chuckwn

chuckwn

Well Known Member
How to ruin your day: The adapter broke off when I tried to remove it to perform a compression test. Next, one of the adapters came out with the the plug (which is not uncommon) and when I tried to remove it to replace the plug, it crumbled (picture two).

These are Emag/Pmag adapters and have only 200 hours since new. It is my opinion that they are made of a non suitable material for this application. I have also been running four Lightspeed adapters for 1600+ hours with no problems at all. Subsequently, I read that the Emag inserts must be on the spark plug for installation and removal (because they are made of an inferior material).

Fortunately there is good help and advice out there. Lightspeed sent me four new adapters and got the plane back in the air (and saved my trip to OSH).

Thomas Shpakow at G3i suggested using the blade of a big Craftsman screwdriver (along with some penetrant) as an extraction tool.

I let the penetrant soak in overnight and then carefully hammered in the blade of the screwdriver to grab the threads. A wrench was applied to the square shaft of the screwdriver and voila! (picture three).


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Your observation mirrors my experience w/ these adapters.. It's hard to tell 'em apart, but PMag's adapters are not the same and are much weaker than adapters supplied by Lightspeed... You definitely do not want to try to use procedure suggested by LSE (of torquing the adapters alone to 25 ft/lbs) if using PMag-supplied adapters..

It's best to follow procedure suggested by supplier... and even then be extra careful :) But if it was my choice, since price is the same, I would skip ordering adapters from PMag altogether and just get 'em from LSE instead..
 
Another example of why you are a test pilot with products like these with limited field testing. Better you caught this in your hand. Extraction could have been a mess. Looks like you took care in extraction as well.
 
While I doubt any of us are qualified to know what the installed base is on these things, it is easy to draw conclusions on how big the problem is when your samples size is small.

As another data point, I have had no issues with mine but I did and do follow their recommendations on how to use em and take care during installation and removal. Not saying you did not though and mine may fall apart on the next removal, I duno???
 
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Before blaming E-mag for an inferior product, it would be nice to know how these units were installed.

If you follow the directions E-mag provides, the adapters will provide many hours of service. A friend had an LS setup on his -7A and suggested I torque the adapters first, as Light Speed recommends. Upon trying this, I crushed an adapter.

When installing E-mag's adapters, torque on the sparkplug and use some anti-seize compound on both the plug and the adapter. When removing them, use a big socket and turn on the adapter, not the sparkplug. You can then remove the plug from the adapter with socket wrenches with no problem.

By doing this, I have not had any issues whatsoever.

As for the suggestion of using steal adapters, that might be a good way to crack a head. Steel expands at significantly different rate than the brass adapters and doesn?t give as much. Thus having a steel plug in an aluminum head might not work out so good in the long term. I strongly suggest you stick with a brass adapter from the supplier of your choice.

LifeofReiley said:
use the steel ones purchased from here.

http://www.sparkplugadapters.com/index.html
Click to expand...
 
Expansion rates of inserts;

N941WR said:
As for the suggestion of using steal adapters, that might be a good way to crack a head. Steel expands at significantly different rate than the brass adapters and doesn?t give as much. Thus having a steel plug in an aluminum head might not work out so good in the long term. I strongly suggest you stick with a brass adapter from the supplier of your choice.
Click to expand...



I have had this conversation before with engineers about spark plug adapters. Our conclusion was that brass was introduced way back as a solution that if failed, the material was easier to extract than a carbon steel insert. Based on that a standard aviation style spark plug outer shell is made up of carbon steel, which is retained in an aluminum head with a heli coil thread insert. So by using a steel adapter, the thermal expansion properties are every close, if not the same as standard plug that?s made out of steel. I?m not saying we should all change our adapters to steel, however all non-ferrous adapters are delicate and require periodic maintence. The weak link is the bore of 14mm and outer of 18mm when the thread transitions to the 7/8 hex head. A very thin area.

Examples: Depending on the material used for a spark plug adapters and linier expansion rates depending on temperature. (microinch/(in Fahrenheit))

Aluminum Bronze 68 ? 572 Fahrenheit (9.0)
Copper-Base Alloy - C62300 (Aluminum bronze, 9%) (9.0)
Copper-Base Alloy - C62400 (Aluminum bronze, 11%) (9.2)
Yellow Brass 68 - 572 Fahrenheit (11.3)
Admiralty Brass 68 - 572 Fahrenheit (11.2)
Aluminum Alloys range from (12.8 - 13.2)
Nickel based steel range from (6.5 ? 8.3)

This is good stuff,
Thomas Shpakow
 
G3i Ignition said:
I have had this conversation before with engineers about spark plug adapters. Our conclusion was that brass was introduced way back as a solution that if failed, the material was easier to extract than a carbon steel insert. Based on that a standard aviation style spark plug outer shell is made up of carbon steel, which is retained in an aluminum head with a heli coil thread insert. So by using a steel adapter, the thermal expansion properties are every close, if not the same as standard plug that?s made out of steel. I?m not saying we should all change our adapters to steel, however all non-ferrous adapters are delicate and require periodic maintence. The weak link is the bore of 14mm and outer of 18mm when the thread transitions to the 7/8 hex head. A very thin area.
Click to expand...

So it sounds like steel inserts may indeed be the way to go, what material are the adapters you supply with your G3 ignition?
 
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