Thoughts on moisture problem inside insulators/and distributor caps :VIDEO

[Jlaa]

BTW I note that Kontact Chemie Plastik 70 is a confomal coating. I don't know anything about conformal coatings, but I think, @Alphasud40, you use conformal coatings with circuit boards right? Wonder if you might share some knowledge about conformal coatings that are available stateside and whether they might work inside distributor caps?

 

[Jlaa]

Okay, I found a conformal coating comparison chart here: Amazon.com

In the text, 419D and 419E are mentioned to "create a robust moisture barrier."
419D goes up to 125C and 419E goes up to 130C
419D has 1000 mil/V dielectric strength and 419E has 1100 mil/V dielectric strength
Both 419D and 419E have poor chemical resistance ... but I assume we don't care about that?

422C goes up to 200C (Great!) and 1076 mil/V dielectric strength .... at the expense of "fair solderability" .... but we don't care about solderability.

4223F has excellent chemical resistance (which we don't care about?) but is heat cure only
4200UV also has excellent chemical resistance (which we don't care about?) but is UV light cure only.
4225 has mediocre dielectric strength.


So maybe the right choice is either 419E or 422C?

 

[nocfn]

So where are we on this, have you sprayed this in any particular place or component? Is there a a pic of a properly cut (aka added) slots so we can see the depth (vis a vie are we cutting as deep as the "cover"?)

 

[Jlaa]

Hello @nocfn, I have not yet used any conformal coating but I know @jhodg5ck recently purchased some. He may wish to share his results here publicly. Regardless, I think it would be good if we all shared results.

 

[nocfn]

@Jlaa - My search does not find a recently cut cap with "ALL" the new slots that illustrate appropriate depth of the cuts. Do you or others have one to post?

 

[Jlaa]

@nocfn - were you able to look at @robm.UK's encylopedic report on this subject, replete with photographs of cuts?
Here is a duplicate upload:

 

[gsxr]

Here's a photo showing the depth of the cuts I made with a Dremel... they are similar in depth to the factory cuts. I don't think it's necessary to cut any deeper:

 

[nocfn]

Just speculating that the precision of the Dremel may be better than a ripping action of a saw blade.

 

[gsxr]

Just speculating that the precision of the Dremel may be better than a ripping action of a saw blade.

Dremel works GREAT. Details here:

FYI - Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot] | M119 Engine

Hi all, I have been meaning to address this on my little used 500E for years.... it is a problem I myself recognised about 5 years ago when I first looked at an m119 distributer cap..... Compare to any other distributor cap of the era such as an m104 and you will see there are NO ventilation...

www.500eboard.co

However, airflow doesn't care how pretty and neat the slot is... won't affect functionality either way.

 

[nocfn]

Dave it looks like there is an O-ring inside your cap, is that on purpose or was that one that came off the insulator?

 

[gsxr]

Dave it looks like there is an O-ring inside your cap, is that on purpose or was that one that came off the insulator?

Nope, no O-ring present... it's an optical illusion in the photo.

The O-ring resides on the insulator and is basically just a dust seal of sorts, which also keeps the insulator pushed tightly against the head so it doesn't rattle around. The O-ring has no function electrically.