dizwiz24

I have a question.

As everybody knows I had a newer style vented opti cap installed on my 93 Corvette Convertible when I had the LT4 hot cam kit installed. \

My question is this....I see a hose running from the distributor to a vacuum source on the plenum, ok thats where the vacuum comes from....but where does the air inlet for the vented opti cap come from.....?

Does anybody have maybe a picture of the vented opti cap? Is there supposed to be a hose connecting air inlet for the distributor to something? Because I only have one hose I can see coming off from the distributor..., and its a vacuum hose.

just curious. Any response would be appreciated....

Thanks,
Dave

bogus

the input air comes from a little hole you have to poke in the intake tube... it is best the closer to the throttle body on the flat part, versus on the crinkly part.

Rick93Z07

Yea, I'd suggest reading read Tech Tips & yours is hooked up backwards. Vacuum source goes to cap, not base. Base port goes to fresh air source (TB air hose). Air entering aluminum base reduces the chance of condensation in cap. I routed mine to the car's interior and used a cheap filter.

AquaMetallic94LT1

Mine is hooked up the other way too. I used the stock GM vacuum harness which is setup to use the small port for the vacuum connection. The large cap pot fit on the line that goes to the source of air. I hooked mine into the rubber air hose after the MAF sensor so it can account for the going through the distributor. I recommend the GM harness because it limits the amount of vacuum in the distributor. I had my own setup initially and the air inlet port got clogged causing high vacuum in the distrbutor which lead to the cap pushing on the rotor and destroying it.

Rick93Z07

Aqua,

About your rotor rubbing against the cap.

There is an 1/8" gap between the rotor and cap for air to freely pass through. There is no rotor seal to prevent free flow. I do not think a few inches of engine vacuum sucked your rotor into the cap, especially considering all later Optisparks were installed like that. I have seen rotors contact & scuff caps with the vacuum connected to the base. Invariably, rotor to cap contact is due to the base bearing being dislodged on installation due to excessive force and misalignment. The installation job is very tricky and experienced LT1 GM mechanics sometimes get it wrong. Often the car runs for weeks before malfunctioning.


[Modified by Rick93Z07, 8:09 AM 11/24/2001]