C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

94 LT1 Optispark Modification

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Old May 4, 2006 | 04:09 PM
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Default 94 LT1 Optispark Modification

Chris
I'm currently modifying a new Optispark for my 94 LT1 Corvette. I'm following the procedure that is on the Corvette Fever Tech Article web site where Chris Petris of Corvette Clinic modified an optispark. I've run ito a couple of issues. Has anyone tried this modification? Here are the issues.

1. The article mentions a .187 drill bit. Is it a 3/16" bit or does it have to be a .187".

2. The only 3/16" tees I can locate have barbed ends and won't fit in the 3/16" hole. Is there a source for these?

3. I can't locate a 7/32 Y fitting. Is there a source for these?

I'm in the midst of doing the Opti, water pump, new wires, plugs, cleaned radiator and all new hoses job on my LT1. I've posted may times about other issues and had great responses. Thanks to all and thanks for the help.
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Old May 4, 2006 | 04:31 PM
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1. 3/16" is .187

2. cut the barbs off. That's the best bet.

3. Check pepboys.

While you are at it, add a drain to the waterpump weap hole. That will allow the coolant to run off away from the opti in the first place.

also, take the cap off the opti and make sure the rotor is tight and then seal the cap to the body with RTV.
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Old May 4, 2006 | 04:37 PM
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with bogus
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Old May 4, 2006 | 04:56 PM
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I agree with the above statements as I recently did everything you mentioned. Unfortunately my new wp is leaking from the weephole. I'll have to r&r it. Ugh! Dealer ok'd to take it back. Just wsh they'd pay for my labor. I know, wishful thinking.
As far as drilling the holes into the distributor cap, be extremely careful as this plastic is very brittle. So brittle that I used a dremel because even the smallest drill bit started taking chunks off. Freaked me out so I used a dremel with excellent results. Don't forget to use high temp silicone to seal the cap. Good luck!
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Old May 4, 2006 | 04:59 PM
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oh, yea, Rick makes a great point. I used a dremel with a high speed dentists drill bit! That cut through the cap material like a hot knife through soft butter.
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Old May 4, 2006 | 05:23 PM
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Originally Posted by bogus
1. 3/16" is .187

2. cut the barbs off. That's the best bet.

3. Check pepboys.

While you are at it, add a drain to the waterpump weap hole. That will allow the coolant to run off away from the opti in the first place.

also, take the cap off the opti and make sure the rotor is tight and then seal the cap to the body with RTV.
Yea Im 100% with ya on adding a drain to the waterpump weep hole reguardless of how perfectly RTV sealed you get the opti-spark unit.....After the plastic drain was epoxied on the waterpumps weep hole ,I then ran a piece of rubber tubing well away from everything that dosn't like water when the water pump decides to go bad without a tube to carry the bad waterpumps water away from things, it's just gets flung all over everything (opti again) while your driving.

Last edited by 95NOSvette; May 4, 2006 at 05:27 PM.
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Old May 4, 2006 | 05:41 PM
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Thanks everyone. I got the tees in the holes by sanding down the barbs. Everything fit real nice. Now for the cap. In the article Chris melted it with a sodering iron. Anyone try that?

Rick, you mentioned you used a dremel. Because of the higher speed? Did you use it with a regular drill bit? I don't have any high speed dentist's bits.

What size Y fitting did you use for the cap? How did you attach to the cap?
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Old May 4, 2006 | 06:21 PM
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I think I used a 1/4"... but pepboys has a ton of those y-connectors.

As for mounting, I used epoxy. It worked fine.
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Old May 4, 2006 | 10:33 PM
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Originally Posted by 95NOSvette
Yea Im 100% with ya on adding a drain to the waterpump weep hole reguardless of how perfectly RTV sealed you get the opti-spark unit.....After the plastic drain was epoxied on the waterpumps weep hole ,I then ran a piece of rubber tubing well away from everything that dosn't like water when the water pump decides to go bad without a tube to carry the bad waterpumps water away from things, it's just gets flung all over everything (opti again) while your driving.
Even with the drain tube make sure the opti is well sealed with rtv. A drain tube won't do you any good if a hose lets go. Ask me how I know this.
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Old May 5, 2006 | 02:05 PM
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Originally Posted by jrzvette
Even with the drain tube make sure the opti is well sealed with rtv. A drain tube won't do you any good if a hose lets go. Ask me how I know this.
Yea my new opti is wearing a half tube of RTV thats what I meant is that you should do both no matter what.....Joe

Last edited by 95NOSvette; May 5, 2006 at 02:07 PM.
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