My GAMI fiasco

Tony_Scarpelli said:
Based on everything you said about this guy, I think this guy is full of crap.
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I just noticed this. As I've said, I'm not happy that he has been cutting corners on my oil changes by not sending samples for analysis. And he does "yes me to death" by promising work that is never done, or at least doesn't get done until at least a week after he promises to get to it. But for someone that is full of crap, he has done a lot of good work on my airplane over the last 3.5 years.

He discovered the mouse nest and spar corrosion that my pre-buy mechanic missed.

He has found and fixed at least two induction leaks.

He replaced my flap cables a couple of years ago and adjusted my flaps to remove the "sag" that was causing them to be partially deployed at all times, and also correctly adjusted the 10, 20, and 30 degree detentes.

Recently, he correctly identified and replaced a bad plug.

Also recently, he adjusted my main gear down actuator so that the gear comes far enough forward to lock consistently. That was a real problem that almost had me schedule a visit to Bob Russell (Cardinal guru in Kenosha).

There's probably other jobs he's done for me that I've forgotten. He is not a bad mechanic. He just doesn't have any business sense nor any sense of what he can or can't realistically accomplish in a day's work. And he's a frustratingly poor communicator. That's why he has lost so much business, and will probably lose mine.
 
I keep coming back to the ignition since it is so easy to test. If you are cruise running on one mag, do you get the same flow/roughness/EGT discrepancy on each that you get with both mags? If so, that would suggest the problem is induction leak or mechanical. If the two mags individually behave differently, it would strongly suggest something in the ignition, plugs, leads, or mag.

Bear in mind that your two mags probably fire all tops or all bottom plugs (I think that's how Lycoming does it) so there will be a difference just from that.
 
nrpetersen said:
I keep coming back to the ignition since it is so easy to test. If you are cruise running on one mag, do you get the same flow/roughness/EGT discrepancy on each that you get with both mags? If so, that would suggest the problem is induction leak or mechanical. If the two mags individually behave differently, it would strongly suggest something in the ignition, plugs, leads, or mag.

Bear in mind that your two mags probably fire all tops or all bottom plugs (I think that's how Lycoming does it) so there will be a difference just from that.
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Most I have seen fire tops on one side, bottoms on the other.
 
Henning said:
Most I have seen fire tops on one side, bottoms on the other.
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As I recall, that's the way it is on the IO-360.

I'm having the plugs checked and the mags IRANd tomorrow at a professional shop (Waterford Aviation). If everything checks out okay there, they will look more closely at the engine, boroscope the cylinders and measure the valve lift.

I did do a (very brief) cruise power LOP mag check over the weekend. On both sides there was a sharp rise in EGTs and definite loss of power, a change in engine sound definitely, but no significant increase in roughness (I managed to find a sweet spot there). On the other hand I've suspected an ignition problem for a long while as my rpm drops running on one mag at runup are borderline unless I lean the mixture a fair amount. I'm going to let the pros try to sort it out.
 
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azure said:
As I recall, that's the way it is on the IO-360.

I'm having the plugs checked and the mags IRANd tomorrow at a professional shop (Waterford Aviation). If everything checks out okay there, they will look more closely at the engine, boroscope the cylinders and measure the valve lift.

I did do a (very brief) cruise power LOP mag check over the weekend. On both sides there was a sharp rise in EGTs and definite loss of power, a change in engine sound definitely, but no significant increase in roughness (I managed to find a sweet spot there). On the other hand I've suspected an ignition problem for a long while as my rpm drops running on one mag at runup are borderline unless I lean the mixture a fair amount. I'm going to let the pros try to sort it out.
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There has to be an ignition problem. I just re-installed an IRAN'ed D2XXX mag on an O-360 and the drops are minimal and the smoothness is impressive. It starts soooooo easy too. We just put 4 new Champion finewires in the bottom and 4 massive plugs in the tops.
 
Update: 7 of 8 plugs are out of tolerance (the new one is, predictably, still ok), but I went with their recommendation to replace all of them since I am switching from Champion to Tempest on JP's advice.

I want to see what effect changing the plugs has before doing anything else, so I've decided to put off IRANing the mags for another session (which might be very soon, if the problem isn't fixed).

Also having the shop take care of some minor but vexing mechanical issues that my mechanic has been procrastinating on all summer: leaky nosewheel strut, a bit of shimmy/vibration.
 
azure said:
Update: 7 of 8 plugs are out of tolerance (the new one is, predictably, still ok), but I went with their recommendation to replace all of them since I am switching from Champion to Tempest on JP's advice.

I want to see what effect changing the plugs has before doing anything else, so I've decided to put off IRANing the mags for another session (which might be very soon, if the problem isn't fixed).

Also having the shop take care of some minor but vexing mechanical issues that my mechanic has been procrastinating on all summer: leaky nosewheel strut, a bit of shimmy/vibration.
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Thanks for the update. Sounds like a logical plan. Hope this was the issue...
 
I just realized I had this thread open and hadn't posted an update in a while. The plane is back in the shop this weekend for a few things, but the top priorities are inspection of timing, harness, and mag insides. The new plugs accomplished one thing: less CO in cabin (was getting a trace in cruise on every flight with the old plugs, and often a couple dozen ppm on landing). They did NOT seem to give me more power (well actually they did, but the weather also suddenly turned C-C-COLD at exactly the time I got the plane back from that stint). And they did NOT affect the large rpm drops when running on either mag alone. The GAMI spread is basically the same as before. The GAMI folks sent me replacements for #2 and #4 in the hopes of evening things out a little more, but Jeff and I agreed that we should do a thorough check of the ignition system before swapping out the nozzles again.

Also on the docket: reseal a seeping fuel panel atop the right wing (minor leak but getting worse, and my regular mechanic has made at least a half dozen empty promises to get it done -- sorry Dave, you lose), and see if the cabin heater can be tweaked to give me more heat. Right now with OAT in the -15C range, it is JUST BARELY adequate to keep my fingers from freezing.
 
Liz, I am sorry you are having so many issue with the Branded Bird. Hopefully the winter months can be productive and get all that stuff straightened out. Hope you have April in the back of your mind for a BBQ at KMGY. I plan to do it again this year.
 
Thanks for updating the thread. I often wondered how it turned out. The IO-360 usually can be made to run LOP but occasionally, the stars don't align (or there is a lot of effort required to try to make them align). It is interesting that the plugs helped with CO situation.

Please keep updating us.
 
Marauder said:
Thanks for updating the thread. I often wondered how it turned out. The IO-360 usually can be made to run LOP but occasionally, the stars don't align (or there is a lot of effort required to try to make them align). It is interesting that the plugs helped with CO situation.

Please keep updating us.
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I think it makes a lot of sense. Bad plugs ==> incomplete fuel burn ==> more CO.

Tim -- I'm planning on it. April... seems like a LONG way off right now. (4-6 inches of snow expected by midnight tonight, probably more down your way.)
 
azure said:
I think it makes a lot of sense. Bad plugs ==> incomplete fuel burn ==> more CO.



Tim -- I'm planning on it. April... seems like a LONG way off right now. (4-6 inches of snow expected by midnight tonight, probably more down your way.)
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I get the incomplete fuel burn, what I don't get is why your exhaust system is prone to leaks or why your exhaust pipe allows CO in. I fly behind an IO-360 and have a CO ppm meter. I never see any CO. Is this common to your flavor of Cessna?
 
How is the CO getting in the cabin, that is your greater question. Do you have a bad exhaust system? That could also lead to unequal back pressures and uneven cylinder conditions.
 
Will you ever save enough on gas to make a GAMI conversion pay off? So you can run an IO-360 LOP - you go from 9gph @ 120ktas to 7gph@ 105ktas. . . .. if you rent wet that makes ZERO sense - even if you own - 2gph [and it nots the entire flight obviously, only during cruise] you save 1000 gallons over an engine? Does it cost more than $6k to order, install and maintain the GAMI's?
 
The likeliest route of entry is the lousy door seals -- both rain getting in during cruise and small amounts of CO in the cabin are endemic to the breed (Cardinals).

In every Cardinal I have flown in (two as PIC, and one other as passenger), the smell of exhaust is quite noticeable on final approach with the gear down.

However, I did ask Jeff to check the heater muff as part of the whole cabin heat project.
 
comanchepilot said:
Will you ever save enough on gas to make a GAMI conversion pay off? So you can run an IO-360 LOP - you go from 9gph @ 120ktas to 7gph@ 105ktas. . . .. if you rent wet that makes ZERO sense - even if you own - 2gph [and it nots the entire flight obviously, only during cruise] you save 1000 gallons over an engine? Does it cost more than $6k to order, install and maintain the GAMI's?
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The GAMI's are not that expensive themselves. But when you keep having to go back to the shop like this; I imagine you will eat away at your savings.
 
azure said:
The likeliest route of entry is the lousy door seals -- both rain getting in during cruise and small amounts of CO in the cabin are endemic to the breed (Cardinals).
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And before anyone gets on me about the doors not being airtight anyway -- yeah I know, I'm being tongue in cheek here.

The point is, with the gear down at low airspeed, the airflow around the fuselage is different from in cruise. I've always seen the highest ppms on short final and right after touchdown, yet cannot reproduce this in slow flight in the practice area. That part has always puzzled me, and the only explanation I can think of is that boundary layer turbulence and even ground effect has a lot to do with wafting the exhaust in from the exterior. But I've never carried a CO meter in any other Cardinal.

I'll still be interested to hear what the shop finds.
 
Well, I got the plane back today and parted with slightly over an AMU in the process. Here is (most of) what they did:

1) Checked the heater, all the hoses and shrouds were fine.

2) Did the 500 hour checks on the mags. Both mags needed new rotor drive gears (cracked) and they said it looked like they had been poorly assembled at last overhaul. New points and capacitor for the right mag, minor internal timing adjustment on the left.

3) Resealed panel atop right wing.

4) Bled left brake, finally got out the air bubble that my regular mechanic had tried three times to purge.

Large rpm drops on one mag are unchanged (about 100 full rich in winter, but I was seeing 175-200 full rich on hottest summer days). The crew chief at the shop says he thinks this is not abnormal or suspicious as long as the rpm drops are within tolerance when leaned out (they have always been or I wouldn't be flying it that way).

I will say that I noticed right away on takeoff that the Branded Bird has more pep than before. For the first time in a long time it feels like there's a 200hp engine under me!
 
azure said:
I will say that I noticed right away on takeoff that the Branded Bird has more pep than before. For the first time in a long time it feels like there's a 200hp engine under me!
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You sure it's not just a lighter wallet? ;)
 
azure said:
I will say that I noticed right away on takeoff that the Branded Bird has more pep than before. For the first time in a long time it feels like there's a 200hp engine under me!
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So there were multiple problems (plugs & mags) which always makes it tougher to diagnose. Glad to hear the ignition system is now in good repair and the engine is running better. Bet the EGTs are much more uniform and well behaved.
 
azure said:
The likeliest route of entry is the lousy door seals -- both rain getting in during cruise and small amounts of CO in the cabin are endemic to the breed (Cardinals)
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I doubt it or I would be smelling it in mine or the gear up/down wouldn't matter in yours.

Has the steering rod boot been looked at?
 
bnt83 said:
I doubt it or I would be smelling it in mine or the gear up/down wouldn't matter in yours.
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I should have been more specific: the problem seems to be endemic to Cardinal RGs. I was a passenger once in an FG and did not smell the exhaust. I don't know the exact reason for the difference, but the airflow under the belly is going to be significantly different for a gear down RG vs FG.
 
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