A couple of months ago I had a thread about my ‘73 Delta 88 which had quit running without warning and wouldn’t start. I eventually traced the problem to a corroded connection at the coil.

Well, the same @#$@% thing happened with my ‘77 Toronado a few days ago. This car has been about as reliable as the sun rising every morning. Always starts and runs pretty well. Never gave an ounce of trouble in this regard in the three years I’ve owned it.

Until now.

Like the Delta 88, I had it started was getting ready to go off somewhere with it when it just died as sure as if I had flipped a switch. It will crank and crank all day long, but not a hint of catching and starting. I checked fuel supply, and there’s plenty of that. I even tried starting fluid but to no avail.

I assume there is still compression, so it’s an electrical problem. I verified with this little tool that there is no current getting to the spark plugs.

So I went through the troubleshooting section in the service manual. Remember that the ‘77 Toronado featured a unique, one-year-only ignition system (called “Electronic Spark Timing," or EST for short) with an external “pulse generator disk” and pickup senser mounted down low on the front of the engine, a temperature sensor (long since corroded away and disconnected, but the car ran fine without it) whose readings were used to adjust the timing, and other assorted contrivances. There is even a fuse in the fuse panel labeled “EST” that was suggested by the manual as the very first thing to check. The fuse was fine.

Anyway, I got to the point where it said to check the distributor cap, rotor, and coil (the coil is mounted on the distributor cap in this car), and lo-and-behold, look what I found when I removed the cap and exposed the rotor.

What the he!! happened here? What could have caused this critical piece of metal on the rotor to get bent like this? There is certainly nothing in the action of the rotor to cause this, and there is no way it could have been bent during installation because the rotor is screwed down, and the cap is placed straight down on top of it. The cap can’t be put on at an angle or something and catch the tab in some way and bend it.




So I am, of course, buying a new rotor.

But I’m still curious about this. This problem did not just happen. If you look at the old tab closely, you can see pitting on the EDGE of it, not in the center where it would be if it weren’t bent. This suggests that, even in the bent condition, the tab managed to make contact with the terminal under the distributor cap, and the engine ran. Something caused it to suddenly stop working. Maybe the pitting got too severe. Who knows?

What I am slightly wondering is, will replacing the rotor actually fix the problem? It certainly seems like it could, and certainly the rotor should not be like that. But it did apparently work. If it failed because the tab finally stopped making contact, I would think that I would have seen the engine getting more difficult to start or maybe misfiring once in a while and not just dying completely and all at once.

I have a new rotor, new cap while I’m at it, and new coil while I’m at it on order from my favorite vendor, Amazon, and the parts should be here in a couple of days (with “free” shipping!). I could get them locally, but I try to buy ACDeclo brand parts whenever I can, even if they’re all made in China, anyway, and the local parts stores don’t always have Delco. They’ll have their own house brand, which would probably work ok, but I’m in no hurry.

One thing I did notice is that the underside of the old coil says, in big block letters, “Made in China.” I assuming that this is not original, so this car has been worked on before. Perhaps the tab was bent when it was installed by whoever did this work in the murky past, but that’s seems very unlikely because how could you not notice it at the time? If it was bent, why didn’t you at least try bending it back to its original shape as much as possible?

Here's what the rotor should look like. On the old rotor, the area under the tab in the center is blackened. I'm guessing that this is a clue about something undesirable. Arcing? Would a little discoloration be expected over time?

 

What does the button and its surrounding area look like under the cap where the rotor rides?

 

One word - heat. Electrical resistance over time created arcing. The arcing is most likely the result of degradation of the metal (moisture/condensation). When arcing began, it continued unabated. The arcing produced significant heat which yielded to malformed metal.

 

If you have a new cap and rotor on order let us know if that fixes the problem. The mild discoloration and burning in your first pic is to be expected and no cause for alarm.

 

Good question. Here's a photo of it. It looks to me like you would expect it to look after enough miles. Definitely pitted. The new cap comes with one of these, so it will be replaced.


This thing actually sits in a hole in a rubber disk about two inches in diameter that it located right below the coil which, as I said, sits on top of the radiator cap.

 

So you're saying that this happened as a result of use, not prior to installation, which never made any sense to me, anyway. That's interesting. This rotor looks just like the Delco rotor I ordered (the other aftermarket ones I've seen are functionally the same but look slightly different), so I'm wondering if it's the original. As I said, the coil is apparently a replacement, but that doesn't mean that the rotor was changed at the same time. Even if it was changed, it might have been decades ago.

This makes me think I should look at the rotor on my other Toro, the '78, which probably has the same setup as far as the distributor goes.

Thanks! Yours is the best explanation I've heard.

 

I certainly will. I probably won't get to it for several days as the parts are on order.

 

Yes. My working "theory" anyways.

Not all metals are created equal & not all vehicles necessarily succumb to same amount of moisture/condensation (based upon storage, driving conditions, etc.). Plausible theory. I'd suggest the metal deformation most likely resulted from overheating caused by arcing over an extended period time - basically a simple failure perhaps exacerbated by driving conditions + possible metal fatigue?

 

Like yourself, I'm sure, you've seen quality degrade over the decades as parts manufacturers shave pennies/dollars to increase net income. Contact points is one example of times past & especially today. The materials are substandard & manufacturing QC is all but gone. The metal they use make me wonder. I've installed contact points (sometimes same manufacturer) w/ great longevity & others which began to fail before you back them out of a garage. Sometimes it's a veritable guessing game (I'm sure you can relate).

 

I recognize I should shut up & not beat this to death; but, I thought I'd share a historical perspective - about contact points, again (sorry). Recall the days when they actually made a good set of contact points for many various types of vehicles/tractors/implements, etc.? You had a solidly secure circular piece of quality metal you could, in fact, actually hand sand with an abrasive (sandpaper, Emory cloth, etc.) to gain additional life from points as they pitted/corroded, etc. - a nice big fat beefy piece of solid metal. At some point manufacturers decided we don't need all that frick'n metal in there so let's create a hole/cavity directly in the center of the point(s) metal - eh, that should be enuff to gitter dun. The bean counters - always looking out for our best welfare.

 

I sure hope that was a typo.

 

It looks as if there is a groove around the circumference of the "button" and there is a circular shaped gouge in the side of the rotor contact. This indicates the rotor contact somehow got out from beneath the rotor button. I'd check to see if the button is able to move laterally in the rubber disc. It's possible the disc is what caused all this to happen.

Or it could be someone installed the cap so the button pushed the rotor contact to the side and the engine ran because there was electrical contact. Then after some time, the parts wore until there was no contact, and the engine stopped running.

 

"That" is too damn funny - nice catch.

 

Seen rotors burn due to bad/high resistance plug wires. I've not seen the tab get damaged.

 

If the button moves around in the cap laterally, not just in and out from the spring, that is what caused the issue. What happens is it gets hot and melts the plastic surrounding it.

 

No, it actually DOES sit on top of the radiator cap! Didn't I say earlier that the ignition system was a one-year-only thing?

Yes, I meant distributor cap. Thanks.

I could edit that post and fix what I wrote, but I'm not going to. I like it the way it is.

 

Heck no - it adds 'flavor'.

 

These grooves are to be expected. Here's a view of the underside of the coil that was on the '77 (the "made in China" one). The rubber disk with the hole in the center sits in the grooved area, and the little contacting pin sits in the hole with the back side up against the bottom of the coil (the yellow part in the photo). The pin is on a spring to keep it fully extended. The coil is screwed down on top of all of this, and the grooves come from the circular cutouts on the bottom of the coil pressing into the rubber.

As I said earlier, the new cap comes with a new rubber disk and a new contact pin.

By the way, anyone know what brand this is? I tried googling the part number, but I didn't come up with anything. Interesting that the C in China is not capitalized.

 

I took the distributor cap off of the '78 this morning, and I saw that I should have replaced parts on it years ago. I acquired this car in 2017 with about 80,000 miles on it, and it's got about 90,000 now. I replaced the plug wires and spark plugs, but I didn't touch the distributor, and I should have. The car had been sitting outdoors under a cover for 14 years before I got it. But it ran OK once I cleaned it up and such, so I never thought much about the distributor. But after seeing what's under there, as I say, I should have replaced components much earlier. I'm going to replace the cap, coil, and rotor on this one as well.

The rotor from the '78. Not too bad, really, and the metal is not bent.





Here's the two rubber insulators. As I mentioned above, these sit on the underside of the coil and hold the contact pin in place. The grooves come from the recess that they sit in.






Here are the contact pins. The '78 is much more worn and not shiny.





Here's the coils from each. The one on the left has the part number but no brand. The one on the right has a part number stamped into the other side, but the stamping is not complete as it looks like there should be a number preceding the five shown. Possibly an 3 or an 8? It even looks like there could be TWO numbers to the left of the zero, perhaps a 1. So the number could be 1309031 or 1809031. I'm leaning toward a 3 next to the zero. But googling all of these possibilities still turns up nothing.







The distributor caps. The one from the '77 looks nearly new while the one from the '78 looks old enough to buy everyone a beer.

You can see the grooved recesses that put the groove marks into the rubber insulators.





Undersides of the caps. The '78 has a brand and part number, Standard Motor Products DR-450, so it's obviously not original. The metal contact tabs around the outside are much more worn and corroded than on the '77. No brand or part number on the '77.

You know how Rockauto usually shows parts availability sorted into three categories, "economy," "standard replacement," and "premium?" Well, the DR-450, which is still available, is shown under the "economy" heading. Spare no expense, right?

What's interesting is that two of the "standard replacement" caps are cheaper than this one under the "economy" category.





Parts for the '78 were ordered this morning and should be here some time next week. I should be able to put the '77 back together this weekend with the parts ordered yesterday while the '78 should be buttoned back together by the end of next week.

Then they'll both run like tops, right?

 

Yeah, I am familiar with the HEI distributor parts.

You totally misunderstood what I was talking about, so let me show you.





It's hard to troubleshoot this from my computer here in Phoenix, but the hole in the bottom of your distributor cap appears to be wallowed out. it's definitely different than the other distributor cap.









Also note that the button mark on the bottom of the coil appears to be off-center. This would mean it was skewed when the coil was installed, and is likely why the rotor contact was bent and the pin has that circumferential groove worn into it.

 

Cattle & pigs wallow, don't you need mud to wallow?

 

You're right! I completely missed your point before, and now I get it. So the edge of the bent metal tab has been pressing against the side of the metal button, not making contact at the tip like it's supposed to.

But this kind of takes me back to an earlier question. As kludgy as this was, it did work, and for quite a while. So what made it suddenly stop working? Is it possible the no-start problem is something else, and the discovery of this problem with the rotor is just incidental?

I guess I'll find out when I put the new parts in and see if it starts.

 

Yo...Kenneth......

You realize I get an e-mail of the original post you created even if you subsequently deleted it, right?

Honestly, I was taken back by your exemplary presentation complete w/ arrows & text dialogue. Who'd have known, right?

 

So we're saying that the bent metal tab, which we still don't know how it got bent, has been contacting the pin on the side like this, and it's been doing it long enough to cut the groove that is now in the side of the pin.




If you can accept the idea of bending the tab and allowing a groove to be cut, it seems like a pretty good way for the pin and tab to make contact.

Obviously I will put in new parts and without bending the tab, but I still wonder why this should suddenly stop working. Like I've said, I'm not convinced that this issue is actually the cause of the no-start situation.

Like a good Joe Padavano acolyte, I'm throwing money at this by replacing every ignition part I can. That means a new ignition coil, rotor, and cap as I've said, and I'm also replacing the ignition control module, which is the thing being pointed at by the yellow arrow below.

I'd replace the capacitor next to it, but I can't find it on any of the parts sites. I hope it's still good.

I should have all the parts by tomorrow morning, and then we'll know.

 

I'd like to replace the ignition control module on the '78 while I'm replacing the coil, cap and rotor, but it's a different thing from the one on the '77. It has only three pins (two on one side, one on the other) instead of four like in the '77 (two on each side). Yellow arrow below.

The module for the '77 is available everywhere, but the one for the '78 is not available anywhere that I can find. The service manual just calls it a "3-pin module." The one in there says "Standard" on it, so I'm assuming it's Standard Motor Products just like the cap. I removed the two hold-down bolts and looked at the bottom for a part number, and there is a number, 9302. However, googling "Standard Motor Products 9302" turns up spark plug wires with that number. No ignition module. I couldn't find anything on ebay, either.

Since the '78 actually starts and runs, I'll assume the old module is ok. Not sure what I'd do if it ever failed.

 

Make sure to cover this in a Front Wheel Driver. The 77 and 78 ignition systems were space shuttle compared to everything else in that time, and fewer people understand them now than did when the cars were new. Never mind their technology has been adapted to most cars by now. Oldsmobile didn't gain its engineering reputation and recognition by sticking with the status quo.

I have no idea how that rotor contact got bent up like that but I've seen plenty more unexplainable things in 55 years working on cars.

 

If you are a member of the TOA and have kept your issues of FWD, go find the March/April 2023 issue. I have an article in there that talks about these two cars and, while I didn't talk specifically about their distributors, I did spend time talking about their ignition systems. I would talk about the current problems in a future article if I there is something useful to say. That'll kind of depend on how this all turns out.

 

And the answer is.....Yes!

I replaced four parts in the distributor, the cap, rotor, coil, and control module. Put it all back together, said a brief prayer, and turned the key. It fired right up. “Just like New York” as my father might have said. Runs fine. Took it for a spin around the block and got it up to about 55 with no problems.

The control module I picked up this morning at O’Reilly after ordering it online last night. Standard Motor Products, and it’s made in the U.S.A. (for those who keep track of such things.)

The coil I bought at Autozone. Duralast brand, made in China. But it was less than half the price of the Delco ($30 versus about $80), and I could get it same day. The Delco could have come from Amazon, but it was not available for immediate delivery (would have been a couple of weeks), so I went with the Duralast. It’s working fine.

The cap and rotor, both Delco, were made in Mexico.


The new rotor and module installed in the distributor.






New cap with the new coil mounted.




There's a cap that goes over the coil and holds the wires in the end connector in place. I cleaned it up as best I could. Note the words "Latch." There's a plastic ring that goes over this that holds down the plug wires. It seems like overkill to me because it takes a good tug to remove the wires, so it's unlikely they'd pop off on their own. I've never seen a distributor with one of these hold-down rings. But that's not what's stopping me from putting it on. It just takes so much downward force to get it to latch that I just don't have the strength or the will to get it on. I've left it off of both Toros ever since I've gotten each one and have never had a problem.





As I said earlier, the cap comes with a new contact pin and rubber insulating ring. Here's the new (on the left) and old contact pins side by side. The new one looks pretty much like the old one except for the groove worn into the side of the old one. Hopefully, we'll have no more of that!





Here's the old (left) and new ignition control modules. The old one has a part number (actually two numbers) and made in China on the edge. The D1906B is a Delco part number. Interesting that the GM-brand/ACDelco part is made in China while the Standard Motor Products part is made in the U.S.A.






Finally, here's what is molded into the top of each of the old and new rotors for the '77. The new one doesn't say AC or Delco or have any part number on it. Just this little symbol that looks like an H.





By contrast, the rotor I took out of the '78 does say Delco-Remy and Made in USA on it. But I'll be replacing it with a Delco part.

 

It would have been a pain to do it this way, but maybe you should have initially replace everything except the control module, just to see if the first 3 parts did the trick - they are all self evident in their function whereas the module's electronic operation is more complex and hidden internally. It wouldn't surprise me if the module is the part that suddenly failed and stopped the car from running.

 

Yes, I could have done something like this. Replace one part at a time and see which one did the trick. Next time!