AC Delco Distributor (Page 2/2)
Patrick MAR 02, 08:29 PM

quote
Originally posted by pmbrunelle:

I did a teardown on two ignition modules...



That's quite interesting.... and informative!

donuteater306 MAR 02, 11:17 PM
Thanks PM. for sharing that. At the shop where I had worked we used a lot of KEM part...our supplier stocked their products. Never really had an issue or a come-back except for externally mounted voltage regulators on some 70's GM vehicles. Delco, at that time, held up much better.

I'm assuming that since my distributor came with the regulator and pick-up they they're both low end quality. I'm gonna roll with them and just bring my two known to be good modules with me.

Would be nice to know what AC Delco gave me tho. I bet it's a "delco" part but like Ogre said, maybe from their lower-end line.
Notorio MAR 03, 12:11 AM

quote
Originally posted by pmbrunelle:

I did a teardown on two ignition modules:




How does one tell what kind of module one has?
theogre MAR 03, 01:35 AM

quote
Originally posted by pmbrunelle:
I did a teardown on two ignition modules:
<snip>

Comparing the two, the Wells/WVE unit is pure junk, so I'd suggest installing your original GM module, no matter how old it may be!

You could keep the jobber unit as an emergency backup, but I wouldn't count on it working when you need it to...

My previous Fiero would only run with a genuine GM module; it wouldn't even start with the jobber stuff! I don't have any explanation for that.


Sorry but 20 - 30+ year old OE vs current new made by X doesn't mean much.

Wells "transistor" on left is very likely a MOSFET that easily handles amp load driving the I-coil and generating less heat doing the job. Middle leg and tab are connected inside so doesn't matter if middle is cut short. Tab and back is path for heat removing then many ways to dump heat from MOSFET to metal bottom then to dist case.
Other is a PIC/MCU/etc does the rest.
Not sure if board is conformal coated or not from this picture. black parts seems so. If true then some water won't matter if cover leaks.
Proper solder melt at higher temps like Most if not all RoHS lead free solder needs higher heat (~ 420°F) and you have a lot more problems when solder melts here in the car.

GM use spot welding for 2 main reasons...
Standard Lead solders melt @ lower temps (~ 360°F) and pushing it hard here. RoHS types etc didn't exist except as special alloys costing more. (RoHS started in ~ 2004 but many things didn't comply until Years later.)
Spot welding is fast and cheap to make a ICM.

1 spot weld wire looks like is connected to the driver trans "chip" directly (white/gold square on left.) and Can't solder there regardless of type.

IOW Can save old ones but saying their better.... don't count on that. Very Likely that Wells MOSFET handles 2 or more times the power at a fraction of heat generated that must be dumped vs. the old design worse many w/ a bipolar transistor driver.

Yes, I don't like RoHS solders and said can have problems but here higher melt point and less joints make the problems less likely.

If only "a genuine GM module" starts the car... You have other problems cause this like iffy tach filter and more. Is a wonder even they will run long w/o frying regularly.
MarkS MAR 03, 09:51 AM
"Sorry but 20 - 30+ year old OE vs current new made by X doesn't mean much."

My day job might tell me a different story. The design might be OK but unless Wells / WVE or whoever has a materials source program like DFARs 252.246-7007 / 7008 to combat counterfeit parts, the ultimate reliability those plastic SOT's inside the Wells / WVE device is suspect. Maybe they do, don't know but these days, its a concern.

I bought a rebuilt Cardone points distributor for my 65 w/ a 400. It came with points and condenser. Ultimately, I was going to replace those with a better set of components but for start up, initial run-in, I figured I'd use what came with the distributor. Well, I should have replaced them right off the bat. After 100 - 200 miles, the condenser shorted leaving me stranded. Bought NOS Blue Streak's as replacements.


------------------
1965 Tempest 400 CID
2018 Chevy Colorado Z71 3.6
2017 BMW X3 3.0 T
2015 BMW 535iX M Sport
2008 G6 GT "Street" Coupe
2005 Buick 3.6 Rendezvous

[This message has been edited by MarkS (edited 03-03-2020).]

pmbrunelle MAR 03, 05:54 PM

quote
Originally posted by Notorio:
How does one tell what kind of module one has?



The plastic of what I call the "GM module" was embossed with the Mark of Excellence:
https://en.wikipedia.org/wiki/Mark_of_Excellence
From memory, the logo was a square about 3/8" wide.

Obviously, the plastic embossing could be faked, but this came from a low-miles Fiero that looked like it had little of anything ever replaced.

I didn't do a full in-depth comparison of the two modules; comparing the two modules was not the primary objective of my exercise (which was to convert the modules into "cam" sensors). But with a multimeter in diode test mode, someone could easily figure out what kind of power switching device is used.

The GM module was potted (about a 3/16" thick layer) with a clear jello-like substance.

The Wells/WVE module had a thin layer of acrylic-like conformal coating.

I normally want the enclosure to be sealed; I consider the conformal coating to be a last line of defense, not a primary protection. In the distributor though, you could say that the moisture would be driven out with the heat.

We had a crisis with counterfeit parts at work. To manage it, we did a "stress test" procedure that would kill assemblies with counterfeit parts during our end-of-line tests. Assemblies with genuine parts would survive the stress test. If you were making ignition modules, you could do something similar to this if you doubted whether your incoming parts were good or not.

I'm not close with purchasing, so I don't know what are the best practices to avoid receiving counterfeit parts in the first place.
Edit: some items we can buy direct from manufacturer, so that's probably a good thing...

[This message has been edited by pmbrunelle (edited 03-03-2020).]

pmbrunelle MAR 03, 05:59 PM

quote
Originally posted by donuteater306:
Would be nice to know what AC Delco gave me tho. I bet it's a "delco" part but like Ogre said, maybe from their lower-end line.



Hard to know without cutting it open... but as long as it works, I guess you don't need to know what's in it.