difference on the valve stem temp? Seems like the 50 F difference there would not be that significant when it comes to the valve stem temperature. I'm certainly not qualified to challenge his numbers, but it's not clear how these were measured or how the CHT temp change impacts valve stem temp.

If I understand him correctly, this is not an issue if you run mogas or unleaded avgas.
Mickey Coggins
"Hello, world!"
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Old 03-03-2021, 06:22 AM
Scott Hersha Scott Hersha is offline
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,790

Iíve been using this app to set and program power settings on my O-360-A1A powered RV4. The interactive app simulates the power charts from Lycoming, and can be set up for various types of Lycoming engines in the setup program (click on the ĎIí in the lower right corner for instruction. Iíve programmed power charts in my GRT EFIS, and I can check it against the app on my iPad in flight to see if itís accurate. It seems to be accurate.
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
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Old 03-03-2021, 08:19 AM
BoydBirchler BoydBirchler is offline
Join Date: Jul 2020
Location: Indianapolis
Posts: 71

Mike Bush's assumption is that you are using leaded fuel, not an issue for me since I use a non-leaded 93 octane fuel.

As an aside I have freed quite a few sticking valves, by dropping the valve into the cylinder : I have never seen one that had lead residual baked on to it (operating with leaded fuel), all of the stems were coated with coked on oil....

Last edited by BoydBirchler : 03-17-2021 at 07:25 AM.
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Old 03-16-2021, 07:00 AM
VF84Sluggo VF84Sluggo is offline
Join Date: Apr 2010
Location: Gulf Breeze, FL
Posts: 26

Ok, I finished reading the suggested AVweb articles, watched the YouTube, looks like all this time I didn't know how to operate an IO-360.

WOT ALL the time? REALLY? Wow. Even if just local "sightseeing" at 1000 ft, not going anywhere in particular or in any particular amount of time?

Setting, say, 24" and 2400 RPM on a cross-country is bad juju?

Leaving prop RPM back and mixture leaned when landing?

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Old 03-16-2021, 09:00 AM
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db1yg db1yg is offline
Join Date: Mar 2006
Posts: 635
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I looked at Lyc power software Scott referenced but it is only accurate at best power mixture! Since so many of us run exclusively lean of peak, is there any software than also takes fuel flow into consideration? I would like to have it available on my iPad for quick calculations.
Dave B.
RV9a/ECiIO360/James Cowl/WW RV200 Prop
Flying since 3/06 and still smiling!!!
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