Hello all,

I've been a lurker on this site for years and have found tons of useful information-I'm building a 95 trans am M6. I have read about every thread related to opti, delteq, ltcc, and 24x conversions but I need some advice.

This motor is pretty much still new - about 800 miles on it. It is a 383 with a MSD 6AL and a crane cams igintion coil. I have been having optispark nightmares. I got the car with the motor in it and only a few hundred miles on the motor. The guy I bought the car from said the opti went out so he replaced it with a delco. I bought the car and within 50 miles the opti went out. I stripped it down, could hear the rotor rattling around in there. So I bought another AC Delco from summit, 50 miles later, it goes out again. Now I bought a delphi from amazon and just put it in. So far so good (25 miles) but it has a slight stumble every now and then at random rpm and power levels which I didn't notice before.

I'm so fed up with pulling the opti out every week and I really want to be able to trust my engine if I want to go on a road trip or the like. So here are my options:

1: Buy a used Delteq system: I don't like this because there is no support already, what if I need a brain in 5 years? Plus it still doesn't completely the optispark, although I imagine I could trust the opti part as long as it has the Mitsubishi sensor.

2: LTCC: Same issue with not eliminating the optispark, and seems pricey compared to an optispark. Plus I am worried about those who have had problems with high rpm breakup etc.

3: EFI 24x conversion: Nice, but I really don't like the idea of putting $2k into an lt1 ignition system. At this point I feel like an ls1 swap makes more sense but I already have my motor built and I am happy with power levels, I just want reliability.

4: Keep the opti: I like this idea, seems like it would be good enough for my usage, but i want something I can trust and that is fading very quickly with each one I replace. I have found thread after thread here where people say if you can't get an lt1 to run with the opti you are doing something wrong. My question is, what would be wrong that would causing this? It seems like a pretty straightforward job, I made sure the opti fit flush before bolting it in and I was meticulous about making sure everything was right. Does this just mean I have to keep replacing them until I get a good one? Or has opti quality just gone to junk recently?

Thanks in advance for the help!

 

Here's a picture of the car:

 

Keep the opti and pitch the aftermarket ignition crap.

 

X2 with 96CapriceMGR.

Stop replacing the Opti for the Rotor. Replace just the Cap and Rotor. MSD sells one that has stronger (metal) rivets; the only thing I'd do after market is the stronger Rotor and the cap that comes with it.

The stock ignition system of the LT1 is very capable. It's the most reliable version you can get. The stronger the coil the WORSE it is for the Optispark optical sensor. If you're running high compression then tighten the gap on the spark plug, don't up the voltage.

I get the frustration. It's one thing if you didn't have to pull half the accessories off to do it, but it's kind of intrusive to replace. But, if you are cooking through Opti's that fast you need to find what's making them go bad and fix that. The problem isn't the Opti, it's something else.

 

^^ I agree with him. Get rid of the msd box. Make sure the rotor screws are loctited in place before you install the opti and go from there. The only reason I'm going 24x is because the motor is already out of the car and I have sourced the majority of the parts for cheap. The most expensive part for me will be tuning.

 

+3 for stock ignition. I went 24x simply to modernize the car, not because I was having ignition trouble. Hell, I had 3 bad coils right off the bat with 24x. So at this point the opti was more reliable for me than 24x has been If you want, I have the ICM, coil, otpti wire harness, and vacuum harness I could sell so you'd have spares for troubleshooting purposes. Send me a PM if you're interested, I'm more looking to get rid of them than make money off them.

 

ditch the 6al box. its putting too much spark through the opti. keep it stock. any aftermarket ignition box will decrease the life of the opti. its not made to handle the extra electricity the box put through it and will fail.

 

Agree with the above, stock ignition and pull apart a new opti and loctite everything.

 

Thanks for the replies. I'm thinking that this weekend I will take apart the last AC Delco that went out, assuming the optical part looks good and it is a Mitsubishi sensor maybe I will just buy an MSD cap and rotor, make sure the rotor screws are loctite-ed, and then ditch the 6AL and put the delco opti/msd cap back on.

I noticed one weird difference between the delco units and the delphi-the two delco units had only one vent port but the delphi has two. Does anyone know anything about the difference? I just have a vaccuum line run to each one as it is now.

 

when you opened the failed opti's...was there any green slime or evidence of condensation inside the Opti?

there should be 2 vent ports on the opti. One going to the intake elbow and the bottom one to the DS intake manifold. There should be blue/white check valves on the line leading to the intake manifold.

courtesy of shbox.com

http://shbox.com/ci/opti_vent.jpg

If your venting is not configured correctly the opti wont vent and crud will "quickly" build up inside (read 500 mi +/-)

and use loc-tite on rotor screws

 

If you are running manifold vacuum to both you are pulling vacuum in the option making the cap flex in and making it very easy to arc all over the place.
The line ****** said is in the elbow is just fresh filtered MAF read air. The manifold vacuum is restricted by the check valve so the fresh air flow is greater and there is not a real vacuum pulled on the vacuum, just enough to get fresh air.

 

OK, this is how I have it configured at the moment. The last delco only had one port and I ran that to the DS intake manifold. Not sure if I had a check valve or not, I'll have to make sure that's there.

I stupidly returned the first delco without taking it apart but I'm going to take apart the second one this weekend to see if the rotor broke or if the screws came out etc. (waiting for the E4 deep socket to arrive).

 

you need the vacuum harness for the Opti to be installed correctly with the check valves is the right orientation. Just having a vac hose run direct to Opti with one nipple....I would think would draw to much and cause cap to flex/arc as Caprice notes. Aside from arcing it can also pull the cap onto the rotor...which results in plastic shavings all inside the Opti..not good

your previous Optis would have had a nipple on the base and another on the cap for the 2 Opti vent hoses to attach

if you only had one hose hocked up, Opti was not venting correctly

earlier years LT1 Non Vented Opti should not fit your 95 as the earlier one was spline driven vs the dowel pin type for your model year

 

So I just got ahold of the previous owner. Turns out he went through two delphi optisparks before he sold it to me with the same issue....eating the rotor after just a few miles. This seems very strange to me...thats 4 delphi/delco optis in about 100 miles total, all with eaten rotors. Could there be an issue with cam walk or something? Could the msd 6al or a wiring issue be causing these? It seems more like something mechanical to me. I'm kind of at a loss, any help appreciated.

 

Can you pull the optispark, take pictures of the cam and timing cover, along with the optispark where it connects to the cam, and the inside of the optispark and post them here?

 

Seems quite possible it is a cam-to-opti-connection issue. Something isn't lining up right and causing the rotor to wobble. Just a guess. Do you know if the cam snout had to be drilled for the opti shaft?

 

I agree, I'm wondering if the Cam wasn't provisioned correctly for the LT1.

 

If the dowl pin is too long it can eat the opti by putting outward pressure on it. Vacuum line still seems like a possible issue too.

 

I agree with the vacuum issue, just for ***** and giggles, on the next opti, don't connect any vacuum lines to the opti, just cap them off, but while your doing this, don't drive it if its wet or humid out. See if it lasts more than 100 miles. I'd also pull the 6al just to eliminate one more thing. And when you put the opti on, make sure as you are holding it on before you put in the screws to hold it to the block that all 3 screw connection points are touching the block, that the screws are not "pulling" or distorting the opti as you tighten them down to the block.

 

^This.

I would definitely start with both of these. But take apart one of the failed Optis and look around for anything that may have caused it.