I need to change my optispark on my '94 LT1. Should I just replace it with stock, or is there a better aftermarket unit out there?

 

There are no aftermarket optis. You can modify yours and add the vent tubes like the later style have however.

I replaced mine with a new stock unit, first one lasted 72k.

 

I agree with james... mine lasted 92K. the later models require replacing the front timing plate. Not fun... as James said there are vent kits that will help the longevity... good luck its pretty straight forward.

mo

 

Mine went out Saturday at 69K miles. :mad :mad :mad :mad :mad

I got my new one in today. I ordered it from Jeff Kopp for $337.

I found some cheaper from local parts stores and from Auto Zone, but none of them came with the cap and rotor. Once you ordered the cap and rotor, it was higher than the new GM unit that comes complete.

 

Agreed, Jeff Kopp (18carfan here on the Forum) is the best source for new, GM parts. Things to consider changing while doing the Opti are:

1) water pump -- with that many miles, it is only a matter of time before the water pump fails and leaks coolant all over the Opti, thus destroying the Opti.

2) spark plugs wires -- since you need to remove them from the Opti anyway, might as well change them out with a new set. Many members use and recommend Taylor 8mm wires (myself included).

3) spark plugs -- if you do the wires, might as well do the plugs, too. The platinum spark plugs that came on the car last about 75k miles. May I suggest NGK TR55 plugs. These are not platinum-tipped, but are a better quality plug and the platinum tips often fall off and wind up in the motor!

I suggest ordering the Opti and the water pump from Jeff Kopp, and the plug wires and plugs from Chris at http://www.speeddemonmotorsports.com . This is a good weekend project. Also, I recommend adding a bottle of Red Line Water Wetter to the coolant -- it reduces coolant temps about 5-10 degrees. You can buy it at Pep Boys.

P.S.- welcome to the Forum!! :seeya

 

No matter which way you go, be sure to use some hi-temp RTV sealer and go over all the mating surfaces. The GM seals get cooked, brittle and shrink ( I think that's the real reason these things go bad ). Especially around the PCM connector. It's a really bad design with poor materials (the late OPTIs are designed much better).

To take the OPTI apart you'll need a very small torx (T5 I believe) and a very small reverse torx (don't remember the real name, but it is labeled an E10, I think). I bought the 2 tool sets at Kragen's for about $10 each.

It's not really that tough a job, but if you haven't worked the engine before, you spend twice as much time trying to figure out how to get wrenches on bolts. It looks impossible sometimes, but there is always a way.

If you are really adventuresome, then you could install a late model (95-96) Opti, but that requires a new timing chain cover. They are about $100 cheaper and much better design. Plus the cap has a vacuum vent system to circulate some air through it to keep moisture under control.

I think there's a TECH TIP on this replacement.

Here's some more good info on the Opti -
www.charm.net/~mchaney/optisprk/optisprk.htm

:cheers:


[Modified by John Row, 10:33 AM 7/11/2002]

 

I definately agree with 94vette, if your going to change the optispark I would change waterpump, sparkplug wires, and sparkplugs all at the same time. No sense taking a risk with an old waterpump.
I had to do all this at 48,000 miles! :mad

 

Wouldn't you suggest replacing the timing chain also while in that area? How many miles do they usually go to? I've got 124,000 miles on my opti, wires, and timing chain. Think mine is in need of some care?

 

I've heard of some c4's still running at 180,00 plus still on the same timing chain ? ? ? ? ? It all depends on how much you enjoy wrenching ? ? ? ?

 

Yeah, timing chains aren't part of the usual Opti/water pump/plugs/wires replacement. I think they last quite a bit longer than the other parts.

 

Thanks for all of the insite, I have already changed the plugs and wires to try and battle a skip when the motor is hot. I did this about a 400 miles ago. I used the stock AC Delco plugs (or what Advance said was stock) accually the opti is to battle a two part problem

a: running hot 212 down the interstate
b: the hot skip

Unfortunatly I am geograghically separated from my car for another couple of months. :flag So I won't be able to do anything but order parts immediatly.

What is the best way to get a hold of Jeff Kopp? Does he have a Web site I can look at??

Thanks again!!!!!!!!

 

(800)728-8267

 

Another good source for the non-vented opti is Sam Smith ($270)

Sam Smith [SamSmith@fairwaychevy.com]

:yesnod:

 

I have been undestanding that the '94 thru '96 had the improved vented optispark. In the catalouges I have looked at they group the 94-96 together. Does anyone know for sure if this is the case, because they are about half the price of the earlier models.

:confused:

 

The B-bodies started using the new style in '94 but the F-bodies and Vettes didn't switch until '95. Always wondered why but that's the story and why some show '94-'96 useage like that.

 

I'm sorry, but I don't know what "B" bodys are, the "F" is camaro right ? ? ? Call me stupid, go ahead....... :cuss :cuss :cuss :cuss

 

Impala, Caprice


[Modified by STL94LT1, 9:52 PM 7/12/2002]

 

For years I have used Bosch Platinum in at least a dozen different vehichles, some of which accumulated 100,000+ hard miles on the same set of plugs...NEVER had one fail on me! "platinum tips often fall off"...don't think so, at least not with Bosch. :)

 

Thank you so much, I'm old school and all these CODE names DRIVE ME NUTS