Parts is Parts, Until They're Not

[ensys]

Gentle Readers:

Has no one else noticed that the current supply of Pick-Up Coils has gotten very dicey of late?

In the course of this summer (Jun. and Aug.) I have purchased two such coils (from RockAuto), only to find that both were hopelessly inoperative. Both were sourced from Standard Products, and while both exhibited proper resistances (the only (short of oscilloscope exam) test promoted by the FSM), both were useless in actual operation.

Of course, since the opportunity to test either occurred outside of the narrow "warranty" period, I've had to eat the cost of both, leaving me highly skeptical of Standard Products in specific and Rock Auto in general.

Which leaves me to wonder; am I the only one to be in need of Pick-Up Coils, and if not, what are others doing in the face of this dearth of this part so necessary to proper ignition.

I will note that the only thing that has allowed acceptable operation, has been the deployment of a No-Name, oddly configured coil out of a none-to-precise "rebuilt" distributor body purchased during my get-new-parts phase of problem-solving.

So, again, what has worked for everyone else?

 

[Racer X]

Pickup coil for . ? . ? . ? . ?

[ensys]

My bad.

Ignition Pick-Up Coil. In the distributor.

[Zed Head]

1 hour ago, ensys said:

both were useless in actual operation.

 

1 hour ago, ensys said:

deployment of a No-Name, oddly configured coil out of a none-to-precise "rebuilt" distributor body

 

1 hour ago, ensys said:

Has no one else noticed that the current supply of Pick-Up Coils has gotten very dicey of late?

 

They aren't often bad.  So, not really a high volume part.  Probably not a large population of pickup coil buyers out there that could give an opinion.

It would be interesting to know how they failed in operation.  There's an air gap involved, and, of course, an ignition module, and some wires.  It's not clear if a complete new distributor worked for you, or the pickup coil alone in the same distributor that other two failed in.

The short answer though, I think, is no.  Because it's not a common problem.

[kickstand80]

What is the condition of the magnet in your distributor? They often break but some seem to still function where others don't. It may have some impact on the ability of the coil to pick up the induced A/C signal that the Ignition Module needs to fire. 

[Zed Head]

The pickup coil contains the magnet in the 280Z distributors.  I think he has a 77 280Z.  

I'm not really sure what's inside the 280ZX "pickup coil".  The magnetic material is under the stator ring.  I'd guess it's just an iron ring wrapped with copper wire.  

https://zcardepot.com/products/distributor-pickup-coil-280zx?_pos=1&_sid=35eb01fb4&_ss=r

[ensys]

 

Right you are: a '77 280Z that until this year, was still running, after 200k mi., on the original distributor (with orig. pick-up coil) without incident.

But all good things must come to an end, and for the p-u coil, this resulted in ignition spasms that increased in occurence and duration of undrivable operation, until there was only a good idle with hellacious mis-firing (with much shake, rattle, and roll) at any revs above that.

Like you, I never suspected the p-u coil's fault and spent much time and money looking for the source of the ugly behavior. When it came down to "I've tried everything else", I bought the first replacement coil, the installation of which resulted in the very same behavior, so I kept looking elsewhere.

Three months later, I was back to "I've tried everything else" again, and I bought another replacement, thinking the crappy condition of the first upon receipt may have been more meaningful than I thought. Sadly, the second would not produce any spark at all. DOA. Mind you, all three passed the only test specified in the FSM, the check of resistance of the coil.

In between the two, I had purchased a "rebuilt" distributor body, as a despirate extension of my earlier "throw fresher parts at the problem" that resulted in a replacement ECU and ICM (among other parts), all to no avail. It was this distributor body that brought the p-u coil that looked to be out of some other application, along with some other oddities.

Finally, having little hair left to pull out in frustration after the utter failure of the second "new" p-u coil, I threw that puppy (the "rebuilt" distributor... (30Sep. edit)) in for lack of any other approaches to the problem. Lo and Behold, the engine got sweet once again! I was astounded. I moved the p-u coil to my own already rebuilt distributor (with its fresh cage and new bearing balls), and the engine is running fine once again.

There is a larger moral to this tale of woe; as a result of the violent behavior during the first p-u coil's recurring spasms of slow failure, the crank nose drive gears began to shear their keys and spun the distributor/oil pump drive gear press-fit on the spindle shaft. Fortunately, we're only talking a few degrees, and with the deployment of a new spindle shaft, I have been able to dial in a usable ignition timing for the time being; tho I know that when time and opportunity permits, I will have to address the crank drive gears in a more meaningful manner.

Thus, I urge you, Gentle Readers, to never take misfires lightly.

 

Edited September 30, 2022 by ensys

[Patcon]

Some people drill and pin the spindle gear to prevent that

[ensys]

 

Mr.Patcon:

Clearly, the obvious best solution, and one I would have pursued were I not machine-tool disadvantaged. But then, the situation with press-fit gears on the spindle shafts has been previously well addressed.

The core issue of this thread is the symptoms of failed pick-up coils, the potential dire consequences in the event of their non-performance/failure, the complication of diagnosing such a non-performance/failure, and the current difficulties in sourcing properly operating replacements.

Bottom line, beware of Standard Products' replacement pick-up coils, and of Rock Auto's lack of due diligence in distributing products that are well below an acceptable level of performance.

As consumers, we should demand better.

Just $.02 from the cheap seats.