What is an optispark? Where is it located? Which years did they come on? And why do I need to ensure I don't get any water on it? Just noobie questions...

 

DO NOT GET IT WET!!! I just got mine back last week, cost me $650 to replace it and the water pump. All because I was going to try to pressure wash the engine to purty it up. DON'T DO IT

 

Check out this site, good opti info ...
http://www.charm.net/~mchaney/optisprk/optisprk.htm

 

Dont forget to fill out your personal profile. If I knew the year of your Vette I could comment on your concerns. Or are you looking to buy?

 

Opti spark distributors came on all C4s (except for ZR1s) from '92 through '96. It's located on the front of the timing cover and is driven by the cam.

 

...and sits behind the water pump, and below the thermostat. Earlier years (92+) were more susceptable to moisture. You really do want to avoid soaking it!

 

If you have a '95 or '96 it isnt as bad...they have drain/vent tubes... earlier are akin to the spawn of satan once they get really wet.

 

I've known the spawn of Satan, a former boss and my third wife both were. Even the early opti ain't that bad. Trust me.....

 

Your third wife and my first, damn does this mean we're related?

 

With wives and bosses set aside I thank you for yor feedback. I spent all week using a toothbrush and soapy water (Dawn) cleaning the components. I read on the forum some horror stories about getting components wet where others didn't have a lick of problem. I felt more safe than sorry. From what I see from the link this is the "distributor" or electronic ignition. Thanks all. Even for the humor.

 

The optispark is the "distributor" on 92-96 LT1 and LT4 Corvettes
If you get it wet you could possibly fry it, coolant will destroy it. To replace it yourself you going to spend hundreds of dollars and if you have it done you could spend a couple grand. The Opti is behind the crank pulley and beneath the waterpump. If the Opti goes bad you end up changing the waterpump as well just for insurance and of course no better time for a tune up and changing heater hoses as well. I had 15 hours changing mine out including the tune up etc. Do not get it wet.
All the LT1 cars had an Opti including the Camaro's Trans AM's and Impala's, Roadmaster's 9C1 Caprice's etc.

 

Well all the bad aside, and that article was good nice pictures, but there is some good to the opti. It's intent is to the give the engine management that ability to control the engine timing down to 1/360th of a degree. The optical disc provides for phases. Being directly driven from the engine it is or was an excellent design for the time period. Problem is it got a bad rap because of where it was mounted, directly below the water pump. And what is deadly to the optical disc's, you guessed it coolant. It just won't evaporate like water and leaves a film, corrosive too, on the discs.

In most cases the opti spark can sustain some water, it's survival is improved if the opti case is well sealed and the plug wire boots are tight and have a good dose of silicone grease in them.

In some cases wetted opti's have survived by allowing them to dry out. And in some cases even getting sprayed with coolant - survive that (I know mine has from a hose leak.). The earlier generation opti's have weep holes but the later generation a vacuum source was applied to the drain to help eliminate moisture. Just like any distributor setup, mositure will corrode the metal parts and over time a soaked opti will eventually fail if that was the case.

No way am I saying it is ok to spray down the engine. But if you ever look at the passenger side of the opti spark after driving in heavy rain, you'll know two things, 1) it can sustain getting wet and 2) why it is so important to ensure the boots have ample grease.

But as the other's said if you do have to replace one, it is wise to replace the water pump at the same time as you have to remove it. Murphy's law says if you don't the next week after the water pump will fail and take out the new opti.

A couple other component not mentioned too often during opti jobs is replace the seal for the water pump drive shaft. It has tight tolerance and will cause a nasty oil leak if it has any wear. (ask me how I know this$$##$@@#$!)

Sometimes the more knowledge you gain daym helps when your getting it repaired especially if someone else is doing it. They won't tell you about the little things that should be taken care of when a procedure is done. The quote the time and parts and do just that. I learned the hard way too!

 

Hi all, I'm new here and happened to find this forum AFTER I pressure washed my new inherited 94 engine. It was gunked up fairly well, even though it is in great shape, so I liberally sprayed Gunk (organic) cleaner all over the engine (especially in the front) and then proceeded to use a powerwasher to hose it all off. Well, it looked great and started right up but later became undriveable and conked out.

I then found out about the Optispark (from here) and was showing the car to my Dad telling him about the theory that the Opti got fried. I started the car (after a week sitting) and lo and behold it started and ran well (no more backfiring, sputter, die).

Needless to say, I feel very lucky but now I am very nervous about this part. I intend to replace it with an MSD distributor and was thinking about replacing the water pump with an electric one too. Does that make sense? From the looks of the electric units, they don't appear to go back in place of the mechanical unit. Do I retain the gutted mechanical housing or something like that?

 

MSD does make a replacement for the Opti, (you can't use a "standard" distributor on these engines) as does an outfit called Dynaspark. The MSD unit is fairly new so there isn't much info on how it holds up over time, but I would suspect, given their reputation, that it would hold up well. The Dynaspark unit has been around for a few years and many members here, including your truly, have replaced their OEM with a Dynaspark and are very pleased with the results.

www.dynaspark.net

 

Here are some pics I took at the National Corvette Museum


You can easily see where it resides and why a water pump leak can cause problems.

 

LOL, that's where I started! I was thinking of just ditching the rotor setup altogether with the Gen III and a Delteq coil conversion. I heard mixed feedback on the latter however. The MSD looked like an adjustable version of the Dynaspark and seemed like a bigger mfg. - that's pretty much the only reason I was thinking MSD.

This Opti job sounds like an unholy beast so I want to do everything at one time (waterpump, hoses, gaskets, etc.). It is currently running well, but given that I inadvertantly 'rinsed out' the Optispark with engine high pressure water (and god nows what else I blew in there), I thought it would be safe to replace it and put in an electric water pump for safe measure.

 

I sure wish it was that easy to get to... That's probably what the engineer was looking at when he designed this god awful mess.

 

I still think Ron's pictures should be made a "stickey". Thanks again for taking the time to share them.
-Chris

 

An Opti swap isn't as horrble as it may sound, but it's no walk in the park either. If you need tech tips about how to do it, lemme know and I'll post a set of tips I wrote up after I did mine a coupla years ago.

I recommend the DynaSpark as a replacement for your first-generation OEM Opti. I installed one in my '94, and it's been great so far (over 2 years, and 20k miles).

While you're in there that far, definitely also swap the water pump, all coolant hoses, serpentine belt, and plug wires, unless these items are already fresh. You'll never have better access to all of them than while you're in there this deep. Also swap the shaft seals on the water pump drive, Opti drive, and crankshaft if they're showing any signs of leakage (consider swapping the WP and Opti shaft seals regardless -- swapping the the crank seal will require removal of the damper hub).

Be well,

SJW

 

Thanks much - really appreciate it. I got to speak with another Vette shop owner and he said to wait for the Opti to choke up again to see if it really was damaged. He's thinking that the moisture may have been limited. He also said that the MSD and Dynasparks he's put in for people mostly seem to fail mechanically and he doesn't recommend or warrant them. He recommends sticking with the GM part and adding a vacuum and drain fitting. I'm not sure that I agree with sticking with the old GM style part however. It seems pretty prone to trouble.

Like you he also suggested plug wires, serpentine, waterpump, seals, etc.. I had already planned on doing all that given the apparent trouble involved in getting that Opti out. He also didn't think the electric water pump was such a great idea. In his opinion, I was just trading one issue for another.

I really miss the days when I could just buy an Accel cap and rotor and call it a day! I still can't believe this design...