Inductor Mag Timing Question

[WingsOnWheels]

So I am trying to install and time my mags. I have done this before without an issue, but this is the first time I have use one of the inductance timing boxes rather than the basic resistance buzz boxes.

I have Bendix S4-20/21 mags with the P-Lead noise filter. I was under the impression that the inductor-type box worked with the filters install (I don't have a set of the adapters at the moment), but that may not be correct.

Round 1: I installed the mags and connected the timing box to the p-lead connection on the filters and the ground lead to the engine. Received no indication of points open/closed as the engine was turned (went around a couple times and checked my connections to be sure).

Round 2: I figured the timing box wouldn't work with the filters, so I unscrewed the P-Lead plug in the point cover and pushed the timing lead into the hole to touch the spring and move it away from the case. Turned the engine with the other hand, still nothing.

Round 3: I figured that I wasn't able to move the spring away from the cover plate to keep it from grounding, hence no indication. So, I pulled the right mag, removed the points cover and connected the lead directy the the P-Lead spring. I also connected the ground to the mag case. Turned the mag and watched the points open and close, no indication of change on the timing box.

Round 4: Thought maybe the points are well out of spec and not closing (even though the mags came from a running engine), checked with an ohm-meter. The meter indicated the points were opening and closing.

I thought that the timing box may be bad so I called the manufacturer and they told me to test it using the coil from a relay or other device. The timing box tested as working correctly.

Any ideas what the heck I am doing wrong????

Thank,

[Larco]

Is the mag switch on or off?

[WingsOnWheels]

Originally Posted by LARCO

Is the mag switch on or off?

Not yet wired, so it doesn't matter (ie, no P-Leads run to connect).

I don't have to time the Mags right now, but I figured I might as well since I am mounting them so I can install the harness. I'll recheck the timing again before 1st start.

[Walt]

Not sure which timing box you are using, but I just timed a set of Bendix S4 mags yesterday using an Eastern E50 with no problems.

[WingsOnWheels]

Originally Posted by Walt

Not sure which timing box you are using, but I just timed a set of Bendix S4 mags yesterday using an Eastern E50 with no problems.

The E50 is what I have used in the past, nerve had any problems. I picked up the Inductor Magneto Sync since it is supposed to be less prone to erros since it measures the change in coil inductance rather than resistance across the points. There is supposedly no error from shorted contacts. All well and good in theory, but not if it doesn't work. This might need to go back to ACS.

https://www.aircraftspruce.com/pages...nchronizer.php

[aerhed]

I dunno what's wrong with your box, but if you're clipping onto the p-lead spring without the capacitor you can just use your ohmeter. Does it have a continuity beeper?

[DakotaHawk]

Originally Posted by WingsOnWheels

So I am trying to install and time my mags. I have done this before without an issue, but this is the first time I have use one of the inductance timing boxes rather than the basic resistance buzz boxes.

I have Bendix S4-20/21 mags with the P-Lead noise filter. I was under the impression that the inductor-type box worked with the filters install (I don't have a set of the adapters at the moment), but that may not be correct.

Round 1: I installed the mags and connected the timing box to the p-lead connection on the filters and the ground lead to the engine. Received no indication of points open/closed as the engine was turned (went around a couple times and checked my connections to be sure).

Round 2: I figured the timing box wouldn't work with the filters, so I unscrewed the P-Lead plug in the point cover and pushed the timing lead into the hole to touch the spring and move it away from the case. Turned the engine with the other hand, still nothing.

Round 3: I figured that I wasn't able to move the spring away from the cover plate to keep it from grounding, hence no indication. So, I pulled the right mag, removed the points cover and connected the lead directy the the P-Lead spring. I also connected the ground to the mag case. Turned the mag and watched the points open and close, no indication of change on the timing box.

Round 4: Thought maybe the points are well out of spec and not closing (even though the mags came from a running engine), checked with an ohm-meter. The meter indicated the points were opening and closing.

I thought that the timing box may be bad so I called the manufacturer and they told me to test it using the coil from a relay or other device. The timing box tested as working correctly.

Any ideas what the heck I am doing wrong????

Thank,

I've got the same problem. I bought a buzz box and tried to time my mag. Couldn't get it to buzz! Had my A&P come over, and he used his old-fashioned home made buzz box - no problems! He couldn't figure out how to get my fancy buzz box to work either.

My neighbor has an identical buzz box. I couldn't get his to work either. I must be doing something wrong, but I have the instruction sheet and followed it exactly!

[Walt]

Sounds like advertising hype to me
A buzz box simply compares the impedance (or inductance because it a coil) of the internal buzz box transformer to the transformer in the mag. When the points open the mag xfmr has a higher impedance than the buzz box xfmr, this cause the current to flow through the buzz box xfmr which then lights the light.

[WingsOnWheels]

What timing device were you using? Something like the E50 or the solid state Inductor version I have?

Originally Posted by DakotaHawk

I've got the same problem. I bought a buzz box and tried to time my mag. Couldn't get it to buzz! Had my A&P come over, and he used his old-fashioned home made buzz box - no problems! He couldn't figure out how to get my fancy buzz box to work either.

My neighbor has an identical buzz box. I couldn't get his to work either. I must be doing something wrong, but I have the instruction sheet and followed it exactly!