This isn't a "whos better" thread.

Today I started the replacement of the Opti on the 94. It has 97k on it. I was very surprised to see after I pulled the water pump a MSD Opti. I had thought the one on it was orginal. Appartently it has been replaced at one time.

Anyways I'm taking advantage and thought I'd post a couple of pics of the two side by side.

The MSD does have a couple of vents top and bottom in the plastic housing... but the Petris unit has added 2 more in the metal housing along with the others.

 

Cool/interesting post and pics. Thanks for posting!

 

Keep an eyes for those T vent tubes. I tried that mod on my 92, got the idea from a Corvette Fever article and they were rubbing against the hub and after all that work and money I had to remove them.

What's wrong with the MSD Opti?

 

I will watch for that thanks!..
Well the car as shown all the signs of the Opti going bad. Stumbles/misses on acceleration and gets worse the hotter it gets.

I had thought it was the orginal one in there. I did a spark plug change and still the same thing. So I decided that since I was gonna change out the plug wires, ignition coil....what the heck... lets change the Opti too! Just picked up a new water pump, thermostat,gaskets as well. I'm hoping to do all this only one time.

 

should I replace the ignition module since I've got the coil out?

 

are you sure that is a msd opti, or could it be a stock opti with a msd cap.

edit to add. the pdf for the msd installation. As you can see it has a timing adjustment screw. Does yours have that screw? I dont think it has the drain holes in the bottom that yours does, and that petris converts with the vacuum tees. You can see in the pdf file the 92-94 msd comes with a vacuum harness like the newer optis use, ie 95-97 style.

http://static.summitracing.com/globa...1_frm29722.pdf

 

Just had my MSD opti replaced which lasted 6,000 miles. The water pump did not fail. Lost the low frequency pulse and spark intermittently. Had the opti replaced at a Chevy Dealer who diagnosed the problem.

 

Lots wrong w/ the msd opti.

It seems > 50% of people who've installed one have had to tear it back down within 5k and get it warrantied due to typical bad optispark symptoms

 

Hmmm interesting, I have two of them, I wash the engine and they have been great.

I think maybe people who mess with the timing plastic screw claim to have problems.

 

My MSD needed to be replaced after 4K miles due to an internal failure that contaminated the optical sensor. MSD fixed it under warranty. No timing screw adjustment caused that.

 

You guys that have installed the Petris unit on a 94 car. Which side of the MAF did you guys put the "air in" connection. pre or post?

 

I dont have a maf, but I was told to do it as close to the throttle body as possible. The air you pull out of the fresh air hose is still going into your engine through the vacuum port, so I would think you would want the air on the metered side. BTW the link I referenced to msd above shows where to hook up the vacuum hoses. If you dont have vacuum hoses on the existing opti, then I was correct. It is not a msd opti. Rather a stock opti with a replacement msd cap.

 

Post.

 

Finished this swap yesterday. I ended up with the following new parts.

Plug wires
Brand New Water Pump
New Thermostat
New Ignition Coil
New Ignition Module
Petris OptiSpark

Car fired up ran exceptional smooth.... but the SES light was on.
Pulled the Codes H42

After a bit a troubleshooting found that the New Ignition Module was causing it. Put the old back in...No SES light and the car is running perfect.
My wife took it out for the test drive and came back with a huge smile...
says to me shes ready to go to the track!...

 

Nice..but whats with the crappy ICM's...soon its going to be impossible to even get simple parts for these...

 

now, did MSD reimburse you for your time in swapping out their unit?

Dont get me wrong. it seems the people who get one thats makes it past 10000 miles have a solid-performing unit.

Its just not worth the risk of their $h1tty quality control.

I go with the OEM part.

Thats either:

AC Delco new-old-stock w/ a custom vent I add (or a Petris unit) for 92-94

Or Delphi new-old-stock for a 95-96.

Dont trust remanufactured units. I got burned on an AC Delco one a month ago.

 

I replaced my opti last year in July with A Delco unit. I also reolaced the water pump with a new AC/DELCO water pump.

The Opti and water pump were factory installed. I had only 75,000 miles but apparently water caused a failure of the opti. I decided to stay true to AC/DELCO with OEM parts. BIG MISTAKE!!!!

One year later The water pump cracked in the center and wet down the opti. I have all the same failures that I had with the original 18 to 19 old factory units. (Delivered in Dec.'02) Mid America doesn't even want to replace the water pump much less the opti that was damaged by their water pump. A lot of labor and $500.00 for about 9 months of relieable transportation just doesn't seem worth the effort. If Mid America doesn't replace both the water pump and Opti I will never purchase any item from them again.

I need some suggestions. I have heard a lot of praise about the Petris modified Opti. The local custom build Hot Rod shop always goes with MSD but i've heard of problems with those units witin a year of installation also. How do I get in touch with him. Should I have my original water pump rebuilt or is there a quaility water pump available that may last more than a year.

I want to do it with parts that will last this time not MId America junk. I Love working on my cars but I like driving the Vette.

One Thread read that he washed his engine and never had Opti problems. Do you mean you wash it with indiscrimunate amounts of water being sprayed around the Opti and there is no failure? What Opti are you using?

HELP PLEASE!!!. I don't want to spend the end of the summer replacing an Opti the rest of my life!!!!!

EnjoyYour Freedom-Pray for Our Troops,
MudBottomsDogMan

 

Look for pics of my Petris opti experience in the feedback section

 

One more time, that is not a msd opti. That is a stock opti with a msd cap. Look at the msd link I linked above. You can see the wiring connector is different and you can see the timing adjustment screw that is not on the stock units.