Lt1, what were they thinking
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Joined: Nov 2013
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From: Hidden Valley Lake California
Lt1, what were they thinking
I just picked up a 1992 Lt1, I love it, it is the time of making everything plastic, so a little challenging, but the plus is they made so many, the parts are readily available, now my question, what the hell were they thinking when they put the distributer under the water pump???? and if they were going to do that why didn't they put guards for the rain??? and why didn't they put a drain line for the weep hole on the water pump??? these things can all be remedied and at 72,000 miles the previous owner has replaced the Opti spark and the water pump, and everything that was done to it is in a folder, so I was able to follow his pain!!!!
Melting Slicks
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From: folsom california
I just picked up a 1992 Lt1, I love it, it is the time of making everything plastic, so a little challenging, but the plus is they made so many, the parts are readily available, now my question, what the hell were they thinking when they put the distributer under the water pump???? and if they were going to do that why didn't they put guards for the rain??? and why didn't they put a drain line for the weep hole on the water pump??? these things can all be remedied and at 72,000 miles the previous owner has replaced the Opti spark and the water pump, and everything that was done to it is in a folder, so I was able to follow his pain!!!!
Le Mans Master
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From: Everett WA
C4 of Year Finalist (appearance mods) 2019
They were way too busy considering how to build the car around the heater core to think about those other minor items like where to hide the opti-spark.
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Le Mans Master
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There are, perhaps, eleventy billion threads on this topic. Suffice to say that while it isn't completely free of problems, the Opti is blamed for about 10x as many problems as it actually causes. In real life, external water infiltration (from road or water pump) is very rarely the cause of any problem, since the distributor is sealed. The biggest hassle with the Opti compared to an old-school distributore is that it is harder to service than an old-school distributor. The big advantage is much more precise timing and crank position info. There is little question that a DIS is better, but I'm sure it was also more expensive.
Last edited by MatthewMiller; Jun 6, 2018 at 12:07 PM.
Le Mans Master
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From: near the thumb in the mitten
The Opti isn't a big deal now. When it came out, it was very unpopular with techs. Why did they put a distributor under the car in the splash zone. Only came as a $750 assembly. In 92 the first year recalled them. Limited diagnostics didn't help. The 94 Opti ll they became more reliable. The LT1 went from oh so cool to the redheaded step child in a blink. IMO it would have been better if it had. DIS. DIS did go through alot of reliability issues from 85-89 as it was slapped on all but the V8 engines.
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From: Hidden Valley Lake California
I was talking to a co worker about it, he said he has a 37 flati just like what I was describing, and there it is, I found a kit that complexly eliminates the optispark, pricy.
Last edited by gemsvette; Jun 7, 2018 at 06:04 PM.
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My method for fixing the opti was to get an LS...and the Corvette that it came in...
Actually, I put a Petris in my 94, its a pretty fantastic design with vents, it pulls air from after the MAF and runs it back into the brake booster vacuum port. I had an MSD in there which was much thicker and required different longer mount bolts and it had vents on it, but whoever installed it didn't connect those vent ports to anything, one didn't even have a line connected to it and it let oil in, the other just wrapped around the drivers side valve cover and connected to nothing. Here is my point, a properly installed Opti is a good reliable product, but these cars have a ton of other systems that produce the same symptoms when they fail and everyone blames the Opti and then replaces it incorrectly as a troubleshooting step. As far as why GM did it, they wanted a clean looking intake system...the end.
Actually, I put a Petris in my 94, its a pretty fantastic design with vents, it pulls air from after the MAF and runs it back into the brake booster vacuum port. I had an MSD in there which was much thicker and required different longer mount bolts and it had vents on it, but whoever installed it didn't connect those vent ports to anything, one didn't even have a line connected to it and it let oil in, the other just wrapped around the drivers side valve cover and connected to nothing. Here is my point, a properly installed Opti is a good reliable product, but these cars have a ton of other systems that produce the same symptoms when they fail and everyone blames the Opti and then replaces it incorrectly as a troubleshooting step. As far as why GM did it, they wanted a clean looking intake system...the end.
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Joined: Nov 2013
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From: Hidden Valley Lake California
My method for fixing the opti was to get an LS...and the Corvette that it came in...
Actually, I put a Petris in my 94, its a pretty fantastic design with vents, it pulls air from after the MAF and runs it back into the brake booster vacuum port. I had an MSD in there which was much thicker and required different longer mount bolts and it had vents on it, but whoever installed it didn't connect those vent ports to anything, one didn't even have a line connected to it and it let oil in, the other just wrapped around the drivers side valve cover and connected to nothing. Here is my point, a properly installed Opti is a good reliable product, but these cars have a ton of other systems that produce the same symptoms when they fail and everyone blames the Opti and then replaces it incorrectly as a troubleshooting step. As far as why GM did it, they wanted a clean looking intake system...the end.
Actually, I put a Petris in my 94, its a pretty fantastic design with vents, it pulls air from after the MAF and runs it back into the brake booster vacuum port. I had an MSD in there which was much thicker and required different longer mount bolts and it had vents on it, but whoever installed it didn't connect those vent ports to anything, one didn't even have a line connected to it and it let oil in, the other just wrapped around the drivers side valve cover and connected to nothing. Here is my point, a properly installed Opti is a good reliable product, but these cars have a ton of other systems that produce the same symptoms when they fail and everyone blames the Opti and then replaces it incorrectly as a troubleshooting step. As far as why GM did it, they wanted a clean looking intake system...the end.
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I think the problem with the Opti is not so much the unit itself, but all the labor involved in replacing one. I had a 95 Impala SS with the LT1, I changed the Opti in under 1hr. I know packaging in a car like the C4 is a compromise, but I think GM could have come up with a better solution.
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From: Hidden Valley Lake California
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i'm thinking the LT-1 engine was not designed around the corvette, but as a stand alone engine design. no way could the corvette designers and engineers have anticipated all the issues when they stuffed it into the C4 chassis.
Last edited by Joe C; Jun 8, 2018 at 09:24 AM.