Installing Magnetos

[Tri-Pod]

Hi folks,
I removed both mags to check points, E- gap and inspect the impulse coup.
Ready now to go back together.
The left mag, w/imp coup, has a red tooth clearly visible and is the center one of 3 beveled teeth.

The right mag has no clearly visible pain, but with a loupe, I think I can see a faint resemblance of red but it is on a beveled tooth adjacent to the center beveled one. Definitely not certain though.

Should I assume CENTER beveled tooth, same as the left one ? Or ?

I know I can can put it in and out in different positions until correct, but just wondering if it might be set up differently internally.

PA22-160
0-320 B2B

Thanks,
:)

[Chris Iriarte]

The overhaul manual should cover proper timing -- barring that, take the top off and verify the distributor position against where you think the mark is.

Chris

[Lownslow]

Assuming that a reputable, qualified person or repair shop assembled the magneto, you should be able to use the beveled tooth as reference in the window. If you are not familiar or qualified to perform magneto repairs or inspection I recommend that you do not disassemble the mag.

Lou

[Steve Pierce]

Should be the beveled tooth. You should feel the magnetic force on the gear as the tooth comes up in the window. Turn the mag with the painted tooth and see what I am talking about.

[Tri-Pod]

Thanks guys,
I did see in the manual where it says to get the red (bevel) in the window, then center the rotor in the magnetic neutral position.
Much clearer now, thanks again folks.

I think I will send these off for a 500 hr insp, $395 at QAA. If they need more (an overhaul) it's $595, or recons off the shelf for $695.
The last log entry for the mags is a 500hr insp by AD 536 hrs ago. No mention of an overhaul or any other attention noted ... that I can find.
The impulse coupling is the integral pin type but the data plate was never stamped.
The bushing was changed to steel but is a bit worn. The drive gear is a little wobbly and there is metallic "paste" present that indicates bushing material (dust) mixed with the lubricant. The plate was not stamped for this either.

Is there a good mag man on the forum here that is set up to repair these, or any recommendations welcome.
The harness looks good, so I think I'd rather stick w/the Bendix than going the slikk route.

Thanks again,
:-)

[P.o.P.]

Assure the 10-51324 Impulse Spring is replaced while it is off.

#1 cause of Mag Failures in my book.

#2 is defective or worn out Oil Seals.

If you have oil in the breaker comp. it is

time for a Seal.

[Tri-Pod]

Hi PoP,
I did notice that in the manual .... remove and discard (never reuse) the coupling spring.
I took the coupling apart to determine the type. I will mention this to whoever does the work to assure a new one goes back in.
Both breaker compartments are bone dry.
The fellow at qaa said the 500hr insp included bearings, seals points and the "high wear" items.
I just hope the block, coil and rotors are OK. If they are the older types that are to be replaced, a decision will need to be made. Maybe a trade in would then be in order.
I'm just hoping that these are basically OK and just need a touch-up.
Regards,
:icon_wink:

[Steve Pierce]

I have had excellent service out of these guys. http://www.aircraftmagnetoservice.net/

[Chris Iriarte]

Ditto ... just had my mags done by them. They were 100 hrs past their 500 hr inspection and AMS discovered my impulse coupling was the wrong type for my Bendix SN-20s. Gave me a good price on an overhaul (the other only needed a 500hr inspection).

Chris

[Tri-Pod]

Well, I got them back from qaa. One needed a coil and the coupling. Both needed overhaul.
All went well ....except. they put the gear on 180 deg out at the coupling.
It times up perfectly, very near the end of the slot.
They said ..."It happens, human error."

Thanks guys