Group Poll: How many hours between mag overhauls?

You have two of them. If one fails you can continue to fly on the
other. Best thing to do is replace ONE. Then you have one new one and
one old one. I consider mags to be 2000 hour lasting accessories, or
replace when they fail. You could easily argue that you don't have to
replace them until you rebuild the engine. It really is up to you. But
with mags, you do have a backup if one fails and the likelyhood of both
failing at once is small.

Doug wrote:

You have two of them. If one fails you can continue to fly on the
other. Best thing to do is replace ONE.

Better than replacing two?

My Slicks gave a problem on left mag drop at 1200 hrs and were repaired.
Until the problem, mag maintenance hadn't even occured to me - there's
just too many things to be aware of in aircraft ownership - I guess that
one just slipped under the radar.

Tony
--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

In article ,
"Jim Burns" wrote:

To the group: At how many hours do you rebuild or replace your mags? or do
you wait for a problem to arise first?

Jim

"tony roberts" wrote in message
news:nospam-A30BC4.22543423042005@shawnews...
My Slicks gave a problem on left mag drop at 1200 hrs and were repaired.
Until the problem, mag maintenance hadn't even occured to me - there's
just too many things to be aware of in aircraft ownership - I guess that
one just slipped under the radar.

Tony

Slick says at 500 hours they should be pulled and inspected. Mine were in
near new condition at 500 hours.

Mine were just rebuilt 4 hours ago and now I have left mag problems
again - it has dropped 100, 400, and cut out.
My A&E is away so I'm grounded until he gets back


Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

In article ,
"Dave Stadt" wrote:

"tony roberts" wrote in message
news:nospam-A30BC4.22543423042005@shawnews...
My Slicks gave a problem on left mag drop at 1200 hrs and were repaired.
Until the problem, mag maintenance hadn't even occured to me - there's
just too many things to be aware of in aircraft ownership - I guess that
one just slipped under the radar.

Tony

Slick says at 500 hours they should be pulled and inspected. Mine were in
near new condition at 500 hours.

O-320 that had a brand new pair of Slicks installed when the engine was
field-overhauled 6 years ago. At the 500 hour mark last annual, we
pulled them and examined them. My A&P said they still look like new
inside.

On Wed, 20 Apr 2005 06:26:43 -0700, "Jim Burns"
wrote:

To the group: At how many hours do you rebuild or replace your mags? or do
you wait for a problem to arise first?

Jim


Back to you: What type/manufacturer of magneto on what engine
installation?

The answer varies from magneto to magneto and installation to
installation.

For instance, I can't recall ever doing a manufacturer-mandated (as
opposed to FAA mandated) 500 hr inspection on a Slick magneto that
couldn't use a set of new points and the crap dug off of the
distributor block.

I can't recall ever doing a 1000 hr inspection on a Slick magneto that
didn't need a set of new points and a new distributor block.

Unless prices have changed a big bunch, you can't buy a new set of
points and a new distributor block + an hour or so of labor for much
less than the price of a new Slick magneto.

I would really not get into the practical maintenance requirements for
a dual Bendix/TCM magneto, given a choice.

TC

Presently I have Slick 4200 (4201 and 4251 as I recall) Series mags on
a Cessna 172M.

The timing to the engine has not changed since the initial new
installation, and remains within specs. They are now at about 900 hrs
since new. This is flat country so I 'm leaving them alone for now.

I've never experienced a rough mag since I quit renting aircraft 1600
hrs ago. I'm now at 1700 hrs TT over 40 years all (well most) with 80
octane or autofuel.

On 24 Apr 2005 19:29:31 -0700, "nrp" wrote:

Presently I have Slick 4200 (4201 and 4251 as I recall) Series mags on
a Cessna 172M.

The timing to the engine has not changed since the initial new
installation, and remains within specs. They are now at about 900 hrs
since new. This is flat country so I 'm leaving them alone for now.

I've never experienced a rough mag since I quit renting aircraft 1600
hrs ago. I'm now at 1700 hrs TT over 40 years all (well most) with 80
octane or autofuel.

My alleged experience is derived from private owner-flown aircraft,
rental/trainer aircraft, corporate-owned/professionally flown
aircraft, and charter aircraft.

Average annual utilization of all these types was around 400 hours a
year-the higher utilization of the last three types pulled down by the
first type.

If you are telling me that noone has has to twist your Slick mags in
900 hours, I believe you-but I will say that this is not the norm in
my experience. In theory, the plastic point "cam" stuck into the split
shaft is supposed to wear at the same rate that the points erode,
keeping the point/gap internal timing relatively unchanged. You're
probably living right, it never seems to quite work out that way for
me.

As I indicated, on company aircraft, we yanked them at 500 for
inspection and pitched them at 1000. We figured it was a small price
to pay to eliminate the "rough mag since I quit renting" problem
you've mentioned. On customer aircraft, internal inspection was
predicated by a couple of small mag-to-engine timing changes or one
large one.

Regards;

TC

Hey TC... 200 Series Bendix shower of sparks type.

Jim

wrote in message
...
On Wed, 20 Apr 2005 06:26:43 -0700, "Jim Burns"
wrote:

To the group: At how many hours do you rebuild or replace your mags? or
do
you wait for a problem to arise first?

Jim


Back to you: What type/manufacturer of magneto on what engine
installation?

The answer varies from magneto to magneto and installation to
installation.

For instance, I can't recall ever doing a manufacturer-mandated (as
opposed to FAA mandated) 500 hr inspection on a Slick magneto that
couldn't use a set of new points and the crap dug off of the
distributor block.

I can't recall ever doing a 1000 hr inspection on a Slick magneto that
didn't need a set of new points and a new distributor block.

Unless prices have changed a big bunch, you can't buy a new set of
points and a new distributor block + an hour or so of labor for much
less than the price of a new Slick magneto.

I would really not get into the practical maintenance requirements for
a dual Bendix/TCM magneto, given a choice.

TC