Power settings

[Davidg]

I’m having a doubt on how to manage my cruise power setting. Since I bought my mooney I use to do as the previous owner told me: rpm at no more than 2400 on a M20 J with an IO360. 
The manual says that with this power settings I’m having 50/55 % of power bitween FL80/120. 
For having 65% of power at FL 120 I have to set the rpm at 2600, knowing that the max rpm setting is 2700. 
Is it a problem to cruise at 2600 ( nearly max speed) for hours? Does it have an impact an engine life time? 

[Bartman]

The engine is rated at 2700 continuous power. I can’t quantify it but I think I use a little more oil at higher RPM. Here is how I run my J

• Takeoff full RPM and full rich.
• Climb 2700 RPM and adjust mixture in the climb to maintain target EGT.
• Level off and close cowl flaps as speed increases and CHTs decreasing.
• don’t touch prop control until speed stabilizes.
• I usually set 2450-2500 in cruise if lower than 8k.
• My Prop balance is optimized at 2500.
• Lean as desired. In cruise I am almost always LOP.
• The higher you go the more RPM you need to maintain power.
• Above 10-12 it is my experience that 2600 works well
• The one time I cruised at 15k it felt best at 2700

[ArtVandelay]

At or above 6500, it’s full power, 2400 RPM, at 10000 or above I bump up the RPMs to 2500, and at 15000 to 2600, and always LOP.
My prop was dynamically balanced at 2450 RPMs.

[Bartman]

I forgot to state that the higher I go the closer I run to Peak EGT. Above 10k I would typically cruise at peak EGT or maybe even a couple degrees ROP.  It does give just a little more power. Also, I have the A3B6D and the magnetos are set at 25deg BTDC and from what I have read, it does make a difference over the 20deg limitation on come other engines. 

[RoundTwo]

12 minutes ago, Bartman said:

The engine is rated at 2700 continuous power. I can’t quantify it but I think I use a little more oil at higher RPM. Here is how I run my J

• Takeoff full RPM and full rich.
• Climb 2700 RPM and adjust mixture in the climb to maintain target EGT.
• Level off and close cowl flaps as speed increases and CHTs decreasing.
• don’t touch prop control until speed stabilizes.
• I usually set 2450-2500 in cruise if lower than 8k.
• My Prop balance is optimized at 2500.
• Lean as desired. In cruise I am almost always LOP.
• The higher you go the more RPM you need to maintain power.
• Above 10-12 it is my experience that 2600 works well
• The one time I cruised at 15k it felt best at 2700

What is your target EGT and how did you come up with that number?

[Bartman]

https://www.avweb.com/features/avweb-classics/pelicans-perch/pelicans-perch-64where-should-i-run-my-enginepart-2-the-climb/
 

I read these articles by John Deakin many years ago.  

[redbaron1982]

What about running 26/26 for an hour? I understand that the IO-360 that we have in our M20J does not have a power setting that cannot be used constantly, correct?

As long as CHT are below 400F there shouldn't be much to worry, am I correct?

[ArtVandelay]

What about running 26/26 for an hour? I understand that the IO-360 that we have in our M20J does not have a power setting that cannot be used constantly, correct?
As long as CHT are below 400F there shouldn't be much to worry, am I correct?

I’ve been told the tests they used to certify engine consist of 3 50 hour runs;
1 of the runs are at 100% horsepower, and 1 is with temperatures at the limits. But that doesn’t mean the engine will run to TBO .

I run the engine at lower RPMs because it’s a little less vibration and noise.
I run the engine LOP because I think it keeps the engine internals cleaner, like valve stems and I like the higher fuel economy.

[Bartman]

I ran my engine at 26/26 and other high power combinations for break-in and later for a speed test, but I do not cruise low enough to see that MAP.  My engine monitor is set to alarm at 380 and that seems to be a commonly accepted maximum, but I have never seen a CHT over 360 in cruise.  If it is hot outside and gets over 360 in the climb, I lower the nose to flatten the climb and increase speed, and if I have previously leaned in the climb to maintain Target EGT the I add more fuel to go more ROP.  That brings the temps down quickly. 
 

I agree with @ArtVandelay above.  I generally cruise 7K - 9K and LoP at 2450 for the same reasons he stated. I will also add that my plane has no Hobbs meter and only the original tachometer.  As has been discussed before the tach is 1:1 at about 2550, records more time as RPM increases and records less time at lower RPM settings.  I cannot point to data to support this but it is commonly accepted.  
 

So from my perspective there is some element of longevity both from a wear consideration, and also from a timer recorded on the tachometer perspective.  Lastly the IO-360 is known to develop cracks and I generally cruise where the engine feels smoothest, which is 2500 +/- 50 RPM. 

[EricJ]

I generally only have two prop settings:   full forward or 2500 rpm.   Throttle goes to WOT at takeoff and stays there until descent to land.   Mixture controls fuel flow, EGT, etc.   

Nothing wrong with running at 2600 rpm, either.    HP is proportional to RPM at WOT, so the higher the RPM the more power it will be making.