Spark plug socket size

[The-sky-captain]

What size socket do I need to remove a plug from an IO 360? I seem to have lost my socket and need to pull a plug that went bad over the weekend. Are these sockets interchangeable with auto plug sockets from the big box auto part stores? Thx,

[Hank]

I think there are two primary plug sizes, but I don't remember them. Seems like fine wire plugs have a larger body than massives.

[MooneyBob]

7/8". It has to be long enough to receive the plug. I got mine from Sears. I bought longest one they had.

[MB65E]

Yup- any 7/8 deep well should work. Some "aviation" ones have a insulator in top to protect the threads, and magnet to hold the plug. Lead size varies... 7/8 or 3/4, just depends on the lead. Please use a torque wrench and anti seize. 35Ft lbs on the plug (Lycoming). They Changed from 30ft lbs years back.

Edit- Continental Cylinders have a lower torque... be careful with the C65 cylinders their delicate.

-Matt

[The-sky-captain]

Great! Thanks for the info!

[N601RX]

The magnet is a good idea, I got one one from spruce that had the magnet and rubber thread protector. I think it was around $20, but a dropped or damaged plug is over 3 times that.

[Mooneymite]

Just don't drop the plug after removal.....especially a fine wire!

 

[The-sky-captain]

Speaking of fine wires, that's what I'm thinking about going with as my massives are to the point of being shot. From what I understand they last a lot longer and will run LOP better which should increase efficiency. Any comparisons from those that have used both would be appreciated.

[Hank]

I just bought a plug socket at Spruce, $20-25, it's at the hangar. Their $14.95 plastic jar of antiseize will last me and my closest ten or so pilot buddies our natural lives, and can be passed on to the next generation. Harbor Freight has been running torque wrenches on sale for ~$10 all summer, your choice 3/8" or 1/2" drive--either will work, buy whatever fits your socket.

[Mooneymite]

>>>>Any comparisons from those that have used both would be appreciated. <<<>

 

I think most fine wire to massive comparisons will be mostly subjective.  I changed my massive's out for fine wires and the engine "seems" to run smoother.  I can run the O-360 "a little" leaner, but I can't give you any hard numbers/facts.

 

I changed plugs because my massives had about 400 hours on them and I was having trouble keeping them from lead-fouling.  After I removed them, I found one that had a bad resistor, so the new plugs would have been an improvement regardless of type!

 

The other change was I went from Champions to Tempest, so who knows what made the difference?  However, I will tell you that after spending all that money on fine wires, I'm trying to convince myself "it was worth it"!  

 

YMMV.

[yvesg]

As part of the Mooney Caravan, I was lucky enough to win a set of massive from Tempest in Oshkosh this summer. I replaced them a few weeks ago and realized that the old ones have been there since engine overhaul about 750 hours ago. Some had the electrode oval shaped and had some rust on them. Used a 7/8 long socket.

Yves

[bonal]

I would not trust my engine to a 10 dollar torque wrench and you should use the proper socket to protect the threads. Just put in a set of tempest massive and it seems to make better power in climb and I was having fouling issues that have since stopped. As for torque I used 30 not 35ft lbs. I will be looking into that. What ever wrench you use be sure to unwind it after use.

[M016576]

Yup- any 7/8 deep well should work. Some "aviation" ones have a insulator in top to protect the threads, and magnet to hold the plug. Lead size varies... 7/8 or 3/4, just depends on the lead. Please use a torque wrench and anti seize. 35Ft lbs on the plug. (Changed from 30ft lbs years back).

-Matt

That is mostly true- if you buy the tempest plugs- you need a extra deep 7/8 socket... The standard deep well sockets won't reach. I spent the better part of a day driving around town looking for a socket deep enough to work (rather than buy the 25 dollar "aviation" socket online). After Home Depot, diamond and 4 auto shops I finally found one....

Also, the torque specs vary based on who makes your cylinders. 30ft-lbs is still the rec. for a continental cylinder.

[tony]

^{there is nothing wrong with the $10 dollar torque wrench.  Actually when I checked them (I have two) they were both right on the money and did not require any adjustment.  If you have tempest plugs the only deep socket I found that was deep enough was from NAPA.}