I have been flying regularly a Recently purchased a 1958 Piper with 2140 TT engine/aircraft, 301 smo engine, and pulled it out of the hanger yesterday to attend a pancake breakfast and the engine would not start. Subsequent investigation revealed no spark from either mag, ignition switch removed from wires, mag grounding p-leads removed from both mags, no spark so removed both mags and neither produce any spark. How can that be???? Any thoughs? I am an IA/DAR with many years experience and clueless where to look.:roll:
Simultaneous double slick mag failure
- Thread starter Big Cubs
- Start date
Dodd Wamberg
PATRON
Dover, NH
I had the same thing happen on newly overhauled slick mags. I sent them back to the overhaul shop and they said the coil failed.
cubdriver2
FRIEND
upstate NY
Skippy says go steal Freddy's mags and go fly
Glenn
Glenn
mike mcs repair
Registered User
chugiak AK
points not opening...
was 20 years ago slicks would burn up in first 15 hours because some idiot worker at slick was not lubing the cam wiper the points rode on... overhaul guy knew all about it... once he fixed them they lasted....
hard starting is usually points/gap/egap, and if you have a "slick start" booster it will 'hide' that clue and get you started and yet mags are not performing as well as they could be.....
was 20 years ago slicks would burn up in first 15 hours because some idiot worker at slick was not lubing the cam wiper the points rode on... overhaul guy knew all about it... once he fixed them they lasted....
hard starting is usually points/gap/egap, and if you have a "slick start" booster it will 'hide' that clue and get you started and yet mags are not performing as well as they could be.....
SteveE
SPONSOR
Jenks, OK
Iv'e also had the little spring clip on the points move and not allow the points to open. the screw and nut that hold the point together was loose and moved the alignment out of square and it grabs on the edge and will not open. Very strange that both would be bad at the same time.
wireweinie
FOUNDER
Palmer, AK
You say it was recently purchased? How much was it flown in the previous years? When was the last 500 hour inspection done? I have seen mags fail after little use. Just recently saw one fail when the nylon gear under the distributor block peeled some teeth off. This aircraft was only flown 5 or 6 hours a year and has a total of 50 some hours since mag overhaul. The engine guys were not surprised about the failure when we told them how little the aircraft had flown. I've also come to the conclusion that you need to watch Slicks closely for the first 50 hours or so after overhaul. If you're going to have major issues it seems to happen around that time. After that you're probably good.
Web
Web
WhiskeyMike
MEMBER
West Boxford MA
Yup, get Bendix mags, or the newfangled electronic ignition...
mike mcs repair
Registered User
chugiak AK
Long shot wild idea. Bad engine ground, somehow sending all the starting current through the plead system??
OK Guys, I get it. Nothing in the logs when the Slicks were installed but as they say "Throw away Mags". Am a huge Bendix fan and have always advised my customers o go Bendix.
I wind up with Slick. First mag failure in 60 years and over 23,000 hours so have reinstalled them in a garbage can and shiny new Bendix in the mail.
I wind up with Slick. First mag failure in 60 years and over 23,000 hours so have reinstalled them in a garbage can and shiny new Bendix in the mail.
behindpropellers
Registered User
NE Ohio
Spark Plug Resistance. I don't have the numbers written down but if your plugs have high (or low) I can't remember right now... It will cause your coils to fail. I'll find out the numbers and re-post.
Tim
Tim
Cub Builder
MEMBER
North Central AR
Plug resistance should be 1000 to 5000 Ohms. Easily checked with your Meter during annual. Too high of a resistance will break down the coils when it's easier to spark internally in the mag. Mike Busch made a big deal of plug resistance a couple of years ago and called out Champion for having problems with their plugs going out of spec.
-Cub Builder
-Cub Builder
fobjob
MEMBER
Salt Lake City, Utah
The brightness of the spark is proportional to it's temperature, which is proportional to it's ability to light a (non-optimum) mixture....the Slicks always seemed to have a weak spark compared to the Bendixes....seemed like to me, anyway....never actually measured the voltage/current. On the other hand, look which brand has the most AD's......
skywagon8a
MEMBER
SE Mass MA6
If a bad/no engine ground was determined to be the problem, something else was not hooked up correctly because when you cut off the P-leads the mags will always be on/hot. The engine needs no connection to any other part of the airframe to operate. Now if you are referring to the starter not operating correctly, the ground strap could have been the problem.
mike mcs repair
Registered User
chugiak AK
i think he means that FRIED THE MAGS....
wireweinie
FOUNDER
Palmer, AK
Kind of what I was thinking. No ground strap with mags grounding through the airframe. Could lead to a whole bunch of electrons going places where they shouldn't. Like the mag coils.
Web
Web
