EI = more lead deposits?

[maus92]

Last year I installed a SDS EI system that replaces the left mag. I retained the right mag in my setup. The plane has been in service since year 2000, and the engine has about 400 hours. The top plugs are fired by the SDS, and the bottoms are fired by the mag. The mag was rebuilt last year, and is timed at 25 BTDC.

I am in the middle of the annual condition inspection, and noticed large chunks of lead deposits in (at least) two of the bottom plugs, and another large chuck deposited on the threads of the #3 lower plug hole. Previously, I've never seen much fouling / chunky lead nuggets on my lower plugs - is this to be expected with a hybrid ignition setup like mine, or is it simply coincidental? Note that I have "normal" mag checks with no indications of "missing."

[WAM120RV]

Hi

Are you sure it?s lead not carbon? I have run a similar setup to you and the bottom plugs always foul up more due to that being where the oil accumulates when the engine is stopped. The is still noticeable with mag drops check now I run two Emags, but the difference in the drop between them is no where near as significant as when running one standard mag.

[maus92]

Originally Posted by WAM120RV

Hi

Are you sure it?s lead not carbon? I have run a similar setup to you and the bottom plugs always foul up more due to that being where the oil accumulates when the engine is stopped. The is still noticeable with mag drops check now I run two Emags, but the difference in the drop between them is no where near as significant as when running one standard mag.

The chucks are light gray in color. I dropped the one that was deposited in the plug hole; and I haven't cleaned the plugs yet so I'll check that.

[FasGlas]

It's a common practice to install the EI on the bottom plugs. The hotter spark helps burn off oil and lead that tends to make it to the bottom plugs.

[maus92]

Originally Posted by FasGlas

It's a common practice to install the EI on the bottom plugs. The hotter spark helps burn off oil and lead that tends to make it to the bottom plugs.

Maybe, but it is not uncommon for the EI to be installed on the top plugs because of coil location.

[terrykohler]

When I installed EI on my O320, the engine ran very smoothly on first startup, but within about a minute started running REALLY rough. Shut down, pulled the plugs, and found the bottom plugs on the EI side badly coated with lead - so bad I first thought I might be dealing with a melted piston. After cleaning, and restart, it took about 3-5 minutes before they fouled again. Pull and re-clean. Repeat.

Bottom line, the EI runs much more efficient (hotter) than the mag, and I was burning off lead deposits that were dormant until the mag was replaced. Took a few cleaning cycles, but it's been trouble free and smooth in the several years since.
Terry, CFI
RV9A N323TP

[Ralph Inkster]

Two things:
1. Are you still running the original timing settings that came with the CPi?
Check your CPi timing settings, if you are still running the initial factory map, it may have only 10 BTDC at 500 rpm, and graduate up to 24 BTDC at about 1500 rpm, and 24 after that for higher rpms. If this is the case, you are probably starting on the CPi on it's start setting (8 or so degrees retarded from lowest rpm/timing setting)- than idling at 10 BTDC. You may actually be idling only on the weaker magneto spark as it is firing earlier than the EI. As you rev up the engine, the CPi timing would come closer to matching the mag timing. I suggest you review the lower rpm timing settings on the CPi.
2. Lead balls are usually caused by rich or over rich conditions during starting. Do you prime when starting? Try pumping the throttle a couple times instead, just prior to turning the key. Do you aggressively lean during idle? The lead balls issue may be compounded by the issue described above.

[maus92]

Originally Posted by Ralph Inkster

Two things:
1. Are you still running the original timing settings that came with the CPi?
Check your CPi timing settings, if you are still running the initial factory map, it may have only 10 BTDC at 500 rpm, and graduate up to 24 BTDC at about 1500 rpm, and 24 after that for higher rpms. If this is the case, you are probably starting on the CPi on it's start setting (8 or so degrees retarded from lowest rpm/timing setting)- than idling at 10 BTDC. You may actually be idling only on the weaker magneto spark as it is firing earlier than the EI. As you rev up the engine, the CPi timing would come closer to matching the mag timing. I suggest you review the lower rpm timing settings on the CPi.
2. Lead balls are usually caused by rich or over rich conditions during starting. Do you prime when starting? Try pumping the throttle a couple times instead, just prior to turning the key. Do you aggressively lean during idle? The lead balls issue may be compounded by the issue described above.

Yes, running the initial SDS map.

We looked at one of the bottom plugs today and decided it was carbon and not lead. Lead tends to ball up, while these chunks were more irregular. All the bottom plugs have debris which is unusual for me, however there is substantial carbon build up on the cylinders tops and on the piston faces. I wonder if the switch to EI is *somehow* responsible for loosening carbon deposits? I do not have a primer, but I do pump the pcl several times for a cold start.

[maus92]

Originally Posted by terrykohler

When I installed EI on my O320, the engine ran very smoothly on first startup, but within about a minute started running REALLY rough. Shut down, pulled the plugs, and found the bottom plugs on the EI side badly coated with lead - so bad I first thought I might be dealing with a melted piston. After cleaning, and restart, it took about 3-5 minutes before they fouled again. Pull and re-clean. Repeat.

Bottom line, the EI runs much more efficient (hotter) than the mag, and I was burning off lead deposits that were dormant until the mag was replaced. Took a few cleaning cycles, but it's been trouble free and smooth in the several years since.
Terry, CFI
RV9A N323TP

Interesting.

[DanH]

Originally Posted by maus92

Interesting.

...but very unlikely.