Been following up in more detail the September 26 past $5K worth of repairs p.o. had done to the LT4 less than 1,000 miles ago. He took the car to a highly regarded all-gen Corvette specialist to have the intake manifoild leak addressed which had fouled the Optispark, which i'm guessing was factory since the odo read 51,475 miles when it entered the shop. They charged him $465.67 for a "GM05, Distributor, Corvette, 1995-1996." Actively following Opti threads here, outside "research" as it is, and going to different vendors' sites, i called this shop, gave them the R/O # for the work and asked them what brand Opti they installed. Somewhat to my surprise and fully to my dismay, they said they replaced to Opti with a Duralast, but he also sounded less than 100% certain. Don't know what superlative to add here... "****!" "Hmm..." "Ugh..." I guess time will tell. If Duralast, now there will be this nagging concern when or if the LT4 begins having symptoms or just dies outright at roadside. "Grrrrr..." If, in fact a Duralast was installed, at $465.67, the shop had to have been laughing all the way to the bank, not to mention the unscrupulous action of a shop so highly regarded. I'm not going to go future-tripping with "what-if's" and throw money to correct what might not be nor happen. And, i shudder to think what said shop did with the factory (assumed) Opti which likely had, at the least, a Mitsubishi sensor worth saving...What a waste that Opti is not in my possession. Oh well, live well, wait and see.

 

My experience with my project C4 has not instilled any confidence in mechanics, either specialty or otherwise. A local specialty shop did my cluster rebuild on my early C4 under the PO (which was done properly), but if they did any of the repairs leading up to that then they don't know what they're doing.. This forum and my two hands are the only thing I've come to find reliable these days!

It took three Power Steering pumps from AZ to get one that both fit and worked. This is where we are now unfortunately.

 

Not sure what you expected a professional to use? They use parts they can get, you can get duralast optisparks., so they use them.

I think a lot of this "parts store Optis are junk" stuff comes from people who replace an opti that isn't bad in the first place, and still have intermittent issues they blame on the opti. It is SO EASY to jump to the opti being bad on these cars, I'm man enough to admit that I've done it... Twice. First time when I had just bought the card and the second time was recently, you can find the thread of me saying I had to eat crow about parts stores Optis being OK... Except I was wrong, my parts store Optis is still fine, and my issue was a connection at the coil wiring harness.

FWIW, parts store Optis with a lifetime warranty really aren't a bad deal. The job of replacing the opti isn't too bad, knock it out in a couple hours in the garage kinda deal. That said, if I had an LT4 with a compromised Opti I would bite the bullet and buy a torqhead setup.

 

Your points are well taken and agreed on all. Pretty certain from looks of things my 94 LT1 has orignal Opti. I looked at the Torqhead setup, certainly seems the way to go if ever the Opti shoots craps in the LT4.

 

I've put this up before. Here it is again. These numbers can be viewed with a mirror from the right side of the car. If you have a Delco opti, it will have a GM PN and the date code. Decipher the date code and if it is prior to the assembly date of the engine (on the front pad) it is original to the car.



1992 Spline drive. "2C05-1" = 1992, March 05, 1st shift. The engine assembly date is below.


Flint Engine Plant, October 15, Manual Transmission


The opti is 5 months newer than the engine. It can not be the original. I bought this car from the original owner. I asked him if he had had distributor trouble. He said he had had it about 3 months and it wouldn't start one morning. He called the selling dealer, they seemed to know what it was, they picked it up and returned it to his driveway that afternoon. There is a work order in the file that came with the car. IIRC, there was a TSB on the early optis. They were changed out.

I was surprised that it was not the original opti, but date codes, supporting paper work and the OO's recollection all collaborate. Cheers.

 

Thanks, @IHBD I missed that your thread about date codes, massive amounts of info on this wonderful forum. I'll write down how to interpret the date code and check mine out.

 

A few month before I sold it in 2023, my ZR-1 developed a sporadic single cyl misfire at >4,000 RPM. I thought it was plug wires, and bought a set of OEM from Jerry's Gaskets, but the original wires tested ok. I consulted Marc Haibeck and he felt it was going to be a coil and I should replace all 4. He suggested Duralast over chinee Delphi, so that's what I bought at Vato Zone. They had them on the shelf and there was some promotion on them where I paid for 3 and got the 4th one free. About $165 and the car was fixed. The guy I sold it to in Michigan keeps me apprised on its status. So far, he's done nothing to it except put gas in it and change the oil every year. Duralast coils for LT5, FTW. Go figure...

 

@IHBD, i'm happy to hear that.

 

Steve, Have you ever considered looking for a junkyard opti to rebuild? While I don't know all the cars that used an opti some here do. I know quite a few cars used them back in the day. Dan

 

I would think that the odds of finding a junkyard that has scads of 30 year old cars sitting there are quite low. The reality is, junkyards (read "auto recyclers") are there to sell parts - not just look at them. These operations do not sit on units that don't sell parts. Unless they are "specialty yards" ie: Mustang specialties - Vette specialties etc., they are crushed and sold as scrap metal for melting. There are three large recyclers in my area and you have to really search for units that are older than 15 - 20 years.

 

I suspect you are correct. Dan