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View Full Version : Electrical Suppressor, coil 108561 importance/function?



Jonathan
07-14-2019, 08:48 AM
So the ballast resistor and ignition coil connections on our cars are a bit of a weak point. Wires or connectors getting hot and melting themselves off. Wires getting stiff from the heat or shortened from redoing the connectors a few times and wiggling themselves off. Most of those connections will leave you with a car that won't start.

I had one of my ballast resistor connections come off the other day. It happened years ago and so wasn't hard to spot. It's the one on the lower right hand side of the resistor. The wire is getting kind of short and there's not a lot of extra slack to make a good connection.

I was looking over those connections as well as the ones on top of the ignition coil. On the right side of the coil, where there is the double connection, one of those wires is for the 'suppressor, coil' part number 108561. Mine doesn't look great and thought I'd clean it up or even replace it. Replacements don't look to be available though.

What is this part for? Can you run without it? I had assumed this was one of those gadgets relating to reducing electrical noise with the radio, but now I'm not sure. Does it actually help the engine idling stabilize because it cuts down electrical noise FROM the radio?

My tach needle bounces wildly from time to time. Mostly when you ease up on the gas (not sure why it happens then). It spazzes out a little on the gauge, but the engine idle itself isn't hunting. Just the gauge reading. Then it tends to stop doing that part way through a nightly drive, like maybe it's dependent on temperature somehow (hot engine/cold engine?) I have been trying to trace that out and it's one of the reasons I was in poking around with the ignition connections. I have not gone back under the instrument cluster to check the ground connection on the gauge, but that's next.

I had the suppressor thing off and checked for continuity with a multimeter and it seems to have some. From the diagrams, it appears to have it's ground from where it screws into the bracket on the backwall. That looks clean enough even though the outside of the suppressor is a little rusted up and dirty.

Just wondering how crucial this thing is and could you run without this one where it is. Or where I might get a new one if it's somehow causing my tach needle fluttering.

opethmike
07-14-2019, 10:22 AM
When I had the PRV, I removed my suppressor coil. Big mistake, the next day I was attacked and eaten by a horde of zombies. So I definitely do not recommend removing it.

Bitsyncmaster
07-14-2019, 10:36 AM
That is a capacitor on the +12 volt (lower voltage if you still have resistors) side of the coil. The schematic shows it as 2.2 uf. I don't think it's for radio interference but is there to give you a better spark. So you should not read any resistance and in fact you should see it charging up (going to infinity) if you leave your ohm meter on it long enough.

Ron
07-14-2019, 01:51 PM
+1

J, check out this article (https://mgaguru.com/mgtech/ignition/ig108.htm) about point type systems.

Jonathan
07-14-2019, 03:29 PM
That is a capacitor on the +12 volt (lower voltage if you still have resistors) side of the coil. The schematic shows it as 2.2 uf. I don't think it's for radio interference but is there to give you a better spark. So you should not read any resistance and in fact you should see it charging up (going to infinity) if you leave your ohm meter on it long enough.


+1

J, check out this article (https://mgaguru.com/mgtech/ignition/ig108.htm) about point type systems.

Thanks guys, that's helpful.

Jonathan
07-15-2019, 08:09 AM
It did turn out to be something that got bumped loose. Completely separated really. The original -ve side wire on the ignition coil had a cut in it. There was one of those splices on that wire years ago from some PO job and I had removed it and put some electrical tape around the spot to cover it. Over time, it must have gotten weaker and that's where the break was. I repaired the wire and the car started right back up. So that's that.

Pic from 2013 showing splice still on the wire:

60662

Broken wire under piece of tape:

60661

Riley88
07-15-2019, 06:41 PM
I had a "breakdown" my first ever real one awhile back. I was on the side of the road nuking it, got towed, embarrassed. Next week i went to troubleshoot and first thing i check , yeah the cabling came loose off the ignition coil. The roads are crap where I live, so it just worked itself loose. Sometimes im like, is the car falling apart?nope its the roads

Bitsyncmaster
07-15-2019, 07:23 PM
It did turn out to be something that got bumped loose. Completely separated really. The original -ve side wire on the ignition coil had a cut in it. There was one of those splices on that wire years ago from some PO job and I had removed it and put some electrical tape around the spot to cover it. Over time, it must have gotten weaker and that's where the break was. I repaired the wire and the car started right back up. So that's that.

Pic from 2013 showing splice still on the wire:

60662

Broken wire under piece of tape:

60661

If the wires are long enough, crimp ring terminals on to replace the quick connect tabs used on the coil. Then the terminal is bolted down tight.

AirmanPika
07-21-2019, 08:33 PM
When I had the PRV, I removed my suppressor coil. Big mistake, the next day I was attacked and eaten by a horde of zombies. So I definitely do not recommend removing it.

Welp...that answers that. I'm keeping mine on.