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  #21  
Old 05-11-2018, 09:17 AM
Canadian_JOY Canadian_JOY is offline
 
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Bill - just out of curiosity... Have you seen any data that would allow you to characterize the lifecycle performance of 18mm auto plugs vs 14mm auto plugs?

There have been some good discussions here regarding using 18mm auto plugs, thanks to some vendor-supplied spark plug thread adapters failing. As a result I'm giving consideration to using 18mm plugs on my P-Mag, but won't be looking to go down that path if, for instance, the 18mm plugs have a demonstrably shorter life expectancy than their 14mm cousins.
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  #22  
Old 05-11-2018, 09:21 AM
Canadian_JOY Canadian_JOY is offline
 
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To build on the OP's experiences, I should also point out that our O-360 experienced a failure of the P-Mag circuit board very early in our Phase 1 flying. It took some back-and-forth conversations with Brad at EMagAir to get to the heart of the problem. I replaced the circuit board and all is well. While it was failing I had similar high EGT while running with a rich mixture.
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  #23  
Old 05-11-2018, 11:10 AM
BobTurner BobTurner is offline
 
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Location: Livermore, CA
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Quote:
Originally Posted by jbell2355 View Post

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.
I like your attitude. Having said that, let me remind you that you bought an experimental airplane, with an experimental ignition system. It may well be that there is no other airplane in the world exactly like yours, so mechanics, cfi?s, etc., can easily be confused by what is normal, or not, for your airplane. For example, I have been in a fair number of Cessnas with a fouled plug or other malfunction, and on a mag check they ran so badly that it was clear that something was wrong. But perhaps your experimental ignition was able to smooth over the roughness due to the loss of one cylinder, I don?t know. As a non-builder, but PIC of an experimental airplane, you have a significant responsibility in your hands. Yes, consult others, but ultimately the responsibility for safe and legal flight rests with you.
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  #24  
Old 05-11-2018, 11:24 AM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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Quote:
Originally Posted by Canadian_JOY View Post
Bill - just out of curiosity... Have you seen any data that would allow you to characterize the lifecycle performance of 18mm auto plugs vs 14mm auto plugs?

There have been some good discussions here regarding using 18mm auto plugs, thanks to some vendor-supplied spark plug thread adapters failing. As a result I'm giving consideration to using 18mm plugs on my P-Mag, but won't be looking to go down that path if, for instance, the 18mm plugs have a demonstrably shorter life expectancy than their 14mm cousins.
I use the Autolite 386 plugs on my IO-320 and have put over 300 hours on a set before changing. Plugs still looked good (no erosion of the insulator and almost no electrode wear) and performed without flaw. The 386's are hotter than I would like, but there are no other options in 18mm. I tried some NGK plugs that were cooler, but they are not resistor plugs. I added some resistor caps to compensate, but had a lot of noise, so went back to the 386's. I have done a pretty exhaustive search and found that only the 386 is offered in 18mm with a resistor. Everything else is non-resistor. I think the 18mm plugs are limited to just the tractor market. The mags don't do well with the extra resistance and the tractors don't worry about the noise.

Larry
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Last edited by lr172 : 05-11-2018 at 11:30 AM.
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  #25  
Old 05-11-2018, 01:48 PM
rick9mjn rick9mjn is offline
 
Join Date: Aug 2017
Location: northern ill
Posts: 21
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to....jbell2355
....thanks for sharing, and may we all learn something from this thread,
....
Thanks to you, for having the personal courage to put your experience out there.
You exemplify the best in a positive safety culture.
Many will learn from your event,
and you can rest easy at night knowing that,
while it may have been painful for you,
you've given back to others
and they will hopefully avoid the same pain ,thanks to you

...good day rick
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  #26  
Old 05-11-2018, 02:32 PM
Canadian_JOY Canadian_JOY is offline
 
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Location: Ontario, Canada
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Thanks for that feedback on the Autolite 386 plugs, Larry.

When you say they're a hotter plug than you would like, what symptoms are you seeing which drive you to this conclusion? Just plug color (white vs tan deposits), or other indications?
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  #27  
Old 05-11-2018, 04:43 PM
vic syracuse vic syracuse is offline
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Quote:
Originally Posted by jbell2355 View Post
In retrospect, it all makes sense and I obviously would not have flown had I known what was going on. I took my first flying lesson in April of last year, earned my PPL in July, and bought the plane in October. I am NOT a seasoned pilot with years of experience, nor am I a motorhead. I had never been in the plane before and did not know what was normal for it. I paid a mechanic to complete an inspection moments before I climbed into the plane for the first time with a CFI who DID have time in the plane. Given the situation, I had confidence in the airworthiness of the plane, and would have expected the CFI to point out any abnormalities.

I subsequently flew in the plane with 3 other CFIs who were all witness to the runup and mag drop, and none of them made a fuss about it. I get that all of you would have immediately identified the problem, but for a brand spankin' newbie like me, and also the CFIs I flew with--we missed it.

I was also constantly consulting with GRT, the builder, and the pre-buy mechanic. The mechanic borescoped, did compression tests, replaced plugs etc, and sent me away to fly home.

The lead didn't become disconnected - it was disconnected the first time I flew it, as evidenced by the mag drop and EGT.

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.
You have an absolutely wonderful attitude, and I have no doubt that you will continue to learn. We all have. Everyone on this forum, no matter how much experience they now have, had to learn it all. Hurray to you for your willingness to learn.

I hear you on getting so many people to look at it. My only advice as you continue to fly throughout your life is that if it doesn?t feel right to YOU, then don?t give up until it does feel right.

Vic
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  #28  
Old 05-11-2018, 05:03 PM
007 007 is offline
 
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Location: VanAire, Co
Posts: 25
Default Mag Check

Not understanding the purpose of a mag check is not as uncommon as many of us believe.
A short while back, I was conducting a "BFR" , or flight review,
when my student did a mag check. He switched from "both" to each mag VERY quickly. I ask him why he cycled the mags so fast. He said "If I do it slow, it will pop and be rough".
He had never heard of clearing a fouled plug by leaning!

Another student noted the roughness of his engine during the mag check, but continued the check list. When ask what the roughness was, he replied, " Oh, that will go away about five minutes after we go to full power and take off."

Lots of student/pilots learn what to do, but not why we do it.

I hope more people will "confess" their mistakes here on this site. There are many knowledgeable folks here who are glad to help.

007
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  #29  
Old 05-11-2018, 06:12 PM
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Danny King Danny King is offline
 
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Location: Southlake, Texas
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Quote:
Originally Posted by jbell2355 View Post
In early October, I signed a purchase agreement on a beautiful RV7A built by a physician here in Michigan. He had his CFI friend fly the plane up to my neck of the woods for a pre-buy inspection. I got the green light from the A&P and sent the wire transfer – the plane was mine!

The CFI and I hopped into the plane for a few landings and then I flew him back home solo. I recall during that first run-up that the engine seemed to run rough on one mag, but the CFI didn’t seem too concerned and it was my first time in the plane, so I didn’t know what was normal. On my 2 hour return flight home, all alone in a new plane, I started getting a high EGT annunciation on cylinder #4. This was disconcerting for me, having never had this kind of engine monitoring info and being new to the aircraft.

Back home, I consulted with the builder who told me that he hadn’t had this issue before. At first it seemed it had to be related to the pre-buy inspection, but what could the mechanic have done that would cause this? We did a little troubleshooting and decided it was probably a bad EGT probe. I flew the plane regularly and found that the annunciation was mostly an issue on climbout and that with proper leaning (or lack thereof), I could mostly manage the high EGT. Cylinder head temps did not appear out of line.

I flew the plane for 25 hours and brought it back to the pre-buy mechanic for a supervised oil change. I uncowled the plane and was shocked to see that the #4 high tension lead was disconnected from the upper plug on cylinder #4 (Lightspeed Ignition). The only good news was that we now knew the source of the problem. The mechanic was very nonchalant about the fact that he left the plug unplugged, and didn’t seem bothered by it at all. I wasn’t very happy, except for the fact that we thought we had solved the problem.

I flew the plane home after the oil change, excited to finally be rid of that irritating flashing red light, but it was still there! For the next few months, I swapped EGT probes, installed a new one, had them tested, checked for wiring problems, and spent a lot of time messing around trying to diagnose the problem. I was about to send the GRT EIS monitor back to be tested, when I shared some engine monitor info with Doug Hamerton at Aero Sport Power (the engine builder). He felt that, based on the data, I was leaning #4 lean of peak and that’s how/why the temp was going back in line with the other cylinders which were leaned ROP.

At this point I had put 80 hours on the engine. I had the mechanic on my field take a look and he told me I had a leaking exhaust valve, so I had him pull the cylinder. Based on the amount of carbon buildup, we decided to pull all the cylinders and have them looked at by Doug.

https://ibb.co/hAkrGJ
https://ibb.co/dPf2Oy
https://ibb.co/i3zJwJ

Aero Sport did their thing and a few weeks later the cylinders were remounted. 2 new pistons, 1 new #4 cylinder and the rest just cleaned up/painted. Once it was all put back together, I fired her up and did the ground run procedures.

Then I flew it, and still had the **** EGT problem!

This isn't the end of the story, but I’m going to stop the story here for a day or two. You should know that we did subsequently find and fix the problem. I’m curious whether anyone would have saved me all this hassle I've been through if I would have asked sooner.

And Klaus, you’re not allowed to answer.

So...what happened here?
--------------
A disconnected plug wire would have been discovered with the first mag check when #4 cylinder cut out completely when the other mag or ignition was grounded! I guess I'm missing something here.
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Last edited by Danny King : 05-11-2018 at 06:20 PM.
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  #30  
Old 05-12-2018, 07:44 AM
bk1bennett's Avatar
bk1bennett bk1bennett is offline
 
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Default All?s Well that Ends Well

Quote:
Originally Posted by jbell2355 View Post
In retrospect, it all makes sense and I obviously would not have flown had I known what was going on. I took my first flying lesson in April of last year, earned my PPL in July, and bought the plane in October. I am NOT a seasoned pilot with years of experience, nor am I a motorhead. I had never been in the plane before and did not know what was normal for it. I paid a mechanic to complete an inspection moments before I climbed into the plane for the first time with a CFI who DID have time in the plane. Given the situation, I had confidence in the airworthiness of the plane, and would have expected the CFI to point out any abnormalities.

I subsequently flew in the plane with 3 other CFIs who were all witness to the runup....

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.
Great attitude! Thanks for posting your experience. As others have said, you are not the only one who learned from it. Obviously, you have an honesty about dealing with situations like this that is going to serve you well as you advance through your piloting days. By honesty, I mean that you see facts objectively and make decisions based on facts rather than emotions, pride, denial or any other factors that detract from good ?aeronautical decision making.?

However, one of the takeaways has to be that you need to be better educated on your power-plant,IMO. I know I do. I read a lot of accident reports and it amazes me that many of the problems start with bad engine integration or maintenance practices. I am a long way in my build from installing and running the engine, but you can bet that I will be paying close attention to every detail and will be doing it by the book!

Your comment about flying with CFI?s who didn?t recognize the problem reminds me of an experience in my student days. My CFI, and the owner of the plane, was with me while I was taxiing for take off. I noticed a problem with the nose wheel steering and told him something was wrong. I had enough experience to know something had changed. The resistance to turn inputs was rapidly increasing. He took the controls and said he didn?t detect any problems. I took the controls back and said this is getting worse. It got so bad that I stopped short of the runway. We got out and the nose wheel tire was completely flat! It had been hemorrhaging air while we were in taxi. From then on I knew that I was going to be Pilot In Command listening to my own instincts and judgment.

Thank God you had a great learning experience and that neither you or your aircraft have any scars! Blue skies!

Brian
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