[PH-SCP]

Hi Guys,

I am using an E-magnet with NGK spark plugs on one side of my O-320-D2J engine and have installed adapters in each cylinder to reduce the thread size from 18mm to 14mm.

During recent inspection I found one of these adapters cracked (in fact completely broken). I ordered and received new adapters from Aircraft Spruce but I don't know with which torque value to install them in my cylinders. Your advice is more than welcome.

Here's a picture of new and old:

 

[N941WR]

It is simple, you don't torque the adapter.

After putting anti-seize compound on both the sparkplug and the adapter, hand thread the sparkplug in the adapter, start them in the cylinder, and then torque the sparkplug.

That will set both to the proper torque.

 

[PH-SCP]

Thanks Bill, really appreciate your quick answer. Makes a lot of sense, should have thought of that myself but didn't, that's why I love this forum so much

 

[molson309]

I used 25-ft/lbs for the torque on the adapter, and 15 ft-lbs for the plug. Until I did this the adapters were constantly coming out when I removed plugs. Never a problem with splitting them using this method. And, as a previous poster mentioned, always use anti-seize on both the adapter and the plug.

 

[Walt]

I used 25-ft/lbs for the torque on the adapter, and 15 ft-lbs for the plug. Until I did this the adapters were constantly coming out when I removed plugs. Never a problem with splitting them using this method. And, as a previous poster mentioned, always use anti-sieze on both the adapter and the plug.

This is precisely how Lightspeed engineering recommends doing it.

 

[krw5927]

From Emagair website (makers of the Emag & Pmag):

Auto Spark Plug Adapters - Plug adapters permit the use
of 14mm automotive type plugs with a ¾” reach. [Not
tested with engines that use long-reach (13/16”) aircraft
plugs.] 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).
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.

http://www.emagair.com/Manual LC114v20.pdf (Page 11)

Actually they don't mean 18ft/lb. That's not a torque. They intended to say 18 ft*lb. But you get the idea....