Spark plugs, or do a whole project?

[tass]

I had a dud spark plug appear the other day - caused me to pretty quickly turn back and land when things turned very rough after setting up for cruise. After pulling the plug on cylinder 3 (which showed much higher EGT as compared to the other cylinders) I saw that the insulation was broken away, so I just replaced both plugs since the other didn't look great either. They were most recently replaced over 300 hours ago so I will probably just replace all the rest of them anyway.

Anyway, there's a couple of things happening all at once
* Replace the plugs (~$300)
* The 500 hour magneto inspection is due (~$1000)
* I am considering replacing the wiring harness, since it's a little rough-looking and might even be original to the plane. ($400?)

Would anyone actually recommend doing this work, or instead doing the work to switch away from Slick magnetos?

I could instead:

Put in P-mags, with the added benefit of being able to use automotive plugs.

Or, an alternative such as getting a system32 EFII, which I expect is a much more expensive proposition but gives:
* More HP
* Fuel injection, no more carburetor and carb heat.
* Automatic mixture control
But, I also need backup power, since I only have the 1 battery+alternator (EFIS has its own backup). This would be a nice addition anyway, since having the GPS, autopilot and radio have backup power would be helpful.

What have others done in this situation?

 

[Ironflight]

What have others done in this situation?

In my case, I did the simplest economical thing, which was to go with dual P-Mags. No additional airframe wiring (to assure power to the ignition), replaces al of the things you’re talking about replacing/servicing.

Don’t get me wrong - I think the EFII/SDS offerings are going to be the way of the future, but it’s a more costly retrofit. If you’re ready to go all the way with money and commitment, they are good options! But the quickest, cheapest retrofit in my case was to go with P-Mags, and I am very happy with them.

 

[Toobuilder]

Not sure I've ever seen someone go from "change a plug" to "install EFI" in one post, but it sounds like you are spring loaded to modernizing the engine systems at some point. If thats the case then I'd suggest you stick your toe in the water with an ignition change first. That said, I'd suggest you go with the SDS CPI over the Pmag for a few reasons. First off, the CPI installation sets the stage for the future upgrade to the EFI component, so much of your work is already done when you decide on the full monty EFI. Second, the Pmag carries its own set of mechanical complexity and inspection requirements that the CPI does not. With the Pmag, you are just trading one maintenance pig (Slick) for another (Pmag). Also does not hurt that the CPI is substantially less expensive than the Pmag - particularity if you source the common parts (coils, wires, plugs, etc) locally.

In the immediate term, I'd even suggest that you keep one of the Slicks installed if it helps ease your mind. The single CPI can be adjusted to compensate for the Slick's deficiencies, no problem.

 

[tass]

Not sure I've ever seen someone go from "change a plug" to "install EFI" in one post

Yeah it's a bit of an escalation, to be sure

Unsaid in the post, but I've wanted fuel injection for a while. Basically if this engine goes, I'm definitely replacing it with something injected. I figure if I got an EFI system, it would make the current engine happier and last longer, though.

Thanks for the info on the SDS stuff, I'll look into it.

 

[Marc Bourget]

I didn't spend a lot of time analyzing this but the first thought that popped to mind was - with two "distressed" plugs in the same cylinder, is there something (for example a sharp edge) present that caused some detonation?

 

[Sam Buchanan]

A simple upgrade would be to IRAN the right (non-impulse) mag and replace the left mag with a SureFly. This is the upgrade path I followed when I wanted to eliminate the mechanical impulse coupling on the 500 hour mag. This is a reliable option with your single battery system and uses the existing plugs and harness. All in all, an easy route to take without going all-in on a high-$$$ upgrade.

 

[Tommy123]

I went with dual SDS ignition but that would require a second battery (if you are interested in not having a ignition failure). I really like the SDS.
Or you could keep a mag and go with a Surefly (they use Slick harness witch you provide)
I just installed a Surefly on a C-182 and the owner is very happy with it.

 

[Carl Froehlich]

Tass,

The way forward, without a redesign of your electrical system, is dual pMags and back fit of the AirFlow Performance injection system.

If you really want EFII or such, I’d be happy to go over the needed changes to your electrical system. I do not consider the backup battery guidance (what I’ve seen at any rate) to be adequate.

Side note. I’ve never seen EFII or SDS make any claim that their system provides an increase in engine horse power.

Carl

 

[wirejock]

P-mags

I'm with Paul. Two P-mag kits won't be a whole lot more than rebuilding two mags plus the spark plugs. Check with Brad. Looks like the price has gone up a little.

You need the auto plug wires. You will need a gear for the left impulse side and two studs. You might need a gear for the right if the mag gear isn't good. You need the spark plug adapters. Eight plugs from an auto part store are pretty cheap. There's a little wiring needed to add a breaker(s) inside.

 

[Ralph Inkster]

If your plan is to get more flying in this season:
- Overhauling your current mags would be quickest.
- Replacing one or both mags with P-Mag or Surefly EIs would be just as quick assuming either have good stock on hand.
- Other brand EI systems like Lightspeed, SDS CPi, etc. are easy to install but require more effort, which relates to more time & planning.

For EI/EFI systems plan to have your plane down for longer (example summer/fall seasons or similar time frame)
- You will have to get a Duplex style fuel valve which is on perpetual backorder from the two most popular valve mfgrs. If you are seriously planning these systems, order the valve early.
- You will have to run fuel return lines all the way back to each tank.
- You will have to upgrade your electrical / charging systems to suite the new system.
- The actual system components install fairly quickly & system wiring harnesses are relatively easy to install once you understand them.

 

[RV8JD]

I didn't spend a lot of time analyzing this but the first thought that popped to mind was - with two "distressed" plugs in the same cylinder, is there something (for example a sharp edge) present that caused some detonation?

+1. A plug with a cracked insulator and some of it missing can be a sign of detonation or preignition. Might want to use a borescope and look at the top of the piston for telltale signs.

 

[A1AVIATON47]

take a look

Generation 3 Ignition “aka” (G3i) is all about aircraft engine performance. From high horsepower demands too fuel economy along with engine efficiency. G3i focuses on designing and developing engine management and performance products from ignition systems to aircraft engine supercharging.



G3i developed the first magneto interfaced-based electronic aircraft ignition control system that interfaces with most Slick & Bendix aircraft magnetos for Lycoming and Continental aircraft engines.

 

[Marc Bourget]

+1. A pluge circumference with a cracked insulator and some of it missing can be a sign of detonation or preignition. Might want to use a borescope and look at the top of the piston for telltale signs.

I believe the initial signs will appear around the circumference.

 

[RV8JD]

I believe the initial signs will appear around the circumference.

Marc, you inadvertently mangled my post when you quoted it above.

 

[daddyman]

My 2 cents

You won't be sorry with an electrical ignition.
I went with P-mag.
Was not sorry.
Better fuel economy, but I never hit the break even point (sad).

The cost to rebuild the slick mag was not cheap, and added harness was part of the equation.
I kept the left mag (with the impulse) believing I could have prop started it. (probably not).

My mag failed at 560 hours.

Change both if you can.

Daddyman

 

[Rick_A]

G3i

Generation 3 Ignition “aka” (G3i) is all about aircraft engine performance. From high horsepower demands too fuel economy along with engine efficiency. G3i focuses on designing and developing engine management and performance products from ignition systems to aircraft engine supercharging.

G3i developed the first magneto interfaced-based electronic aircraft ignition control system that interfaces with most Slick & Bendix aircraft magnetos for Lycoming and Continental aircraft engines.

I haven’t seen a reference to G3i for quite a while. I considered installing a G3i when I was first building my 7A but went another direction. Are many people using this system?

 

[tass]

Wow lots of info here, thanks all. I'm leaning towards P-mags, being that it's a good middle ground before doing anything more major.

I will get the borescope out and look for signs of detonation (thanks to those who pointed it out).

In the flight just before I had the plug failure, I did have carb heat on for quite a while - I was at 13,000 ft, had low carb temp warnings, and going in and out of clouds. I forgot to turn it off until after I landed, so maybe 30 mins or so. This is what I suspect caused fouling, but I don't really know that for sure.

 

[cubdriver]

PMAG

I've had good experience with PMag. Easy to install - easy to time - blow into a tube. They work great.

 

[Walt]

If it was the ‘37by’ plug I’ve seen lots of cracked insulators, seems common to them.

 

[David Paule]

.... had low carb temp warnings, and going in and out of clouds....

If you keep the carb for any length of time, replace the carb temp with an ARP Carburetor Ice Detector from Spruce. It has a probe inside the carburetor and reliably detects ice. I've had one on my C180 for about 30 years and regard it as essential equipment. I bought another for my RV-3B project, which is carbureted with Pmags.

Dave

 

[tass]

Borescope

I didn't spend a lot of time analyzing this but the first thought that popped to mind was - with two "distressed" plugs in the same cylinder, is there something (for example a sharp edge) present that caused some detonation?

I need to get more experience with the scope, but I took a couple of pics from inside cylinder 3.

Valves:

Cylinder wall. Line of oil was from where the cylinder was originally sitting:

Bottom spark plug:

Does this look like too much gunk around the valves to suggest detonation? Is there too many deposits which would suggest something wrong?

Should I try get clearer images?