opti spark

[Frank K.]

What is a good replacement for my 93, and were can I buy?

[Leif A.]

Re: opti spark

What is a good replacement for my 93, and were can I buy?

A '67...they're all over the Internet...

[Bill H.]

Re: opti spark

Well, don't buy one on ebay, guys who do get to replace them again within a year. Same with the Accel.
You can go with a GM unit but you still won't have the venting system that started in 1994 (IIRC).
The only opti I will use is the MSD. Billet construction, o-ring cap gasket and the venting system. Summit Racing has them in stock, $466.00
I had the chance to pull the MSD apart on my 92 after 10k miles, looked brand new inside. 30k miles on it now, no problems.
If you plan to have the car judged, then GM only of course.


Ah, my 92 sits beside my 67 in the garage

[Joe R.]

Re: opti spark

That's cute Leif! And true!!!!!

Frank,

They are all over E-bay and various prices. As low as 50 bucks for one that is sealed and guaranteed for life. And several hundred bucks for a Delco like your Corvette had from the factory.
I went for one of the cheap guaranteed forever ones and the timing was not the same as the factory Delco. Runs good but not as good as the Delco which gave me a little more advance in the timing.
You can get someone to go into the computer program and set one of the cheaper ones like the Delco.
Good luck,

JR

[Frank K.]

Re: opti spark

I understand the GM is a repeat failure We discussed at a weekly corvette military members show that every C4 ,minus the ZR1 of course has had a failure in the Opti spark. Sooner or later it would be replaced along with the water pump. When I ordered my C4 I started day 1 buying parts. The reason I never purchased a opti was GM was telling us the repair was completed on a late 92 recall and if you did not wash your motor down there would be no problem. Well we all know now there was no attempt to correct this event. Well thanks for the info because the discussions we had at these shows verify the MSD as the one time replacement.

[David L.]

Re: opti spark

The 93-94 GM optispark distributors are very poorly vented.
Refer to the link below:

Dave

https://www.forums.ncrs.org/showthre...746#post705746

[Bill H.]

Re: opti spark

I understand the GM is a repeat failure We discussed at a weekly corvette military members show that every C4 ,minus the ZR1 of course has had a failure in the Opti spark. Sooner or later it would be replaced along with the water pump. When I ordered my C4 I started day 1 buying parts. The reason I never purchased a opti was GM was telling us the repair was completed on a late 92 recall and if you did not wash your motor down there would be no problem. Well we all know now there was no attempt to correct this event. Well thanks for the info because the discussions we had at these shows verify the MSD as the one time replacement.

The recall ( and Joe could verify, or correct me) just changed to an opti with drain holes. The venting started in 94.
When I wash my motor, I don't even bother covering up the MSD. I don't hold the hose on it but, I've got no concerns about getting it wet,

[Joe L.]

Re: opti spark

The recall ( and Joe could verify, or correct me) just changed to an opti with drain holes. The venting started in 94.
When I wash my motor, I don't even bother covering up the MSD. I don't hold the hose on it but, I've got no concerns about getting it wet,

Bill------


They were actually vent holes. The original design did not include any venting, at all. I suppose they could also be called drain holes, but I don't think that was their specific function.

1st design-----early 1992-----no vent provisions

2nd design-----later 1992-94-----3 1/4" holes on bottom of housing for venting.

3rd design-----1995-96------vacuum powered venting

[Wayne W.]

Re: opti spark

They might be poorly vented, but they damn sure are not sealed. They get full of water and oil. The last one I changed was full of oil, leaked down from above. It sat there on the bench and drained out for days after removal. I dont see where the later venting is going to help that problem much. Fact is, young engineers are destined to make the same mistakes of their predecessors. We learned in the 1920s and 30s that you dont place the ignition down low in front of the engine exposed to road grime, water, and engine secretions. Make the same mistakes and expect different results?

[Bill H.]

Re: opti spark

They might be poorly vented, but they damn sure are not sealed. They get full of water and oil.

Yep, the one on my 92 had the bearing so rusted that it destroyed the bearing cage. The balls were laying in the bottom of the opti.
That's why I went with the MSD.

[Frank K.]

Re: opti spark

Thanks! The no 1 corvette shop in ct wants $1,500.00 to place a Chinese one on. The other shop is not interested. I guess I will order the MSD today and start reading for my own install.

[Bill H.]

Re: opti spark

Frank, the procedure is in the FSM. It's not that hard but takes some time.
Couple things:
Mark the rotor position on the block, this will help when installing the new opti ( the spline drive has one larger spline to orient the rotor).
Some guys pull the power steering pump which is a pain, do yourself a favor, buy a power steering pulley puller/installer ($24). Removing the pulley lets you see the left side of the opti (for putting the plug wires on) and makes the whole job much easier.
The wiring connector on the MSD may be incorrect, this is because the opti also fits the Caprice and it comes with the "Caprice connector". This is not a big deal, just 4 wires to connect to the harness under the right side injector cover. The info should be on the MSD website, if not, let me know, I have the correct wire to wire colors.
The vacuum vent line that is clamped to the bottom of the MSD should be installed before you put the opti on the engine (hard to get pliers on the clamp if the unit is on the engine).
If you haven't pulled the waterpump before, note that there are 6 bolts on it, not 4.

[Jim T.]

Re: opti spark

Any one with the last year 1996 opti have a failure due to down pour of rain driving on an interstate? No problems with my LT4 opti yet, it has been about year since driving in the downpour with no known problems with the opti so far.

[Pat M.]

Re: opti spark

Any one with the last year 1996 opti have a failure due to down pour of rain driving on an interstate? No problems with my LT4 opti yet, it has been about year since driving in the downpour with no known problems with the opti so far.

Never had a problem with mine, but it's only been driven in a heavy downpour once, and a light rainfall only a couple of times.