Spark plug maintenance?

[bnt83]

You can end up with a plug that has a nice fat center electrode and really thin ground electrodes that glow red-hot and start causing preignition, too. That's not a desirable form of wear.

Dan

Thats a better reason.

 

[Tom-D]

You can end up with a plug that has a nice fat center electrode and really thin ground electrodes that glow red-hot and start causing preignition, too. That's not a desirable form of wear.

Dan

That will not happen before the plug fails for other reasons.

 

[Silvaire]

Bottom line - as an A&P I do not charge extra for rotating the plugs

 

[Bill Watson]

We rotate plugs top to bottom, front to back every annual minimum (not sure if more often than that), and we flew this plane about 300 hours last year. However, I think this plane got a new set of plugs somewhere between now and last annual.

I'm thinking that while going front to back/top to bottom will effectively swap polarity on a Lyc 4 cylinder. Doing the same or similar on a 6 cyl Lyc will not swap polarity. A function of firing order as I understand it.

Whether it's a worthy thing to do correctly or to do at all is in question, you may notice different wear patterns than you may be used to seeing if you aren't swapping polarity.

I'm sure the proper swapping pattern for a 6 cyl Lyc is in one of the recent posts.

 

[VanDy]

How many people anneal the sparkplug gaskets when they rotate or remove/install the plugs?

 

[Silvaire]

I always install new gaskets. What are talking here, about four bucks?

 

[gkainz]

It appears (I haven't checked the logs - hearsay info) that these plugs have 160 hours on them, rotated at 100 hours.

 

[Tom-D]

I always install new gaskets. What are talking here, about four bucks?

Normally you will remove clean the plug 4 times in 500 hours and then throw it away.

The seating surface of a plug is not flat, it is slightly conical, So if you simply turn them over as you re-install, they will reform and make a good seal.

new each time, is a little over the top anal if you ask me.

 

[Silvaire]

...new each time, is a little over the top anal if you ask me.

Same might be said for flipping over and re-using a thirty cent gasket (if you ask me)

I've got a bin full of them and don't think much about it. Customers like seeing new gaskets under the plugs after an annual and I don't charge them anything for them. Plugs are only torqued to 30-35 ft/lbs so it's nice to have soft new gaskets but to answer your charge - No, I'm not going to refuse to release an aircraft just because there are no new plug gaskets available. That would be anal.

 

[Dan Thomas]

I always install new gaskets. What are talking here, about four bucks?

About that. I used to save them up and anneal two or three hundred at a crack. Clamp a steel rod in a vise, bend it so its free end is over a can of water, hang a whole bunch of gaskets on the rod, use another rod to poke six or eight at a time out toward the end, heat them red with oxyacetylene and push them off into the water.

Dan

 

[Silvaire]

Dan

You have written a perfect example of the lengths people will go to - I think it's a mental thing. Because they are made of copper people's minds simply refuse to see them as what they are - GASKETS. At what other time do you go out of your way to re-use a thirty cent gasket?

 

[Tom-D]

Dan

You have written a perfect example of the lengths people will go to - I think it's a mental thing. Because they are made of copper people's minds simply refuse to see them as what they are - GASKETS. At what other time do you go out of your way to re-use a thirty cent gasket?

This became normal when they ordered by snail mail, and the part returned by pack mule.