I need to buy a Opti replacement for my 94 Z28. I want to replace the cap and rotor also. I was going to buy the Accel unit from Summit but they say they are for 1994 1/2 to 1996... Im guessing thats a "vented" unit. How do I know if mine is vented or non? I belive it is non. Why does Accel not offer that same unit in a "non vented" style? Im considering buying a $150 Opti replacement that they have at Advance Auto (Without module, whatever that means) and then buying a $99 Accel cap and rotor kit, but the cap and rotor kits do not say vented or not.. Is it the cap & rotor that houses the "vent" or is it the distributor its self? Confused.. All I know is my Z28 has not ran in 4 months and im ready to get this fixed already but Im worried about buying the wrong parts and dont know what to get..Help please.. I have used the search button and im still learning but I need some help if you have any to offer..Thanks guys!

 

you should have the nonvented opti. If you had vented, there would be a vent tube on the intake elbow. Only 95 and up have vented. Id just get an ac delco opti. Its the most reliable of whats out there right now. You can get one on ebay for $300 or so

 

Do those come with the cap and rotor?

 

The AC-Delco is complete with cap and rotor and ready to install.

 

The 94 B-Body had the vented Opti, so that's probably why they refer to 1994 in the Accel listing. The F-Body and Y-Body 94's were all non-vented units. Only Accel can tell you why they have ignored the 92-94 non-vented replacement market,

The "module" is most likely the optical sensor. Do not buy bitsd and pieces and try to build your own Opti out of unknown quality components. Buy a "complete" unit, from a reliable source.

The vented unit air supply line connects to a nipple on the body of the Opti, the vacuum source connects to a nipple on the cap, so you need both pieces for a "vented" Opti.

Shoebox has a photo:



There have been reports of failures with new/complete AC/Delco replacements, with the Summit units, with the Accel units and with the MSD Optis. None of them seems any more reliable than the other. The DynaSpark seems to be relatively trouble free, but is expensive.