Spark plugs change

[MooneyBob]

My Tempest fine wire plugs are on their way.

Should I attempt to change them myself? I am pretty handy around cars and other machinery but I never change the plugs in the plane.

Anything to be aware of? What's the best practice? ( I know, see your A&P).

Thanks

[BigTex]

I swapped mine out. Pretty simple. Confirm the gap and torque them to spec.

[orionflt]

Bob,

you should be able to change them out yourself with no issues, but I recommend you have a few specific tools available:

feeler gauge

torque wrench

anti seize

 

pulling the old plugs is self explanatory but be sure to use 2 wrenches to keep the leads from twisting when you remove them and do not handle the connector or spring. also be careful you don't drop the plugs (you may want a back up set of plugs)

when installing the new plugs double check that they are properly gapped (I have never needed to regap a new set of plugs) once again be careful not to drop any or you might as well just throw it out because it will crack the internal ceramic. apply a dab of anti seize to the threads and install the plugs torque to 30 foot LBs then reinstall leads. the leads should be snug but not overly tight about 1/8 turn more then finger tight.

 

found a good slide show that does a better job then I do at explaining the process.

 

http://www.slideshare.net/razdjp/how-to-install-aircraft-sparkplugs

 

Brian

[MooneyBob]

Thanks Brian.

[N201MKTurbo]

Use new copper gaskets, Apply a tiny dab of anti-seize to the threads ( not the threads on the ignition lead nut ) Don't over tighten the ignition lead nut. If you can't get it off with your fingers it is tight enough. Don't get the cigarette dirty or greasy, if you do clean with MEK before assembly.

[MooneyBob]

Don't new plugs come with the gaskets?

[pinerunner]

It looks like you've checked and know that, as an owner, you're legal to change plugs. Since the head is a softer metal, aluminum, be picky about the torque. I recall a Busch or Deakin article mentioning that, if you drop a plug, trash it and replace with a new one because damaged plugs can break and provide hot spots that can lead to the dreaded pre-ignition much quicker than getting your LOP wrong. He tells a story of old-fashioned mechanics in the piston hayday beating up a fallen plug with a ball-pien hammer so no one could make the mistake of reinstalling it. They also give the example of a plane that they worked on (with pictures) that went into pre-ignition on take-off, and burned a hole in the top of one piston; the culprit was a plug gone bad shedding bits of ceramic that provided hot spots.

 

I think its worth it for us owners to change our own plugs but take it very seriously. A little homework and you can be right up to speed along with your mechanic.  Inspecting your plugs can give you cheap feed-back on how well you're treating your engine.

[orionflt]

Don't new plugs come with the gaskets?

yes they do

[RangerJim]

Take extra care not to cross thread the lead nuts.  Don't ask how I know this.

[Mooneymite]

I swapped mine out. Pretty simple. Confirm the gap and torque them to spec.

 

I was under the impression that fine wire gaps were set by the factory....?

[carusoam]

I think the first oil change, spark plug change, and fuel tank drain change are best done with your mechanic.

Over or under torquing something can get expensive quickly...

The best thing is that you build a relationship with a mechanic that will let you do more and more work under his watch....

Bring coffee and donuts. It appeases the gods somehow....

Best regards,

-a-

[orionflt]

I was under the impression that fine wire gaps were set by the factory....?

Always confirm the gaps anyway

[orionflt]

and Bob, if you want help just bring everything over to KUKT on a weekend and I will oversee your work, also if next weekend is suppose to be nice we may be able to squeeze that photo flight in. I will check this weekend to see if all the players will be available.

[Mooneymite]

From a Lycoming publication:

 

Installation torque for all spark plugs is 420 

inch-pounds (35 foot-pounds). Installation torque for 5/8-24 lead nuts is 80-90 in. lbs. and 

110-120 in. lbs. for 3/4-20 lead nuts. Always use new gaskets (P/N STD-295) when 

reinstalling spark plugs.

 

However, I think the torque value presupposes a dab of anti-seize applied to the threads.

[carusoam]

Bring coffee and donuts to KUKT????

Hmmmmmm,

-a-

[MooneyBob]

Good idea Brian. I will get back to you.

[orionflt]

Bring coffee and donuts to KUKT????

Hmmmmmm,

-a-

Maybe we should do some kind of "mid Atlantic" better known as NJ Mooney get together. I have a grill, we could cook burgers and dogs, would be a good time

[Seth]

I'm in - let's make it sometime in May as my April is booked

[carusoam]

Mike has been unusually quiet lately...

Best regards,

-a-

[MooneyBob]

Yes, lets do something together.

[orionflt]

I'm good for may, maybe we should start a new thread for this

[Seth]

Yes, sorry for the thread creep

[flyingvee201]

When is comes time to clean these new plugs at the next annual or whenever....if you are bored and a pyro...

You can re-use your sparkplug gaskets instead of buying new ones (I know that they are not that expensive to buy new ones), but before you reinstall them you need to anneal them first to soften the gasket again to give you a good seal.

 

Get a propane torch and heat the gasket until its cherry red.  I use a coat hanger and let the gasket dangle and put the torch to it. Once its cherry red immediately put the gasket in a container with clean cold water. Keep in the water until its cold again.

You are DONE!!   Its annealed and softened again ready for use.  Repeat with the next gasket.