So, I buy a beautiful '94 LT1 triple black coupe. I commence to detailing and cleaning and clean the engine. After that the engine runs poorly so I take it in to be diagnosed. The mechanic says that it is the distributor cap and rotor and we might as well replace the wires while we are at it. (Cleaning the engine got water into the already cracked distributor) He has to pull the water pump to get at it and the total will be over $700. Ouch. He does an oil change on it and I tell him I want to sleep on it before scheduling the big job.

I go to a reputable mechanic that is known to be a bit more reasonable and he can do it for about $100 less. Ok, let's do it. He has it in his shop for 10 minutes and says he can't do it that the bar underneath the car is not removeable and he would have to pull the engine to do the job and he doesn't have that kind of equipment in his shop.
I call the first shop back and make an appointment to get it done next week.

Now what I am wondering is: Is the guy right that the engine may have to be pulled to get at this?

The first mechanic gave me a written quote and was under the car doing an oil change so I am hoping that he will stick by his quote if it turns into a bigger job.

Can anyone offer any insight to all this

 

Do a search for 'opti' and you will find many stories on the distributor, it's challenges, costs, and related equipment/work/approaches that should be changed/done.

BTW, whereas the $700 is closer to being right, and the diagnosis of it being distributer related might be correct (classic after washing engine -- distributor is behind/below water pump), sometimes just letting it dry out also works.

Also, a 'crack' diagnosis sounds more like a subjective 'guess' based on symptoms, rather than upon an actual inspection.

So it's possible the 'mechanic' is not familiar with the Corvette's LT1 engine -- you should ask for references on other LT1 engine cars he has worked on first, otherwise ... (read some of the horror stories herein).

Also, he might be able to just replace the 'cap and rotor' instead of the whole unit, so perhaps that is what the mechanic is thinking and price quoting, but some of the other internal components tend to 'die' too, so it might not be a long-term fix.

lastly, FYI, if/when I have to replace my opti-spark distributor, I plan on doing it myself and using a Dynaspark brand unit instead of stock (since the 94 was 'unvented' whereas the dynaspark is vented, like the 95-96's are). It is more expensive ($600), but I only want to do it once...

Hope this helps, but do a search and read on...

 

The engine does not have to be pulled to repalce the Opti, but it would be much easier obviously with the engine out.

The first mechanic was right in that the water pump has to be removed to get at the Opti. I would suggest that you replace the water pump while you have it off, unless it's like a super low mileage unit.

It was probably not a crack in the cap that caused the issue. The seal between the cap and the body of the distributor is not that great. You will probably have to replace the whole unit, not just cap and rotor.

 

Replaced my Opti 3 times in a 3 month period, don't ask, and I can do the compleate job in a couple of hours and no the motor does not need to be pulled and yes the water pump does. THe opti is prety stright forward remove the damper, Water pump and then the Opti. It is a PITA to work on but not anything a good mechanic should not be able to handle. BTW if I where going to pull an Opti with any miles I would replace the entire unit and with a new GM part not a reman. You have an idea of what the labor is going to cost so you have to consider what it would cost to do it twice. Shop around for the Opti but you can get one from Chris May for a lot cheaper then a local dealer.

 

I have a triple black 96; and the first thing I did was to start cleaning up the engine bay (as well as learning what/where everything was under the hood). Fortunately, I have the vented opti, so it still started after hosing. Now that I have read more about the opti than I ever wanted to know, I don't use the hose under the hood anymore!

Before you pay to repair your opti, I would suggest you do not replace it with the same original unvented opti. For about the same cost (most of it is labor), you can vastly improve your distributor by upgrading from the original. I am not quite sure, but it appears that upgrading to the newer version opti is as much cost as going to an aftermarket unit. Perhaps someone else will chime in with more info about choices and reliability.

As the previous post indicated, he is going with an aftermarket unit. You may be anxious to get back on the road, but it would be wise to bone up on your ignition options as quickly as possible.

 

Upgrading an Opti is not as simple as one might think. It requires a new timing cover, vacuum harness, Opti wiring harness from Opto to main engine harness and the Dowl pin on the cam needs to be looked into. The labor will jump up quite a bit if they have to do this job because to do it correctly the oil pan needs to be droped and for shure the Damper hub and timing cover will need to come off. Now there is a mod for the older style Optis in the tech section that will add the vacum feature with a mod. I do agree that the Dynaspark is also great alternative to the stock GM unit and IMHO well worth the couple of hundred exrta bucks. In your situation where they say you just need a cap and rotor you could also go with the Delteq and do it yourself for around the same price you are looking for and it only takes about 1 hour to install the Delteq system.

 

You can get a new Opti from sources listed here for bout $350. Do not just do the cap and rotor, you don't save any money and the whole thing should be replaced. As stated many times, these things are notoriously susceptable to water intrusion.

That said, I've done the fix twice on my car (once because I mis-diagnosed my problem and once because I foolishly powerwashed my motor). I have a '93 and never bothered with all of the fancy fixes everyone raves about here (Dynaspark, upgrading to the vented version, etc). That doesn't mean that they are worthless, just that I don't think it's necessary. I drive my car a lot harder than most (although not often in the rain) and have had no opti problems other than my own stupidity.

There is a ton of labor, so quite honestly, $700 sounds like a steal to me. Even if you do get the part for $350 that equates to the same in labor, and it's at LEAST a half a day job for someone who:

1. Has done it before
2. Has a very advanced tool set

I assume that includes all the other stuff you'll need...gaskets, sealants, new coolant (you're removing the WP), blah blah blah.

Just be sure he knows what he's getting into so he doesn't come back to you with a "I didn't realize what a PITA it was so it's actually going to cost $1500" and you're fine.

Why not do it yourself? It's a helluva good experience and will teach you many of the ridiculous nuances of the Corvette LT1 nightmare...

 

If you want to upgrade a stock opti to vented see my picks.Some vacuum fittings and a 95 cap is all that is needed along with the hoses.That being said I bought the Dynaspark it is the best choice for a 92-94 car as a replacement and comes with the venting system.I power wash my engine now and have no problems with it is waterproof. It is a couple of hundred dollars more than the stock but by the time you buy the cap,hoses,fittings etc it is abot $100 more and worth every penny.

 

I need to clear up a misunderstanding about Opti.

Is it just the 92-94 (unvented) years that need upgrading or is it all years? Are the million or so posts in this forum about "Opti-Crap" only referring to the 92-94,.... or is it all years?

Is there a valid reason to upgrade a 95-96 (vented) to another aftermarket brand? If so, which one?

My '96 is still stock at 115k. I don't want to do all that labor and simply replace the cap & rotor if there is a more reliable alternative....but my original lasted this long, so how bad can it be?

In other words, is there a "good Opti" and a "bad Opti", or are they all bad?

 

92-94 are the only "Unvented Optis"
The 95-96 vented Opti has less problems because it keep more moisture out better then the non-vented version.

The only "Opti" replacment available other then GM is Dynaspark.

Delteq and LTCC have systems that eliminate the high voltage side of the OPTI (THe cap and rotor are no longer used) but the Optical portion is still used.

IMHO the Opti is the most mis-diognosed part on the LT1 cars. If the car is misssing for any reason many will tell you to replace the Optispark when often it has little to do with the problem. Now, the Opti has earned its reputation and has a much higher failure rate then other ingnition systems such as the HEI. After reading to many post to count and talking with People such as Pete at Delteq I think the replacment Optis are not the same quality as the OEM ones. I went with the Delteq system and still recieved two bad Optis out of the box when I installed my new motor. The first one had a dead miss at 4000 RPMs and the second died with in a week. I used to think the high voltage side (Cap and Rotor) was the source of problems in the Opti but after my problems I now know that the optical section is often to blame as well. The good part about the Dynaspark is the quality seems to be better then the GM units but at twice the price I guess it should be.

 

I'll agree wholeheartedly with this statement. Due to the fact that the Opti IS often a cause of problem it's the first thing everyone tells you to replace. But sometimes it's not.

Twice my symptoms were common Optispark failure modes and twice my opti was fine. The first time (I was a recent Corvette convert at the time and just learning) it was simply plug wires. The second it turned out to be my f^%&*ng security system. The third was actually the opti as mentioned above, but a result of my screw up (the powerwash).

The optispark is a fantastic system, very accurate. You just have to be careful of water and make sure your water pump doesn't leak on it.

 

My Corvette Club is sponsored by the Dealer and my price for GM cap & rotor was $166. I believe this is a better deal than anything from Autozone's or other reman unit. What other parts should I pick up?

Would you advise replacing the optical sensor while doing the cap & rotor?

What about replacing the wire harness?

It's a given that the plugs & wires will be changed out.

Any other words of wisdom before the patient gets up on jack stands?

 

When folks say they "replaced the opti", do they mean the entire unit, or just the cap & rotor.

Does the vented 96 opti need additional sealing between the cap & body to keep out moisture?

Thanks for the help!

 

I had washed my motor on several occasions and noticed every time that it ran like crap for a few hours but always went back to normal. My water pump also leaked onto it, but only degraded the way it ran rarely. When my piston decided it liked the oil pan better than the cylinder and I had to pull it all out anyway I started looking into options. I am in school and work part time so I wasn't going to be doing any $600 dynaspark anythings to go along with the $2000 engine rebuild I already had to come up with money for, so I found a used opti with 13k on it for $80 but when I got it the damn bearing was bad in it. I found a company in Cali that sold just the bearing for 20 bucks. I put the bearing in it and sealed it with good silicone after making my own "venting" system using steel tubing and it's been running great ever since. I guess it's time to hit the pressure washer and see what happens.

 

Replacing the cap and rotor may buy you time or not.Most people replace the whole unit as the bushings wear out too.Washing the engine may cause rough running with out doing a thing to the opti.The design allows a lot of water to drip around the plug wires and they arc over till you get a heat cycle on them.Same with the coil.

If you have any codes that point to the Opti a cap and rotor will do you no good because a bad cap and rotor does not trigger any.The car runs like crap though.Also if you take it off you need to inspect it very well there is no cleaning of the optical sensor.For all the trouble it is to replace it I would (and did) go with the whole unit and RTV the cap and plug very well.

 

Thanks! Never thought to consider the bearings. I agree that for a little extra $$, an entire new unit makes sense. The first one lasted 10 years, so a complete replacement is totally reasonable to me.

All the advice I've read points to eom GM part & avoid Autozone, etc.

 

Wohhhhh, 3 times in 3 months!!?? I gotta' ask, what went wrong with your #1 and #2 install??

 

check out "my pictures"
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this stuff had 130000 + miles on it. replaced with oem stuff, did it myself and saved alittle dough. notice wp bearings...