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Scott DellAngelo

Well Known Member
Anyone know what size socket I need to fit on the auto plug adaptors? I need to haul tools to the hanger tomorrow and since I moved the airplane I know I do not own the right sized socket and need to go buy one. Anyone? I am thinking from memory it is a weird size (1 1/8") or something? Something in my foggy memory says it is not the same size as a typical aviation spark plug.

Thanks,
Scott
 
Scott,

I don't recall the size but I do recall that you are supposed to torque the plugs, not the sockets. - I hope that helps.
 
I'm pretty sure the LSI adapters

are same size as std plugs, 7/8". torque is 25 lb ft. on the adapter and 15 on the plugs.
 
N941WR said:
I don't recall the size but I do recall that you are supposed to torque the plugs, not the sockets. - I hope that helps.
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Torque BOTH. The adapters get torqued to the same torque you'd otherwise use on aircraft plugs. Then the automotive plugs get torqued to their own spec -- which is always lower than the torque you use on the adapters.
 
Ok 7/8" does sound a little better than 1 1/8". I put them in as E-mag suggests which is to torque via the spark plug to 15 ft*lb. I just need to get them out to run a compression test and I only have the bigger fitting.

Thanks for the help,
Scott
 
dan said:
Torque BOTH. The adapters get torqued to the same torque you'd otherwise use on aircraft plugs. Then the automotive plugs get torqued to their own spec -- which is always lower than the torque you use on the adapters.
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Not recommend per E-mag. They only want you to apply torque to the plugs.
 
N941WR said:
Not recommend per E-mag. They only want you to apply torque to the plugs.
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Wacky. What torque do they recommend?

The Lycoming overhaul manual specs out 420 in-lbs (35 ft-lbs) for conventional aircraft plugs. I'm just curious what torque E-mag recommends for both plug+adapter.

FWIW, Lightspeed recommends 25 ft-lbs for the adapters and 15 ft-lbs for the automotive spark plugs. http://www.lightspeedengineering.com/Products/Sparkplugs.htm
 
I believe the reason they gave for torquing only the plug is that then there is little stress between the threads of the adapter and its top. The adapter threads I.D. and O.D. are fairly close in size and it would be possible to over torque and pull the top off without the plug threaded in place. Anyway, if you torque the plug, you are automatically torquing the adapter.

Bob Kelly
 
TRUST LIGHTSPEED...

videobobk said:
I believe the reason they gave for torquing only the plug is that then there is little stress between the threads of the adapter and its top. The adapter threads I.D. and O.D. are fairly close in size and it would be possible to over torque and pull the top off without the plug threaded in place. Anyway, if you torque the plug, you are automatically torquing the adapter.

Bob Kelly
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If you think that is a problem, then install the plug into the adapter held in a vise. Torque the plug to 10ft lbs. Then use your 7/8 deep socket or the one that you use on the aircraft plugs to install the adapter (and the plug) into the cyl. head. Torque this to 25ft lbs... http://www.lightspeedengineering.co.../Sparkplugs.htm Then go back and torque the plug to 15ft lbs. :rolleyes:

Leave the adapters in place. Take the comp reading from the lower plugs if they are still the stock ones. If not, then get the proper adapter for the 14mm plugs.

If the adapters came from the "P" mag people, you might want to order yours from LIGHTSPEED. :confused:
 
What a lot of hassle

I never used a torque wrench on a sparkplug yet..Then again I been hand torquing plugs for 30 years and haven't stripped many or them...:)

I just got my differential compression guage and it came with an 18mm plug adaptor.

The problem of course is that the half the time the plug comes out on its own, the other half the adaptor comes out on the plug.

A bit of a pain but the simplest was seems to be too have a 7/8ths socked on hand to pull the adaptor when doing th compression test.

Cheers

Frank
 
Maybe that's your problem....

frankh said:
I never used a torque wrench on a sparkplug yet..Then again I been hand torquing plugs for 30 years and haven't stripped many or them...:)

I just got my differential compression guage and it came with an 18mm plug adaptor.

The problem of course is that the half the time the plug comes out on its own, the other half the adaptor comes out on the plug.

A bit of a pain but the simplest was seems to be too have a 7/8ths socked on hand to pull the adaptor when doing th compression test.

Cheers

Frank
Click to expand...
Maybe you should use a torque wrench. And torque like the book says.
Then the plug will come out without removing the adapter.

So your test gauge came with a 18mm and you need a 14mm, they cost about a buck two nintyfive at any auto parts store.

In fact you should also be using a compression gauge for the best results finding condition of engine. ;)

GOOD LUCK
 
yeah maybe..:)

Oh you can get an adaptor for cheap?...Cool...I'll look out for one.

Cheers

Frank
 
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