I was thinking about my vented opti the other day, and how to keep it operating.

We know that moisture is a damaging culprit. It is opined that the vented optis work better than the earlier models. However, the vent tube is connected to the intake boot, putting the opti under negative pressure.

When we design buildings here in South Florida (hot + muggy), it is a major no-no to allow the building to be negatively pressurized. If there's a leak, moisture intrudes.

I was thinking of disconnecting the opti from the intake boot and hooking it to the pressure side of the smog pump. That should put the opti under slightly positive pressure, so when water does splash on it, it isn't drawn through any leaks in the seal.

This would literally cost nothing to do. Anybody done this?

 

the reason for a neg press it there are bad gasses created from the hi eletrical transitions from the rotor to the cap...you need to get those gasses out.
Injuneer has spoke of it before, he can probly give you a more in depth explanation than me

 

mainly O3(ozone)

 

most all old style caps have a little vent on it anyway....I see alot of people at the track drill small holes in them

 

Clean air is introduced into the opti from the intake elbow and exhausted through the vacuum hose that goes to the intake manifold. So, it has a continually changing circulation of clean air.

 

Here is a little trick I found to find leaks in the opti that can let bad things in. Hook a vacuum pump to the opening that normaly has air drawn out by the engine. Place your finger on the air intake opening and pump it up.

If there are no leaks then the vacuum pump will quickly leak down and you can locate the leak with soapy water and address the problem.

I had a brand new opti that was leaking under the cap and around the sensor mouting screws. Those areas were sealed up and now no leaks using the vacuum pump.

If you dont have a vacuum pump you can suck on the hose too, just make sure you dont do this in from of your buddies.

 

So what kills the opti? Is it the O3 or is it water getting in?

I was under the impression it was the water. If you used pressure rather than vacuum to remove O3, then you can address both issues at once. That way when the opti does leak, it leaks air out rather than water in.

 

Like you mentioned, And in my experience, moisture is 99% of the damaging culprit.......If the vented style optispark unit is just sealed nicely with some silicone RTV, rather than to just rely on the "inadaquate" sandwiched rubber seal(like most people do)... IME, none of these moisture problems (and failures because of it) are an issue any longer and they seem to last a long long time after this .........I've been sealing them like that for many years after my first opti failed from a waterpump leaking on(and in) it...Since then I have yet to have one last less than 80+ thousand miles on any of my (past or current) opti-spark distributor cars..................Joe