94 Opti-Spark replacement nightmare

I replaced my Opti-Spark and water pump a few months ago with remanufactured units from Napa. I paid around $350 for the Opti parts and was very meticulous while doing the job.
This weekend, I pulled the stuff off again to have a look at it ( due to codes pointing me in that direction ). Sure enough, the Opti was all rusted up inside and the cap portion had some really strange looking corrosion around the contacts. The corrosion isn't like anything I've ever seen, it's really thick, very nasty looking stuff.
Never without a plan, I had a new GM unit on the bench ready to install.
So, for those of you out there doing Opti replacements with After-Market parts, how did you seal the thing up? I used Silicone Gasket Goop to seal the edges between the distributor, the "spacer", and the cap. The vent in the cap was sealed as well.
Is it possible that I sealed moisture inside, causing the rust? Was the Silicone a bad idea?
I suspect the Blue ATV used as a sealant is the cause of the strange corrosion, but the rust is a bit of a mystery.
Thanks,
-Kevin
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If you bought a GM / Delco opti-spark unit for that car you should NOT open it. It is designed to breath through the vent hole . These motors are ones where a rebuilt distributor is a very bad idea. The only crucial thing on this car is really to make sure that you have a new gasket on the water pump.
--
Brian
ASE Certified Parts Specialist.
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My first purchase was $170 cap/rotor kit and $175 distributor unit. Both were remanufactured units from A1 ( napa ). I was forced to use my "spacer" piece which brought on the need to seal it up.
The cap/rotor kit included the vent, which is only applicable on 95 and newer models. Basically it was a universal cap/rotor kit for all 93 and newer models. Since my OEM Opti had no vent, I sealed it.
This time ( this weekend ) I replaced the entire unit with a GM replacement part, which I will NOT open up. It's already installed.
I'm just trying to figure out what went wrong with the first replacement. I'm certain the Silicone played a role.
-Kevin

seal
in
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Thanks for confirming a $350 mistake. So... the silicone not only introduced the moisture, it increased the rate of corrosion.
Maybe you can explain the lime green color that's all over the business end of the rotor, and the contacts?
Mold? LOL! ...or a byproduct of burning silicone?
Thanks,
-Kevin

due
all
to
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The green colour comes probbably from corroded cupper or brass. Cupper salts use to be green. Regards / Don

very
Was
strange
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There are instructions on the Net for replacing the 94 parts with 95 parts, with the vent. The 94 units were sort of sealed, but the oxygen in the trapped air gets ionized to ozone, which causes accelerated corrosion. The vent was a big improvement.
Actually, there are two hoses on the vented units. One draws clean air from a nipple in the elbow in front of the throttle body, and the other is connected to manifold vacuum, I think at the throttle body, so the system is not just vented, but provided with a continuous flow of clean air. It doesn' need a _lot_ of air, so I'd use an orifice in the vacuum connection, small enough to not interfere with the engine idle.
-Mike-
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