dkkim73 Posted March 11 Report Posted March 11 Hello All, I took my Acclaim in for the local A&P to look at. We'd talked about some work including servicing the AMSAFE inflators, and a possible weak cylinder/hot spot on valve. Most specifically, I'd asked for him to look at fuel flow and idle fuel pressure and mixture settings on this visit, due to stumbling on go-arounds I'd been noticing. The gentleman, who is well-regarded locally, also has a reputation for being extremely thorough, has recommended replacement of all cylinders as a "starting point". I won't go into all of the rationale here, but it includes some things like recently-low compressions, possible cracks between the fuel and spark plugs, etc. Note that the hot compressions were all good a couple months ago and the plane was cleared out of annual at the Mooney Factory Service Center (about 30 tach hours ago). They did boroscopy and remote assessment was primarily that there was one hot spot on an exhaust valve to watch. I do subscribe to SavvyMx and have received advice, also from others, that a more conservative step-wise approach would be good. Including lapping valves in place and a ring flush procedure. Rotocoil replacement, etc. And the fuel thing is quite possibly entirely separate. Many (an overwhelming # of, actually) details aside, I am trying to find shops reasonably close for a 2nd opinion. Am currently based at KBIL. Got two good recommendations but they are in Texas. Anyone have detailed experiences with shops in the region who might be more amenable to a step-wise approach and working closely with Savvy? Thank you, David Quote
LANCECASPER Posted March 11 Report Posted March 11 16 minutes ago, dkkim73 said: Hello All, I took my Acclaim in for the local A&P to look at. We'd talked about some work including servicing the AMSAFE inflators, and a possible weak cylinder/hot spot on valve. Most specifically, I'd asked for him to look at fuel flow and idle fuel pressure and mixture settings on this visit, due to stumbling on go-arounds I'd been noticing. The gentleman, who is well-regarded locally, also has a reputation for being extremely thorough, has recommended replacement of all cylinders as a "starting point". I won't go into all of the rationale here, but it includes some things like recently-low compressions, possible cracks between the fuel and spark plugs, etc. Note that the hot compressions were all good a couple months ago and the plane was cleared out of annual at the Mooney Factory Service Center (about 30 tach hours ago). They did boroscopy and remote assessment was primarily that there was one hot spot on an exhaust valve to watch. I do subscribe to SavvyMx and have received advice, also from others, that a more conservative step-wise approach would be good. Including lapping valves in place and a ring flush procedure. Rotocoil replacement, etc. And the fuel thing is quite possibly entirely separate. Many (an overwhelming # of, actually) details aside, I am trying to find shops reasonably close for a 2nd opinion. Am currently based at KBIL. Got two good recommendations but they are in Texas. Anyone have detailed experiences with shops in the region who might be more amenable to a step-wise approach and working closely with Savvy? Thank you, David Unless this guy specializes in recent Mooneys I would thank him for his time and pay him and get it out of there. Call Brian Kendrick if you want someone to look at it that knows what they are doing. Mooneysupport.com 4 Quote
Fritz1 Posted March 11 Report Posted March 11 Brian Kendrick in TX is my go to guy, knows more than other people Tel. 830 370 1190, extremely thorough, close by Arlins in BZN, Mooney knowledgeable, good all around shop. Quote
EricJ Posted March 11 Report Posted March 11 1 hour ago, dkkim73 said: Hello All, I took my Acclaim in for the local A&P to look at. We'd talked about some work including servicing the AMSAFE inflators, and a possible weak cylinder/hot spot on valve. Most specifically, I'd asked for him to look at fuel flow and idle fuel pressure and mixture settings on this visit, due to stumbling on go-arounds I'd been noticing. The gentleman, who is well-regarded locally, also has a reputation for being extremely thorough, has recommended replacement of all cylinders as a "starting point". I won't go into all of the rationale here, but it includes some things like recently-low compressions, possible cracks between the fuel and spark plugs, etc. Note that the hot compressions were all good a couple months ago and the plane was cleared out of annual at the Mooney Factory Service Center (about 30 tach hours ago). They did boroscopy and remote assessment was primarily that there was one hot spot on an exhaust valve to watch. I do subscribe to SavvyMx and have received advice, also from others, that a more conservative step-wise approach would be good. Including lapping valves in place and a ring flush procedure. Rotocoil replacement, etc. And the fuel thing is quite possibly entirely separate. Many (an overwhelming # of, actually) details aside, I am trying to find shops reasonably close for a 2nd opinion. Am currently based at KBIL. Got two good recommendations but they are in Texas. Anyone have detailed experiences with shops in the region who might be more amenable to a step-wise approach and working closely with Savvy? Thank you, David This guy is in Wyoming (not too far for you), and seems to be very knowledgeable about Mooneys. A hangar neighbor with a K takes his airplane all the way up there for annuals. I don't have any personal experience with him. https://knr-inc.com/ 1 Quote
LANCECASPER Posted March 12 Report Posted March 12 41 minutes ago, EricJ said: This guy is in Wyoming (not too far for you), and seems to be very knowledgeable about Mooneys. A hangar neighbor with a K takes his airplane all the way up there for annuals. I don't have any personal experience with him. https://knr-inc.com/ Kerry used to do articles for the MAPA magazine - very knowledgable. Quote
Fly Boomer Posted March 12 Report Posted March 12 1 hour ago, dkkim73 said: The gentleman, who is well-regarded locally, also has a reputation for being extremely thorough, has recommended replacement of all cylinders as a "starting point". I don't know anything about your airplane, how long you have had it, how many hours on the engine, how your predecessor flew it, or how you fly it, but I would be stunned if you needed six cylinders. Not saying it's impossible, but I would absolutely want some additional opinions -- not least of which is from Mike Busch's organization. 2 Quote
dkkim73 Posted March 15 Author Report Posted March 15 Thank you guys for the good info and thoughts. I did speak to Brian Kendrick... On the original issue: he thought the mixture was likely too lean based on the story (assessment of the local guy) where we had all thought maybe too rich previously. Might also explain some marginally-higher TIT's on takeoff. The local guy just did a fuel check on my request, said all he had to adjust was mixture to get rid of stumbling. Flight testing pending. As for the cylinders, he thought lap #3 (hot spot, low compressions recently and intermittently in past) and flush #4 (lowish recent compressions). Anyhow, I did find a shop less than 2 hrs away recommended by a DPE. The guy I talked too was very open to valve lapping, suggested it de novo in fact. Oddly the place I'm looking to commute to soon. So hoping to get them to try that on the 2 low/lowish cylinders. Went to the shop yesterday evening. I can see and hear the compression findings. The cracks in the three cylinders (2,4,5) are not macroscopically visible but show on eddy current. Some say this is too sensitive (the local A&P works on a range of aircraft including turbines and has a lot of gear). He seems totally sincere that he thinks this is a real relevant crack but also says he replaces them right away and has never seen a failure and can't give me any predictive #s on failure rate. So... maybe ECI is too sensitive a test (several say yes), or my CB glasses? He's offered to advance the work, let me pay later, etc, so I think this is just his philosophy (shop is busy so I'm sure I'm not a cash cow, probably more of a sad idealistic foundling with a nice plane). I'm currently planning to fly the plane to the other site and have the less invasive things done first. At least a few knowledgebale, though remote, folks, encourage this and say the AC is flyable. Part of me thinks, hey 1450 hrs SNEW, the two problem cylinders still original... maybe order a few spares? Maybe talk myself into more? Still not yet had an oil analysis or scoping into the camshafts etc so I don't know how long replacing a bunch of cylinders (1-6) would extend things vs a full overhaul, vs going on-condition. If the bottom end is solid, I might be inclined to throw newer jugs on and let it ride (Mike Busch is having indigestion as I think this right now about the first part, probably approves of the second). Any thoughts appreciated, D Quote
EricJ Posted March 15 Report Posted March 15 Knowing where the eddy current imaging is reporting cracks, one option is to keep an eye out there with periodic inspections, dye pen, etc. If they're not evident on the surface and it doesn't spread, great, if it does, you know where to look. Sounds like you've got a good handle on it regardless. 1 Quote
Fly Boomer Posted March 15 Report Posted March 15 11 hours ago, dkkim73 said: I might be inclined to throw newer jugs on and let it ride (Mike Busch is having indigestion as I think this right now about the first part, probably approves of the second). The Mike Busch comment made me laugh, but that's kind of sickening, and it's not even my airplane. Clarence, a mechanic in Canada, once said he was not too impressed by the TSIO-550s in the Mooney or the Cirrus, and he had seen a bunch. Sorry for your woes. Quote
dkkim73 Posted March 15 Author Report Posted March 15 10 hours ago, EricJ said: Sounds like you've got a good handle on it regardless. Well, clearly I come across better in print. I'd had that exact same thought about knowing where to look, and managing it expectantly. 1 Quote
dkkim73 Posted March 15 Author Report Posted March 15 28 minutes ago, Fly Boomer said: The Mike Busch comment made me laugh, but that's kind of sickening, and it's not even my airplane. Clarence, a mechanic in Canada, once said he was not too impressed by the TSIO-550s in the Mooney or the Cirrus, and he had seen a bunch. Sorry for your woes. I appreciate the thoughts. I read a lot of Mr. Busch's writings in the early AvWeb, and catching up on all his work since I became an owner, I have to say he does make a lot of sense. The Savvy people (I subscribed to Mx) seem very knowledgeable and helpful. They have a very empirical approach, review data logs, etc. I think the challenging thing is the sheer heterogeneity of viewpoints among A&Ps. I'm not philosophically opposed to a top and running it over nominal TBO with inspections to "get the value out of it", I just wish I had a better sense of probabilities. My own motivation to do more prophylactically is driven primarily by wanting to have use of the airplane (e.g. bigger hit now vs. multiple potential downtimes for maintenance). As for the TSIO-550(G3)... one does read a lot of stories. I am given to understand it is a very thermodynamically efficient engine, and some aspects of it seem very elegant to me. Certainly a lot of power, and I would hope the derated application (280hp in the M20TN) would improve reliability. The cylinders do sound like a perennial weak point, though. What is the collective wisdom on choosing replacement cylinders? I read things about new-in-box Continental cylinders sometimes not being right, etc. Some rebuilders will re-do the cylinders. Or is that costly overoptimization of a part that is simply more likely to need work or replacement regardless? D Quote
GeeBee Posted March 15 Report Posted March 15 When someone says, "replace all 6 cylinders" that is a non starter for me. There may be some weak cylinders but they all don't go bad and they don't go bad in 30 hours. Fix the exhaust valve and get the FF right. Take it from there. 3 Quote
Fritz1 Posted March 15 Report Posted March 15 Sounds like you are making all the right moves. I trust Kendrick's judgement. Regarding tweaking new or overhauled cylinders I have heard good things about Gann in Georgia and Victor in CA. New Conti cylinders apparently leave room for improvement, think Gann hones the valve guides and puts a fancy multi angle grind on the valves and valve seats, think he has a stock car guy that does this kind of thing for him. Best way to find out what is what is to call them. Getting an airplane that is new to you into the shape you want typically takes 2 years, nothing you did wrong, nothing the seller did wrong, nothing the broker did wrong, probably nothing the pre-purchase guy did wrong, just the nature of the beast and the cost of doing business. You carefully expand the envelope without getting into trouble, fix whatever pops up the best way you can immediately and eventually you have a reliable bird that goes wherever you want whenever you want. 3 Quote
Fly Boomer Posted March 15 Report Posted March 15 7 hours ago, dkkim73 said: What is the collective wisdom on choosing replacement cylinders? I read things about new-in-box Continental cylinders sometimes not being right, etc. Some rebuilders will re-do the cylinders. Or is that costly overoptimization of a part that is simply more likely to need work or replacement regardless? I'm not up to date on the latest, but I am attuned to the argument that valve seats concentric with the valve guide is a good idea. Also, the argument that valve guides reamed or honed after being pressed in is better than assuming they won't change size or shape while being pressed in. Finally, I'm a sucker for the upsell so, if I had to put on cylinders, I would give a hard look to the builders that can give assurances that, in some cases. their cylinders are "better than new". Best of luck on this journey. Quote
jlunseth Posted March 21 Report Posted March 21 Here is a current article from Mike Busch (just a few days ago) and the link to a Wings seminar he is putting on. https://www.savvyaviation.com/ending-the-war-on-jugs/ Here is the FAASafety Seminar: "Ending the War on Jugs" Topic: Safety information to determine cylinder condition and tips to remedy issues prior to removal. On Wednesday, April 3, 2024 at 19:00 Central Daylight Time (17:00 PDT; 18:00 MDT; 20:00 EDT; 14:00 HST; 16:00 AKDT; 17:00 Arizona; Thursday, April 4, 2024 00:00 GMT) Select Number: GL13127672 Description: Historically, the rule A&Ps were taught about cylinders was simple: If the compression reading was less than 60/80, the cylinder had to come off for repair or replacement, period. This works well for mechanics, who are always happiest when they have clear-cut guidance to follow. But it was bad news for aircraft owners, who have to shell out several thousand dollars each time a jug gets yanked, and occasionally suffer catastrophic engine failure when the cylinder installation isn't done precisely right. In recent years, we've developed far more effective methods of assessing cylinder condition, catching problems early, and remediating them without the need for costly and risky cylinder removal. In this webinar, Mike Busch discusses these modern methods, techniques, and practices. To view further details and registration information for this webinar, click here: http://www.faasafety.gov/SPANS/event_details.aspx?eid=127672 The sponsor for this seminar is: FAASTeam 2 Quote
Danb Posted March 21 Report Posted March 21 David my Acclaim had poor compression like many had, I purchased it 13 months ago, the pre purchase agreement highlighted the low numbers a few around 40/80 therefore I wanted a complete top done before I took the plane, now a year later it’s flying like a sewing machine smooth as silk for a piston plane. Still learning flying it LOP which it likes opposite on my Bravo. The acclaim went a year and half without an oil change based on the lack of care I chose to do quite a bit prior to me taking the plane. After my first year things are going well. Your bandit is beautiful I hope you get it ironed out, I just lost my electric trim no more bragging about no issues. D 1 Quote
dkkim73 Posted March 22 Author Report Posted March 22 Thank you all for the info and PM's. I'll watch for the seminar. I had seen that Savvy article before, very helpful. Update: after some bush-beating and a number of calls, working with Savvy, etc, I found a shop in the region that is experienced in lapping valves in place, amenable to step-wise approaches, and Savvy-friendly. Currently planning to get them the plane for a couple days in the first week of April. Local maintenance did reveal a too *lean* mixture with other fuel set-up in parameters (low metered/unmetered, high metered/unmetered fuel flows, MP's) all nominal. So hopefully that explains the original problem (stumbling/taxi cuts/lack of power on go-around). I just got back home and have yet to flight-test. @Danb TY re: the paint job! Isn't it? It's a beautiful plane, and really engineering-wise a thing of beauty. Still a bit surreal to be able to fly it. I was a bit surprised when I got oriented to the AC that all the trim control is linked through the AP. And man is that a lot of trim turns for a Cessna/Piper pilot if you go the muscle route... I will pray for your electric trim. We need a patron saint of aviation maintenance. David Quote
dkkim73 Posted March 22 Author Report Posted March 22 On 3/15/2024 at 12:37 PM, Fritz1 said: Getting an airplane that is new to you into the shape you want typically takes 2 years, nothing you did wrong, nothing the seller did wrong, nothing the broker did wrong, probably nothing the pre-purchase guy did wrong, just the nature of the beast and the cost of doing business. You carefully expand the envelope without getting into trouble, fix whatever pops up the best way you can immediately and eventually you have a reliable bird that goes wherever you want whenever you want. This makes a lot of sense, and I've heard similar things intimated before. It's like an older used car, but at a higher level. I'm thankful that the bones seem solid. I am a struck at the range of approaches to things, e.g. cylinders. Minimalist vs. maximalist. It's kind of an art out there. Not entirely dissimilar from medicine. And probably some other complex domains. Quote
dkkim73 Posted March 22 Author Report Posted March 22 On 3/15/2024 at 12:37 PM, Fritz1 said: Victor in CA Looking at their "built" engine options is like being a starving orphan outside a candy store in a Dickens novel. ETA: I did have a nice conversation with one of their folks last week. Very interesting and he was kind and helpful. I'm waiting to hear back on an inventory on refurb'ed cylinders (in case I end up needing at least 1 or 2, hopefully not). Quote
carusoam Posted March 22 Report Posted March 22 (edited) Hey DKK… sorry for coming in so late… I have a couple of thoughts to share… There are two models of cylinders for the IO550 the G and the N… Gs are known to be very robust… Ns are better known to have crack potential… they have the fancy cooling fins, and the cylinder weighs a few pounds less than the G’s… Before getting too deep, let’s discuss compression testing for Continental cylinders… be sure the mechanic is following the procedure, with the proper orifice for the test… when the mechanic is not familiar, you get a common low compression reading. Also… often, the rings align… and give a crummy reading too… fly it, test it warm… and try again. Both cylinder types are equally susceptible to how the plane is flown… Turbo normalized engines can be run hard, and often experience suboptimal cooling at altitude… If the prior owner preferred to run his plane in full flaming dragon mode… it is possible to wear out a set of cylinders in 1k hrs…. Often, new owners find out that they have mismanaged their cylinder temps and don’t get to the halfway mark…. Nothing wrong with full flaming dragon mode… from a technical point of view… it is the ultimate go fast mode. It costs a bit more fuel and a TOH earlier than a similar bird that is flown LOP, at a bit slower speed…. A knowledgable owner or mechanic can use a dental camera and inspect the cylinder walls for the cross hatch pattern that is supposed to be there… this tells more than the single compression test… If the cylinder bore is polished smooth in spots… it is probably time for an cylinder OH… same thing for the valves… same camera…. The valve surface should look like a pizza…. Nice concentric patterns… when there is a hot spot visible at the edge… it is time to get that valve situation fixed… not something you want to wait on. valves don’t last very long once they stop rotating. The constant rotation each cycle keeps them evenly cooled…. Sticky valves have a tendency to stop rotating… and their heat damage begins to appear…. Cylinder health has little to do with the rest of the engine… they are most sensitive to air cooling issues, and how hard they have been run… The NA IO550 on the Acclaim’s sister ship… the Ovation, is known to make it to 2k hrs without any cylinder issues… Key things about temp control…. The G1000 has a white box for leaning ROP in the climb…. Keeping CHTs below 380°F in the cruise is best for their longevity… tough to do in very thin air…. See if you can download the flight history from your engine monitor… this will tell you a great deal of what to expect before peering into the cylinders with your dental camera… Fortunately, the TN’d IO550 is quite popular… it isn’t unique to Mooneys… Setting up the FF properly is important… at idle, and at full throttle… Keep in mind… you need to know what rpm your engine is turning… most Acclaims start life limited to 2500 rpm… The really loved Acclaims get their rpm upped to 2700rpm with a FF to match… at 2500rpm you may see 25gph… 280bhp at 2700rpm you may see 27+gph, with a preference for a higher number closer to 30+… 310bhp The IO550 in this application is very stout. If you are climbing full throttle to the FLs… be sure to follow the procedure for leaning during the climb, keeping an eye on TIT, and watching the CHTs… All stuff you probably remember from transition training…. PP thoughts only, not a mechanic or CFI…. fun stuff you learn over the years… Go MS! Best regards, -a- Edited March 22 by carusoam Quote
LANCECASPER Posted March 22 Report Posted March 22 On 3/21/2024 at 11:10 PM, dkkim73 said: Looking at their "built" engine options is like being a starving orphan outside a candy store in a Dickens novel. ETA: I did have a nice conversation with one of their folks last week. Very interesting and he was kind and helpful. I'm waiting to hear back on an inventory on refurb'ed cylinders (in case I end up needing at least 1 or 2, hopefully not). To keep cylinders happy on the Acclaim make sure the breather tube is kept clean. When it "cokes" up the pressure in the cylinders changes. It's an easy one to comply with and should be one of those things checked between annuals during oil changes. https://www.mooney.com/wp-content/uploads/2020/12/SBM20-312.pdf IMO, since so many cylinders were being changed and people weren't watching it closely enough, they overreacted a bit with this Service Bulletin. By eliminating the hose going to the exhaust pipe, now the oil from the breather would go on the belly. My goal is to keep the breather hose clean enough that I don't have to do this one. https://www.mooney.com/wp-content/uploads/2020/12/SBM20-319.pdf Quote
John Mininger Posted March 24 Report Posted March 24 On 3/11/2024 at 8:30 PM, LANCECASPER said: Kerry used to do articles for the MAPA magazine - very knowledgable. And thankfully Kerry's articles are still available on his website: ShopTalk Index (knr-inc.com) It would be great if an archive of all Jerry Manthey's articles were available. I have to think that MAPA still has them. Quote
NewMoon Posted March 26 Report Posted March 26 On 3/15/2024 at 11:36 AM, dkkim73 said: I appreciate the thoughts. I read a lot of Mr. Busch's writings in the early AvWeb, and catching up on all his work since I became an owner, I have to say he does make a lot of sense. The Savvy people (I subscribed to Mx) seem very knowledgeable and helpful. They have a very empirical approach, review data logs, etc. I think the challenging thing is the sheer heterogeneity of viewpoints among A&Ps. I'm not philosophically opposed to a top and running it over nominal TBO with inspections to "get the value out of it", I just wish I had a better sense of probabilities. My own motivation to do more prophylactically is driven primarily by wanting to have use of the airplane (e.g. bigger hit now vs. multiple potential downtimes for maintenance). As for the TSIO-550(G3)... one does read a lot of stories. I am given to understand it is a very thermodynamically efficient engine, and some aspects of it seem very elegant to me. Certainly a lot of power, and I would hope the derated application (280hp in the M20TN) would improve reliability. The cylinders do sound like a perennial weak point, though. What is the collective wisdom on choosing replacement cylinders? I read things about new-in-box Continental cylinders sometimes not being right, etc. Some rebuilders will re-do the cylinders. Or is that costly overoptimization of a part that is simply more likely to need work or replacement regardless? D Just went through this on my 08 Acclaim. PM me and I am happy to share what I did/learned. Quote
dkkim73 Posted March 26 Author Report Posted March 26 On 3/21/2024 at 10:54 PM, carusoam said: There are two models of cylinders for the IO550 the G and the N… Gs are known to be very robust… Ns are better known to have crack potential… they have the fancy cooling fins, and the cylinder weighs a few pounds less than the G’s… ... Cylinder health has little to do with the rest of the engine… they are most sensitive to air cooling issues, and how hard they have been run… ... The IO550 in this application is very stout. If you are climbing full throttle to the FLs… be sure to follow the procedure for leaning during the climb, keeping an eye on TIT, and watching the CHTs… All stuff you probably remember from transition training…. ... Thanks for all the thoughts and info, Andrew! I am not sure what kind of cylinders are in there. The logbook mentions replacing a prior cylinder with part # "658178A3"; a search on the web doesn't make clear what type of cylinder it was (G or N). CHTs have been, for me, pretty easy to manage in cruise (knock on my wooden head). I think it's the Acclaim cowl and baffle design and the lack of a cowl flap control for me to mis-set. E.g. from a winter flight yesterday: 334F was highest during full power/full rich climb to 12K. Then 25/2500/lean gave temps 250-280 (almost seems too low). Summer at high altitudes might be different. Not sure what this means about the history, but hopefully it was not hard to control for the prior owner. I don't have any digital logs predating my ownership. No idea if he went max power high altitude or was more conservative. I guess work on 4 cylinders could be due to anything, including the breather tube problem (serviced recently). The flight was to a different shop nearby with experience lapping valves in place. I'll let you know what I hear next week! D 1 Quote
carusoam Posted March 26 Report Posted March 26 @dkkim73 the cylinder model should be easy to tell, just by looking at it… the cooling fins for the G are very uniform… like most engines we ever see… the cooling fins for the N are alternating short, long, short, long… Not a really good description, but that is what came to mind… Best regards, -a- Quote
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