[Dmntxn77]

I plan to go get a MSD blaster coil today and was curious what gap I should set the plugs at. I have a bored throttle body, K&N FIPK, and 3" exhaust also.
Thanks

 

[Angelous]

depending on your plugs I would go .060

 

[Phaze]

stock is .45 on the 5.2....

so yeah, depending on the plugs. A conservative gap would be .50-.55

You can always try taking one plug and expanding the gap, putting it back in, and then run it until you feel the engine misfiring on that cylinder.

As soon as you find the limit on the plug, I would bring it back in .05

 

[93zjbeast]

stock is .45 on the 5.2....

thats weird, under my hood it said to gap to .035 ???

 

[peltandra]

stock is .45 on the 5.2....

thats weird, under my hood it said to gap to .035 ???

Same here, .035 on 94 ZJ 5.2.

MSD coil is junk, BTW. Went back to stock after I developed a high-rpm miss/stumble.

She runs smooth now.

 

[slomatt]

I also had issues with a MSD coil and have reverted back to the stock one. My MSD started missing when warm and then would cause the engine to shut down when on the freeway at speed. I'm guessing it was heat related, but I switched back to the stock coil and have had absolutely no problems.

- Matt

 

[Phaze]

whoops. I've got mine gapped .10 too far then as of last week.

I'll get those back to .35 tomorrow!

 

[zacharykro]

i have the accel, which is higher output than the msd. my stock gap is .035

i have it at.04

should i go further??

 

[AndyZJ]

You could probably gap it out to .045 or even .05. The thing with gapping is, if the spark can jump the gap then the propagation can begin sooner and this should give you a bit more power. On the other hand, if the system can't handle the added gap, you can destroy the coil, the cap/rotor, the plugs, or have misfire city going on. So experiment a little. I'm gonna gap a little bigger and see what happens to mine.

 

[zacharykro]

whats the advantage of the larger gap?

 

[MyNameIsJerry]

whats the advantage of the larger gap?

Like Andy said (in fancy words), as long as the spark can jump the larger gap, you will make a little more power.

 

[DankNesS]

ive run my MSD coil, box, and wires flawlessly.. just added a msd fuel pump aswell. i gapped mine to .055 with no problemo running like a freagn BEAST.
maybe with the MOPAR performace pcm is why im not having problems with my msd coil.. it adjusts the fuel ratio better for modded engines then the stock pcm would be my guess

 

[zacharykro]

how many volts is your coil?

 

[AndyZJ]

With the gap closer to .1, the propogation of the flame front can begin sooner. The sooner the flame can begin to expand, the sooner it can move through the space in the cylinder and drive the piston down creating power. The thing to remember is that the gap is determined by cylinder design, compression ratio, air/fuel ratio, and a few other things. Messing with it can make your whole ignition system work harder to jump the gap. So be careful to what extent you gap the plugs. I'd start with .005 amounts at a time.

 

[zacharykro]

i had it at .045 then moved it back to .04. it feels like its workin better

 

[Brunner]

I also had issues with a MSD coil and have reverted back to the stock one. My MSD started missing when warm and then would cause the engine to shut down when on the freeway at speed. I'm guessing it was heat related, but I switched back to the stock coil and have had absolutely no problems.

- Matt

I had the exact same problems. I spoke with a tech at MSD last year and he recommended adding some type of tube to funnel air to the coil for improved airflow on the highway. I would have thought that the airflow would have been better at higher speeds but apparently not.

So I put in a 3" rubber hose from below the rubber engine skirt and haven't had a problem since. Hope this helps, it seemed to work for me.