Black94Z28

iTrader: (12)

Looking at the summit catalog and they have an gm performance parts opti for 93-early 94 and a opti from late 94-97, how can I find out what I have on it now? The current cap is a MSD cap. I know one is vented and non vented, so where should I look for the vent? just want to make sure I know for sure how to tell them apart. I heard if you get the wrong one you need to change the timing cover. Thanks

ss.slp.ls1

iTrader: (36)

Don't get your opti from Summit. Get it from "thepartsladi" on Ebay.

You need a '93-'94 optispark. It is non-vented but you can also order a MSD cap & rotor and that basically converts your opti to vented which helps keep moisture out of your distributor. Just be sure to thread lock the rotor screws when you put the MSD cap & rotor on.

96capricemgr

iTrader: (1)

The catalogue confusion on the optis is because in 94 the f-body and Vette got the early "unvented" setup but the b-bodies and Fleetwood(d-body) got the later vented setup.
There was no midyear change, it is a difference in model that the catalogues just can't get right.

Z28Camaro30Ann

iTrader: (15)

X2

Go with AC Delco from someone more reliable when going for an Opti...just upgrade to the vented MSD Cap/Rotor

DriftR

iTrader: (4)

What he said ^ (to the letter)

Black94Z28

iTrader: (12)

Here is a pic of my opti, not sure what the previous owner did with it. Not sure if he put a new opti on or just the cap. Not sure if this will help or not. Also the little nipple port next to the harness plug was never hooked up to anything, not sure what thats for. Anyways...

96capricemgr

iTrader: (1)

That is not where the vent is on a stock vented setup. I would guess that is the MSD vent retrofit for the "unvented" style.

Z28Camaro30Ann

iTrader: (15)

It has definately had the MSD conversion but I cant tell if that opti itself is stock or not. That top nipple you see is one of the 2 vent lines. one runs from the opti to the middle of the driver side on the intake manifold, just under another vaccum hose... The other vented line runs from the opti to a small hole in your intake elbow. They are there to create a small vaccum inside the opti to help it vent better and keep moisture out. all you need is a small rubber hose about 24" long or so and stick it on there.

96capricemgr

iTrader: (1)

The MSD opti has a timing adjustment screw that would be visible from that angle. It is not there so it is a stock base.

Z28Camaro30Ann

iTrader: (15)

So there ya go. You have a stock opti with the MSD cap/rotor conversion. You need to get a hose on that nipple though and try and hook it to your intake elbow to help vent that thing.

Are you wanting to upgrade your opti? Just know what your running with? Or what are your plans for it???

If that opti is not messing up, and the cap/rotor are good to go, leave it be. If you wanna upgrade....I used the MSD distributor, but there are a few options you could take.

flyinZ

iTrader: (15)

Yep, you need the 93-94 Opti, not the 94-97' unit.

Whats wrong with an GM opti from Summit?

Black94Z28

iTrader: (12)

I just wanted to make sure which opti I had. Wasnt sure if I had the vented or non vented one. My car kept running rough and died on me when i was going 40 mph, then wouldnt start for a couple hours, fired up ran, shut it off, tried again and kind of dieseled for a second or two and then white smoke came out of the intake tube, leaving me to guess its the opti

BTC

Unless there has been a cam swap on your car, you would need the unvented type drive, which is a splined shaft.

RamAir95TA

iTrader: (2)

If that's the vented conversion, where is the other fitting? In order to draw in vacuum there needs to be both an inlet AND an outlet.

flyinZ

iTrader: (15)

The inlet port is at the top and the outlet port is at the bottom of the cap, I believe.

Z28Camaro30Ann

iTrader: (15)

yeah, the outlet is a larger port, almost looks the same as where the coil wire goes into the opti on the bottom driver side of the opti...