Replacement for optispark?

[Rick Dorminy]

I found a good shop to replace my front main seal. Now, while I am at it, I want to replace the infamous optispark. Is there a quality aftermarket replacement? One that doesn't require alot of modifications. My engine needs a good cleaning but I am afraid to for fear of ruining the optispark. Since I am going to replace it anyway, i would just as soon replace it with something better.
Any suggestions?

[Jim T.]

Re: Replacement for optispark?

Do not know about a aftermarket replacement for the optispark. Do know that my 96 LT4 has a optispark that has sourced vacuum air circulated through the system to keep the moisture level down. Any 96 Corvete optispark unit is designed for this. It might of been available in 95, not sure. Depending on how many miles are on your Corvette you might also consider a new water pump if the engine is going to be disassembled for optispark replacement along with the front seal.

[Rick Dorminy]

I did find a replacement but.......

it is very expensive. It is an optispark from Ecklers that has the vacuum air like yours. It is about 600.00 though. I can get an OEM for a '92 for around 250.00. I just thought someone may have produced an aftermarket optispark that was better but wasn't outrageously expensive.
I don't know if the LT4 one will work or not. Some have told me to use one from a 94-97. They are vented.
Anyone know if that will work?
I will be replacing the water pump too.

[Joe L.]

Re: I did find a replacement but.......

Rick----

The Ecklers unit is, basically, a 92-94 style Optispark which has been retrofitted with a vacuum vapor extraction system, like that used for 95-96 Optispark units. There are instructions on the net and also as published in one fo the Corvette magazines in the past for doing this yourself. I don't have the web-site or magazine edition at hand.

There is/was also a system on the market which completely eliminates the Optispark disributor and replaces it with a "coil-on-plug" ignition system. It's a MAJOR mod, though, I don't know how well it works or if it's even still available and I wouldn't touch something like this "with a ten foot pole".

You can use a 95-96 Optispark on a 1992-94 LT1. However, to do it you have to also change the engine front cover, cam sprocket, and modify/change the camshaft. I think that it's a lot easier and cheaper to just add the vacuum extraction system to the 92-94 distributor. Or, even, pay the premium to Ecklers to get one from them which already has the mods.

By the way, the "jury is still out" on whether the vacuum extraction system works any better at increasing the durability of the Optispark distributors compared to the earlier ones with 3 holes on the bottom for ventillation. Some time ago I discussed this issue with the fleet manager of the City I used to work for. They had both early and late style distributors on LT1 engines in Caprice police cars. He told me that they really didn't have a lot of distributor problems with them, but the failure rate was about the same for the early or later style units.

Curiously, the early style units (without vacuum vapor extraction) are considereably more expensive in SERVICE from GM or Delco than the later, vacuum-extracted units.

[Wayne W.]

Re: I did find a replacement but.......

Funny, Young engineers. We learned in 1932 with the ford V8 that under the waterpump and low on the front of an engine wasnt the place for an ignition system. Actually it was known long before that, but those engineers were young too. Learn from history least you repeat it.

[Joe L.]

Re: I did find a replacement but.......

Wayne-----

The "driving force" behind this design was a fellow by the name of Anil Kulkarni. I believe that he is from India. He probably wasn't either born or in this country when the Ford lessons were learned.

[Wayne W.]

Re: I did find a replacement but.......

Now, did GM fire him or did they give him a raise for making them so much money?

[Joe L.]

Re: I did find a replacement but.......

Wayne-----

Well, they were so proud of him that they were going to make him the lead person for design and development of the Gen III engine (i.e. LS1). However, as I heard it, he had some very "strongly held" opinions as far as direction that the Gen III program should go in and that was at odds with excecutive management. So, he was given "another assignment" with GM Powertrain.

[Tom H.]

Re: I did find a replacement but.......

MSD has come out with a cap and rotor that is supposed to be more reliable than the original. There is a description of it at their site, and Jeg's and Summit both list it. I'm going to try one when I replace the water pump on my 95.

[Terry M.]

Re: I did find a replacement but.......

Joe,
If your city had early style optical distributors on their police cars they were Camaros. All B & D bodies 1994-1996 with the 5.7 (which = LT1) had the vacuum on the distributor, and used the later unit. F and Y bodies followed the early/late cycle that Corvette owners have grown to love/hate.

[Jim T.]

Re: Replacement for optispark?

Rick as mentioned by Joe Lucia there is a good article on removal and repair of the opti-spark and converting a pre 95 Corvette unit with sourced vacuum. You can view this article on Corvette Fever's web page. Click on tech articles and look at Opti-Spark Options.

[John H.]

Re: I did find a replacement but.......

Wayne, you and I may be the only ones around that still remember the Kong/Jackson distributor for flatheads; their caps sealed a lot better than Henry's did

[Joe L.]

Re: I did find a replacement but.......

tom-----

The thing is, I don't know that the original caps and rotors were unreliable. I've never really heard of any problems, anyway. Usually, the Optispark problems are associated with moisture intrusion into the unit and resultant "clouding" of the lens on the optical sensor. If the MSD caps SEAL better to the housing than the stock ones, then that would be an advantage. It would make the overall unit more reliable but the cap and rotor, themselves, would be no more reliable.

[Joe L.]

Re: I did find a replacement but.......

Terry-----

We didn't have any Camaros; all were Caprices. However, I now see where I "went wrong" on this. We did have a lot of 1993 Caprices. I thought that they used the LT1 with the "early design" distributor. However, I see that the 93 models used the Gen I engine and not the Gen II as did 1994 and later. Thinking about it, the fleet manager must have thought that I was trying to compare distributor reliability between the 93 (i.e. conventional HEI) and the Optispark and that was the basis of his response. I feel a bit "sheepish" now; he probably thought that I was nuts trying to make such a comparison, especially since the HEI are usually virtually trouble-free.

In any event, in the somewhat distant past, I also remember reading an article somewhere regarding the reliability of Optispark distributors. The report was that GM had found, after the last design had been out for awhile, that there really wasn't very much difference in failure rates of the "naturally aspirated" distributors versus the vacuum extracted version.

Actually, there were THREE designs of the OptiSpark. The first design was used on PRODUCTION on about the first 7,000 1992 LT1 Corvettes. This design had NO ventillation. They failed rapidly and were recalled. My car was one of these. The distributor failed the day that the car turned 3,000 miles.

The second design was very similar to the first, except that it had 3 small holes provided in the bottom of the aluminum housing for ventillation. Mine was replaced with one of these and it's performed just fine ever since. This involves only about 40K miles, but, for this sort of thing, just plain age is probably about as significant a factor as mileage and it's been about 13 years now.

The third design was the vacuum-extracted unit. It was used on 94-96 Caprice, Impala (and similar GMs), as well as 95-96 Corvettes and 95-97 Camaros. In addition to being vacuum extracted, this design changed from shaft drive to paddle drive. That's why they cannot be easily retrofitted to earlier cars without many other modifications. Also, the installation of this unit (or, the second design unit modified to add vacuum extraction) on an earlier Gen II engines requires the addition of the vacuum harness and fitting to the intake plenum (drill and tap required).

I realize that you are likely aware of all the above but I offer it for the benefit of others that might not be.

[Joe L.]

Re: Replacement for optispark?

Rick-----

I just wanted to let you know that I did respond to your e-mail regarding the OptiSpark issue. However, the e-mail was "kicked back" as undeliverable. Most likely, this was due to some sort of "spam filter" program that you are using. Although this is not the first time that exactly this sort of thing has happened, I can tell you that it's extemely frustrating to spend the time to compose an answer to someone's e-mailed question and then have it all go for naught. Also, while I always try to respond to e-mails (eventually), I have a "personal policy" that I will not spend the time to recompose one due to these "kickbacks". So, I'm sorry to say that my response is "lost for good".

I realize that spam is a scourge. However, I don't use any sort of spam filter for just this reason. Also, and incidentally, I always scan through my yahoo mailbox "bulk mail" because every now-and-then a legitimate and/or important message gets directed there.