Spark plug gap with MAD 6AL

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sinlinson

sinlinson

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I'm running a MSD 6AL on my mildly built 360, .030 over, Comp Cams Xtreme Energy 230/236 hyd. (.230/.488- .236/.491), Edelbrock aluminum heads 650 Holley Brawler carb. Car is not driven much, less than 200 miles last year. Running NKG 4554 R5671A-8 plugs. Started having hard starts, running rough and blowing smoke until warmed up. pulled the plugs and they were black. Pretty sure my issue is just starting it every once in a while and not driving it enough. Question is what plug gap are you guys running with MSD boxes? I've read up to .050, but looking for opinions. Thanks in advance.

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It looks like it's running pig rich, try jetting the carburetor down a notch or two. I would start the gap at .045 and not exceed .055. Begin with the basics on the tune up, 16-17* initial timing and around 34* total timing.
 
Don’t change anything until you get that plug out of there.

That plug is at least 3 ranges too COLD.

And why the racing plug? You don’t need a racing plug.

You need something in a 5 heat range.

Get those in there first and then start reading the plugs.
 
The wider the gap, the more stress you put on cap, rotor, wires. That spark is looking for an easy path to ground, and if it can punch a hole through the rotor easier than it can jump a plug, it will. In other words, there is a practical limit to the benefits of a wider gap. I would not go over .040-45, just personally. That's inches, not metric
 
Agree, needs hotter NGK 5 heat range plugs.
What is the initial timing? Nice looking car.
 
Thanks for the feedback. I've never fiddled with plug heat ranges. These plugs were in the car when I bought it. I just ordered some -5 heat range plugs. I'll switch them out and check the timing. Hopefully that will solve my fouling (soot) issue.
 
sinlinson said:
Thanks for the feedback. I've never fiddled with plug heat ranges. These plugs were in the car when I bought it. I just ordered some -5 heat range plugs. I'll switch them out and check the timing. Hopefully that will solve my fouling (soot) issue.
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Getting the correct plugs in there is a start.

After that you need to work with ignition timing.

Once that is sorted out you can start tuning the carb.
 
From the horses (MSD’s) mouth.

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Looks to me like that’s so stinky rich there’s something up with the carb. Stuck needle? Float level? Is it dripping fuel out of the booster?
 
Newbomb Turk said:
Don’t change anything until you get that plug out of there.

That plug is at least 3 ranges too COLD.

And why the racing plug? You don’t need a racing plug.

You need something in a 5 heat range.

Get those in there first and then start reading the plugs.agree, .044 here...
Click to expand...
 
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