Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

Coil Pack cylinder splits

TASEsq

Well Known Member
Patron
I’m installing SDS coil packs.

How do people split up the top and bottom plugs between the coil packs? Does it matter?

Option 1:
Right coil pack does all top plugs
Left coil packs does all bottom plugs.

Option 2 (which I think? Is how mags are setup?)
Left pack - 1 & 3 top plugs, 2 & 4 bottom plugs
Right pack - 2 & 4 top plugs, 1 & 3 bottom plugs

How do most people orient the coil packs on the mag holes?

I was thinking that pretty much they would only fit with the coil packs oriented outboard - but this means the left coil pack plug would be facing up? (Water ingress)

This has the advantage of the bottom plug positions on each coil correspond with the bottom plugs on that side of the engine (the top plug positions on the coil are reversed, so the top leads would have to cross over to the opposite side of the engine)

A pic below of outboard orientation of the coil packs, and a couple of rudimentary drawings of the question i’m poorly trying to get across!
 

Attachments

  • IMG_0305.jpeg
    IMG_0305.jpeg
    756.4 KB · Views: 23
  • IMG_0252.jpeg
    IMG_0252.jpeg
    191.3 KB · Views: 22
  • IMG_0253.jpeg
    IMG_0253.jpeg
    183.9 KB · Views: 22
  • IMG_0309.jpeg
    IMG_0309.jpeg
    127.9 KB · Views: 20
Last edited:
I’m installing SDS coil packs.

How do people split up the top and bottom plugs between the coil packs? Does it matter?

Option 1:
Right coil pack does all top plugs
Left coil packs does all bottom plugs.

Option 2 (which I think? Is how mags are setup?)
Left pack - 1 & 3 top plugs, 2 & 4 bottom plugs
Right pack - 2 & 4 top plugs, 1 & 3 bottom plugs

How do most people orient the coil packs on the mag holes?

I was thinking that pretty much they would only fit with the coil packs oriented outboard - but this means the left coil pack plug would be facing up? (Water ingress)

This has the advantage of the bottom plug positions on each coil correspond with the bottom plugs on that side of the engine (the top plug positions on the coil are reversed, so the top leads would have to cross over to the opposite side of the engine)

A pic below of outboard orientation of the coil packs, and a couple of rudimentary drawings of the question i’m poorly trying to get across!
Hey Trent,
A bunch of Rv-14's and Rv-10's up here in QLD are very happy with Upper and Lower.
These are on CPI2 Ignitions and EMF-6 SDS Systems.

1766488653690.png
 
Are you not able to mount one coil pack on the upper case and one on the mag mount? Upper does upper plugs, mag mount does lower. No plug wires through the aft baffle.
 
Are you not able to mount one coil pack on the upper case and one on the mag mount? Upper does upper plugs, mag mount does lower. No plug wires through the aft baffle.
I probably could - but then my 3D printed baffle grommets would be wasted 🤣😇
(The baffles already had these holes so the easiest path was grommets to fit the MSD wires).
 

Attachments

  • IMG_9630.jpeg
    IMG_9630.jpeg
    1.2 MB · Views: 14
  • IMG_9631.jpeg
    IMG_9631.jpeg
    1 MB · Views: 13
  • IMG_9629.jpeg
    IMG_9629.jpeg
    994 KB · Views: 11
  • IMG_9628.jpeg
    IMG_9628.jpeg
    1.1 MB · Views: 15
Not SDS, but LSE, did the top/bottom coils split.
IMHO mounting the coils on the engine is not the best idea, mine are on the engine mount... but again, that's me (we've already discussed the pros/cons in other threads).

PS
Also using some made by a friend 3D pass-thrus for the wires :)

Ign Schematic.JPG
 
Also keen to hear why the choice of one way over another.

I think the lycoming method had to do with the lower plugs being fouled? If you lost a mag, then at least you had two upper and two lower plugs.
 
I mounted my coils on the mag pads and wired them like normal mags. Left coil fires1&3 top and 2&4 lower, right coils fires 2&4 top and 1&3 lower. No issues for nearly 500 hours.

I do like the upper/ lower ign switch too. I think you’ll be happy either way.
 
As to labeling, I went with “PRIMARY A” and “BACKUP B.” I also made my labels green and red respectively. It enables me to keep the architecture straight in my mind.
FWIW, both my SDS coil packs are on the FW.
 
As to labeling, I went with “PRIMARY A” and “BACKUP B.” I also made my labels green and red respectively. It enables me to keep the architecture straight in my mind.
FWIW, both my SDS coil packs are on the FW.
You must be referring to the ecu backup switch?

I’m actually running my coil power through the normally closed contacts of a relay. A momentary test switch grounds one of the two relays for testing at runup.

(Nice diamond 16 by the way!)
 
Thanks! Just a couple of weeks before the 50 ship I think I was 6th alternate. I still don’t know exactly how I ended up -4 in the slot of the right diamond. Infinite thanks to the tireless work done by the key players to make that event possible!!!!!!
ECU? Ah, so you’re installing an SDS EM-6.
I considered going full SDS EFI but settled for the CPI2. I didn’t decide to toss the mags until the very end of the Rocket build. The thought of completely redoing the fuel and electrical systems at that point was, frankly, exhausting…
I do kick myself from time to time though…
 
The old arrangement for mags was done to make it easier for folks to rotate plugs, something required for evening out electrode wear due to changing polarity on mags. No such issue with modern EI, so no reason not to arrange things things in a top / bottom arrangement or whatever fits your wire routing plan. My engines are set up for all top on a coil and also for bottom.
 
Thanks! Just a couple of weeks before the 50 ship I think I was 6th alternate. I still don’t know exactly how I ended up -4 in the slot of the right diamond. Infinite thanks to the tireless work done by the key players to make that event possible!!!!!!
ECU? Ah, so you’re installing an SDS EM-6.
I considered going full SDS EFI but settled for the CPI2. I didn’t decide to toss the mags until the very end of the Rocket build. The thought of completely redoing the fuel and electrical systems at that point was, frankly, exhausting…
I do kick myself from time to time though…
50 ship! We can only dream here in Australia.

This was us last year at the pacific airshow. I’m the odd one out 😇
 

Attachments

  • IMG_1628_Original.jpeg
    IMG_1628_Original.jpeg
    207.9 KB · Views: 14
Back
Top