BC12D Cowling Fairings for Screened Plugs.

[flyguy]

Re: BC12D Cowling Fairings for Screened Plugs.

How to start this: just thinking about the "uneven electrode erosion due to polarity" subject. I checked a bucket full of used plugs that I have and as far as I could determine each one had a center electrode that was "eroded" worse than the outside electrodes.

I humbly suggest that perhaps the fact that the center electrode is surrounded by a poor thermal conductive ceramic whereas the outer electrodes are metal-to-metal to the cylinder head, may mean that the principle eroding factor is excessive temperature and not electron/ion arcing effects.

I submit this for consideration.

Darryl

[flyguy]

Re: BC12D Cowling Fairings for Screened Plugs.

Duplicate deleted

[Guest]

Re: BC12D Cowling Fairings for Screened Plugs.

The cup replaces the washer.

Hank

ahh...

So I wonder if accidentally leaving the washer on the (plug) raises the plug up enough to cause and arc with the cap screwed all the way down?

Dave

[Hank Jarrett]

Re: BC12D Cowling Fairings for Screened Plugs.

Only if you put the washer inside the cup. If the washer is between the cup and plug hole it would only recess the plug out of the combustion chamber by the thickness of the washer (which would also happen if you put it in the cup along with getting the plug top too close to the cap).
You don't want to do either.


Hank

[flyguy]

Re: BC12D Cowling Fairings for Screened Plugs.

I find that some of the cups I use have quite different thread depths.

Some seat right at the top as is best, but the others have threads that go down so far that I would never screw them down tight because of the resulting closeness to the top of the plug and connector.

DC

[Mick W]

Re: BC12D Cowling Fairings for Screened Plugs.

I find that some of the cups I use have quite different thread depths.

Some seat right at the top as is best, but the others have threads that go down so far that I would never screw them down tight because of the resulting closeness to the top of the plug and connector.

DC

Absolutely , & this is the problem , perhaps once Wirelocked , it might be an idea to screw the Dust Caps out up to the Wire , & put a blob of Silicone or something on to prevent it vibrating back down ??.

[Hank Jarrett]

Re: BC12D Cowling Fairings for Screened Plugs.

On mine the wire hole is drilled at an angle THROUGH the edge of the cap. When safety wired it can't rotate at all, in or out. I think a couple of them even have holes through the edge of the cap in several places (probably from someone switching caps around).

Hank

[Mick W]

Re: BC12D Cowling Fairings for Screened Plugs.

On mine the wire hole is drilled at an angle THROUGH the edge of the cap. When safety wired it can't rotate at all, in or out. I think a couple of them even have holes through the edge of the cap in several places (probably from someone switching caps around).

Hank

That's a better idea than a'blob', I'll do that , thanks Hank .

[flyguy]

Re: BC12D Cowling Fairings for Screened Plugs.

all of mine are drilled so i can use a small cotter pin.

[Mick W]

Re: BC12D Cowling Fairings for Screened Plugs.

all of mine are drilled so i can use a small cotter pin.

Only the Casing drilled on mine , hence the Cover being screwed to the bottom of the thread . I will drill them !!.

[Edwin Otha]

Re: BC12D Cowling Fairings for Screened Plugs.

I have some of the Ercoupe style and the Breeze cups. The Ercoupe have the casing drilled and the cotter pin will be in the screwdriver slot to the other side of the casing. this keeps the cap from turning. You don't have to screw them to the bottom of the thread. The Breeze cups have a bail wire system for the dome cap.
EO

[Mick W]

Re: BC12D Cowling Fairings for Screened Plugs.

" The Ercoupe have the casing drilled and the cotter pin will be in the screwdriver slot to the other side of the casing. this keeps the cap from turning."

On my Ercoupe Cups , the Screwdriver Slot does not extend the full width of the Cap , easily remedied I suppose .

[Mick W]

Re: BC12D Cowling Fairings for Screened Plugs.

" The Ercoupe have the casing drilled and the cotter pin will be in the screwdriver slot to the other side of the casing. this keeps the cap from turning."

On my Ercoupe Cups , the Screwdriver Slot does not extend the full width of the Cap , easily remedied I suppose .