Slick magneto question

Bushcaddy · #1 05-07-2009, 12:32 PM

I have my magnetos out for the carbon brush replacement. After reading up on that I figured I would have to retime them so I looked into that. One of the guides I found stated "be careful when removing or reinstalling the magnetos because the rubber isolators may fall off into the accessory case". I had already removed the magnetos

and can find no evidence of rubber isolators on them. I can't see inside the holes on the accessory case because I have just enough room to remove the magnetos. Slick publication L-1363 makes no mention of these isolators. The Lycoming overhaul manual shows a diagram (4.1) of some "rubber cushions" on a mag that looks nothing like my slick 4370 or 4381. So my question is: are these isolators on slick mags? If I don't see them on my removed mags are they likely inside the accessory case somewhere? I can't imagine that something that would fall off so easily would be in such a position

Geico266 · #2 05-07-2009, 02:14 PM

I'm no expert, but I've installed 2 different sets of Slicks on airplanes. I have never seen anything like you are describing.

airguy · #3 05-07-2009, 03:04 PM

Time for an inspection mirror and a flashlight...

Russ McCutcheon · #4 05-07-2009, 05:56 PM

No worries, you don?t have these. Have fun!

az_gila · #5 05-07-2009, 06:25 PM

Quote:

Originally Posted by airguy

Time for an inspection mirror and a flashlight...

..get a Parts Catalog for the engine.

My Lycoming O-360 parts catalog for the Wide Deck "A" series only shows the cushions on the right magneto for the -A4A and -A4J engines.

The engines that use the cushions also have an "Adapter Assembly" for the right magneto, which appears to look like the spacer for an impulse coupler. However, the cushions appear on the non-impulse magneto.

All of the other "A" dash numbers should have no cushions to drop...

ABOVE IS FOR THE RV GUYS....

I forgot Don has a O-235...

None of the dash numbers appear to use drive cushions...

Bushcaddy · #6 05-07-2009, 07:45 PM

You guys are the best. Thanks for helping me keep my lunch down

Gil, you have a good memory...O-235 L2C it is.

BTW I did try the inspection mirror...couldn't quite get the angle due to the closeness to the firewall...would have taken a borescope!!

Geico266 · #7 05-07-2009, 07:53 PM

Quote:

Originally Posted by Bushcaddy

You guys are the best. Thanks for helping me keep my lunch down

Gil, you have a good memory...O-235 L2C it is.

BTW I did try the inspection mirror...couldn't quite get the angle due to the closeness to the firewall...would have taken a borescope!!

Better pull the pan off just in case!

Kidding!

Gsuit · #8 08-17-2009, 09:27 PM

Quote:

Originally Posted by Bushcaddy

I have my magnetos out for the carbon brush replacement. After reading up on that I figured I would have to retime them so I looked into that.

How did this turn out for you? Did you have to re-set the timing of the mag with the timing pin and also time the mag to the engine upon reinstallation?

Jim P · #9 08-17-2009, 10:24 PM

If you follow the tech data, internal re-timing is a really simple using the specified tool. I'm not sure I'd attempt to re-assemble without re-timing as you never know if something moved internally.

deene · #10 08-18-2009, 07:23 AM

Isolators are used in 6 cylinder models (and two fairly rare 4 cyl config's as noted earlier)...

Not sure I understand the timing question...mags have two "timings", internal and external. The internal timing sets the point gap (adjustable) and distributor-cam relationship (fixed by gears in proper relationship). External timing is set by correct mag gear/chrank relationship and small rotation of mag on mounting ring to fine tune the firing point correctly.

For Slicks, the internal/external gear setting is done by the small pin, just be sure to remember to remove the pin before moving the prop for setting the final timing with a mag timer (buzz box).

The internal timing is addressed in the Slick manual and really is simple with the timing tools (pin and small inexpensive steel plate tool that holds the main rotor is place while setting the internal points with the buzz box). Although, my Tech Counselor friend and expert engine builder, Seth Hancock, often does both internal and external timing without the Slick tools.