My GAMI fiasco

Have you taken John Pauls advice yet and done the flow check without the nozzles attached?
 
Dav8or said:
I suppose this is sort of a PM thing, but I looked at your dealers list for my state and LASAR is on the list. I use them for my annuals and like them a lot and highly recommend them to all Mooney owners. I'm sure they will sell and install your products, but they are not LOP advocates. They have told me not to run LOP or their will certainly be problems.

What I'm hoping to find is a shop, or mechanic that is enthusiastic about LOP to really work at getting my engine to run smooth past 15 degrees LOP.
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Dave,

I highly recommend Woodland Aviation in the Sacramento area (Davis). They are top notch, and can perform and evaluate the lean test. They are known more for Bonanza work, I think, but they can work on anything.'

Thanks,

John-Paul
 
flyingmoose said:
Have you taken John Pauls advice yet and done the flow check without the nozzles attached?
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Oh, I've definitely taken JP's advice. See post #29. As to whether it's been done, I'm not sure. It sounds easy enough but I am not much of a mechanic and don't really have the time to putz with the airplane during the academic year. So I asked my mechanic to do it, which he was supposed to have done last night. Hopefully I'll find out whether he did, and what he found, sometime today (already tried calling him twice this morning, try #3 is coming up after my office hours).
 
azure said:
Oh, I've definitely taken JP's advice. See post #29. As to whether it's been done, I'm not sure. It sounds easy enough but I am not much of a mechanic and don't really have the time to putz with the airplane during the academic year. So I asked my mechanic to do it, which he was supposed to have done last night. Hopefully I'll find out whether he did, and what he found, sometime today (already tried calling him twice this morning, try #3 is coming up after my office hours).
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You may want to try the induction leak test I described.
 
Henning said:
You may want to try the induction leak test I described.
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Sure, in fact my mechanic has performed that test more than once since I started this adventure. Induction leaks were my first thought, followed by fuel servo trouble and mag timing issues. See post #1 in this thread.

Of course there could always be a new induction leak that's complicating things now... never a dull moment when it comes to airplanes.
 
Well it seems my mechanic has gone into full incommunicado mode. At least from me. I have it on good authority that he was planning to be at the airport this afternoon to work on someone else's plane. That's fine, if you haven't already promised me to work on mine two days ago and not done it and not had the decency to let me know that you haven't done it. This is not a guess on my part, I was out there today to check and he hasn't done jack on my plane.

So I give up on him. Does anyone know a GOOD mechanic in SE Michigan who is actually taking on new customers? Everyone I've talked to is booked many many weeks in advance.
 
azure said:
So I give up on him. Does anyone know a GOOD mechanic in SE Michigan who is actually taking on new customers? Everyone I've talked to is booked many many weeks in advance.
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Go here :

http://www.landings.com/evird.acgi$pass*193800885!_h-www.landings.com/_landings/pages/search/certs-ap.html

put in your Zip and click go.
 
azure said:
If they forgot something like that (now I'm not a mechanic but I have to believe that's common knowledge among mechanics) then I stand by what I said, they're incompetent. If they refused to go back in on their own dime once called on the mistake, they're not even worthy to be called professionals.
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Yeah, it's hard to mount the propeller when they have the accessory case sticking out the front of the plane :)
 
Tom-D said:
Go here :

http://www.landings.com/evird.acgi$pass*193800885!_h-www.landings.com/_landings/pages/search/certs-ap.html

put in your Zip and click go.
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And the point of that exercise was ... ?? :dunno:

(I mean, yes, I am a little surprised that there are 8 certificated A&Ps in my zip code, but so what? Having the cert doesn't mean they still work on planes, and it doesn't say whether they are someone I would trust my airplane to.)
 
Well he called me out of the blue this morning to say that he did the bottle test and it showed pretty much equal fuel flow to all cylinders.

He did not check to make sure the probes were on the correct cylinders. That is something I could do, but would need to borrow a heat source (all I have is a soldering gun, expect that applying that much heat would NOT be a good idea).

He is waiting for the instrument needed to check for cam lobe wear which he has to borrow.

So he is working on it, but very slowly. Not sure whether I would get results any faster by getting on the multi-week waiting list of a "real" shop. The only difference would be, I might have a better idea of what to expect. (Or maybe not.)
 
azure said:
Well he called me out of the blue this morning to say that he did the bottle test and it showed pretty much equal fuel flow to all cylinders.

He did not check to make sure the probes were on the correct cylinders. That is something I could do, but would need to borrow a heat source (all I have is a soldering gun, expect that applying that much heat would NOT be a good idea).

He is waiting for the instrument needed to check for cam lobe wear which he has to borrow.

So he is working on it, but very slowly. Not sure whether I would get results any faster by getting on the multi-week waiting list of a "real" shop. The only difference would be, I might have a better idea of what to expect. (Or maybe not.)
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EGT probes location confromation? Use a head gun to heat each pipe on the exhaust with the probes installed. They are sensitive enough it will work fine.
 
bnt83 said:
EGT probes location confromation? Use a head gun to heat each pipe on the exhaust with the probes installed. They are sensitive enough it will work fine.
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Did you mean a heat gun? Yes, I did say that I'd have to borrow something to apply heat. I know what's entailed. I also know how much of a PITA it is for me to wrestle my cowl back on alone -- would need help with that anyway.
 
To verify, you did the bottle test with the GAMI injectors in, or out? If they were out, did you put the GAMI injectors in and do the bottle test? I seriously doubt you have equal flows with the GAMI injectors installed. You also need to do all four mixture settings.

The test you want to model is the EXACT system as your engine sees minus the heat of the rotating engine. Having the GAMI injectors out is pretty useless because a gross defect in your fuel delivery would have given you trouble no matter which injector was in.
 
docmirror said:
To verify, you did the bottle test with the GAMI injectors in, or out? If they were out, did you put the GAMI injectors in and do the bottle test? I seriously doubt you have equal flows with the GAMI injectors installed. You also need to do all four mixture settings.
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I wasn't there. My mechanic did the test sometime last night and told me the results this morning. From what he said he did the test with the GAMIs off (he is trying to call GAMI to find out what the acceptable tolerances are in gph).

The test you want to model is the EXACT system as your engine sees minus the heat of the rotating engine. Having the GAMI injectors out is pretty useless because a gross defect in your fuel delivery would have given you trouble no matter which injector was in.
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I generally don't give my mechanic the third degree about his methods, unless he gives me reason to believe he missed something or took an unacceptable shortcut. He did the bottle test and got results that he said suggested my fuel delivery system was healthy. Small differences between cylinders, and he's checking to see if they're within tolerance.

It looks like it isn't fuel delivery, but more likely the air side. Induction leak or cam lobe wear (assuming the EGT probes aren't mixed up, which I seriously doubt, but still want to verify). It sounds like he's leaning in the cam direction. :(
 
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Cam lobe wear would have shown up in your oil changes.
 
Tom-D said:
...put in your Zip and click go.
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Wow, 50 A&P's in my zip code and I'm the only one with a pilot's license. Why would anyone want to be an A&P if they aren't a pilot? :dunno:
 
azure said:
Did you mean a heat gun? Yes, I did say that I'd have to borrow something to apply heat. I know what's entailed. I also know how much of a PITA it is for me to wrestle my cowl back on alone -- would need help with that anyway.
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A hair dryer would work too.

Also while a soldering gun may be difficult to use I doubt it gets any hotter than your exhaust does anyway
 
So here is what JP actually said.

John-Paul Townsend said:
I'm not sure if I mentioned to you performing what's sometimes called the "Bottle Test." It's similar to the procedure described by the poster above, but instead you perform it WITHOUT the injectors installed. Use only the lines.

Here is the reason: The GAMI system (and any fuel injection system) assumes the flow going TO the nozzle FROM the line is the same for each cylinder. If it is, then we can take a specially tuned set of injectors which will deliver a little more fuel to your leanest cylinders and a little less fuel to your rich ones, so they all reach peak EGT right about the same time. However, let's say you have one or two cylinders that are getting a LOT more fuel to the nozzle than the others. They will run very rich, even if we make the nozzle orifice smaller than the others. We need to be sure they are all the same prior to the nozzles. Here are some brief instructions: http://www.gami.com/gamijectors/bottletest.php
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You said:
From what he said he did the test with the GAMIs on (he is trying to call GAMI to find out what the acceptable tolerances are in gph).
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If you ask your mechanic to do the test without specifically asking for something you will get just that--non-specific results. You said you don't know what he did. You should have told him what to do based on the advice you received here.


Are you doing oil analysis? Just curious.
 
flyingmoose said:
So here is what JP actually said.



You said:

If you ask your mechanic to do the test without specifically asking for something you will get just that--non-specific results. You said you don't know what he did. You should have told him what to do based on the advice you received here.
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I'm the one that advised the bottle test with GAMI on. If the test was done with the injectors on, and he has equal flow, he has two serious problems. 1) A pressure and flow imbalance in the fuel manifold. 2) A serious air leak in the air manifold.
 
flyingmoose said:
So here is what JP actually said.



You said:
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Should have been "off". Corrected.

If you ask your mechanic to do the test without specifically asking for something you will get just that--non-specific results. You said you don't know what he did. You should have told him what to do based on the advice you received here.
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No, I said I wasn't there. In that sense yes, I don't know what he did. I didn't watch him perform the test. But we discussed JP's advice earlier in the week and I tend to trust that he did the test correctly, especially given the results. (Seems highly unlikely that two different problems would conspire to give a null result.)

Are you doing oil analysis? Just curious.
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Yes, I told him when I first bought the airplane that I wanted him to send oil samples for analysis periodically. He has always said that my oil "looked clean". I suppose that could be construed to mean that it literally looked clean to visual inspection only, if I wanted to doubt that he was doing the due diligence that I expect of him, and that he KNEW I expected.

To be 100% sure I texted him about the GAMI bottle test. I hate to do even that, as it feels like I'm checking up on him as if he were one of my students. (He's incommunicado again though, with his phone turned off, and I don't expect an answer before sometime next week.)
 
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I'd insist on a different method of communication. Airplanes are by their nature somewhat time-critical machines (at least for me) and being put on ignore for days at a time in unaccepatable.

azure said:
Should have been "off". Corrected.


No, I said I wasn't there. In that sense yes, I don't know what he did. I didn't watch him perform the test. But we discussed JP's advice earlier in the week and I tend to trust that he did the test correctly, especially given the results. (Seems highly unlikely that two different problems would conspire to give a null result.)


Yes, I told him when I first bought the airplane that I wanted him to send oil samples for analysis periodically. He has always said that my oil "looked clean". I suppose that could be construed to mean that it literally looked clean to visual inspection only, if I wanted to doubt that he was doing the due diligence that I expect of him, and that he KNEW I expected.

To be 100% sure I texted him about the GAMI bottle test. I hate to do even that, as it feels like I'm checking up on him as if he were one of my students. (He's incommunicado again though, with his phone turned off, and I don't expect an answer before sometime next week.)
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wabower said:
I'd insist on a different method of communication. Airplanes are by their nature somewhat time-critical machines (at least for me) and being put on ignore for days at a time in unaccepatable.
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A different method of communication, as in... what? Telepathy? Sorry for the snark, but seriously... he doesn't check email very often because he's never home. He has a day job and then comes to the airport to work half the night.

The reason I hesitate to fire him is exactly as you say, my airplane is rather time-critical. Next week is better than two months from now (based on the waiting lists). Yep, the aggravation factor makes him almost not worth it. At some point that "almost" is going to wear out too. Just not yet.
 
azure said:
A different method of communication, as in... what? Telepathy? Sorry for the snark, but seriously... he doesn't check email very often because he's never home. He has a day job and then comes to the airport to work half the night.

The reason I hesitate to fire him is exactly as you say, my airplane is rather time-critical. Next week is better than two months from now (based on the waiting lists). Yep, the aggravation factor makes him almost not worth it. At some point that "almost" is going to wear out too. Just not yet.
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How well do wrenches fit your hand?
 
azure said:
Which numbers? The fuel flow gauge is stock Cessna (replaced with a rebuilt 2 years ago when the MP side died). The EGTs are from a JPI EDM-700. AFAIK neither has been tested for accuracy. That might be worth a try, but actually that makes me wonder about something else. If the EGT probes weren't properly placed, would that affect the point at which the reading peaks? Or just the indicated temperature?
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About the only thing that EGT probe placement could do to cause you trouble with this would be if they were too close to the cylinders. In that case they actually end up in the burning end gas much of the time and this can really mess up finding peak.

First thing I'd do is try a "Coke bottle test" where you feed the output of each injector into identical separate containers and run the boost pump until one of the bottles gets fairly full. Then carefully measure the volume of fuel collected from each injector. John Paul should be able to give you the relative flow rates for this at whatever ff you test (preferably as close to cruise ff as possible). If there's a mismatch there, either you don't have the injectors GAMI thinks you have or there's an imbalance in the fuel manifold or injector lines.

If that's good it's likely something is affecting the relative airflow through your cylinders. This could be a problem with the exhaust, cam lobes, cam timing (especially if the imbalance is left/right), valve lift, or intake restriction. Lycoming IO360s are supposed to have fairly good mixture balance with stock injectors, how bad was yours before GAMI and were things off in the same direction?
 
Hey Liz,

It sounds like you are not sure if your oil is getting analyzed or not. If your mechanic is sending the samples off you can and should be on the e-mail list to get the results. This is true whether you use AvLab or BlackStone. I know they will both e-mail the results to you and keep the old tests on record so you and they have a decent trend of what is going on. I have been using AvLab and will use Blackstone for the sample I pulled today. I have heard great things about Blackstone and after talking to them they committed to putting the last four samples I had analyzed at AvLab in their database so my trends could continue.

If you are not getting the results from your own engine give the company a call and ask to be put on the e-mail list.
 
Oil analysis is a good practice however if you are concerned about cam lobe wear to the extent that would cause the issues we are discussing in this thread you are going to see it in the oil. Furthermore, such cam lobe wear is not a normal situation and once it manifests itself the result is rapid deterioration of both the cam and lifter .

So if you're really concerned about it and think that it might be the cause of your issue cut open your filter and have a look-see. The evidence will be there if it is.
 
Silvaire said:
Oil analysis is a good practice however if you are concerned about cam lobe wear to the extent that would cause the issues we are discussing in this thread you are going to see it in the oil. Furthermore, such cam lobe wear is not a normal situation and once it manifests itself the result is rapid deterioration of both the cam and lifter .

So if you're really concerned about it and think that it might be the cause of your issue cut open your filter and have a look-see. The evidence will be there if it is.
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My mechanic has definitely been cutting open the filter for visual inspection -- that much I'm sure of. But -- and again I'm not a mechanic so I'm only going by what I've read -- I'm not sure that visual inspection is enough. I found an Australian airworthiness bulletin AWB 85-014 that talks about this. Although they recommend inspecting the filter for metal, they also say that "cam lobe wear debris alone can be difficult to detect in the filter". Apparently it is often related to (caused by?) tappet body wear and damage to or wear of the lifter faces. They say that periodic inspection with a boroscope might be a more reliable way to detect the problem.

They also say that the majority of recent cases of filter contamination have been found to involve spalling of a now superseded Lycoming tappet body that was supplied during 2009-2012. They do say that the problem isn't limited to a particular P/N, however, and they stop short of implying that the part is defective. The AWB is from November 2012.

The other thing about this that makes me REALLY nervous is that apparently the first symptom of cam lobe wear may be a subtle decrease in engine power, slower climbouts and reduced cruise speed, which I've observed for over two years and attributed to my airframe being slightly out of rig after replacement of my wing spar carrythrough in 2011. (Although I would have *thought* that I would be seeing much more drastic degradation by now, I wonder if that's necessarily true. What do the mechanics here say?)

So I want to be sure that my guy has actually been sending my oil for analysis, for one -- and thanks for the tip, Tim, I wasn't aware that owners could get the analysis results directly from the company. But maybe it's time to inspect the camshafts too (not sure if that actually requires a boroscope), and make sure I'm not sitting on a time bomb.
 
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azure said:
...But maybe it's time to inspect the camshafts too (not sure if that actually requires a boroscope), and make sure I'm not sitting on a time bomb.
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AFAIK It's not possible to visibly inspect the camshaft without pulling a cylinder off.
 
Henning said:
Kinda, you can dial indicate the lift/duration.
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My guy did say something about the instrument he needed to borrow being a "dial". Maybe this is what he has in mind. Silvaire did say "visibly".

So I guess my next question is, is the "dial" thingy indication a sensitive enough test?
 
azure said:
So I guess my next question is, is the "dial" thingy indication a sensitive enough test?
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It's certainly sensitive enough to show if valve opening lift and duration are within spec.
 
azure said:
My guy did say something about the instrument he needed to borrow being a "dial". Maybe this is what he has in mind. Silvaire did say "visibly".

So I guess my next question is, is the "dial" thingy indication a sensitive enough test?
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Yeah, if there is enough wear on the cam to cause a difference in induction, it can certainly be measured on a dial indicator. If pitting is bad enough that may even show in bounces.
 
I see numerous engine problems at the shop almost every week. So far there's never been a lobe failure that didn't produce enough whiskers in the filter to remove all doubt that something was amiss with the innards.

Some lifter spalling can slip by with only a few flakes.
 
azure said:
My guy did say something about the instrument he needed to borrow being a "dial". Maybe this is what he has in mind. Silvaire did say "visibly"...
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That was because someone had mentioned a borescope but I'm with Wayne, the metal from this amount and type of wear doesn't just disappear. It's also ferrous so washing the filter element in a pan of solvent and sticking a magnet in there as is common practice would surely bring up some evidence.

Because what you are looking for here is not normal wear on a very high time engine, you are looking for a failure mode wear indication. Something that would occur fairly rapidly and get bad quick.
 
A couple of notes on oil analysis and cam spalling.

I had an O-360 in my Maule. I did most oil changes but had the Mom & Pop shop do changes at annual time. I ordered the oil analysis kits and provided units to the shop when they did the changes. All anaylsis results came to me by mail and now by email. Very useful oversight on the engine for a non-wrenching, non-filter splitting owner. Very important data for the shop as well, when combined with filter examinations. I'd recommend ordering a kit of 6 or 8 and providing the sampling units to your mx when doing oil changes.

I had to replace a cam on the 0-360 due to cam spalling. Analysis trend analysis clearly showed something was happening before anything was found in the filter. When a subsequent filter analysis disclosed more metal, we decided to pull the cam and found the spalling.

As someone here suggested, it can be difficult to pick up early signs of spalling by filter analysis alone. My sense is that the oil analysis prompted the shop to take a much closer looks at the filter contents.

What caused the spalling? I had a situation where I was sharing my hangar with a neighbor's cub. Each time he flew, my Maule had to be moved out of the way. I chose to put the Maule back in the hangar by starting it up. Multiple, consecutive cold starts on any engine is obviously a bad thing. It happened more than I ever expected and I paid the price.

After some shopping around, I finally got lucky with a good shop on our private field. Sounds like some shopping around is in your future.
 
I've actually seen my oil filters split open sitting on my mechanic's portable table in the hangar. One time he showed it to me and said, see, no metal, it's clean. I'm not 100% certain that he does it every time, but he does do it.

I was the one who mentioned using a boroscope (based on the Aussie AWB). The same AWB also said that cam wear debris is sometimes missed visually.

So maybe it's unlikely that cam wear could be causing performance degradation over the last 250 hours. Maybe the induction effects are new -- though I had done a lean test last year (the first time I considered springing for GAMIs) and noticed the same 0.8-1.0 gph spread with #1 and #2 richer than #3 and #4. The only thing that's new is that the spread seems unfixable by tweaking the nozzle diameter. No way of knowing whether it would have been fixable a year ago.

I have to say, though, that JP mentioned to me in a private email that he knows of one case of cam lobe wear that was discovered in the same way despite visual filter inspections at oil change. He didn't know whether they did trend analysis.
 
Bill Watson said:
...As someone here suggested, it can be difficult to pick up early signs of spalling by filter analysis alone...
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I agree but in this particular case they are talking about enough wear to cause the valve to not open fully and degrade engine performance.

That's a lot of metal.
 
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