Torx size on Optispark?

[markd79ta]

Does anyone know the torx size of the screws used on the optispark caps? I am replacing the cap on the Roadmaster instead of buying a whole new optispark. I know somebody who has had good luck with this on a proper functioning opti. Nobody knows the size. The set is $86 at SnapOn, but I only want to buy the one I need.

[Injuneer]

Do you mean the "reverse Torx" screws that hold the cap on.... either R4 or R6. But you can take one of the Torx head screws out of the top plate on the throttle body, and use the head of the screw as a "socket".

[markd79ta]

Originally posted by Injuneer
Do you mean the "reverse Torx" screws that hold the cap on.... either R4 or R6. But you can take one of the Torx head screws out of the top plate on the throttle body, and use the head of the screw as a "socket".

THANK YOU!!!!!!!!!!!!!!!!!!!!!!!

[Injuneer]

The more I think about it, I think the designation is "E4" for "external Torx", not R4. But the TB screws work fine.... just don't mess up the threads.

[markd79ta]

Yep, it is an E4...my set ends at E5 or I lost the E4...big sigh Anyhow, I will try the TB screw, and see how that works. The guy who owns the speed shop near my house also offered to loan me the E4 socket if I need it.

Thank you very much for the info. I am looking forward to tearing into this. My Roadmaster Wagon has almost 150,000 miles on the original Opti and water pump which is really hard to believe. I changed the plugs at 100,000...kept the same wires.

[TraceZ]

Originally posted by markd79ta
My Roadmaster Wagon has almost 150,000 miles on the original Opti and water pump which is really hard to believe. I changed the plugs at 100,000...kept the same wires.

If you plan to sell the car, just do the cap. If you intend to keep it for awhile, do a new water pump and opti.

Your current parts are living on borrowed time, man. It is not a metter of "if", it is a matter of "when", and it will be soon... guaranteed.

[markd79ta]

I am doing the water pump, wires, plugs, cap & rotor, belts along with anything else that is worn or damaged.

The internals of the opti should be fine unless they are damaged by water. I will know more after I break it open. However, the guy at the speed shop stopped replacing optis that were functioning correctly in favor of replacing the cap and rotor. It should be all good. However, if it dies, it is not that difficult to replace it.

[TraceZ]

Originally posted by markd79ta
I am doing the water pump, wires, plugs, cap & rotor, belts along with anything else that is worn or damaged.

The internals of the opti should be fine unless they are damaged by water. I will know more after I break it open. However, the guy at the speed shop stopped replacing optis that were functioning correctly in favor of replacing the cap and rotor. It should be all good. However, if it dies, it is not that difficult to replace it.

That seems reasonable. I was under the impression you were going to reuse the pump.

[markd79ta]

Originally posted by TraceZ
That seems reasonable. I was under the impression you were going to reuse the pump.

That would be BAD!!! The weep hole is starting to seep coolant, I have been monitoring it pretty closely...the reason I am starting the project. I have the shinny new pump on my bench at home. However, the $299 for the non-vented opti made me go the cap & rotor route. The opti functions perfectly right now, but I know the cap and rotor are toast as well as the wires.

[markd79ta]

Thank You Fred!!!!!!!!!!!!!!!!!

Originally posted by Injuneer
Do you mean the "reverse Torx" screws that hold the cap on.... either R4 or R6. But you can take one of the Torx head screws out of the top plate on the throttle body, and use the head of the screw as a "socket".

The TB screw worked fine. I used a vice grip on the unthreaded part to break the screws loose, and I put it in my drill to loosen and tighten the screws. It worked great. The torx screws that hold down the rotor were a whole 'nother story. I had to drill them out...what a pain. They were a size smaller then anything I have ever seen! The opti is working GREAT! Those old cap, rotor, and wires were really worn out after 150,000 miles. The car is running great; although, my drivers side rockers are clicking a little...driving me insane. I guess I will need to do those at some point.

Take Care!!!

Thanks again!

[Injuneer]

You have to understand the various failure mechanisms of the Opti. Most of the liquid that leaks in comes inthrough the poor seal on the harness connector - back half of the case. Once water gets in there, it will corrode the bearing (extremly poor quality bearing in the back case) and will cause the bearing retainer plate to rust. That rust tends to collect in the optical sensor window. All those parts are in the back 1/2 of the Opti. That is a valid reason for considering a full replacement.

It may also cause carbon tracking in the cap. And the ozone from the high voltage discahrge in the cap causes additional corrosion.

At 50K miles, I started getting the DTC codes for the low resolution pulse. The cap/rotor were still like new, but the optical sensor was full of rust and the bearing was so worn the shaft would barely turn. I actually bought one of the first of the Electromotive Super Direct Ignition/Opti-Eliminator and ran without the Opti for almost 2 years.

Since then I've gone to a "vented" Opti, feeding an aftermarket ECU and driving 8 LS1 coils, and the unit has been problem free for almost 4 years. Getting the high voltage functions out of the Opti seem to eliminate most of the problems.

[markd79ta]

Originally posted by Injuneer
You have to understand the various failure mechanisms of the Opti. Most of the liquid that leaks in comes inthrough the poor seal on the harness connector - back half of the case. Once water gets in there, it will corrode the bearing (extremly poor quality bearing in the back case) and will cause the bearing retainer plate to rust. That rust tends to collect in the optical sensor window. All those parts are in the back 1/2 of the Opti. That is a valid reason for considering a full replacement.

It may also cause carbon tracking in the cap. And the ozone from the high voltage discahrge in the cap causes additional corrosion.

The Roadmaster was a '94, and it had the vented opti???...I found that kinda odd. I didn't think that those came out until '95. Anyhow, the opti was problem free. The optical sensor was like new as well as the bearing and the code wheel(lack of a better term). The inside was completely clean, free of debris, and no sign of any water(or rust). I was surprised to see how good it looked. It will be interesting to see how long this lasts.

[Agent Z28]

I apologize for hijacking this thread, but my curiosity has been piqued by the following reference: "Electromotive Super Direct Ignition/Opti-Eliminator". Could you describe this in a bit more detail ?

[Injuneer]

The Electromotive SDI/Opti-Eliminator was just that... an add-on ignition system that totally eliminated the Opti. It used four dual-terminal coils to fire the ignition in "lost spark" mode (2 cylinders at once, one on the compression stroke and one on the exhaust stroke). The system included a 60-tooth crank wheel and sensor that bolted to the front of the stock LT1 damper, a chip that took the crank sensor signal and synthesized replacement high resolution and low resolution pulse signals to replicate what came out of the now-missing Opti, a controller that allowed you to either use the PCM to set the ignition timing, or use a dial module in the controller to set the timing, and a 4-coil pack to fire the plugs. It was basicly the same ignition that was used on the GN/GNX Buick Turbo V6's.

If you've followed this so far, you realize this system, which uses crank position signal to synthesize the Opti cam position pulse pattern will not always synch correctly with the sequential fuel injection system used on the 94+ LT1. It worked fine on the 93 LT1's, with batch fire injectors. It worked "fair" with the 94+ sequential injectors, but 1/2 of the time it would synch incorrectly and fire the injectors 180-degrees out of phase. Surprisingly, this is not a big problem, since the injectors tend to stay open most of the time at max power/max RPM.

But when they put the system on a 96 OBD-II LT1, it would not work.... the mistimed injectors caused enough of a "bobble" in the firing pattern that it kicked off the misfire detection provided by the crank position sensor added for OBD-II. That was the end of the SDI/Opti-Eliminator. They put production on "hold" until they could solve the OBD-II problems - which they never did. They only made about 20 of the units and I had one of the first ones. A friend of mine owned 2 of them at one time. You can still pick them up "used" from time to time.

The ex-chief engineer from E'motive now appears to be supporting the Delteq LT1 ignition system design. They now have available a module that allows the optical section of the Opti to drive a Northstar ignition module, and 4 coils in the "lost spark" mode. They are indicating that shortly they will have a Stage 2 module that totally eliminates the Opti.

And, Bob Bailey sells the LTCC add-on black box that allows the optical section of the Opti to drive 8 LS1 coils. As noted, getting the high voltage stuff out of the Opti seems to extend the life.

E'motive timing wheel:



E'motive controller and coil modules:



My current system is the Opti optical sensor driving a MoTeC M48Pro aftermarket engine management system, with their IEX 8-channel ignition driver running 8 LS1-style coils: