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Slick 6351

philb

Well Known Member
Hi Guys,

Purchased my TMXIO-540 from Mattituck (obviously a slow build) - it shipped with a left impulse coupled magneto. I'm aware of the SB for recurring inspection, and had initially planned on keeping the mag and complying. I'm rethinking this though, and may go with the surefly, for basically ease of replacement. I don't much like the idea of crawling under subpanels to install other EI brains, removing prop for crank sensors, etc.

The mag is a 6351, with a lag angle of 35 degrees. It seems like most of what I've seen is 25 degrees - are there any implications (if I were to keep it) of having such a delayed fire (10 degrees past TDC on my 25 degree BTDC engine). Some information I've read is that the 35 degree mags were used more in continentals, and less in lycomings. not sure if this is an issue.

Any recommendations on best place to sell this? Is there demand for it in the continental world? Imagine I wouldn't get many takers in this venue...

Phil
 
The lag angle on the data plate is the angle of delay that the impulse coupling will provide at low RPM when starting the engine. You will still time the mag to spark at 25 degrees before TDC, after snapping the impulse coupling over (or whatever angle the engine data plate requires). This is standard operation for timing an impulse mag.

If say your engine data plate says to time the mag to 25 degrees before TDC, then your impulse coupling will delay that firing by 35 degrees when starting the engine, meaning it would fire at 10 degrees past TDC. This is not a bad thing and will likely not adversely affect starting. A mag that said its lag angle is 25 degrees would provide the starting spark right at TDC.

Once the engine RPM increases to the point the impulse coupling disengages completely, timing will revert to however you timed the mag to the engine (25 degrees in this case).
 
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