Mag with impluse coupling

You would want to install the left mag (typically the one with impluse coupling). That way you could at least start the engine by hand proping if the battery got too low to crank it over.
 
Mag leads to bottom cylinders

... and put the mag leads to the bottom cylinders and EI to the top cylinders
 
Why would you fire the bottom plugs with the mags? Wouldn't the EI give you a better spark on the bottom where you need it most?
 
A different view ..

rv9av8tr said:
... and put the mag leads to the bottom cylinders and EI to the top cylinders
Click to expand...

This is contrary to what some vendors recommend.

Jeff Rose (ElectroAir) recommended EI on bottom plugs where you are more likely to have oil and the hotter spark would burn through it better than the mag.

I have found this to absolutely true.

James
 
jclark said:
This is contrary to what some vendors recommend.

Jeff Rose (ElectroAir) recommended EI on bottom plugs where you are more likely to have oil and the hotter spark would burn through it better than the mag.

I have found this to absolutely true.

James
Click to expand...

Just one data point, but I did the opposite (EI on top) and have never fouled a plug on either ignition system in 550+ hours.
 
If the question was about part numbers...

hughfi said:
Which one should I get? I have an 0-320-E3D 160hp.

Thx.

Hugh.
Click to expand...

...then a 4371 or 4373 Slick magneto would work on the left side. Both are listed as applicable to the 160 HP O-320-D1A model that Vans sells. One is 20 degree timing, and the other is 25 degrees.

If you want to put on a Lycoming suggested magneto, then you can check your equivalent O-320 model number on this list....

http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1443F.pdf

Both are impulse magnetos and you would also need a LW12706 spacer and two longer studs - part # 31C-12.
 
I highly suggest Bendix/TCM mag instead of a slick. I know they weigh more, but they have a better record in my experience, and they don't have an open SB on them right now like the Slick.

I suggest an S4LN-21, 10-51360-30...
 
Top Vs bottom

Klaus at LSE told me to put the EI wires to the top. My presumption is that EI will be timed to fire before the mag much of the time. You want to ensure dry plugs (no oil fouling) to get the most out of your EI advantages.
 
Thanks, and now for second question...

I have never installed a mag (although used plenty :). Does a Mag have just a ground wire running out of it once its installed connected to the ignition switch? Is it as simple as that or is there more complicated wiring involved?

I want to understand what I should expect in terms of installation effort. I realize timing etc. is something I will need some help with from my A&P (I did not build the plane myself).

Any info would be appreciated.

Thx.

Hugh.
 
Slick AD ?

As long as we're on the subject......
My local A&P told me that the overhaul shop he uses is finding no bad mags when they check the AD. Anybody heard different?

That might also factor into your decision.

John
 
hughfi said:
I have never installed a mag (although used plenty :). Does a Mag have just a ground wire running out of it once its installed connected to the ignition switch? Is it as simple as that or is there more complicated wiring involved?

I want to understand what I should expect in terms of installation effort. I realize timing etc. is something I will need some help with from my A&P (I did not build the plane myself).

Any info would be appreciated.

Thx.

Hugh.
Click to expand...

That, plus four wires running to the spark plugs...

;)

Yes, it is that simple. It is automatically grounded to the engine; self contained; and the P-Lead runs to a switch which, when closed, simply grounds it out to prevent it from firing.

I won't say dummy proof, because they are always making better dummies...

:D
 
Not so automatic....

breister said:
That, plus four wires running to the spark plugs...

;)

Yes, it is that simple. It is automatically grounded to the engine; self contained; and the P-Lead runs to a switch which, when closed, simply grounds it out to prevent it from firing.

I won't say dummy proof, because they are always making better dummies...

:D
Click to expand...

You should not rely on any automatic grounding at the magneto - this is a major safety issue.

Use the dedicated ground screw for a direct ground at each magneto...

This previous thread shows a picture of the ground location... it's not very obvious, being just a threaded hole....

http://www.vansairforce.com/community/showthread.php?t=25318&highlight=slick
 
az_gila said:
You should not rely on any automatic grounding at the magneto - this is a major safety issue.

Use the dedicated ground screw for a direct ground at each magneto...

This previous thread shows a picture of the ground location... it's not very obvious, being just a threaded hole....

http://www.vansairforce.com/community/showthread.php?t=25318&highlight=slick
Click to expand...

My bad - I've never actually installed one myself.

Ok, half wrong. If you bolt it on correctly INCLUDING THE GROUNDING SCREW it is "automatically grounded..."

:D
 
again... not quite

breister said:
My bad - I've never actually installed one myself.

Ok, half wrong. If you bolt it on correctly INCLUDING THE GROUNDING SCREW it is "automatically grounded..."

:D
Click to expand...

... your statement sort of implies that their is a grounding connection from the magneto to the engine (as you bolt it on)....:)

The grounding screw should be connected to the shield of the P-lead, and then the magneto switch connects (shorts) the shield to the core of the P-lead to make it "safe" - that is magneto OFF.

No grounding strap or connection is made from the magneto to the engine.

I rate it as being only 1/4 correct....:D
 
az_gila said:
... your statement sort of implies that their is a grounding connection from the magneto to the engine (as you bolt it on)....:)

The grounding screw should be connected to the shield of the P-lead, and then the magneto switch connects (shorts) the shield to the core of the P-lead to make it "safe" - that is magneto OFF.

No grounding strap or connection is made from the magneto to the engine.

I rate it as being only 1/4 correct....:D
Click to expand...

Ok, I thought I had SOME understanding of a simple device.

Isn't it true you cannot get a spark without a complete circuit? If this is, as I suspect, true, then bolting the Mag to the engine IS the "grounding" I was discussing - as opposed to the grounding YOU are discussing which occurs to cause the Mag to STOP sparking. Thus, grounding the Mag to the engine via a direct contact allows the Mag to generate a voltage potential (either positive or negative) between the spark plug tip (connected to the Mag lead) and the spark plug body (connected to the engine block by it's threads).

I believe what you are saying is, having the P-lead connected through the Mag switch to just "any old ground" is not (or, at least MAY not be) sufficient; it must ground directly back to the Mag at the grounding screw to ensure that it creates no spark at all.

When you mentioned a "grounding screw", I assumed you meant it went through the Mag and was tightened against the engine block.

So, if the above is correct then my ORIGINAL description was also correct - just missing the detail that the P-Lead shield is attached to the Magneto ground screw. That would leave my original description 100% correct, just incomplete...

;)
 
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Re-rated

:D
breister said:
......
So, if the above is correct then my ORIGINAL description was also correct - just missing the detail that the P-Lead shield is attached to the Magneto ground screw. That would leave my original description 100% correct, just incomplete...

;)
Click to expand...

OK... I'll rate it back to 1/2.....:D

I was more concerned with the safety aspect of missing the grounding screw and using the P-leads incorrectly.
The grounding screw is hard to see and is un-labeled.
 
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