My GAMI fiasco

azure said:
Roger all of that, but it won't be my guy doing it. He's out of his league with this and knows it. I've already told him I'm taking the plane to Waterford because they are a GAMI dealer. I will discuss all possible plans of attack that I can think of with them, when I see them.

He'll still be doing my oil changes and incidental mx, at least for now. And he knows I want oil analysis done regularly, and I'll trust (but verify) that he does it. But troubleshooting something like what we're discussing... no.
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Verify it by getting the results sent to you.
 
tmyers said:
Thats too bad, next time we meet up somewhere show it to me. For that matter maybe Brian will weigh in since he has a Cardinal.
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mine is:
1968 177 with an O-320
I also frequently do a 1977 177 with O-360

I've never worked an IO-360 in a 177RG which I can't imagine being very pleasant... even more crap packed under the hood may test my patients. Especially when pulling the suction screen which seems like only 50% of mechanics do.
 
I do have one good 177/177RG suggestion tho. Take those stupid southco retainers off and throw them in the trash. It makes R&R of the cowling so much easier when you can REMOVE the southco fasteners from the cowl completely, from the holes that fasten the top cowl 1/2 to the bottom cowl 1/2.

Then lay a pattern on a cardboard box resembling the fastener hole pattern of the cowling and stab holes in it with a screw driver and use it to organize the hardware to ensure you done mix them up when you R&R the fasteners.
 
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bnt83 said:
I do have one good 177/177RG suggestion tho. Take those stupid southco retainers off and throw them in the trash. It makes R&R of the cowling so much easier when you can REMOVE the southco fasteners from the cowl completely, from the holes that fasten the top cowl 1/2 to the bottom cowl 1/2.

Then lay a pattern on a cardboard box resembling the fastener hole pattern of the cowling and stab holes in it with a screw driver and use it to organize the hardware to ensure you done mix them up when you R&R the fasteners.
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It's easier to up grade to Cam-loc s
 
Tom-D said:
It's easier to up grade to Cam-loc s
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They are too expensive IMHO. But yes, they are much nicer.

Southcos just kinda suck period. Removing the retainers made them bearable for me.

The southcos on the firewall mounts still have the retainers in mine, allowing me to open the oil door for my left hand to get a good hold and my right hook goes through the front right inlet, while is stand by the right side and lift the top cowl straight up and off without the southcos catching anything.
 
Mine aren't all the same kind. I'm not 100% sure, but based on the pictures at Spruce, it looks like some of them are already Camlocs.

Anyway the issue isn't the unbuttoning and buttoning part, it's wrestling the lower cowl around the exhaust pipe, getting it lined up properly with the gear hardware, etc. Non-trivial and frustrating even for my mechanic who's done it a dozen times at least now. If you're gonna leave it on and try to drain the oil by sticking your hand in over it, you have to release the fasteners one by one and pry the lower cowl away with one hand. If you slip or aren't strong enough to provide enough clearance, your other hand gets cut up as the metal edge is pretty sharp.

In other news, JP now says we should have declared victory with the last injectors and hinted I should maybe go back to those, since I still have them.
 
azure said:
wrestling the lower cowl around the exhaust pipe, getting it lined up properly with the gear hardware, etc.
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It's just not fun...ever. Fortunately I rarely need to pull the bottom cowl.
 
The lower cowl on the Arrow is definitely a two person operation. Not sure if Vandy wrestled it on by himself or not.
 
tmyers said:
The lower cowl on the Arrow is definitely a two person operation. Not sure if Vandy wrestled it on by himself or not.
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Makes it easier, but I used to replace the second person with a piece of string and got them on just fine.
 
I hope you get your airplane figured out but I've learned so much about LOP operations reading this thread.
 
tmyers said:
Interesting. Love to hear your methods
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Get it into basic position then hold the front up close with a string side to side over the prop flange then work the back into position supporting everything with my knees while laying on my back with my head towrds the tail and get the fastener started IIRC.
 
Update: on Thursday I took the Branded Bird over to Waterford Aviation and let Jeff & team swap out my last nozzles on #3 and #4 for the previous iteration. With the old injectors in, I did GAMI lean tests at 8500 and 6500 that confirmed what I had found before, a spread of somewhere between 0.25 and 0.5 gph, with not enough resolution to really pin it down better than that. #3 and #4 peak together, first, then #1 and #2, basically together.

Sounds great, right? But even with the great spread, I couldn't run LOP smoothly. As soon as 1 and 2 are maybe 20 LOP, the engine starts running rough and I've lost about 10 kts. The problem is that by then, 3 and 4 are 60-80 LOP. The slope of EGT vs T on the LOP side is much steeper for 3 and 4 than for 1 and 2. Any leaner than that, and 3 and 4 start rising back toward the secondary peak and things get REALLY rough.

I found the same behavior at both 8500 and 6500, running <65% power (about 21/2300). Then I tried to run LOP at 4500 at 23 squared (about 65% power). Same issue. Roughness sets in as soon as the richer pair are more than a few degrees LOP.

From everything I've read this is abnormal, but I'm at a loss to figure out how to proceed now. JP is away at the AOPA summit but will confer with him ASAP.
 
Sorry to hear of the continued challenges. Can you summarize what has been done to get this to work? Mags checked? Spark plugs moved around? Etc. Aside of the fuel flow, there are a number of other factors that can be looked at. Just curious if you eliminated any of them.

I chased an electrical gremlin causing my landing gear breaker to pop. After spending a bunch of time with relays, switches, gear motors and wiring, it came down to a slipping alternator belt. Just want to make sure you aren't overlooking factors.
 
Marauder said:
Sorry to hear of the continued challenges. Can you summarize what has been done to get this to work? Mags checked? Spark plugs moved around? Etc. Aside of the fuel flow, there are a number of other factors that can be looked at. Just curious if you eliminated any of them.

I chased an electrical gremlin causing my landing gear breaker to pop. After spending a bunch of time with relays, switches, gear motors and wiring, it came down to a slipping alternator belt. Just want to make sure you aren't overlooking factors.
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Interesting point - the 'kota had an intermittent bit of roughness that we finally tracked down to the harness. A quick look at the spark didn't show the problem but it turned up when the mechanic took a little more time with testing.
 
azure said:
From everything I've read this is abnormal, but I'm at a loss to figure out how to proceed now. JP is away at the AOPA summit but will confer with him ASAP.
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How about ROP, enjoy your plane, save money and life is good. Just an idea. I too cannot run LOP well at this time and find myself more and more saying, screw it and flying ROP using the APS guidelines and getting back to enjoying my plane rather than going looking for problems with it.
 
Dav8or said:
How about ROP, enjoy your plane, save money and life is good. Just an idea. I too cannot run LOP well at this time and find myself more and more saying, screw it and flying ROP using the APS guidelines and getting back to enjoying my plane rather than going looking for problems with it.
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I pretty much agree with that except (1) IF the problem can be solved easily, I would save money by running LOP and (2) there is always the chance that this symptom is the canary in the mine warning me about something that could develop into a VERY co$tly repair down the line. If not for (2), I would be tempted to do as you suggest. In fact I'm still enjoying the plane and have been very close to saying screw it. It is (obviously) very frustrating. :mad2:

To summarize what has been done:

Spider cleaned and inspected (last winter)
Mags inspected (last spring)
Timing checked and adjusted (last spring)
Induction system checked for leaks (several times, most recently at annual, late May)
Bottle test with injectors in and out (within the last month) -- not sure if this was done with mixture leaned however.
 
Have you done LOP mag checks at cruise power yet? I can't remember if you have an engine monitor or not...that would obviously help diagnostics.

How about pressurizing the induction system and checking for leaks? You can do it easily with a compression test orifice connected to a cylinder with the intake valve open. Spray soapy water on every connection in the induction path.
 
As was mentioned above, I would look at spark plug leads and plugs. How many hours/years are on them? An intermittent lead or plug issue is something to eliminate.
 
KSMooniac said:
Have you done LOP mag checks at cruise power yet? I can't remember if you have an engine monitor or not...that would obviously help diagnostics.
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Other than VERY briefly, I haven't run LOP at cruise power at all, only below 65% where there's no possibility of hurting the engine by leaning. I've done ROP cruise power mag checks though, and actually found a bad plug that way this summer. My mech replaced it, end of problem.
How about pressurizing the induction system and checking for leaks? You can do it easily with a compression test orifice connected to a cylinder with the intake valve open. Spray soapy water on every connection in the induction path.
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As mentioned in item 4, I've had my mechanic chase induction leaks a number of times, though not specifically using your method. He's found two or three now since I bought the plane, but none recently.
 
Marauder said:
As was mentioned above, I would look at spark plug leads and plugs. How many hours/years are on them? An intermittent lead or plug issue is something to eliminate.
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I'm really not sure how many years are on the plugs, I'd have to comb through the logs to tell. It's >3.5 though, and hours is >415 or so, since that's how many years/hours I've put on the plane and I only changed one plug (see last post).

But I don't see how an intermittent could be to blame here, since the way the engine runs is very consistent.
 
azure said:
I'm really not sure how many years are on the plugs, I'd have to comb through the logs to tell. It's >3.5 though, and hours is >415 or so, since that's how many years/hours I've put on the plane and I only changed one plug (see last post).

But I don't see how an intermittent could be to blame here, since the way the engine runs is very consistent.
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In order to run LOP you need to have a nonstoichiometric fuel mix combined with proper combustion to make it all work. You spent a lot of time looking at fuel related portions of the problem. The other side of this is the combustion side. Spark plugs not firing consistently in particular will affect EGTs. Think about a fouled plug you find on run up. If you have an engine analyzer, you will clearly see it on an engine analyzer when running on that single mag.

That is easy to see and understand. Translate that into flight, where one or more plugs are changing resistance due to operating temperatures.

I would check the resistance of the plugs and swap a few around (in an organized manner so you can track their movements) to see if things changes. The spark plug harness is also another potential cause. They do break down over time.

Just trying to provide additional things I would be looking at if I were trying to troubleshoot this. BTW - I run an IO-360 as well.
 
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Marauder said:
I would check the resistance of the plugs and swap a few around (in an organized manner so you can track their movements) to see if things changes. The spark plug harness is also another potential cause. They do break down over time.

Just trying to provide additional things I would be looking at if I were trying to troubleshoot this. BTW - I run an IO-360 as well.
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At >415 hrs I'd change plugs just on general principles considering one has already gone bad. On many of these things ya spend more on labor trying to troubleshoot than on parts.
 
azure said:
Other than VERY briefly, I haven't run LOP at cruise power at all, only below 65% where there's no possibility of hurting the engine by leaning. I've done ROP cruise power mag checks though, and actually found a bad plug that way this summer. My mech replaced it, end of problem.

As mentioned in item 4, I've had my mechanic chase induction leaks a number of times, though not specifically using your method. He's found two or three now since I bought the plane, but none recently.
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LOP cruise power mag checks are a much better diagnostic tool than ROP because the lean mixture is harder to ignite and burn. It will give you the most warning of an ignition issue, which can prevent you from running smoothly LOP.
 
nrpetersen said:
Cute trick!

What's the firing order?
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I don't know the firing order off the top of my head. I had a rocker cover off anyway, so it was easy for me to determine when the intake valve was open. :D Otherwise, you can tell when you're at or near TDC by the air getting pushed out (stick your thumb over the fitting) so you can just start there and turn the prop 1.5 turns to get the intake valve open.

Also, tape over the air filter/inlet. I could see the tape "inflate" when I did this, so I knew the air was getting out of the cylinder.
 
mtuomi said:
How are you running stoich mixture and lean of peak at the same time?
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Your not! Spell check got me. You are running a nonstoichiometric mixture where the limiting reagent is AvGas... I thought you guys were pilots, not engine teachers... ;)
 
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Marauder said:
Your not! Spell check got me. You are running a nonstoichiometric mixture where the limiting reagent is AvGas... I thought you guys were pilots, not engine teachers... ;)
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Better run your spell checker again, or go back to the third grade.
 
KSMooniac said:
LOP cruise power mag checks are a much better diagnostic tool than ROP because the lean mixture is harder to ignite and burn. It will give you the most warning of an ignition issue, which can prevent you from running smoothly LOP.
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I know -- but at this point I don't think it's safe for me to be running LOP at cruise power.

Latest update is that JP is tending against the induction leak theory, though he still recommends measuring valve lift, and also borescoping the two leaner cylinders and checking the exteriors for cracks. He agrees that those two EGTs fall abnormally quickly on the LOP side and go into secondary peak behavior too soon. He also thinks there is altitude dependence in my GAMI spread, but I don't think my fuel flows have enough resolution to tell that.

I've also asked him about the chance that bad plugs could cause this -- and also timing being off from spec (too late?)... not sure I want to try the shotgun approach and just replace all the plugs.

Edit: he just replied that he had been thinking I'd already eliminated the plugs as a possibility. Yeah, next step is checking their resistance. He expects they'll all be higher than tolerance by now, so maybe just replacing all the others wouldn't be a bad idea.
 
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azure said:
I know -- but at this point I don't think it's safe for me to be running LOP at cruise power.

Latest update is that JP is tending against the induction leak theory, though he still recommends measuring valve lift, and also borescoping the two leaner cylinders and checking the exteriors for cracks. He agrees that those two EGTs fall abnormally quickly on the LOP side and go into secondary peak behavior too soon. He also thinks there is altitude dependence in my GAMI spread, but I don't think my fuel flows have enough resolution to tell that.

I've also asked him about the chance that bad plugs could cause this -- and also timing being off from spec (too late?)... not sure I want to try the shotgun approach and just replace all the plugs.

Edit: he just replied that he had been thinking I'd already eliminated the plugs as a possibility. Yeah, next step is checking their resistance. He expects they'll all be higher than tolerance by now, so maybe just replacing all the others wouldn't be a bad idea.
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I'm glad to hear you are eliminating the plugs. Keep us posted!
 
kgruber said:
Better run your spell checker again, or go back to the third grade.
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Or maybe you should...

ynepegu2.jpg
 
Marauder said:
Mi apoligies. I dunt pruf reed evirythyng I poost. ;)
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Ya know, ya just don't smell very well. The smell checkers will catch everything so ya just have ta look for the read underlines!
 
Based on everything you said about this guy, I think this guy is full of crap.

he is an old school this is the way I was taught kinda guy.

You request Oil analysis and he yeses you to death and does not perform them and when you call him on it he has this excuse. not likely.

I got a guy like that at my field 50 years experience probably very very good at many things but LOP is rubbish, mogas is rubbish, STCs are rubbish, oil analysis is rubbish, boroscopes are rubbish...condition based maintenance rubbish....does not communicate because a pilot cannot understand the delicate intricacies of the situation besides its a lot of time and I do not need a pilot arguing over my diagnosis.



azure said:
Figure of speech. What he said is that their analysis did not show metal content that he believes had to have been there, given the type of failure only a handful of hours later.

Personally I would tend to suspect that this is a case where some problems can develop very rapidly. But he didn't give me any more detail to go on.
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