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Convert Slick to Autoplugs. Is G3i still in business?

Is this worth doing?

Have read about this conversion, how worthwhile is it, is is basically just a cost saving modification?
Figs
 
Have read about this conversion, how worthwhile is it, is is basically just a cost saving modification?
Figs

You can use $2 auto plugs, for example, Autolite 386 or Bosch M8ACO, or Denso plugs with inserts, and throw them away every year or two. No muss, no fuss, no $25-buck plugs that have to be lead-cleaned and gapped with special tools. So yeah, it appeals to us skin-flints. :)
 
The math makes no sense, if you add the cost of adapters you're losing money.
 
Not so fast, Amigo

The math makes no sense, if you add the cost of adapters you're losing money.

The adapters are reused each removal. Plug prices are closer to $7 now (Denso) and they come gapped. My mag-check dropped to 10RPM after changing the wires, plugs, and adapters.
 
10 RPM Drop Slick or Bendix?

The adapters are reused each removal. Plug prices are closer to $7 now (Denso) and they come gapped. My mag-check dropped to 10RPM after changing the wires, plugs, and adapters.

Are you running Slick or Bendix mags?
 
My mag-check dropped to 10RPM after changing the wires, plugs, and adapters.

Likely due to a timing problem. The RPM drop on a mag check is driven by the timing/mixture (timing is significantly retarded when the cyl runs on one plug vs two). Spark plug type will have no bearing (a spark is a spark, assuming a reasonable AFR), assuming all four of the new and old type actually fired.

Larry
 
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The adapters are reused each removal. Plug prices are closer to $7 now (Denso) and they come gapped. My mag-check dropped to 10RPM after changing the wires, plugs, and adapters.

8 plugs at $7 = $56
Change them every 100 hrs as recommended = $280 (same 500 hrs)

If you need adapters those are $100

Std aircraft plugs $28 ea every 500 hrs = $224

Gain??? Subjective at best.
 
WOW, $7.00 a plug is highway robbery. I pay $2.13 for my plugs here in Florida and that includes the sales tax.

At $2.13 each my 100hr cost is $17.04. My 500hr cost is $85.20, a LOT cheaper than aircraft plugs. BTW, after 7yrs I am still using the original adapters.

 
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Galin my experience is the same as yours. Too cheap not to replace them at each annual. No more time consuming plug cleaning and gaping. In 6 years of use with one Pmag and one slick I have not had any fouled plugs or any ignition related problems. The auto plug conversion along with the antisplat wheel bearing conversion are the two best things I ever did to my plane and reduce the inspection time considerably especially if you're paying someone to do it.
 
Galin my experience is the same as yours. Too cheap not to replace them at each annual. No more time consuming plug cleaning and gaping. In 6 years of use with one Pmag and one slick I have not had any fouled plugs or any ignition related problems. The auto plug conversion along with the antisplat wheel bearing conversion are the two best things I ever did to my plane and reduce the inspection time considerably especially if you're paying someone to do it.

I disagree with the above, almost invariable the plug inserts come out with the plugs, now I have to remove the stuck plugs from the inserts, the reason they come out with the inserts is because the threads are full of carbon so I have to run a plug tap into each insert to clean out the treads. At this point I usually just remove the remaining inserts and clean all the threads.

Along with that how long does it take you to pull your Pmag every year for inspection and/or send it off for software updates?

I can easily clean and gap a set of aviation plugs in less time.
 
The 18mm resistor Autolite 386/388 specs 3000-12000 ohms.

Do they stay consistent over time?

Do you aim at the low end and return/exchange at the high end?

Do folks use the G3i harness and Slicks or do folks use the 18mm plugs with just electronic ignition to avoid plug inserts?

Or, all of the above?
 
I disagree with the above, almost invariable the plug inserts come out with the plugs,

Walt, sounds like you have a plague of P-mag users, torquing plug inserts to 18 lbf-ft, as an assembly, via the spark plug hex. The E-mag spec seems to be based on insert breakage, not industry standard...and I don't buy it.

As you know, the Lycoming spec for the 18mm thread is 35, with Continental a little less. The Denso tech chart says 22 to 29 lbf-ft for an 18mm gasket plug. The Champion aviation chart is says 30-35 for a Lycoming. Me? With antiseize on both threads, I screw the plug into the insert, torque the assembly into the head at 18 applied to the plug hex, then torque the insert hex to 25 minimum.

Back to regular programming..
 
I use NGK BR8ES with my LSE Plasma with great success. $2.50 per plug, throw away at annual. Can one use BR8ES with the G3i? If so, that’s $20 per year.
 
Like Dan notes above, screw the plug into the insert, torque the assembly into the head at 18 applied to the plug hex, then torque the insert hex to 25 minimum. The adapter WILL stay in the head and the plug will come out like normal.

I pick up my plugs at Auto Zone (NGK) for under $3.00 each.
 
From the PMAG manual:

First, install adapters with the supplied gasket on the spark plugs finger tight. Then, insert the combined assembly (plug with adapter) in the engine and tighten to 18 ft/lb (standard auto plug torque) through the spark plug ONLY. Do not torque the adapter itself.

Note 1: If you install and torque the adapters separately, stresses will be focused at the adapter neck and can cause it to fail during installation
 
The instructions for installing inserts from Light Speed is different. You install the adapter first into the cylinder head, and torque to the specified value. Then you install the plug into the adapter and torque to a different specified value, which was 5 ft-lbs less.

The adapters do not come out of the engine when you remove the spark plugs. The adapters are machined from bronze and are not a life-limited component. Put them in once and forget about them.
 
If you use Autolite 386 or NGK AB-6 are both 18mm plugs and I recently purchased 8 of each and spent roughly $40 for the 16 plugs.
No adapter necessary. I've had no issues using these plugs, but will say I don't have an enormous amount of time on them.
Just so you know the NGK's are a 13/16" hex plug, the Autolites are 7/8".
I have Bendix mags on 2 engines and am using these plugs and autoplug wires in both.
Not the easiest conversion but for me the savings in replacing massive electrode plugs and harnesses makes it time vs dollars.
Quality plug wires can be had for $40 to do 2 mags on a 4 banger. Replace A harness for less than $150? Don't think so.
 
As I said in my previous post:

BTW, after 7yrs I am still using the original adapters.

In 7yrs and more than 550hrs, I have not had any issue like what you have had on any of my plugs or either one of my dual pMags. YMMV

 
The instructions for installing inserts from Light Speed is different. You install the adapter first into the cylinder head, and torque to the specified value. Then you install the plug into the adapter and torque to a different specified value, which was 5 ft-lbs less.

The adapters do not come out of the engine when you remove the spark plugs. The adapters are machined from bronze and are not a life-limited component. Put them in once and forget about them.

My lightspeed instructions from 2004 says to install busing on plug, torque plug then torque the adapter. This what I did and have never had any problems.

Klaus did change his procedure since then. Some day I will ask him why.
 
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