Shadrach

My 67F was threaded for tie downs. I upgraded to the LASAR jack points. I needed to cut new threads to make them work. This perplexed Paul Lowen who said he’d never encountered that issue.

I am not familiar with the extended wet wing tanks. What document suggests that the tie down enters the expanded tank? I’m pretty sure the tie down/Jack point bracket is on the back side of the spar. What kind of tie downs does it currently use?

If you’re confident in the gauge is reading, I would be investigating a potential restriction somewhere. Given that neither pump will develop normal pressure, it’s conceivable that there is a restriction somewhere. We have another J owner here thats pushing 30PSI (after a boost pump failure) most of these engines run around 26psi +/- a pound. I’m on the higher end and the Aeromotors boost pump takes me right to redline (old stock Dukes added ~.5psi). 19gph is an excellent full rich number and 15psi is within specs but only just. Have you compared the pressure on one tank and then the other? I’m not trying open a can of worms, but unexplained anomalies make me uncomfortable. Especially when there is a statistically significant sample available.

That works if you stick to warm weather. If I adjusted towards max oil pressure in the summer, I’d likely be somewhere above the green on a cool start up. I would verify that fuel pressure gauge is accurate. If you’re truly within one pound of minimum fuel pressure during cruise, it would be prudent to investigate why. Most Bendix systems are set at least 5-10psi above required pressure.

Has your fuel pressure been verified? I’m 27-28psi boost pump off and right at red line with it on. 15psi is within the green but seems low.

My cowl flaps are placarded against opening above 150MIAS. Though I don’t think leaving them in trail is a problem at any speed. In level flight, the only time cooling might be an issue is at DAs above 10K while operating ROP but even that is rare.

My dukes pump was unenthusiastic for most of its life. It sounded so inconsistent it sometimes generated strange expressions from passengers during prime.

Well I will be a little controversial once again. These are not my “recommendations”, this is my SOP based on my observations from running an IO360 well over 1000 hours with excellent and continued cylinder health. Take off full Rich In climb, lean to maintain take off EGT on leanest cylinder which is #3 for my engine (and most IO360s that I’ve observed) and is consequently the factory instrumented cylinder. All LOP ops should be conducted on the richest cylinder (#2 for me and most that I have observed), that being said, most lycs peak close together. LOP ops can be conducted at any altitude WOTRAO (ram air only in clear air), easily and safely. Speed loss is minimal at lower altitudes. It is difficult to damage a cylinder that is running very cool so that is my focus. Factory temp limitations are way too high for longevity. For climb (ROP), I start making changes if CHT’s approach 370. For cruise, I start making changes if CHTs exceed 350 (rare) in the summer or 330 in the winter. I rarely approach either of those numbers so it’s not much of a concern. In winter it’s a challenge to keep all cylinders above 300 (especially 1&4). Lycoming cylinders can safely be run hotter than 350 in cruise, but the engine just does not run that hot at any LOP power setting that I have been able to achieve. Even worm burning at 1000ft and 158KIAS. (Turbo flyers understand this as they can compare ROP and LOP in ways that NA operators can only demonstrate down low). I run as close to peak on the lean side (richest cylinder) as possible but lean enough to maintain my CHT max of 330-350. The engine almost never needs more than 35 LOP to stay cool. The higher I get the closer to peak I run. At DAs above 10.5 I switch to 100ROP unless I have a nice tail wind. Operationally it looks like running an old carbed engine, except I set 2500rpm and it stays there. At any altitude, pull to slight roughness and enrich to just smooth. Ensure richest cylinder EGT (#3 for me) is selected and enrich to ~1410 (I know that cylinder generally peaks ~1455 at high power), observe CHT trend and adjust as needed. I usually end up between 15 and 30 LOP on richest cylinder It is easy. It is fast. I don’t have to pay attention to what the table says, I don’t have, nor care to pay attention to what percentage power the engine is making. I make the most power I can at the best BFSC while holding conservative CHTs. My primary metrics of concern are CHT and OAT. My engine management strategy is entirely based on what CHT is acceptable and conservative for the given OAT. That number varies throughout the year. There is no simpler way to manage power and temperatures. Optimal temps make for happy cylinders, the rest is overly complicated noise.

Leak was the failure mode for mine both times I sent out for reseal/IRAN by DG Supply twice (they don’t service dukes any longer) and then Aeromotors. The Dukes pump was never a robust device. It sounded like it was laboring, especially on cold days. Some times on cold days it would not turn on the first flick of the switch. I only used it for priming for fear of wearing it out. Upgraded dukes pump spins like a top. I leave it on for pattern work.

Yes they are superior to the original Dukes design. I asked Ole (owner of Aeromotors) about upgrading. He said he would happily sell me one bu that his overhauled Dukes unit would be just as reliable. I’m only about 5 years post overhaul, but I have to say the new pump performs noticeably better. It’s not quieter but it sounds better, builds pressure faster an is unaffected by temperature. I believe the “continuous use” restriction is eliminated.

They used to be. I think the upgraded Aeromotors pumps will prove much more durable.

My guess is that the mechanical pump does drive the boost pump unless the sleeve bearing on the impeller shaft fails. The elimination of the fuel lubricated, sleeve bearing, is just one of many improvements that Aeromotors makes to the dukes pumps during overhaul.

They are not “Continental” cylinders. They are Lycoming cylinders made by a third party manufacturer of cylinders for both Continental and Lycoming engines. That company was Engine Components International (ECI) before they were acquired by Continental Aerospace Technologies back in 2015. Due to Lycomings many challenges ramping up their cylinder production, “Continental“ may be your only choice for new cylinders. What’s wrong with your existing cylinders?

Any competent, full service, machine shop should be able to either repair your existing piece or fabricate the half that is broken.

So the question is under normal circumstances, does the mechanical pump drive the boost pump’s impeller when the boost pump is off?

2300 is achievement for any engine but especially for what some consider to be a temperamental power plant. Did you have any cylinders replaced during those 2300 hours? What made you lose faith in the engine? Metal is not really affect by age. It’s a shame we don’t have any data from tear down. I’d have been tempted to field overhaul an engine that had proven itself to such a degree. One of the reasons we elected to field overhaul back in 2000 was that the internals were in excellent condition in spite of sitting for extended periods of time during its first 33 years.

Class act…

Was the aircraft equipped with a multi cylinder engine monitor? Too bad Churchville doesn’t have longer runways. They could conservatively limit power to 65% for all operations and avoid destroying cylinders…

Some of Lycoming’s recommendations are factually lousy. Read the bolded section below of SI1094. There is no better way to put a cylinders at peak pressure/CHT. The exhaust gas temperature (EGT) offers little improvement in leaning the float-type carburetor over the procedures outlined above because of imperfect mixture distribution. However, if the EGT probe is installed, lean the mixture to 100˚ F on the rich side of peak EGT for best power operation. For best economy cruise, operate at peak EGT. If roughness is encountered, enrich the mixture slightly for smooth engine operation. Lycoming limits power because it’s one way to protect the ham fisted and the ignorant from harming an engine. However, their recommendations are far from optimal. What’s optimal is to know which cylinder is richest and which cylinder is leanest and ensure that the rest are set more conservatively set than whichever of those cylinders is being referenced for setting power. Lycoming and the industry in general has been selling poorly instrumented engines to ignorant pilots for so long that it seems that its never occurred to them that there might be a better way. Or perhaps it’s the legal department that wishes to minimize inconsistencies in recommendations. It’s hard to defend inconsistencies in court… I am grateful that APS, along with JPI, EI, Et al…came along to fill the void. The thing you fail to grasp is that those of us that know that each cylinder is operating in the desired place on the mixture spectrum with healthy CHTs are operating under the “most conservative response rule”. Of course there will always be those that wish to operate like it’s 1960… By the way, Lycoming does not recommend LOP operations, yet you operate your engine LOP. All of your hemming and hawing about how other folks operate sort of reminds me of a person that breaks the speed limit by 10mph and then calls someone that passes at 20mph over a maniac.

Yes, I’d say that just being able to fully deploy the flaps is adequate for airworthiness, but I would never leave mine that way. I have become too accustomed to setting flap position based on number of pumps, rather than the indicator position.

A more correct statement would be that it’s hard to get an O470 to run smoothly with all cylinders LOP. It is not hard to get it to run smoothly with some cylinders LOP and some cylinders ROP. This engine was likely leaned at a high power setting and ended up with an uninstrumented cylinder operating at an abusive, ROP, mixture setting for an extended period of time. It heated up, then began detonating and self destructed. Any time a carbureted engine is leaned to rough and enriched to smooth (standard practice) there will likely be cylinders all over the mixture spectrum. That is why it’s a bad idea to lean a carbed engine above 65% power. It can be done with a well instrumented engine, doing so with a single cylinder CHT/EGT is asking for trouble.

I was think similar. It’s conceivable that even if the pump merely seized that the restriction would be less than with the impeller “windmilling” in the line.

https://aeromotors.azurewebsites.net/ Send an email (or call) Aeromotors. They may have a unit on the shelf that they can send out right away. The trouble is, you may need to wire funds as I don't think they take credit cards. Fuel pressure right at redline is not a concern for operations as Mooney's redline specification is much lower than the RSA fuel system redline (45psi IIRC). The question is what changed? Do you know where it usually runs with the mechanical pump alone? Mine is about 28psi using the engine driven pump alone; the boost pump pushes the needle to redline. You were smart not to fly. The boost pump is your only way of delivering fuel to the engine in the event of a mechanical pump failure. While mechanical pump failures are rare, a boost pump failure can on occasion induce other problems. There have been cases (rare) where internal pieces of boost pump parts have departed the pump housing and fouled the system up stream. If there is anything I can do stateside to help facilitate a pump for you, don't hesitate to PM me.

@AndreiC, what cylinder are you using as a reference for LOP cruise?

What are typical CHTs using book ROP power settings? You should enjoy lower CHTs at equal power when LOP. TIT may be a challenge to attaining the desired LOP power setting.