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-   -   P-Mag timing (https://vansairforce.net/community/showthread.php?t=74689)

FAF 07-25-2011 09:56 PM

P-Mag timing
 
I seem to have wired something wrong on my P-Mags as I am not getting the green LED light to come on to do the initial timing. I have No. 1 cylinder at TDC, confirmed by the TC mark on the flywheel lining up with hole on the starter but when appling power no LED light. The P-Mag troubleshoot guide says that either I should have eithera bad ground or no power. I have doublechecked my wiring, and have confirmed that I have power to the P-Mags with my volt meter but still no LED light. Think I just about read all the old P-Mag post last night and even tried to manual time time today but no joy. Anybody else have this problem? I am thinking it is something simple but I haven't found the problem yet. I always seem to have a problem during Oshosh when all the vendors are at the show. Appreciate any help. Thanks, Frank Foreman

PCHunt 07-25-2011 11:01 PM

I'm sure you have tried this, but the mark will show TDC twice per crank revolution. Make sure you are on the compression stroke by removing one plug from the #1 cylinder and put your thumb over the spark plug hole, and you should feel pressure as you are approaching TDC.

If not, keep turning, and the next time around you will have pressure.

Hope it's that easy! :)

pmnewlon 07-26-2011 06:41 AM

The emag unit uses 'wasted spark' as they call it so all you need is #1 at TDC; doesn't matter if it is compression or exhaust stroke.

Make sure you really have the orientation of the 1-6 connections correct. The #1 connection is FARTHEST from the 3-connection plug.


-----------------------------------------------
CAUTION: Do NOT strike or apply significant inward force to the ignition
shaft. Doing so could damage or misalign the position sensor.

1. Rotate your prop to the engine TDC (or TC) timing mark (see exception Note 4) . By approaching this mark with the prop moving in the direction of normal engine rotation you can minimize play in the gears. Note 1: Be wary of old magneto timing habits. Magnetos are timed using the 25 degree (or other) BTDC marks. You will use the TDC mark ONLY. Note 2: It does not matter whether the engine is on the compression or exhaust stroke for a particular cylinder.

ao.frog 07-26-2011 09:15 AM

Which...
 
... P-mag version do you have?

On the 113 and 114 series, you'll also see a yellow light: that happens if the gear is too close to the P-mag housing. In other words; when the shaft has moved inwards for some reason. (bangs during shipping for example)
Then you need to pry out the shaft with a pair of screwdrivers. The outward movement is 2-5 mm.

This procedure is described in the manual.

If you have an earlier version of the P-mags, then maybe the yellow light isn't visible, but maybe the P-mags still won't accept timing? (if the gear is too close to the housing)

guccidude1 07-26-2011 04:11 PM

P-Mag timing
 
I'm by no means an expert here but I recently installed a 114 Pmag on my o-360 and it timed just as advertised. Check that your ignition switch is off and the power on. This procedure puts the Pmag in the timing mode. The crank should be at 25 degress TDC on either compression or exhaust stroke, as previously mentioned. Dan

FAF 07-26-2011 07:55 PM

Thanks for the suggestions. Mine are less than 1 year old, just know getting around to doing the timing. I again confirmed today that I have the P-Mags wired as per the wiring diagram in their install manual the wires were going to the right switch. P-Mags says that No. 1 terminal is the closest to the manifold pressure & LED light and is the ground and that is what I have done. I have confirmed 12 volts to the NO. 5 pin on the P-Mag but I still don't get LED light. I did read about the shaft moving in and prying it out in the manual, will look at that tomorrow. Thanks everyone. Frank

guccidude1 07-27-2011 03:45 PM

P-Mag timing
 
I talked to one of the Emagair guys at their booth this morning about the timing issue. He said the emergency number on the web site is good and he will answer your questions. He said please call. Dan

NDrv8r 07-27-2011 05:43 PM

pmag timing
 
Quote:

Originally Posted by guccidude1 (Post 561842)
I'm by no means an expert here but I recently installed a 114 Pmag on my o-360 and it timed just as advertised. Check that your ignition switch is off and the power on. This procedure puts the Pmag in the timing mode. The crank should be at 25 degress TDC on either compression or exhaust stroke, as previously mentioned. Dan

I believe the crank needs to be on top dead center for timing the pmag. use 25 degrees for your standard mag.

FAF 07-27-2011 07:53 PM

Thanks Dan for the heads up. I will call tomorrow. Frank

penguin 07-28-2011 11:56 AM

Be sure that the P-lead is connected and grounded. If you have no P-lead its the same as having the ignition switch on, the P-mag will assume you want sparks and will not enter timing mode (no light).

Pete


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