500 hour mag "inspection"

[Danb]

Lance I'm basic clueless with all this mechanical stuff, but still strive to learn, most stuff doesn't sink in. I'll be changing my oil after MAPA in NH next week, that's a big task for me.

[Marauder]

28 minutes ago, Danb said:

Lance I'm basic clueless with all this mechanical stuff, but still strive to learn, most stuff doesn't sink in. I'll be changing my oil after MAPA in NH next week, that's a big task for me.

Remind me next time and I'll show you how to pull a spark plug! 

[philiplane]

Slick seems to be unable to rectify their quality issues, and I recommend replacing their mags with Bendix when it's time for service. I do 500 hour inspections on lots of magnetos and in the past ten years, it's been a rare event that a Slick mag makes 500 hours without requiring a near overhaul. Their parts simply don't last. Bendix on the other hand, will go 1500-2500 hours before requiring many parts. At each 500 hour, it's usually just lubrication, point adjustment, and occasionally a carbon brush on a Bendix mag.

And it doesn't matter whether the Slick replacement parts are from them, or Kelly. None of them last due to the inherent poor design of the lightweight Slick mag. That was one of their early selling points, that it was significantly lighter than Bendix. But reliable electrical equipment must have a certain mass in order to perform well. Comparison of Bendix features with Slick "features: Bendix has a larger diameter distributor block, but Slick reduced their distributor block size, increasing the crossfire potential; Bendix uses a large distributor gear finger pressed onto the gear shaft to transmit spark energy to the block, but Slick uses a small copper tang restrained by a groove in the distributor gear, and the tang often comes loose causing random misfires. Slick reduced the point cam size, increased their point wear; Slick points are half the size of Bendix points. Bendix uses a shaft mounted metal drive gear, Slick uses a splined plastic gear that increases drive failures, gear wobble, and teeth shearing, Bendix uses larger rotating magnet to produce 30-40% more spark energy, especially at low rpm, and uses a better design impulse coupling for reliable starting.

 

[ArtVandelay]

What Bendix models used on the A3B6? (2 separate mags)

[philiplane]

S4LN-21 left mag, with impulse coupling, and S4LN-20 right mag without coupling. These model numbers will also have a specific part number that defines the features such as degrees of lag in the coupling, what type of vents are employed, and a few other details. You will purchase them by a part number such as 10-51360-37 which is found in the Lycoming parts manual for the engine. When converting from Slick to Bendix, this requires a p-lead connection kit 10-52305 for each lead, unless you get the newest style "SC" magneto which will accept the same p-lead connection as the Slick.

Also requires an M2364 Unison ignition harness for 5/8-24 UREM38E spark plugs since the Slick harness is not compatible.

Edited September 7, 2016 by philiplane

[jetdriven]

 

1 hour ago, philiplane said:

S4LN-21 left mag, with impulse coupling, and S4LN-20 right mag without coupling. These model numbers will also have a specific part number that defines the features such as degrees of lag in the coupling, what type of vents are employed, and a few other details. You will purchase them by a part number such as 10-51360-37 which is found in the Lycoming parts manual for the engine. When converting from Slick to Bendix, this requires a p-lead connection kit 10-52305 for each lead, unless you get the newest style "SC" magneto which will accept the same p-lead connection as the Slick.

Also requires an M2364 Unison ignition harness for 5/8-24 UREM38E spark plugs since the Slick harness is not compatible.

You can also undo SI1325c and put it back to 25 degrees of timing and get your horsepower and speed back 

[Danb]

2 hours ago, Marauder said:

Remind me next time and I'll show you how to pull a spark plug! 

Jeez I forgot I've done that too, I am good!

[ArtVandelay]

 

1 hour ago, philiplane said: S4LN-21 left mag, with impulse coupling, and S4LN-20 right mag without coupling. These model numbers will also have a specific part number that defines the features such as degrees of lag in the coupling, what type of vents are employed, and a few other details. You will purchase them by a part number such as 10-51360-37 which is found in the Lycoming parts manual for the engine. When converting from Slick to Bendix, this requires a p-lead connection kit 10-52305 for each lead, unless you get the newest style "SC" magneto which will accept the same p-lead connection as the Slick.

Also requires an M2364 Unison ignition harness for 5/8-24 UREM38E spark plugs since the Slick harness is not compatible.

You can also undo SI1325c and put it back to 25 degrees of timing and get your horsepower and speed back 

I cant find this service instruction on Lycoming site?

[jetdriven]

Of course not, they hide it. But it's out there.  They also pretend that 20 and 25 degrees timing is the same power (it isn't), 25 degrees of timing is dangerous (but not for the A3B6D), and it will void the warranty (it doesn't )

[LANCECASPER]

5 hours ago, philiplane said:

Slick seems to be unable to rectify their quality issues, and I recommend replacing their mags with Bendix when it's time for service. I do 500 hour inspections on lots of magnetos and in the past ten years, it's been a rare event that a Slick mag makes 500 hours without requiring a near overhaul. Their parts simply don't last. Bendix on the other hand, will go 1500-2500 hours before requiring many parts. At each 500 hour, it's usually just lubrication, point adjustment, and occasionally a carbon brush on a Bendix mag.

And it doesn't matter whether the Slick replacement parts are from them, or Kelly. None of them last due to the inherent poor design of the lightweight Slick mag. That was one of their early selling points, that it was significantly lighter than Bendix. But reliable electrical equipment must have a certain mass in order to perform well. Comparison of Bendix features with Slick "features: Bendix has a larger diameter distributor block, but Slick reduced their distributor block size, increasing the crossfire potential; Bendix uses a large distributor gear finger pressed onto the gear shaft to transmit spark energy to the block, but Slick uses a small copper tang restrained by a groove in the distributor gear, and the tang often comes loose causing random misfires. Slick reduced the point cam size, increased their point wear; Slick points are half the size of Bendix points. Bendix uses a shaft mounted metal drive gear, Slick uses a splined plastic gear that increases drive failures, gear wobble, and teeth shearing, Bendix uses larger rotating magnet to produce 30-40% more spark energy, especially at low rpm, and uses a better design impulse coupling for reliable starting.

 

There are no Bendix mags for the M20M.

[DonMuncy]

Plus 1 for Select. Aaron knows his stuff and is a straight shooter.

[Browncbr1]

6 hours ago, jetdriven said:

Of course not, they hide it. But it's out there.  They also pretend that 20 and 25 degrees timing is the same power (it isn't), 25 degrees of timing is dangerous (but not for the A3B6D), and it will void the warranty (it doesn't )

Don't get me started on si1325 and the data plate scandal!    

Unfortunately, I learned about Kelley and QAA slick "overhauls" and si1325 the hard way.  I got my timing back to 25, but I'm going to wait until the slicks die before buying bendix mags, which is what I wish I had done from the beginning.  Or perhaps electronic ign. 

[bradp]

I agree.  When it's time to overhaul or IRAN the slicks they will be going to magneto heaven and I'll replace with Bendix.  Might do it before if the headaches with hot starting continue.  

When I was really having issues Slicks technical assistance was to try to sell me a SlickStart because they know as well as anyone that they are selling a crappy product.  

[jetdriven]

If they're running good right now they may have value to a RV builder. I sold my 88 hour slicks and harness for 850$ iirc to a RV guy.  I should have asked more but a set of new ones was only 1500$. Now it's over 2k. Plus harness. 

I blight some Bendix cores off eBay for 200$, with gears. 

Edited September 8, 2016 by jetdriven

[clh]

17 hours ago, Browncbr1 said:

 

Unfortunately, I learned about Kelley and QAA slick "overhauls" and si1325 the hard way.  I got my timing back to 25, but I'm going to wait until the slicks die before buying bendix mags, which is what I wish I had done from the beginning.  Or perhaps electronic ign. 

Unfortunately, I learned about Kelley Bendix  "overhauls"  as well  1 Year and 150 hours, I have had both the condenser and the oil seal fail.  Kelly's response was to tell me tough luck, but call them and they will sell me another one when something happens again....... 

It is amazing that these guys stay in business producing this type of crap.

[Jim Peace]

Just another thought....I did both of my Slick inspections in 2015.  I purposely staggered it.  Sent one out in the spring and the other in the fall.  Probably best to send to two different shops as well.  I know this is a technique on multi engine planes.  Send the engines out to two different quality shops.

 

 

 

 

[chrisk]

Slightly off topic, but I had my pressurized mags IRANed  1.5 years ago.  The engine ran great.  However on my first flight at high altitude (17,000) I experienced a very slight misfire twice.  --Or at least I only felt it twice.  I later confirmed the two incidents it on the JPI.  I then had a very fun discussion with my local mechanic (who did not do the annual) who thought I was nuts when I told him to pull the mags and send them back to the repair shop.  This was after I inspected the pressurization hose.  --The discussion was even more fun when the mag shop replaced some gaskets and returned the mags with no charge for their work.  It's been fine ever since.

Not sure what the point of the story was, other than maintenance always involves some risk.  No shop is perfect.  The good shops double check the things that will kill you and stand behind their work.  With pressurized mags, you can only test certain things when you take the plane to the flight levels. --And I only do that on my really long flights.  Think about it after you get your mags serviced.

 

[TheTurtle]

Sounds like Kelly is the skip white of mags.

On the topic...  My prebuy squawked the fact that the mags havent had a 500 hour inspection.  They seem to be about 1700 hours old.  Mag checks at runup are fine.  They are slick 4345 LAG 15 ROT L REV B.

I want to have "something" done at annual.  Not sure if an inspection or replacement.  I was looking at those Kelly units on spruce.  glad I checked here first.  What is the conversion process to switch to bendix?  How many AMUs am I going to be missing?  Where do you get your mag inspections done on Slicks if I went that route and whats it usually cost?  Sending them to different shops seems smart as does waiting between swapping each.  But I kind of want to get it all done as well as a new vacuum pump during annual.

thoughts?

[clh]

16 minutes ago, TheTurtle said:

Sounds like Kelly is the skip white of mags.

On the topic...  My prebuy squawked the fact that the mags havent had a 500 hour inspection.  They seem to be about 1700 hours old.  Mag checks at runup are fine.  They are slick 4345 LAG 15 ROT L REV B.

I want to have "something" done at annual.  Not sure if an inspection or replacement.  I was looking at those Kelly units on spruce.  glad I checked here first.  What is the conversion process to switch to bendix?  How many AMUs am I going to be missing?  Where do you get your mag inspections done on Slicks if I went that route and whats it usually cost?  Sending them to different shops seems smart as does waiting between swapping each.  But I kind of want to get it all done as well as a new vacuum pump during annual.

thoughts?

About 6 years ago, I had a 1500+hr Bendix magneto fail in flight.  I replaced them both with Slicks, The one slick was never quite "right".  The left mag would drift about 5-7 deg between oil changes, so I would have to retime the mag as part of the oil change. (and have several mechanics tell me that I am crazy, later to tell me they have never seen anything like that before)  

I ran them 500 hrs and replaced them with Kelly rebuilt Bendix.  In the year I had the Bendix, I have had two down-time events that resulted in replacing parts that Kelly replaced as the re-manufacturing process.  When I replaced the engine (just finishing now), I swapped the slicks that came with the engine with the Bendix.   Bottom line,  I have no good recommendation of a mag, but a couple "bad" recommendations.  

If I had it to do over again, I would probably buy new Bendix,  but then again, would probably just find out they were junk as well. 

Figure 2-3 amu for the installed mags and another 1-2amu fixing them once they "F" up.   

If you are dead set on slicks, I have a new set of slicks (and wires) that i would entertain offers. 

 

[DaV8or]

33 minutes ago, TheTurtle said:

Sounds like Kelly is the skip white of mags.

On the topic...  My prebuy squawked the fact that the mags havent had a 500 hour inspection.  They seem to be about 1700 hours old.  Mag checks at runup are fine.  They are slick 4345 LAG 15 ROT L REV B.

I want to have "something" done at annual.  Not sure if an inspection or replacement.  I was looking at those Kelly units on spruce.  glad I checked here first.  What is the conversion process to switch to bendix?  How many AMUs am I going to be missing?  Where do you get your mag inspections done on Slicks if I went that route and whats it usually cost?  Sending them to different shops seems smart as does waiting between swapping each.  But I kind of want to get it all done as well as a new vacuum pump during annual.

thoughts?

I think it's kind of funny. Here you have a pair of Slicks that have gone 1700 hours without anything done to them, they are working fine, so don't let the internet talk you into junking them. I have Slicks too. I read all this same stuff and sent mine out just past 500 hours for IRAN to Aircraft Magneto Service and you know what? They were fine. They replaced almost nothing. They worked good before and they work good now. According to the internet they should have been melted down, ground down pieces of junk requiring thousands of dollars to fix, but that just wasn't the case.

Slicks are smaller (really nice if you work on your own plane) and lighter. Bendix provide a hotter spark. If your mags really are junk, maybe consider new Bendix, but otherwise IRAN them like I did. I think you'll find it isn't all that bad and they'll continue to work fine.

[TheTurtle]

11 minutes ago, DaV8or said:

I think it's kind of funny. Here you have a pair of Slicks that have gone 1700 hours without anything done to them, they are working fine, so don't let the internet talk you into junking them. I have Slicks too. I read all this same stuff and sent mine out just past 500 hours for IRAN to Aircraft Magneto Service and you know what? They were fine. They replaced almost nothing. They worked good before and they work good now. According to the internet they should have been melted down, ground down pieces of junk requiring thousands of dollars to fix, but that just wasn't the case.

Slicks are smaller (really nice if you work on your own plane) and lighter. Bendix provide a hotter spark. If your mags really are junk, maybe consider new Bendix, but otherwise IRAN them like I did. I think you'll find it isn't all that bad and they'll continue to work fine.

can really argue that   if it aint broke dont fix it.  Somebody thinks they should at least be inspected every 500 hours though.  I hear the vacuum pump is easy to replace with the mags out any way so maybe ill at least get them IRANd

[Browncbr1]

The older slicks seem to have a better reliability record.   I think he decent ones are from the 90's.  If you have good ones, do not send them to Kelley or QAA.  They will send you back a completely different mag with different serial numbers.  This is where all of my problems started.  There is a good mag guy in TX you can search my other posts in this forum where I mention his name and contact.  Can't remember right now.  He will Iran and return your actual mags.  If you have the 4345, then it sounds like you have 20 degree timing setup.   Many on this forum, including me, much prefer 25degree timing.  

 

Regarding your vacuum pump, I wouldnt mess with it unless you aren't getting steady acceptable suction.  They have a high infant mortality rate.   

[Browncbr1]

yea, that's him.. Aaron is great.. 

[DonMuncy]

+1 for Aaron. Knows his stuff, and a nice guy.