I wondered if anyone here knows what the difference in the two opti units is besides just vented and non-vented. Are the electronics inside the same or are they different? What's the advantages of the vented, is it just more reliable? I'd appreciate any comments. Thanks

 

How about it? Does anyone know what I'm asking? I figured someone here had experience with this before.

 

All I know is that the vented is supposed to be more reliable. Keeps the insides dry if they get wet.......I think.

 

If you do a search, you can read all the comments you can stand. Read the sticky about TTT abuse while you're at it.

 

They are not the same. The harness connector is different, so if you replace a vented with a non-vented, you need a new harness that goes from the gray test connector on the passenger side of the intake manifold to the Opti.

Then there is the "drive' mechanism... the 93/94 unvented is driven with a splined shaft that inserts into the back of the Opti and the timing set cam sprocket. The 95-97 vented is driven by a dowel pin that is in the front of the cam, passes thru the cam sprocket and into a hole on the back of the Opti rotating parts.

The diameter of the rotating assembly is different because of the different drive mechanism, so the timing cover needs a different size hole.

The internals are different... the 93/94 slotted disc for the optical sensor is tack welded to the rotating assembly, the 95-97 is retained by the screws that hold the rotor on.

The dividing pan is different... the part that separates the high voltage section from the optical section.

The "cap" is interchangeable, but of course the nipple for the vent won't be there. The electronic optical module appears to be the same.

 

Thanks for the pertinent response. I guess what I'm really wondering is if the caps are interchangeable then why not get the newer cap with the vent if internal moisture is the real problem?

 

Thanks for the recommendation, and I'm glad to see that someone who has been around a while is so tolerant of the ignorance of new people. Next time I'll spend six hours looking through old posts instead of coming on here and asking to talk about cars, which is what I thought we were all here to do.

 

I might have been more "understanding" if you had not ignored the TTT abuse as well. Admitting you are too lazy to search and help yourself reveals a lot about yourself. People shouldn't come to this board and expect to be coddled. Everyone posts of their own freewill and no one is actually "due" a response. The more you post, the more tired you get with answering the same question over and over. That's why there is a search function. Newbies are sometimes ignorant of it's existance. I point it out when I feel it is appropriate.
Easy for the newbie to come in and get all their questions answered and rarely contribute to the education of others. I can tell you that most of my posts have be answering questions and I have probably not started 10 threads since I have been on this board.

I commend Injuneer for giving a detailed reply (as we have grown to expect no less). I guess you caught me on a bad day. Sorry, but that's the way it is sometimes.
I guess I can always unplug my website and go home. Maybe I am burnt out.

 

I think your right shoebox. I always try to play dumb. Please don't unplug your website. It has helped me on several things and saved me a lot of time. Thank you for having it.

If I have a question I always do a search first. Then after a half hour of coming up with nothing I'll make a post.

 

Because there's more to the "vent" than the nipple on the cap. There is also a nipple on the main body. One connection if for clean, MAF measured air from the inlet elbow to the Opti, and the other is the vacuum connection from the Opti to the intake manifold. System doesn't work without both parts.

And, the vent is not there for "moisture".... GM put the vent there to remove the ozone generated by the high voltage discharge... at least that's the official company line.

There is an online guide to converting an unvented cap to a vented cap without using a new cap. The article came from one of the Corvette magazines a few years ago. I don't have a link but (and I hesitate to suggest this ) a "search" might turn up a link.

 

OK.... putting on Moderator cap...

You really didn't need to react in that way. The end result is that you have probably turned off the MOST helpful person on this forum.... one who has spent endless hours of his time creating a website that is used as the "bible" for just about every necessary piece of information about these cars.

I can tell you from personal experience, there are some questions that many of us have answered so many times that it makes us nauseous when we see them asked again. We can suggest a "search", or we can just ignore.

The good Lord helps he who helps himself.... or something like that

 

I do appreciate the help and I only gave attitude because I got it. I will search from now on first and foremost. I'm not trying to upset anyone, I just am at work and can't spend too much time on here looking for things. It was just quicker and easier (me being lazy) to ask the question. I guess being an important and knowledgeable person on a site like this is akin to writing for a magazine and having to answer the same old questions in every issue. It would be easy to tell those people, "just go look it up in the old issue" but they go ahead and answer them anyway. It's just a part of being that guy. I didn't think it would be this big of a deal, honestly.