Shadrach

I don’t care where the thermocouple is mounted; if your take off EGTs are 1450, your engine is not rich enough. Have you ever seen an O360 that would generate a peak EGT of 1700? Regardless of thermocouple position, certain things are obvious from raw numbers.

I also have it on good authority that raw EGT numbers are meaningless. Apparently some of these NA engines peak in the high 1600 to 1700 range...

A lot of NA IO360s will go run acceptably at 100LOP at low altitude, there's just no operational utility in doing so. Down low in cool weather I can lean to a second EGT rise just before it starts to miss. That's typically a bit beyond 100LOP. At lower MP it gets a bit buzzy for my taste beyond about 60LOP. So many of these engines will smoothly run quite a bit leaner than is needed for the power being produced.

I have it on good authority that these engines don't need more fuel flow...

Weird set of symptoms. I would think intake leaks would be most prevalent at idle. I don't think he'd see the 50rpm rise going to ICO if unmetered air was entering the system. Nevertheless the coughing and sputtering during ground ops reads like an intake leak. Seems like starting at the air box and filter and working back would be a cheap first step. As would doing a leak test.

TAT system is not even close to 38". It's a standard NA engine with a turbo normalizer. Max MP is likely something like 31". Given the higher C/Rs, TIT limits are likely not an issue for the TAT system. Those guys would run 80-85% power in LOP cruise. My guess is that it's challenging to run high power LOP in most K models below MP redline and no one wants to climb at 65% or less.

Seems likely that this is an issue with the instrument and not the fuel system. My mechanical gauge reads rock solid in flight at about 27psi (IIRC), turning electric pump raises pressure to a hair under redline (30psi). I would be bummed to be dealing with your issue. I rely on a timer and the gauge to run the tank to (near) empty on long XCs. I get the alarm and sure enough see the needle bobble within a minute or minutes if my estimation was conservative.

For those of us that fly NA Lycomings, The RSA fuel injection does reduce FF as available MP decreases. The system is not perfectly precise, but it does hold a ballpark air/fuel ratio once set by the pilot. The mixture does not really get richer and richer so much as the mixture set at lower altitude is more rich than needed for the power produced as MP decreases in climb. LOP climbs are not really worth it for a high performance single, too much fiddling with the knob for a short lived, minor gain in efficiency and reduced climb performance. I would think the opposite would be true when you have a turbo that can hold a constant MP up to cruising altitude. As I recall both Walt Atkinson (RIP) and John Deakin (RIP) spoke of using LOP climb settings when operating their TN'd Bonanzas. Something else must be a play. Are you not able to run sufficiently lean to keep temps in check? It's as if you're saying that when LOP in cruise, CHTs and ICPs are lower but not when the aircraft changes to climb pitch and airspeed. I know you don't believe that, so I am curious what the issue is.

Nice job on the fabrication! I’ve always thought of windlace as decorative finish rather than functional barrier to the elements. It’s good that it muted your wind noise. You might look closely at the door seal to see if it’s torn or deteriorated.

Mine says the same, but I’d not be happy with it. Currently I see about a 50 rpm drop and no difference from mag to mag. now that I reread the OPs post, chasing an extra 30-40 rpm drop is not worth the effort if all else is well.

That’s my understanding. I priced both when I needed overhaul. Talking to Ole sold me. I posted details of that conversation and my initial impressions in 2019. They’ve done a good job of holding prices. $450 in 2019 and $500 in 2023

Are you using the #2 cylinder as a reference when you lean? Something is very odd. If I leaned to just smooth of rough, I’m pretty sure all of my CHTs would be south of 300.

Did you get your pump from Aeromotors? One of the improvements they make is to eliminate the “wet side” fuel lubricated sleeve bearing and replace it with a dry side sealed bearing. This means the Aeromotors pump is not subject to damage from dry running. Ole Bartlett the owner of Aeromotors told me that his pumps have been test run dry in excess of 10hrs with no signs of damage.

I believe some planes had a small glove box there. My 67F has a radio compass there. Remove the outer passenger side instrument panel and have a look.

I’ve always thought that aft of the cabin was a better location with regards to access, but given the light weight of the O360, wondered if it negatively impacted CG.

Mags have internal timing that is set to spec during IRAN/Overhaul. The fact that they have an identical drop makes me suspect that the timing was precisely but incorrectly set when the mags were installed.

Reads like a timing issue. Given the drop is equal but but out of limits It sounds like the timing is retarded. the Question is whether it’s external or internal.

I did not say that Compression ratio had a bearing on the fuel flow. Compression ratio drives thermal efficiency and ICP. Peak vs mean ICPs are affected by fuel flow. You’ve said a lot there that is conceptually correct but avoided ringing in on the different Factory FF specifications for the same model from its inception until its discontinuation. Given your experience, I’m sure they’re quite a few early C model owners who’ve exhausted their efforts sealing baffles and replacing seals that would love to have someone solve their CHT issues.

Not stats but specifications. One must get used to contradicting numbers if one is going to examine decades of factory technical data...especially POH data.

See @PT20J's post above. Call Aeromotors and schedule and exchange/overhaul. I suspect that pump doesn't owe you anything in terms of typical Dukes service life. The good news is the the overhauled unit will be improved in terms of performance and durability.

Valves are adjustable and seals replaceable. I do not get any hot air in the cabin with the heat circuit valve shut. None, nada, zero. In addition to feeling the temp change from the heat circuit, I can also faintly here exhaust noise when it is open even a smidge (This was not the case prior to ANR headsets). The heat circuit of the ventilation system should be in good condition and adjustment for flight. If it is not, you have zero chance of combatting a CO leak in the air. Better to be cold and conscious than toasty and passed out.

I'll admit to not realizing when others are poking fun at me. Is that what is happening here?

I think an increase in CHT is plausible especially if you're running advanced timing. All the other cylinders are well past peak. The combustion event on the single ignition cylinder is making peak pressure at a lower fuel flow than than the others because of the single point of ignition propagation. In term of ICP, it would be like having one extra rich cylinder.

Agree with the above. Sometime it just doesn't start after it fires. Being too timid getting the mixture in can make for missed start as well. I think that a healthy mechanical fuel pump does a decent job of pressurizing the system even at starter RPM. My engine will start from cold pretty easily in the cooler months just by turning the key with the mixture full rich and no prime. It takes a four or five blades to go from zero fuel pressure to start. Properly primed on the other hand, is like letting go of the prop on a rubber driven balsa model.

Do you recall if the raw EGT number was elevated on #2? Your scenario very much looks like an intermittent ignition problem we had on #2. My partner scrubbed a trip because he could not lean to peak on #2. Pre take off run up went fine. Leaning for cruise there was a noticeable power loss before #2 would peak. Our spread is tight with stock injectors but not as tight as yours. I flew it in the pattern after a good run up. I noticed #2 EGT was fluctuating and elevated at high power settings. Mag check revealed that the bottom plug on #2 was intermittent. Ran it up to full power on the ground and watched a plug drop out around 2200 RPM. I believe that in flight the process of leaning for cruise was speeding up the single ignition combustion event on #2 as the dual ignition combustion event on other cylinders leaned past peak and began to lose power. The net effect was that the single ignition #2 (our richest) was making best power at a FF where the other 3 were very lean of best power.