This is a new one for me. What kind of aftermarket coil did you use and what lead you to think the coil caused the opti to fail? :confused: :skep:

:flag :flag :flag

 

Enlighten a novice if you have the time.

I drive a 94 LT1, 81k so far. The original Opti is still humming along, and I drive it daily.

I anticipate changing my plugs and wires within the next month. I have no skips or loss of performance that is noticeable under normal acceleration, got @27mpg on a 500 mile trip this weekend with mostly Interstate driving.

The only detectable issue I have is static when listening to AM stations, which goes away when the ignition is off. I have also detected intermittent miss under WOT just above 5k rpm. I suspect crosstalk or breakdown on the plug wires, hence my decision to replace the plugs and wires.

I am unfamiliar with the PUCK you refer. What is that?

I plan on using Taylor wires, and was considering the NGK Iridium plugs. Is there a recommended gap for these plugs outside of the normal range called out in the manual?

Regarding the theory of sustained use versus intermittent use, my personal experience leads me to believe that steady state operation in all things is preferred over intermittent operation. And in the case of the Opti, vented or not, I would think this is doubly important. If water enters the unit, frequent use would help prevent corrosion on the contact surfaces, and may possibly help evacuate some of the coolant due to heating up and pressurizing the Opti during normal driving. These are uninformed opinions, based on casual observation, but they appear to dovetail nicely with the direction this discussion is headed into. :cheers:

 

Certainly since you have radio static that is an indicator of a bad plug wire which could also be your high RPM miss. Change the plugs and wires first and I'll bet both problems will go away.

The AC Delco platinum plugs are simply normal spark plugs with a little piece of platinum stuck on the ground strap. Thus when you gap the plugs you gap the distance from the center electrode to this puck. Eventually these pucks will come off and you will have a much bigger gap to jump which can cause any number of problems. It's a very stupid design for more reasons than one can easily go into.


[Modified by Nathan Plemons, 8:34 AM 5/5/2003]

 

I voted for my 92 (deceased), but with well over 110K on the clock with the original opti, I never had a problem. I ran into a hesitation but a quick tune-up solved that (plugs & wires). These cars are meant to be driven! :yesnod:

 

Ive driven my 1993 car 34 k in 5 years, which is not exactly every day.

Both water pump and opti are original and ok, at 10 1/2 yrs old and 76 kmi.

Changing both due to heads cam, timing chain change...

 

OK, I like the puck theory but are the platniums only used on Vettes?

Also, except for Vettes which other LT1s have the cooling air intake 4" off the ground? This seems to be a perfect way to throw water all over the front of the engine.

I don't know how long it takes for the seals to harden and shrink, but once they do, there's nothing to keep any moisture out except driving it to raise the temperature vaporize the moisture to drive it out the vent holes.

It only supports the garage queen theory if the car is driven in the wet then parked in the garage while the inside of the opti is still wet.

 

No, but they do the same thing in Fbody's.

None, but that has nothing to do with it. Moisture does not make its way up the intake with enough volume to make a difference.

No clue. But I agree with your contention.

The opti will also accumulate moisture from dew and such. When not used, it just adds up. Kinda like moisture in the exhaust.

 

Like my sig says, a Jacob's.

Sam

 

Drive that good looking green vette a little more and then tell us about the Dynospark. Did you ever get it wet?

 

If spark plugs loosing the puck was the cause, wouldn't they have about the same opti failure rate as the Vettes.

We're not talking about the intake, just water picked up under the nose that makes it's way through the radiator to the front of the engine. A lot of dirt get sucked up through there, water would too.

 

I think the difference is in the miles. Most Fbody's get driven on a daily basis. I have noticed the more usage, the better these cars run.

the intake is the air intake under the bumper, not the plenum. We are talking about the same part.

 

Opti on the LT4 went out at 48k. Waterpump was leaking on it.. as usual :rolleyes: . Covered under warranty thought! :hurray:

 

In my opinion, everything under the hood should be made waterproof. I had a intermittent misfire due to a leaking front crankshaft seal. The leak slowed and the misfire disappeared. I have yet to remove the opti.

 

I did my OPTI with a vent retro in the coupe at 85K. The car was running a little rough and with all the OPTI info (true or false) I wanted to replace it so it wouldn't leave us stranded on one of our many cruises. Did plugs and wires at the same time. Car runs better.

Upon disassemblling the opti, it seemed fine inside. The cap was severely worn. I think the new cap (that came w/ the new opti :rolleyes: ) is the reason for running better. I'm sure new plugs and wires helped too.

Part of a tune up is distributor cap replacement. GM should have engineered it so the cap could be replaced with out having to remove the OPTI unit to do so :mad

The vert has 57K, thinking around 60-65 to do just the cap.
:cheers:

 

I am the second owner of my 94. In the manuel the opti was listed as being replaced at 24K. I have no idea how the previous owner drove the car when I bought it there were 72,000 miles on it. It was a FL car so maybe excess moisture caused the failure due to climate. I've never had a problem with the opti spark. But the fact that GM did away with it on the C5 and updated it on the LT4 is reason enough to conclude that it's a piece of crap.

 

They did not "update it for the LT4". It was modified in '95 to be vented. ;)

 

Hey Nathan, you ever thought about opening up a shop that only works on intakes? You could call it Plemon's Plenums.

Sam

 

OK I am going to put my anti flame suit on, my vette has 111000 miles on it and I still have the orignal optispark and it run great, however now saying that it sure to go out today! :skep:

 

The Opti is actually a rather good system, unfortunetly, it was the victim of standard GM cost cutting.

It works pretty good, and is not noted to just quit. They kinda just deteriorate... This is good - cause they give ample warning!!!

The updated Dyno Tech piece is, as I see it, the way GM should have made it in the first place.

Their cost of about $550.00 is nothing, considering the potential quality. And, considering what GM tries to sell these things for in the first place...

The cost of converting to a different type of ignition is clobbered by the level of integration in the existing system. To remove all the existing and going purely aftermarket, thats BIG bucks... $2500.00 or so...