231LV

MP is around 29 IIRC and hottest CHT is around 340....I set FF at about 9 gph when running LOP. I have Gami's and the spread is pretty tight....tight enough that when I keep leaning, all the cylinders "wink" out around the same point. I run 2500 RPM which is where the prop is supposed to be most efficient...I will give it a try

Wow! Those are great numbers for a non intercooled, fixed wastegate TSIO360GB. I seem to be temp limited on my TIT (1650) and can't get above 57% hp running LOP and I have a intercooled, Merlyn, TSIO360LB. I don't spend much time up in the FL's and rarely run ROP (unless I am in a real hurry to get somewhere then I'm running 80% at 18-19 gph) so I can't compare what you are seeing to what I am seeing but TIT seems to be my significant limiting factor

Betting it was a slipping coupler...you experienced what most of us see when it starts to slip...OH replaced it

Will do, sir!

I am intercooled...great info and very appreciated!

As a quick followup, I took the plane out this morning after I had my mechanic turn up the fuel flow. I climbed to FL190 at 500 fpm steady, full rich, full prop(2640 rpm), cowl flaps open, 100% power. Hottest CHT was 350, oil temp 173, oil pressure 53psi. The fuel flow "only showed 22 gph" but I assume closer to SL it registers higher (23.5 gph). The only "issue" was the CDT which went over 280 at FL190 and 100% power. I pulled back the power a bit and leveled off and it dropped down to around 275...I am wondering if I need a bit more fuel cranked in to cool the CDT...everything else looked fine.

good to know, thanks

I have been flying this plane for about 20 years so well aware of flying behind a turbo BUT all suggestions are gratefully accepted (as OLD dogs CAN actually learn new tricks). I will have my baffles checked and have the FF adjusted up by another .5 gallon....running around 23.5 gph full throttle with intercooler and Merlyn. I posted on here because I suspected I was running hotter than I should have and since I haven't pushed it up this high, I was operating in a new environment for this engine. My old GB I took to FL220 a few times and I don't recall the temps getting as high as I saw yesterday but that was many years ago before the Merlyn was installed. I am very familiar with Deacon and his articles and have read them over a couple times and yes, I do run LOP during cruise. I think I will try another climb with the nose lower and see what that yields and will report my findings back here. Regarding the GAMI spread, yes I have run it a couple times and all cylinders are very closely matched...in fact, they will all nearly simultaneously flame out if I go too lean. I am suspecting my culprits are climbing too steep, poor fitting baffles and a fuel flow setting a bit on the lower side.

OK it sounds like my engine is working as designed...lowering the nose would have been a prudent move. I was also using about 82% of power available as I knew pushing up the power would increase the heat significantly. I also know that thinner air produces poorer cooling and combined with the turbo working harder equals lots of heat. I was trying to establish parameters for a sustained climb so I tried to keep the climb rate steady but clearly the rate needs to be a bit less to help with cooling. Thanks all

I had an early morning flight today and decided to push into the higher teens. During the climb to 16,500, I noted my hottest CHT (#3) went to 405 degrees and oil went over 210 (triggering the alarm). Outside air temp was 4 C as the temps pushed through 400...I was planning on picking up a pop-up clearance to climb into the flight levels but after seeing how hot things were getting I decided to stay at 16,500. This is the highest I have climbed since overhauling the engine about 5 years ago so maybe this is normal but I don't seem to recall these temps on the old GB engine (the OH was upgraded to an LB). Climb rate was about 650 fpm steady. Everything fully forward (except throttle)and full open cowl flaps...

Agree with other 231 drivers....been flying my 231 since 2003 and never used the boost pump in any circumstance...

Hate to be the bearer of bad news but whenever mine started "twitching" or swinging wildly, my coupler was slipping. I have replaced a coupler maybe 3-4 times in my 20 plus years of ownership. My A&P chased down everything else it could possibly be (including everything mentioned in this thread) before pulling the coupler. Now, we just go straight to the coupler and the problem is solved.

If you pick a top paint shop, none of your concerns are necessary. The best shops do superb prep including straightening, filling, cleaning, ect. Pay a bit more for all new stainless steel screws which go on after the paint and prevent the paint seam from being broken when a screw has to be removed. The quality of paint, at a top shop, will easily last in all but the harshest environments. I had my plane painted three years ago and the shop did a superb job.

As a 20 plus year 231 owner/operator, I can say everything previous posters have said is correct. A 252 lets you set it and forget it as they say but the 231 requires a bit of "finesse" on the throttle. The Merlyn is a great wastegate but it will allow you to easily over boost the engine if you are too aggressive on the throttle. I like to use a whip analogy to describe the way a Merlyn works. Think of the difference in distance traveled between the handle(throttle) of the whip and the tip(engine boost). That is how the Merlyn reacts to throttle input. Hence, I added a vernier throttle which makes fine tuning the engine much, much easier. An intercooled turbocharged engine requires different MP settings...so you will not be able to get 40 inches without risking a head separation. Most 231 drivers will admit(under duress) a 252 is a better engine/airframe combo but you pay for that and the 231 gets you pretty close to the 252 on a significantly reduced budget.

turn on the Master and throw the speed brake switch....if they work, they are electric, if not, vacuum-driven