These days in the automotive industry as well as many others, when dealing with mechanical or electrical failures of major components, the standard practice is to simply pitch the failed component and intall a new unit.

I personally think this policy is incredibly wasteful, expensive, and on a more sinister note, it's a conspiracy to conceal the real cause of these failures; sub-standard engineering, inferior materials of construction, and various other ill-conceived and poorly executed execises in manufacturing cost cutting.

I've made something of a hobby of tracing breakdowns to a single point of failure, and in almost every case, the cause was a crappy component used to save a few cents on the overall unit cost.

Example: The electronic transfer case shift on my 4x4 stopped working (I just knew this would be a problem when I bought the truck new). I tore the unit down until I discovered the point of failure; a pot-metal bushing had disintegrated on the output shaft of a miniature 40:1 planetary gearset on the actuator motor. I fashioned a new part from a six-cent bronze pipe-fitting (more malleable) and reinstalled the unit.

I could list these types of examples all day.

The point of this tirade is this:
Last fall, the tach on my Corvette started jumping around and my idle went lumpy when the car began to get warm (hot). Seemed like something must be crazy with the optical part of the opti-spark. On teardown, I discovered that my water pump was just starting to weep, and due to the cooked seals on the distributor housing, coolant washed the opti-spark bearing dry so it was cogging, causing the erratic cam speed signal to give the ignition fits. I freed and lubed the bearing, sealed the distributor (and added vacuum venting), reinstalled and have had zero problems despite several hose-downs.

The upshot is this: the unit is back in and working. Nothing replaced. I'm not delusional enough to think it's going to last forever, it's just a science project at this point. So far, so good.

I know the seals are useless and the cause of most failures, what I'd like to know is what is it that actually stops working on these things?
Is it the bearing?
Do the optics ever crap out?
Cracks in the housing?
Are there problems with the high-voltage side aside from carbon tracking?

Lemme know what you've seen

 

I try not to pitch stuff unless it is totally destroyed. My dad still kicks himself for throwing away tons of perfectly fine big block blocks just because he was done with him. :)

 

:lol: At what point are you done with a big block? :lol:

 

:lurk:

good to know..

 

Most of my failures are because the optical pickup fails (twice). Other problems that cause failures is carbon tracking on the unit. From my understanding is that once the unit gets wet and is run for any extended period of time while wet, carbon tracking will form and create alternative paths for the current to flow which will generate cross contamination of the spark. My last failure was the optics, but the whole unit looked very rusty inside everywhere. Honestly it failed because I had a problem wih the vacuum tubes being routed with the check valves backwards (100% my fault). Lucky for me, the unit was replaced under warranty since I had only been running it for about 6 months.

I do not think I have had one fail that could be repaired with just a clean up or by putting on a new cap and rotor and I have had 5 of them fail on me on 3 cars in almost 4 years. Figure 3 of them were originals being replaced though. One I could never explain what caused it to fail, and then I have told you about the 5th one. I have only had to pay for two of the replacements though.

 

I took mine out because I thought it had a problem, cleaned it up on the inside, SEALED it up and reinstalled it. It is still working fine even after the waterpump dumped on it (I had put back on the old one - dumb me). New waterpump and all is well. I think the trick is sealing the three pieces well so no water can enter. Robert :smash: :cheers:

 

I agree with you completely on getting it sealed - the foam that Delco used for the gaskets in the Opti seemed to deteriorate - oil and heat I guess!

My '92 had all the "classic" symptoms of a dying ignition - pulled the Opti to find it completely rusted inside - why couldn't they make those encoder wheels out of stainless steel - what are we looking at - a buck difference on a $300 assembly?

I replaced mine with an AutoZone special - did the mod to get it vented and externally sealed the covers with a thin bead of RTV to back up the Delco foam - thought I was all set up for many miles of happy motoring! NO! After about three months, the car would run fine until it warmed up (I posted on this last summer) - I figure, hell it CAN'T be the Opti again - i just replaced it, right?

I replaced the coil, the coil driver, the plug wires - still acting up, I give up and take it to Mr. Goodwrench - twice. Over the course of the car's stay with them, they give me five new injectors and a lot of scope time - they say they think the car is fine and I can come get it if I want - after having it for a MONTH!

Of course, it died on me coming home from the shop - got it home and messed with it for the better part of another month when I had time - too damned stubborn to go back to the shop for a third time. The Vette was as reliable as hell when cold, but let it sit and idle until the water temp got over 180 degrees and it would sputter, buck and die - every time! Ended up buying a new ECM out of desperation - no dice there either!

Of course, had to put up with a lot of ribbing from my buddies about my oversized "lawn ornament" and flak from the wife about selling "my other significant other" - I ended up garaging it for the winter - totally disgusted!

Took it out this spring, tried to fire it - NOTHING! Would spin over nice, but wouldn't light - but I DID get the dead Opti code!

I bought an OEM Opti this time - put it in a couple of weeks ago - purrs like a kitten (guess I needed those injectors after all - car never ran enough for me to find out I had a problem before!!).

I haven't disassembled the AutoZone opti, but I might as well - since I enlarged the weep holes for the venting mod, they voided my warranty!! All I can figure is tht that particular core made it through the inspection process at the remanufacturing outfit - it obviously passed muster with the folks at Goodwrench - they never spotted the problem either. All I can figure is it had a heat-sensitive defect in it - our cold Wisconsin winter must've been enough to finish the job on whatever electronics were acting up inside the unit.

It's too bad they didn't go with coil packs when the LT1 first came out - you would have figured that some technology from the ZR-1's LT5 could have been used - I'm still trying to figure out why they just didn't put those encoders in the old style distributor instead of hiding the damned thing under the water pump and the crank damper!

After all, the distributor is driven off the front or the rear of the cam (LT1 vs. previous small-blocks) - it is still driven by the crank via a chain - accuracy should've been close to the same if it was set up right.

Just my $0.02 worth - LOL

 

Why can't someone market a kit that includes the cap/rotor and the internals that fail? Dynotech is able to get parts to fabricate the dynospark unit, so the parts are obviosly available somewhere.

 

As much fun as Id like to pick on the engineers,I have to remind myself its not always their fault.Many a time,an engineer will design a part a certain way,a certain quality and it doesnt get built that way nor is it manufactured correctly and fails a qc test but still gets put on the parts shelves.
I knew someone who worked at a parts factory,I wont say which company,but one of the big co.'s here.Anyways the new oil pans they made for production,many of them failed the final test when being produced.They were showed how to make the light go green on the test machine when it was red seeing a fault somewhere.Sometimes it was simply getting a bolt hole deburred or straighten somewhere got it to pass but too many defective parts went out the door to supply the quota.

As far as the optis go,it doesnt or wouldnt suprise me if QC was skimped on and inferior parts were used to assemble them at times.
:)

 

Been wondering that myself. I replaced my pump at 50K and took the opportunity to clean the opti. For as much as it costs I was expecting a complicated assembly of electronics. I was stunned & amazed to find only an encoder wheel and a sensor. :rolleyes:

So the active electrical component inside appears to be just a simple 'beam break' sensor. I use/replace those a lot at work. It may be possible to find a suitable replacement off the shelf of a good electronics shop for about $2.00. What do these things cost OEM from GM? $400- $500 ??? I would have tried to match something up already but I don't have a spare opti to compare with.

If somebody with a spare opti wants to tackle this chore they could become a real hero here. Potentially save everyone hundreds of $$.

Or, if somebody wants to send me a dead one I'll work on it...


later
dr

 

My first one failed at 110k. (not bad - seals bad, opti took it out) The second failed 1000k later. Defective out of the box. The third was still working when I had the motor rebuilt. Sold it to a forum member who wanted a spare. Only reason I took it off was I installed the newer '95 vented one with a Meziure over it as I didn't want to have any more problems with it was required with the parts I was using. So far so good. It has about 10k on it.

 

Most people don't repair the OPTI because they are such a PITA to change and it's not worth the risk putting the car back together if the opti still isn't working 100%.