Igniter Repair for Cheapskates (1 Viewer)

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A couple weeks ago, my igniter died. One moment, the truck is idling in my driveway, and the next moment...eh...not so much. :censor:

Not willing to spend a few hundred bucks on NOS (if I can find it), and not thrilled with the idea of spending $100+ on a used igniter, I hunted around the internet and found a good solution. These threads have the answer (1, 2, 3), but I figured I'd write it up again for future reference here on Mud.


Parts:
  • One 4-pin GM HEI ignition module
  • One 1/4 Watt 1000 Ohm resistor (RadioShack 271-1321)
  • Three 1/4" quick connectors
  • One 3/16" quick connector
  • Two eyelet connectors
  • One short piece of wire (6" or so)
  • Two 1" machine screws
  • Shrink tubing
The ignition module that I used was Part #SSTLX301T, from Rock Auto, which is for a 1985 Chevy K10, but I'm pretty sure that it's a standard part across most of GM's line at that time. Just be sure that it's the four-pin module.


Instructions:
  • Remove the old igniter from the truck.
  • Remove the plastic bottom case of the igniter.
  • Clip the wires (I tried removing the solder, but still couldn't get the connectors to budge).
  • Unscrew the old ignition module, and remove it from the case. (See my next post in this thread for a comment about this.)
  • Strip back about 1/4" of each wire end to attach to the quick connectors.
  • Solder one resistor inline to the end of the yellow wire.
  • Attach the other end of the resistor, along with the black wire, to one of the 1/4" quick connectors.
  • Attach the brown wire to a 1/4" quick connector.
  • Attach the red wire to a 1/4" quick connector.
  • Attach the white wire to the 3/16" quick connector.
  • Make a ground strap with the length of wire and the two eyelet connectors.
  • Drill holes in the top of the igniter housing to match the mounting holes in the new ignition module.
  • Apply silicone grease to the bottom of the new ignition module and attach it to the top of the igniter housing with bolts through the holes that you just drilled. One end of the ground strap that you made should be attached to the hole in the ignition module that has the grounding tab.
  • Reattach the igniter to the coil, and connect the wires as follows:
    • White wire from distributor goes to W pin.
    • Red wire from distributor goes to G pin.
    • Brown wire goes to B pin. Eyelet end attaches to + terminal on coil.
    • Yellow and black wires go to C pin. Eyelet end attaches to - terminal on coil.
    • Ground strap attaches to any convenient ground point.
Depending on your skill with electronics and a drill, this is a :banana: to :banana::banana: job. The total cost was under $20. The GM modules aren't supposed to be as good as the Toyota ones (no surprise), but at this price, I can keep a spare handy and find replacements easily.

Old igniter:
oldigniterext.JPG


Inside of old igniter, showing the wires to clip:
oldigniterint.JPG


New GM ignition module:
newigniter.JPG


New ignition module, all wired up. (The resistor, attached to the yellow wire, is encased in shrink tubing, here:
wiredonbench.JPG


Repaired igniter, back in the truck:
intruck.JPG
 
When I removed the old ignition module from the metal housing, it fell right out. However, as you can see here, there is still some silicone grease left in there. I would have expected the grease to have held the ignition module in place a little bit, but it didn't. This suggests to me that the old grease had totally deteriorated between the ignition module and the housing, which acts like its heat sink. Since heat, more than anything else, kills these parts, I think it would be good preventive maintenance to open up your igniter and reapply some heat sink grease to replace the grease that broke down over the last quarter century. Hopefully, this tip will keep a few igniters from dying prematurely.

siliconegrease.JPG
 
Thanks - I thought ignitors were all potted in epoxy - if I can tear mine down and grease it, I will.
 
http://www.amazon.com/dp/B000Z3LS1C/?tag=ihco-20

Apply in thin layers.
Don't use your fingers, or get skin oils in it.
Get rid of as much air space/pockets between module and heat sink as possible.
There's a pic somewhere of Benjamin's addition of more heat sink to the top of the box.

Nice write-up. Thanks for posting w/ part #s

Edit: Ignition Module listed as LX301T - Standard Motor Products.

MODS! -- Could we get this in the FAQ, please ??
 
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As I recall, a 1K resistor is needed somewhere. I first did this mod in 89 on a 142 volvo. Used a distributor from a 75 Volvo 240 and the GM ignitor.

10 years later, my 85 Toy pu lost an ignitor. I still had a handful of GM's, and it worked with the Toyota as well. About every 5 years someone post the mod.:cheers:
 
There's a pic somewhere of Benjamin's addition of more heat sink to the top of the box.

That's actually a great idea for keeping an old igniter alive: refresh the silicone grease on the inside, and add an extra heat sink on the top of the box. Computer heat sinks are cheap, easy to find, come in a variety of sizes and styles, and should be plenty adequate for a bit of extra protection.
 
As I recall, a 1K resistor is needed somewhere.

Yup. It's attached inline to the yellow wire, but I encased it in shrink tubing before taking the picture.

Also, in case it matters to anyone, the original ignition module also had a 1/4 watt 1K ohm resistor between the black and yellow leads. It's underneath the black plastic tab that's sticking straight down from the yellow wire in the second photo, above. So, as far as I can tell, aside from the obvious physical difference and the supposed difference in quality, there's no real functional difference between the Toyota and GM ignition modules.
 
Ya, less heat is a good thing.

heat sink and Mallory-2.jpg



That's actually a great idea for keeping an old igniter alive: refresh the silicone grease on the inside, and add an extra heat sink on the top of the box. Computer heat sinks are cheap, easy to find, come in a variety of sizes and styles, and should be plenty adequate for a bit of extra protection.
 
No mention there is made of the resistor, so I'm curious why it is needed and what it does?

I'm not sure, but it's there on the original. Some of the threads that I saw omitted the resistor but used a different coil. The Accel SuperCoil 140008 was mentioned specifically, but I wanted to go with a more-or-less stock configuration and opted to keep the resistor.
 
I think the resistor had something to do with the ECU. On my 22r PU, it did not work correctly without the resistor.

Here's one of the many Volvos I did the GM mod to.

Bosch_GM_Accel.jpg
 
I'm not sure, but it's there on the original. Some of the threads that I saw omitted the resistor but used a different coil. The Accel SuperCoil 140008 was mentioned specifically, but I wanted to go with a more-or-less stock configuration and opted to keep the resistor.

As I recall, the coil must have a .6 ohm input impedance.
 
I looked on my computer, but my oldest files are 2002. Most of the pics i took were in the mid to late 90's, and either I never uploaded them or just lost them.
 
No worries. The info here is pretty complete.
 
Okay. Well, actually, not ok.

Did everything as noted with stock coil. No spark.
Tried new '72 chevy coil. No spark.
Tried new Pertronix 45001 coil I got for the JD tractor. No spark.

Checked for spark w/AA battery as per FSM, orange-ish spark.
Hooked everything back up. No spark.

Replaced dizzy w/desmog curved dizzy. No spark.
New plug wires. No spark.
Mowed front lawn. No spark.
Ate lunch. No spark.
Applied fervent prayer. No spark.

Info.

B+Y w/1k resistor on Y shows battery voltage. Br shows battery voltage, W shows 3.5 v as does R.
Battery voltage at both + & - on coil(s), all of 'em.
Toy coil w/in normal ranges as per FSM.
Signal generator in dizzy w/in normal resistance range as per FSM.

Some say tach wire may be shorted so try without that wire, which one is that?

Help. Me.

Thanks.
 
From mopar slant 6 threads on the same conversion this is the recommended thermal compound:
http://www.radioshack.com/product/index.jsp?productId=2216879&locale=en_US
pRS1C-2568724w345.jpg


No mention there is made of the resistor, so I'm curious why it is needed and what it does?
There the recommended IGN modules are: "NAPA Echlin TP-45, ACDelco D-1906, or Standard-Bluestreak LX-301"

Didn't use one when I did the conversion on my old Plymouth, but the modules kept dying within days of installing. So after troubleshooting and doing some digging around, I found out that they do not like anything less than 12VDC in continuous use. Added a relay to the circuit and the one I added the relay to never went out on me. It was just an OEM spec igniter (the GM one), but it was a huge upgrade over the stock Mopar ignition controller, and made for a big cleanup in the mess of wiring under the hood.

I'm curious as to what their dwell time is versus a stock 60/62 igniter. I had recently been wanting to get a junked igniter so I could pull it apart and see if I could modify it to adjust dwell time a-la the D.U.I igniters, but seeing the guts in this thread it looks like that wouldn't be feasible.
 
Years ago MISF & I did a dwell angle test on a OE GM module (in his mom's Hurst-Olds) and an aftermarket performance module ("Dynamod" or similar name; in his '69 Gran Prix). Both had 45° dwell at idle. By about 3500 RPM or so the OE module's dwell had fallen off to around 36° while the perf. module still had 45°. For an SBC that might matter. Doubt that it does for any of the F engines.
 
Plus it's two less cylinders, so 4375 rpm is not very likely on a 2F daily driver.

Years ago MISF & I did a dwell angle test on a OE GM module (in his mom's Hurst-Olds) and an aftermarket performance module ("Dynamod" or similar name; in his '69 Gran Prix). Both had 45° dwell at idle. By about 3500 RPM or so the OE module's dwell had fallen off to around 36° while the perf. module still had 45°. For an SBC that might matter. Doubt that it does for any of the F engines.
 

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