Wrench sizes

ccsmith51 · #1 09-15-2011, 06:12 AM

I have RHM40E plugs on my O-360-A1F6D. I need to buy the wrenches for both the lead cap and the plug. The lead cap is 3/4-20, and I think I need a 7/8" wrench for that. What size wrench do I need for the plug? Should I get a socket instead so that I can torque the plugs in?

Thanks,

Vern · #2 09-15-2011, 07:05 AM

You will need a Aircraft Plug socket for the plugs themselves. Top and bottom plugs may need a wrench also depending on your baffles, exhaust configuration.

You will also need a 7/16" to hold the wires where they enter the cap. That keeps them from twisting and damaging the plug wires.You will also need some type of anti seize for the plug threads. Small bottles with a tiny brush are standard.

Typically a 3/4", a 7/8, and a 7/16 " are in my hands when I approach plugs.

And of course, the old adage: " if you drop a plug once, drop it twice: in the garbage!" It cracks the interior insulator and causes trouble later for you.

mahlon_r · #3 09-15-2011, 08:50 AM

http://www.aircraftspruce.com/pdf/20...l/Cat11637.pdf
Socket =7/8"
Lead nut is 7/8: wrench size for RHM plugs and 3/4" for REM plugs
Good Luck,
Mahlon
“The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Mike S · #4 09-15-2011, 09:03 AM

Quote:

Originally Posted by Vern

You will need a Aircraft Plug socket for the plugs themselves.

You can find a deep socket that will fit the plug, but be aware most of the sockets available do not have a large enough interior bore to clear the threaded top of the spark plug.

I took an old spark plug to the hardware store, and tried a couple of different sockets ----- finally found one that worked at Ace, or True Value, dont remember which right now. Sears was a no go, all their sockets were too small in that area.

Quote:

Originally Posted by Vern

You will also need a 7/16" to hold the wires where they enter the cap.

Typically a 3/4", a 7/8, and a 7/16 " are in my hands when I approach plugs.

Yep, hold the fitting on the end of the wire with the 7/16", and loosen the "B" nut with the other one.

Also, get a bunch of sealing washers, ACS sells them by the hundred. I never re use a spark plug sealing washer.

ccsmith51 · #5 09-15-2011, 09:10 AM

Thanks for all the input!!! Now I know what I need to get.

ccsmith51 · #6 09-15-2011, 09:39 AM

Quote:

Originally Posted by Mike S

Also, get a bunch of sealing washers, ACS sells them by the hundred. I never re use a spark plug sealing washer.

Can you tell me where to find them on ACS? I've searched for spark plug washer, sealing washer, spark plug seal, plug seal, etc...

Thanks,

aerhed · #7 09-15-2011, 09:42 AM

Quote:

I never re use a spark plug sealing washer.

I don't want to pick on Mike cuz I still want him to run for president, but I reuse copper plug gaskets amost always. I only chuck 'em when they are deformed or totally torqued out. I can't see any reason to throw them out. After half a dozen torque-ups or a few years of heat cycling they do harden, but every mechanic has been taught to anneal them and reuse. I keep a stringer full of annealed gaskets and one of "as removed" gaskets. I'll occasionaly swap out one that doesn't look good or if they feel hard I'll swap the whole set. In a pinch, you can anneal one with a cigarette lighter, so its no big process. Of course Champion recommends replacing them because they make more money. Your shampoo bottle also says to put 2 ounces in your hand and repeat. If you want them pretty, then stick them back on the plug before you wire wheel the base threads. You all do wire wheel the threads before anti-seize don't you?