Hey everyone,

Well here we go again, the 'ol OptiSpark. I've had my C4 for less than a year. '94, 42k miles, excellent condition. The OptSpark was repalced prior to puchase as evidenced by the repair invoice. The car was having some performance issues, and It was diagnosed that I need to replace it.

I have searched this site and read many threads. I'm a bit concerned for a couple of reasons. Hope those out there who have dealt with this Opti can help out.

My first concern above all is this -- How reliable is the C4 given the fact that so many have stated the OptiSpark could fail at any time without warning. After finding this out, its a bit unnerving imagining I'm on a road trip somewhere on a desolate highway and the Opti fails.

#1 Question to the readers ... Do you feel confident taking your C4 on long road trips? Is the fear of the Opti failing unexpectedly more hype than reality?

Next ... It appears from the threads that every brand of OptiSpark out there has failed soon after install by at least one C4 owner. Given that here is my next concern...

#2 Question. What is the most reliable OptiSpark out there that is readily available to buy? I was at first going to choose the MSD, since it is vented, but then many have had problems with it right out of the box. Then I discovered the Petris brand. From the write-up on their website I thought I had found the best one, untill I read some of the negative experiences by many on here who have purchased it. So anyway, which one do I choose?

#3 Question. Since the front will be apart to replace the Opti, I'm going to replace the water pump. What is the most reliable brand water pump to buy?

I appreciate all the help and advice.

 

I dont think id take mine on a trip of much more then 200 miles from home. Mines a 92 and it has 51k on it. Opti is original and still working great. I too am considering replacing it along with my waterpump but dont know if i should just leave well enough alone right now. My thought too was to by them and just store them in the underfloor rear storage comp in case i am away from home. At least then if you have to have a garage away from home fix it you have the expense of the parts allready taken care of. By the way my first vette, another 92 was sold to a buddy at 50k and is still going strong on the original opti at 98k

 

A vented oem optispark will last 200k miles.

1.i have no concern because i am using a vented oem unit.

2. Oem. in your case its ac delco. Note acdelco is not the same as ac delco remanufactured. If you can find a new old stock acdelco base (its normal to pay $700 for it) Get this. Add a gen 2 (95 thru 96) vented cap and use one of the 3 weep holes at the bottom as an air inlet.

If you plan on upgrading your cam, convert to gen 2 vented Optispark. Those are still available (delphi) for $300.
The gen 2 is a cam dowel pin drive and requires the cam dowel pin be extended. If the cam dowel pin has been pounded in, then they usually cant be retracted.

3. Dont dare replace an oem waterpump that is working fine. in fact, if you do, sell your old one to me. Now: do add a weep hole mod to direct any leaks away from the optispark. New acdelco waterpumps are rebuilt in china.

back to optispark:
The people with oem units that have failed are either
1. Non vented optispark 92 thru 94 users - like myself.
2. 95 thru 96 users where the vent system failed (due to neglect) and seals cracked.

Add a vent to the system and it becomes reliable.

 

I have the MSD on my '96. It was installed by the prior owner. I bought the car at 47xxx miles and at around 52k it went bad. I took the cheapest option and had it rebuilt by MSD for appr. $155.00 including shipping. Knock on wood, I hope it keeps working.

That said, all the opti choices seem to be good and all of them seem to be bad. Once in a while, a NOS opti with the Mitsubishi sensor shows up on Ebay. If you can find one, buy and install it.

As for trips, I took mine to Maine for a couple of weeks the first year I owned it. My wife and I put a couple of thousand miles on it and I would not hesitate to take it anywhere. That is why I bought it. Sure it can breakdown but so can every other vehicle. I have too many more important things to worry about than whether the opti will survive a trip. If I could not drive it without worry, then I would sell it since I don't need a 3300 lb. doorstop.

 

If you have to add water to the coolent can at anytime I would check the waterpump,The opti goes if the waterpump drips water on it .
If the opti goes out without the water pump leaking then it is just a high milage failure.

 

The optispark is probably one of the most feared, most misdiagnosed part ever on any car. Not to say that they never go bad, and there are plenty of bad imitations out there.

That said, I have over 160K miles on my factory opti ('96) with nothing more than a cap and rotor replacement at around 86K. The original cap and rotor were good, but I was having a cam put in, so I replaced it to refresh it. My opti survived a water pump leak very early on. ( A side note on WP leaks, the weep hole is actually directly above the serpentine belt, so the majority of the moisture is actually deflected away from the opti. My opti also survived a burst of the upper radiator hose later on. The opti is also a sealed unit. The early ones had vent holes as the video will explain.

GM revised the design and vented the opti, not to remedy failure for water intrusion as much as to release the gases that build up from iginition. These gases are acidic and corrode the terminals in the cap, by vacuum venting, these gasses are drawn out of the opti cap.

The only issue I've ever had with it, throwing a low resolution code, turned out to be the opti harness. Some coolant had worked it's way into the connector, cleaned it up, new harness, no issues.

Again, not saying they don't go bad, but they are alot more durable than folks give them credit for.

Enjoy...

 

Get the spark out of it.........

 

I've got over 200,000 miles on my 1995 Impala's original Opti. I did put a cap and rotor on about 140,000 miles just for preventive maintenance. I would leave for a 1000 mile road trip without any concerns. My Vette has about 150,000 miles on the original Opti and is very reliable. I'd never turn down a road trip because I was afraid the Opti would go bad. The vented ones are better.

Remember that nearly every cop car in the country had these Opti's on them from 1994 to 1996 and after they got too many miles for cop use they were sold to cab companies that are still rolling their LT1 Chevy Caprice's.

I've had water pumps go bad, get the Opti wet and still had no problems. A lot of times people on the forums will have a miss and immediately blame the poor old Optispark when the plug wires were bad. Any distributor will need cap and rotor maintenance and while the opti will last longer than a standard distributor caps and rotors are a good choice for a maintenance item.

When installing the new water pump take a 1/8" NPT pipe tap and tap the weep hole. Screw in a 90 degree 1/8" threaded elbow from an aquarium supply shop and put some clear plastic tubing on the end. You can direct any future water leaks away from the opti.

Summary would be that they are very reliable and don't worry about a road trip because I take many. Failures are very rare and most times are mis-diagnosed.

Anything electrical can fail any time with no warning. ICM, Opti, ECM....whatever. If it's electric it is very reliable but it can break. You can be on your desolate highway and the fuel pump could fail also. I like them. Since yours is non-vented fix that. Your bearing in the opti shuld be good with your low mileage and you may just have condensation or dirt/dust on the optical sensor. That can easily be cleaned off and save you a new opti. Good luck and don't be afraid of it.

 

will the cap for a 96 work on a 92 dist with no alterations and if so does anyone have a link to the msd cap WITH the vent kit. My opti is still going strong and has only 50k on it so i mignt want to salvage it and just do a cap.

 

Im in a similar situation with my 94, has anyone got a link?

 

Excellent video. It clearly articulated the OptiSpark and it's issues. Now I have a clearer picture. Thanks for sharing.

This is what I particularly found interesting...

Ignition Coil Driver Module

"The ignition coil driver module acts as a switch for the PCM. When installing the ignition coil driver module it's important to coat the heat sink and module base with thermal conductive grease. This grease fills the airspace between the module and heat sink, allowing heat from the module to flow to the heat sink to dissipate heat. Without thermal conductive grease the ignition coil driver module can overheat and fail."

OptiSpark Ventalation Explained

"Proper ventilation system operation is critical to the OptiSpark's performance. The ventilation system prevents moisture build up and clears the optispark of corrosive gases formed by the high voltage arc.

One of the byproducts of the transfer of high voltage is ozone. Ozone is heavier than air and settles at the bottom of the distributor. When ozone combines with moisture and nitrogen in the air it forms nitric acid. This nitric acid attacks the terminals in the distributor and can create conductive paths within the distributor causing missfires and crossfires.

When the optispark was first introduced on the 1992 Corvette, it had a passive ventilation system which consisted of ventilation holes drilled on the top of the case.

The corrosive problem was solved by moving the vent holes to the bottom of the OptiSpark. [These vent holes (or weep holes) had the potential to allow moisture to be sucked back into the OptiSpark.]

The OptiSpark ventalation system was further improved on later OpiSparks with a forced ventilation system. This forced ventilation system has a fresh air inlet and a vacuum line.

The fresh air inlet runs from the distributor to the fresh air inlet duct located just after the mass airflow sensor. By plugging into the fresh air inlet after the mass flow air sensor the fresh, filtered air is accounted for by the PCM and doesn't affect fuel mixture.

To draw air through the distributor, a vacuum line with an inline filter runs from the distributor to the intake manifold. A check valve on the line prevents any to return to the distributor."

Modified Forced Ventilated OptiSpark

I came across this article. Is this the way to modify the Opti to make it forced ventilated?

https://www.corvetteforum.com/techti...=174&TopicID=2


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Just find a baby blue Lab coat and wear it on the journey. You should be fine!