Look at my cap! WTF?! High Res Macro Photos

[kndrewa]

PS-Great pics.

no doubt! if everyone's pictures were this nice, it sure would make things easier.. ..viva la details!

 

[5-90]

Spray wd40 on the inside of the new cap. That should keep moisture away.

AAAAh! NO NO NO!

WD-40 is NOT conductive, and will therefore reduce spark energy available. I've run across plenty of jobs I've had where I just had to clean WD-40 out of something that someone tried to "clean" or "protect" it with.

WD-40 is not RPT not a "miracle spray," and is damn sure not meant to be used on anything electrical!

"WD" stands for "Water Displacer" - which is what it's meant to do. It is not a:
Lubricant
Contact Cleaner
Electrical anything
Lock Lubricant
Part Cleaner

Or any other damn thing - no matter what the can says. I've successfully used it as a lubricant when maching steel - but that's because I ran out of high sulphur tapping oil, and needed something now (and I really didn't like doing it - I usually use something like "Tap Magic" for that.)

Ricky - get a Borg-Warner cap & rotor from All Parts (Branham & Meridian - tell 'em Jon with all the Jeeps sent you) and stop going to Kragens for parts. I spent three years behind the counter there - and they have not improved since. If you can, talk to Ben or Jim when you go to AP. Those are the guys that handle calls from Arabia's, and they know Jeeps fairly well (even though Jim is a GM guy...)

For electrical goodies, check OSH - they carry a decent selection of LPS (if you go to the one on Branham, check across the aisle from automotive batteries) and you'll find stuff there. Hell, you might find me there as well - I spend more time at OSH & AP than I do at home...

5-90

 

[bob mac]

cap has to breath to let moisture evaporate!
you locked the moisture inside every time the humidity goes up, or the temparature changes. lioke the man said....you answered your own question!!

good luck

 

[hawk_sixsix]

Consider that Chrysler consolidated their two distributor cap numbers. They now offer only one of the caps, which looks like the Niehoff FF76A. [Borg Warner and Niehoff caps are identical - same part, different packaging]. The Jeep dealer only offers the one cap for the 4.0L. Even their "service pack" consists of one cap, both rotor styles, and value-line wires.

As for Niehoff, Borg Warner, et al, they were slow catching on to Chrysler's consolidation. But here's how this works in the aftermarket: "Dilbert in Engineering says that both these caps work the same. Keep the one with more sales, discontinue the other one." So they kept the AL72E style cap.

Looking at all of this, well, I don't know about the rest of you, but if I have to choose between a confused OEM and a confused aftermarket, I'm going with the dealer.

The "universal" cap I bought at the Jeep dealer for my '97 has been functioning flawlessly for 10k miles so far, even though Niehoff would have sold me an AL72E.

So theoretically, the caps are the same.

As for the science experiment happening under your cap, my first guess is high heat / high voltage. Check for rotor tip wear / excessive clearance. Check the resistance in your coil windings. Also consider the ventilation issues presented earlier in this thread.

Don't take all of this as gospel; I'm just stirring the pot in hopes you might find a solution.

 

[hotelfinder]

that is what happens when water and O2, gets to brass, copper, other soft metals. Clean her up and seal it better.... The metal has a "patina" on it.... see below

http://dictionary.reference.com/browse/patina

 

[Hudson Bend]

That was not a "patina" . The photos show an acidic "bubbling". Your patina is a soft, thin, sheen which can occur naturally or chemically and which protects brass and bronze pieces from further deterioration by exposure to oxygen (air). His distrib cap demonstrates more of a chemical reaction between elements and electricity that caused a rather violent surface reaction on the metal. Patina is a term most often used with surface treatments on bronze sculpture and other metal crafts.

 

[Nevada City Sparky]

That was not a "patina" . The photos show an acidic "bubbling". Your patina is a soft, thin, sheen which can occur naturally or chemically and which protects brass and bronze pieces from further deterioration by exposure to oxygen (air). His distrib cap demonstrates more of a chemical reaction between elements and electricity that caused a rather violent surface reaction on the metal. Patina is a term most often used with surface treatments on bronze sculpture and other metal crafts.

So, it really just a "violent" patina then ;-).

No doubt the high-voltage electrical energy accelerated the oxidation process, which is really what patina is, only with a fancy art-name (people won't exactly pay big bucks for rust ya know)

 

[hotelfinder]

patina still IMHO