US Spec 1974 Dino Dinoplex Assembly

You currently have a Speedatron unit from Allison Electronics. They were good setups back in the day. However, they tend to have their performance degrade over the years, not total failure, just the car begins to run poorly.

 

I apologize for veering slightly off topic, but just last week I was dealing with inconsistent/intermittent ignition performance problems on a Daytona with 2nd Gen. Perma-Tune setups manufactured 45 years ago and introduced to the car before the current owner bought it nearly 30 years ago.
I wonder if the car having seen less than 4K miles of use since has anything to do with it.

I also had a similar experience few years ago with another one that had older-than-dirt MSD CDI modules and very little little use over the decades.

 

Timo: I don't think it is miles, but rather "time" that slowly degrades the internals in the early CD units. Of course, they can also fail instantly, as is fairly common.

 

Dyke, that's what I believe/suspect to be the case in this car.
Last time I had it in the shop was about 15 years ago and at that time, other than a brief (wiring contact ?) malfunction with one of the PT units, it ran just fine and hasn't been driven much since, only about 1K miles (sad, I know).

OTOH, could more active/frequent use help prevent their slow demise ? (Just a rhetorical question, not need to reply)

 

Timo: I don't think so. More use adds to the amount of heat (both engine and internal) that the units absorb, and I believe that is a major factor. I have had Speedatrons failure under actual driving (immediate failure) and the slow degradation of poorer and poorer running. After all, these units were 30-40 years old.

 

Dyke, like I said/wrote, just a rhetorical question and I tend to generally agree with your heat related assessment.
While the PermaTune units I diagnosed failing/working intermittently last week may have not been subjected to a lot of heat cycles, they do appear to be one month shy of 45 years old.
I think my degradation started long before I hit that age.

 

Like any electronics of that vintage it is the capacitors that dry out and fail. They fail over long periods of time so performance degradation is hardly noticeable at first. Use is not always a factor as they will dry out just sitting.

 

Your friend's setup looks very original and correct, except for the ignition box. The air pump controller and the anti-hop device are still there, with original connectors, etc. He is lucky, those items could be almost impossible to find otherwise. All he has to do, it seems, is to install a correct Dinoplex box (original or replica) with modern electronics inside. Preferably Winterburn or similar, where the original wiring and connections can be retained.

For what it is worth, here is what my old 1973 US spec Dinoplex (poor relica) setup looked like. Not much help, I know, since the -72/-73 version still had the two coils and three pin connector, vs. single coil and six pin connector in 1974. Other than that, though, they were very similar.

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Cool, An original black speedatron. I have a broken one I've been meaning to fix up one day. They were made by General Nucleonics in Pomona California. The company had a CD ignition patent but never used it. What's inside is actually a close copy of my father's circuit but a higher voltage version. General Nucleonics sold the Speedatron name to Allison who made a version in a red cast box of the same casting. Allison sold it's line later on to Crane Cams but by then the CD designs were much more modern and more complex. Fred

 

With respect to failures, They usually boil down to poor component choices or poor design or a combination of both. The old Bosch 3 pin CDIs use a big fat zener diode for a crude voltage control that is always wasting current and would fail quickly if not heat sunk, and then they do fail. So do the discharge capacitors and transformers. The transformers in Delta CDIs tend to be the weak link there and perhaps the one electrolytic capacitor. The speedatron failures might be voltage related and from inspection I thought the transistors were marginal for the job. The discharge capacitor in any CDI can degrade with use, but mating it to the right coil as well as controlling the voltage and rate of discharge can increase its lifetime from years to decades under constant use. I have an old 6V Sydmur partially restored that had a bad transformer (also a copy of my father's design on paper at least) . It failed because one of the output bridge rectifier diodes failed due to high voltage. A cascading failure. It also had a poor choice for discharge capacitor. The oil filled capacitor would get quite hot even when new. There were better choices even then(mid sixties) that ran cool in service. Of course heat and voltage stress is hard on electronics too. It's pretty hard to buy bad components now unless you really try. Although I did have several bad SCRs that I had to weed out about a year ago. I threw out almost 20%. The batch was made by ON Semiconductor but with the Littelfuse logo on them. I contacted Littelfuse and the SCR engineer told me that what I had bought was a batch made during the transition of the SCR line after ON Semi sold the thyristor line to Littelfuse. ON Semi threw QC out the window during the transition, so they let some bad ones through. It was really frustrating. Fortunately none slipped through to my customers because after the first test failure I became really suspicious. I have several left and I'm just going to throw them in the garbage rather than test them. I'm buying from a different company now. Fred

 

The one I have in black is and the somewhat later red one that I have from Allison is as well. Quite possible they made some variations on the red one that could be triggered from something other than points. Fred