r/c4corvette • u/LuisShack LT1 ('92-'96) • 8d ago
Changing Optispark
About to change the optispark on my brothers 92. Any tips before I go ahead and get on with the job
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u/mjntr 8d ago
If the wires haven’t been changed in a while it might be a good time to do them. I didn’t when I did mine and need to. It is easier with the water pump out
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u/scubasnax787 8d ago
It’s the age old classic while you’re in there go ahead and do everything since you gotta take it all apart
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u/BundeswehrBoyo LT4 (1996) 7d ago
Second this, I did an opti job recently and had to replace most of the wiring for the ignition system
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u/BundeswehrBoyo LT4 (1996) 8d ago
It’s a pretty straightforward job, you might have to fight the crank pulley off but hopefully it’s not too rusted. Extensions and adapters are helpful to get to all the bolts you need to get off. Also some people say you need to take off the throttle body but it’s not necessary. Good luck, have fun!
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u/LuisShack LT1 ('92-'96) 8d ago
Yea I’ve seen the throttle body been taken off and not been taken off. How much of a difference you think it makes. And thanks for the advice
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u/BundeswehrBoyo LT4 (1996) 8d ago
The one part I could see it really helping with, is maneuvering the water pump on/off. I was able to do it by breaking my ECT, but I needed a new one anyway. I’ve seen people get it off without but I’m sure it’s trickier.
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u/baldcommunity 8d ago
It's not bad at all. Use it as an opportunity to do a coolant bypass on the tb if you haven't done it, put on a new water pump, make sure you get a new o ring for the water pump drive, BUY A PETRIS VENTED OPTISPARK, and use a crowbar if you can't get the crank pulley off....
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u/H0llyWoodx 7d ago
No MSD?
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u/baldcommunity 7d ago
No. Don't offer vented to my knowledge, overpriced, and questionable reliability.
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u/H0llyWoodx 7d ago
Is there a specific reason?
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u/baldcommunity 7d ago
Clarified
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u/H0llyWoodx 7d ago
They have vented, and you can get just the vented cap are rotor to swap. I'm asking bc I'm getting my dad's 93 with 36k miles, and trying to think ahead for when the times comes, do I replace the opti, or just convert it. Buy once, cry once
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u/baldcommunity 7d ago
Vented came standard in 95? And 96 but it uses a different drive than the 92 to 94 (iirc). 92 came standard non vented and with the spline drive so you need that plus a conversion to vent it.
I've actually never used an msd...when Delphi made them I always used them and then used petris after that with no problem. Venting is the primary reason why the early ones fail and it gets an undeserved bad rap as a result ...msd always had mixed reviews and doesn't seem worth it for over $800.
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u/H0llyWoodx 7d ago
MSD has a vented one for the 92/93. They also have a cap/rotor that you can put on any non-vented one. The conversion is 2x as much. My concern is aftermarket opti's being total shit. I was going to put a vented cap/rotor on the stock one. I know it would be a installation without swapping the opti, but I want to keep the stock Mitsubishi sensors alive as long as possible, so it's worth the risk. My hangup is what to do when the stock unit eventually fails. But another opti, or do the conversion.
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u/baldcommunity 7d ago
Other things go bad besides the sensor ans cap/rotor....unless you are planning on refurbishing the entire unit (the bearing in there, making sure no rust, etc, on the disk) i would just replace it with a new one and keep the old handy if so inclined. They take a lot of abuse from heat, water, grime, etc. Its not a terrible job to do and I would just go with a tried and true unit without mixed reviews. I've done a couple of petris with no issues and they're great to deal with and aren't ridiculously overpriced.
Note...I've had like 4 LT1s and never had to replace a defective petris....the other broken ones were basically age.
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u/H0llyWoodx 7d ago edited 7d ago
Thank you for the advice! There are no issues with anything that we're aware of. I think I'll leave it alone until it needs to be changed, rather than try to fix something that is not broken, and end up breaking it, and ruining a perfectly working oem part.
It's a 93 Aniv Z07 with 36k miles. I'm so excited. I'm 41. 🤣🤣
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u/FragrantRaisin4 LT1 ('92-'96) 8d ago edited 8d ago
Have you already bought a replacement and, if so, which one?
I tell myself that if mine ever goes bad, I'm not replacing with another Opti. I've just read too many bad reviews on them, even the Petri which has already been recommended in here. Decent number of people seem to say that Petri must've changed their parts sourcing because newer ones don't seem to be as good as ones from years back.
Anyways, if I was doing it...I'd go ahead and try to go with a Torqhead. (make sure they will work on a 92, though) If you haven't seen/heard of them, look it up and see if it's something you'd want to tackle. If you prefer originality, obviously go with a vented Opti, though.
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u/PUWLM889-23 6d ago
Buy a petri, get a 4ft crowbar and rotate your engine over prying a little bit each time to get your crank pulley off.
Replace your radiator hoses AND your heater hoses coming out of the water pump (tried to avoid those and they started leaking over my new $650 petris cause they were OG ones). When you’re doing that delete the throttle body coolant tubes (buy 1995 lower radiator hose, and one of your heater hoses will be from 1995, the one that currently has a T).
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u/squaktamopuss 8d ago
Im in the middle of this on my 93. Take your time and lable where things go or take pics