I have read that GM has some issues with their Optis(aftermarket)quality.There have been numerous reports of premature failure usually under 10K miles.Some others have had no problem with theirs.It is not just water or coolant the change in temperatures causes any humidity to condense inside the unit.That is the reason for venting.My own first hand experience with the OEM was the sealing was pitiful especially around the plug on the GENI opti.They redisgned that area in the GENII but still did not do a really good seal around it.I suspect most failures are from water intrusion around that area as it is near the top of the unit.The cap is sealed buy a nitrite seal that does not last forever.That is all the sealing it has.Do you feel like hoseing the engine is a safe thing to do after reading how many have done it with OEM optis only to have to replace them?

The Dynaspark has a serious amount of silicon used on anything that might leak basically waterproof.I feel safe washing my engine now and do it when necessary.

 

You are thinking about the Delteq/LTCC conversions.The Dynaspark looks just like an Opti only prettiers and sealed.The Delteq/LTCC uses the electronics of the opti without using the cap and rotor.

 

You are thinking about the Delteq/LTCC conversions.The Dynaspark looks just like an Opti only prettier and sealed.The Delteq/LTCC uses the electronics of the opti without using the cap and rotor.

 

You are thinking of the Delteq/LTCC conversions.They use the Optical portion of the Opti and not the cap&rotor)The dyanaspark looks like the OEM only prettier and sealed.It is made from billet aluminum not pot metal.

 

I replaced my early-style '93 opti with a vented '96 opti and '95 timing chain cover. I'm not even going to try hosing my engine.

 

AH I got it, i remember seeing that they used the optispark and added mods to it. I just started the engine and now here a wistle so I guess the water pump is going also. I cant waite to see the bill on this one. I thought my boats were money pits. I'm just glad my wife likes this hobby.

 

The Opti was redesigned in 1995 not 94. The other problem is if the car won't start because the opti got wet, the vacuum hose venting won't do you any good.

 

Both of these statements are exactly correct.

The first-generation, passively vented (had only weep holes to drain moisture out) Opti was used on Corvettes from '92 thru '94. The second-generation, actively vented (used intake vacuum to draw filtered air through the unit to draw out moisture) Opti was used on Corvettes from '95 thru '96. The Opti disappeared entirely from Corvettes (in favor of a DIS system) with the introduction of the LS1 engine in '97.

The active-venting on the second-gen Opti was intended only to remove small amounts of condensed moisture. If the car won't run because the Opti has been douched and is loaded with wet stuff, the active venting is of little use. I've heard of one guy who hooked up an aquarium air pump to his second-gen Opti's vacuum hoses and used it to force air through the unit for quite some time, and he reported that he got it dry enough to run again, but I can't vouch for this.

Best bet by far is to avoid getting any moisture inside of the unit to begin with, and the best way I know of to prevent it from happening (in a '92 - '94 Corvette in particular) is to switch to a DynaSpark unit.

Be well,

SJW

 

This is all pretty much correct.

The second-generation, actively-vented Opti was GM's only attempt to revise and improve the design of this assembly. It was a significant improvement over the first-gen, passively-vented Opti, but still had some serious design weaknesses.

The DynaSpark was designed by an aftermarket business, and they started by listing every deficiency they could identify in the OEM units' designs, and then set about solving each of the problems. The billet aluminum housing alone is a big step forward, and DynoTech also eliminated one of the two enclosure seals entirely, thus deleting one of the possible sources of leakage. DynoTech did everything possible to ensure watertightness in the DynaSpark, including sealing the low-voltage connector, which was a key problem area with the OEM Optis. I would be very surprised to hear that even one in a thousand DynaSpark units ever got wet inside. When I spoke with Phil at DynoTech, he actually encouraged me to hose down the DynaSpark once it was installed on my engine -- that says a lot to me about how confident he is in its watertightness.

I did quite a bit of research into the various options that were available to me when my OEM Opti (first-gen) failed at 19K miles. I did a lot of digging on the 'Net, and spent time on the phone with Pete at Delteq (Pete is a great guy, BTW), and with Phil at DynoTech and I concluded that the improvements provided by the DynaSpark are numerous.

I've done a fair amount of mechanical design work in my career, and I'm not easily impressed. But I was quite impressed when I removed the DynaSpark from its box and examined it closely. Phil was really using his head when he designed this thing. It appears to be very well designed, and very carefully fabricated and assembled. Check out DynoTech's website for more details on all of the improvements versus the OEM stuff. It's worth the time spent reading all of this, IMHO.

Be aware of one thing: DynoTech is adamant that you follow their installation instructions EXACTLY when installing this unit, and you should do exactly as they say. Especially if your engine has been modified with non-original camshaft, timing gear, etc, there are measurements that must be made, etc, to ensure that the longevity of the DynaSpark is not compromised.

I was tempted by the Delteq system, as it offered the tantalizing possibility that I might be able to leave my existing Opti/water pump, etc in place, which was a most tempting option, indeed. But, I finally concluded that I simply had zero confidence that I could rely on the optical section of my OEM Opti to continue to provide good data to the ECM for any length of time (and I'm glad I decided this way, as the OEM Opti showed signs of rust around its bearing upon inspection after I yanked it off of the engine).

I also decided that I really wasn't very excited about adding the Delteq system to the already-too-cluttered engine bay in this car. Plus, with the Delteq, I'd have had to either hack my tach filter out of my underhood wiring harness and bypass it electrically, or add an MSD tach amplifier to the setup, or my tach would no longer work -- I don't think this is an issue for all LT1/LT4 Corvettes, but it was an issue on my '94.

The LTCC system was not yet available to buy, and it would have required adding eight coilpacks (rather than the four used in the Delteq system), so it was not an option. Given what I've learned about the LTCC and Delteq systems, I would choose the Delteq over the LTCC without hesitation, if I were to eventually decide to convert the high-voltage section of my ignition system to a Distributorless Ignition System.

So I finally settled on the DynaSpark. And I have no regrets. It was a direct, bolt-in swap for the OEM Opti. The only additional changes required were to rob the low-voltage connector housing from my OEM Opti wiring harness and add it to the DynaSpark's harness (no big deal, as a pin extractor tool is furnished with the DynaSpark unit), and I had to add a (not-furnished) vacuum tee to an existing vacuum hose on the engine, and add a hole in my intake bellows to receive the other vacuum fitting. It all went together very nicely, and preserved the nearly-stock appearance under the hood, for what that's worth. The car has run beautifully since I did the job last year (~10k miles, now).

Be well,

SJW

 

IMHO, a new water pump should always accompany the installation of a new Opti, and it's a very good idea to replace any cooling system hoses that aren't fairly fresh at the time, too.

And there's never an easier time to replace the plug wires than when you're already up to your armpits in the front end of the engine doing the Opti and w/p. The wires are a real PITA to replace, but it's significantly easier to do when you're already into it this deep, as you'll have improved access to the wires where they connect to the Opti.

Be well,

SJW

 

OK, only 95 and 96 models have the revised Opti. The vented redesign is effective in controlling condensation but because the vent is is connected to manifold vacuum it would be no help if it gets wet and won't start. Would I be correct in thinking there are possibly two failure mechanisms at work here? A wet optical sensor and or a corroded optical sensor?

Greg

 

Exactly.There are 2 sets of slots that pass over the sensor Low/res and High/res.The high ones are very close togther and can be blocked by corrosion.The lens on the sensor it self can get blocked or dirty especially with coolant.Water on the lens might have a chance of drying out without residue not coolant.So the statement about water in it is not necessarily true the venting can dry it out and the opti will magically work.Not with coolant it will not totally evaporate.

There is the issue of ozone generated by the coil spark inside the opti also and over time it can be corrosive especially on Gen I optis.

Then there is the carbon tracing effect on the inside of the cap it is a good conductor and spark will follow the path of least resistance sometimes along the carbon trace.This is the failure that throws no codes but runs like crap.

 

So, If I were to clean the optical sensor with contact cleaner in my 2M lab, I need to also wipe it dry to ensure clarity?

 

I would say yes.It is basically similar to a cd player except it looks at transmitted light instead of reflected.I would treat the reciever the same way and contact cleaner might be too harsh for the lens.There are better cleaners for this application like CD cleaner fluid or cassette cleaner fluid that do not leave a residue even alcohol would be better.

 

Thanks