Factory IO-360 engine running warm

[jetdriven]

Mooney 201 - Lycoming engine.

We just installed a factory OH Lycoming IO-360-A3B6. 20 degrees timing, Slick mags, etc.

We have 15 hours on it now, and the CHTs are still flirting with 380-400 and that is 25 LOP and below 4000'. The airplane is noticeably slower flying like this, about 5-7 KTAS slower. The cowl flpas must be half open to maintain <360 CHT. Mixture 80 ROP? forget it. This is about 20 degrees warmer than the old engine, which had 25 degrees timing. The CHTs dropped about 20 degrees in the first 30 minutes on the first flight, yet remain at this higher level 380-400. It never used any oil, and according to Lycoming's break in instructions, break in is complete.

I am just wondering when the CHTs will stabilize at the level we had with the old engine, so i can put in a 25 degree Electroair? Has anyone recently broken in a factory Lycoming engine?

[Pat Stewart]

Not sure what the issue is, 380-400 CHT's seem normal to me. I assume your oil temps are staying around 190-210.

[RV10inOz]

you say 25 LOP at 4000, what MP/RPM and fuel flow?

At 4000 25 LOP might be the reason you have high CHT. maybe 40LOP is more like it.

And is your baffling identical? Subtle things make a big difference.

[sailvi767]

I think he was saying those are this temps in cruise flt while LOP with cowl flaps half open. Sounds like in a climb he would be well above 400. I know some on here have reported that engine break in can take as long as 50 hours before temps settle down to a final range.

George

[jetdriven]

Originally Posted by RV10inOz

you say 25 LOP at 4000, what MP/RPM and fuel flow?

At 4000 25 LOP might be the reason you have high CHT. maybe 40LOP is more like it.

And is your baffling identical? Subtle things make a big difference.

at 25 LOP at 4,000' its 25.5" (full) and 2400-2500 RPM. FF is in the mid-high 9s.

The engine will not run 40 LOP, it will, but rough and the power output is down so bad it loses 10-15 KIAS. Same baffling and new silicone rubber seals.

Correct George, closing cowl flaps the CHT will creep past 380, and climb must be done full rich, cowl flaps 1/2 open at 17 GPH with a 350 CHT. This is nothing like the old engine.