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P- Mag failures
I have a RV-8 with dual P-Mags. Since the engine IOX-370 came with them installed and first flew in April 2017. I wasn?t advised about the blast tubes being required until I started experiencing failures of the Lt Mag. The left Mag is positioned between the oil cooler and the oil filter thereby being more exposed to heat. After three attempts of sending the P-Mag back to factory for rework they sent a new one. I then took the Rt Mag moved it to the left and put the new Mag on the right. After about 40 hours the original Mag failed completely. It?s on its way back to factory as I post this message. When they are operating things are great. I am looking for advise and comments.
To me these mags shouldn?t be this temperamental or unreliable. I think the option of going to regular mags would be expensive since auto spark plugs have a smaller diameter and the cylinders would have to be modified to accept regular aviation plugs. Open to help and comments! |
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Two side comments: - You should thank eMag for providing the replacement. The eMag has an internal tempurature sensor so when you send the unit back they can tell how hot it got. You must have really cook yours. - Unless you have a very unusual setup, your engine has spark plug adapters installed so you can use auto plugs. If you really want to put mags on, then take out the adapters and buy a box of overpriced aviation plugs. Carl |
the manual is important
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If memory serves, the service limit is something like 200F, with internal components supposedly good for 230F or so. BTW, let's remember that blast tubes do nothing after shutdown, when temperatures are highest. |
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I sent them in for a check up since after 5 years / 900+ hours it seems like a pretty reasonable thing to do. |
Which ignition
I put dual 114 series P-Mags on my O-320, RV-9. First engine start was, without question, quick and smooth. The timing setup is so simple - even I could do it :eek:.
Robert |
Are you saying all of your fails were on the Left side? And the Right Pmag failed when move to the left hole? I had multiple mechanical and electrical Pmag fails on my 0-360 A1A, all on the Right side.
IMO, there is a weakness in the design that only presents on certain engines that?s not understood yet. If you have more than one fail with a Pmag you just need to move on to another system. Most people have very good luck with Pmags, no bashing intended, but if you have had a fail your chances of having more is pretty high. Tim Andres Quote:
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What type of propeller do you have? Not knowing what type of failures you were experiencing, it is difficult to offer advice. I ask because a neighbor had a carbon fiber ground adjustable prop and his mags wouldn't even make 40 hours before they would fail. He switched to a Catto and the problem went away. |
Just a data point of one.
Single Pmag 114 in use since 2009 on the left side, unmodified IO360A1B6 angle valve (Velocity w/ MT prop) No failures, no glitches, no issues. Over 600 hours use. It's probably time to send it back for the $135 "Flat Fee Check Up" . From a performance standpoint, it's been excellent on the A curve. |
PMAGs internal power quits at low RPM!!!
One thing that I have not read in the past 16 pages and that worries me the most is the fact that the internal generators in the PMAGs quit working below a certain RPM. Depending on the unit that you own, this may be between 800 and 1300.
My signature shows RV-4 PH-EIL, sadly crashed. Here's the crash report: https://aviation-safety.net/wikibase/wiki.php?id=187798 most interesting is this link in it: https://www.bea.aero/uploads/tx_elyd...A2016-0325.pdf It is in French. To those who do not master it, or have figured out Google translate yet: Paragraph 2.6.5 describes the official conclusion why the engine of Laurent quit on final - His rpms dropped below 1100, where the internal generators on his units quit working and required external power to continue. That power apparently wasn't there at this flight, for whatever reason. And so his engine quit, sending him into the trees, killing him and severely injuring his passenger. He had installed dual PMAGs 5 flying hours prior to the accident. So.... unknowingly, we all lose the primary source of electrons in these PMAGs and have to resort to its backup at a phase of flight where it can hurt the most. Our RV4 has dual PMAGs and I love the smoothness, power, easy starting and low fuel burn. However, this is one aspect of them that I really don't like.. And I've lost a friend to them. |
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