I dissected my opti, here is what I found

[Warren Seale]

It's got 40,000 miles on it and it failed due to a low resolution signal failure. I opened it up and found that it was clean and that there was very little wear. The cap and rotor had minor corrosion and it could have continued to be used for many more miles. There didn't appear to be any signs of moisture intrusion either from wet roads or from a leaky water pump (which I've had already). The gasket was tight. What failed was the optical sensor module. I don't know if the LED or detector failed. I wonder if they're ever going to sell this module as a separate part so that you don't have to buy the whole distributor.

Warren
96 T/A,WS6,M6
79 T/A,WS6,A3,403
72 442,W30,A3

[Joe 1320]

The local auto parts store will sell the optical portion as well as the cap and rotor portion. These parts have already been out for some time. I don't know if GM sells these parts seperate, but the aftermarket sure does.

[TraceZ]

I don't think he was talking about the distributor base, but rather the sensor module itself. Just that one part that the shutter wheel spins past to create the pulse. Yes, it would be nice if we could purchase just that one part.

[Dave Vince]

Question for Joe 1320

Joe your parts store must be alot more knowlegeable than mine. When I went to one auto store, (Discount auto parts), and asked about an Opti-Spark all I got was a dumb look. Even after I explained what it was I got the same dumb look. So I went to Auto Zone, and bought one of their so called "REBUILT" Optical sensors, which comes with the bottom part of the ditributor. I beleive the only rebuilding that is done to these parts is cleaning. After all the work the car had the same exact problem, break up at 3500, and complete shutdown at 4000. A new one solved the problem. I have had terrible results with so called "REBUILT" electrical parts from all of these parts stores. I will never buy another one. I have had to replace the same part a, starter, part 4 times before I received one that worked. My son had the same experience, and finally went and picked up a new one to solve his trouble. Joe, what Auto parts sells the Optical module seperately??

[Joe 1320]

Unless I was walking in my sleep or am missing something, I bought the optical portion from Advance auto parts and then returned it. It was the reluctor wheel and sensor mounted on the base. At the time I wanted a complete plug and play unit, It was only this portion that was under that part number and not the cap and rotor. The cap and rotor was available but was considerably more. I found that it was cheaper to buy a complete opti from a discout GM vendor that to piece it together from the aftermarket.

[Injuneer]

I think both you guys are describing the same thing - the back 1/2 of the Opti.

and bought one of their so called "REBUILT" Optical sensors, which comes with the bottom part of the ditributor.

the reluctor wheel and sensor mounted on the base.

Warren wants ONLY the sensor electronics if I read it correctly. I have heard of people buying only the electronics, but have never actually confirmed that it is available or where.

I don't think I would ever replace ONLY the optical sensor (wheel and electronics ONLY). When mine crapped out at 50K miles, the front 1/2 (cap 'n rotor) was in near new condition. The back 1/2 was loaded with rust, and the rust had blinded the optical sensor. But the bearing was also shot. You could feel it grind as you turned it. Putting a new sensor in the old casing would have been a huge waste of time.

You might want to contact the people who make the Dynaspark unit.... they have obviously found a source for the electronics, if they can mount them in their billet cases. Since the electronics have a Mitsubishi label on them, and since a very similar distributor concept was used in the mid-80's in the 3L V6 produced jointly by Chrysler/Mitsubishi (they had the common sense to mount it on top of the engine, like a "normal" distributor), I suspect there may be only one source for the part.