plug gaps

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Jul 17, 2014 | 11:59 AM

POPAJON

Thread Starter

Fleet Mechanic

Joined: Aug 2010

Posts: 1,574

Likes: 6

From: Cranbrook, Ont., Canada

plug gaps

OK I KNOW this probably has been beaten to death. I have checked the threads but NO CLEAR answers. I have the Dura spark 2 with a heavily modified 400 IE: roller cam, flat tops with a 9:1cr and the other usual mods. I will run a MSD Blaster2 coil. My question is do I need the resistor FROM MSD and can I open the gap up or stay with the stock setting of .045 ?

Jul 17, 2014 | 12:55 PM

fmc400

MSEE

Joined: Apr 2004

Posts: 10,386

Likes: 35

From: Austin, TX

The MSD Blaster 2 coil is a direct replacement for the original coil. You MUST use the factory ballast resistor. Omitting the ballast resistor will stress both the Duraspark module and the coil, causing them to prematurely fail. Set the plug gap to what is specified on the valve cover - if it's 0.045, then keep it at 0.045.

I don't know what you mean by "resistor from MSD." Just use the ballast resistor that's in the harness, unless it has been hacked up.

Jul 17, 2014 | 01:08 PM

POPAJON

Thread Starter

Fleet Mechanic

Joined: Aug 2010

Posts: 1,574

Likes: 6

From: Cranbrook, Ont., Canada

Apparently MSD has a Ballast resistor that can be ordered with the Blaster 2 coil. Thanks for the info . THAT is a simple concise answer. Just what I was looking for. You are well versed in the electrics of these older fords. I have been trying to keep up to date on your posts, BUT I am now in competition with the OLD GIRL for the computer as she to is now retired. LOL

Jul 17, 2014 | 01:10 PM

POPAJON

Thread Starter

Fleet Mechanic

Joined: Aug 2010

Posts: 1,574

Likes: 6

From: Cranbrook, Ont., Canada

Tried to give you some beans but it won't let me so please consider the thanks as a Rep.

Jul 17, 2014 | 01:53 PM

fmc400

MSEE

Joined: Apr 2004

Posts: 10,386

Likes: 35

From: Austin, TX

Thanks for the kind words.

You can easily make sure the factory ballast resistor is there by hooking up the coil and turning the key to RUN - the voltage between the positive coil post (BATT+) and ground should be about half of that across the battery posts (i.e., 6 to 7 volts vs. 12 volts). If the harness is original and never touched, it should be there (it's a long length of special wire built into the harness).

Jul 17, 2014 | 03:04 PM

POPAJON

Thread Starter

Fleet Mechanic

Joined: Aug 2010

Posts: 1,574

Likes: 6

From: Cranbrook, Ont., Canada

It WILL be the original wiring. My Dad bought the truck NEW in '77 and I bought it from him a LONG time ago. So only 2 owners and 36000 original miles. My Dad passed away 2 years ago and This is the last thing he and I worked on together.

Jul 17, 2014 | 04:28 PM

crsmiffy

Elder User

Joined: Jan 2011

Posts: 831

Likes: 1

From: Tanilba bay NSW Australia

Don't do what I did and remove that piece of wire because I thought it was a dodgy join. Wasn't using the vehicle much but eventually the points started sticking together. face palm. Hope it is all going ok bro