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Old 01-06-2011, 03:02 PM   #1
earles113
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Spark Plug Gap.

I've done everything on the ignition upgrade, including 9mm Ford Racing plug wires, motorcraft platinum plugs, Motorcraft cap and rotor, and ignition coil.

I haven't done the 10* bump on the timing, and I probably won't. Not anytime soon. So what should I gap my plugs to? I know .55 is for the complete Six Litre tune up, but what should mine be? The same?

Help is greatly needed.
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kept playing with it til it finally went in all the way.
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Old 01-06-2011, 03:03 PM   #2
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gap them to .55, the larger gap is to make the coil work harder to produce a better spark.
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New nuts are in the plan.
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Old 01-06-2011, 03:12 PM   #3
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Yeah, go ahead and gap your plugs to .55" and see what happens.

No really, gap them to .055" and you should be good.
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Old 01-06-2011, 03:15 PM   #4
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Yeah, go ahead and gap your plugs to .55" and see what happens.

No really, gap them to .055" and you should be good.
lmao, asshat.
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New nuts are in the plan.
"Kids, they see the good in everything and through their eyes, they open ours." - Hank Davis
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Old 01-06-2011, 03:31 PM   #5
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Alright, thanks guys.
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kept playing with it til it finally went in all the way.
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Old 01-06-2011, 04:04 PM   #6
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so why not bump the timing to take full advantage of the tune up??
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Old 01-06-2011, 04:50 PM   #7
earles113
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Update

I have no possible way of doing it.
No timing gun, and no knowledge of how too.

Anyways, the plugs were gapped at .047, and all are now .055. I'm about to take it around the block a few times, should I be able to feel a difference?
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kept playing with it til it finally went in all the way.
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Old 01-06-2011, 05:19 PM   #8
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Go find out and post!
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Old 01-06-2011, 06:55 PM   #9
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I used to have a 1990 351 with a Jacobs Ignition pack and gapped the plugs at .55" and it failed emissions so I had to reduce the gap once a year.
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Old 01-06-2011, 07:39 PM   #10
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Maybe its because I was near a 1/4 tank of gas or that the gaping did something, but she hauled some serious butt down the street.

I have a little bit of an exhaust noise change, aslo.

I dunno, but I hope all of this did something, because I replaced a lot of stuff that wasn't broke. Old, but not broke.
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Old 01-06-2011, 08:09 PM   #11
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With all due respect, Earle, you were probably in need of a tune-up anyway and your replacement of secondary ignition parts is probably the best thing you can do to improve performance. Ignition components do not have to be "broke" to cause problems, just worn and less conductive.

Specific factory spark plug gap for a 1995 5.0L is .052 to .056 and for a 5.8L is .042 to .046, both at 10 degrees BTDC. Be advised that opening your 5.8L gap from factory recommendations will stress your ignition system causing increased wear of parts.

Ford increased the 5.0L spark plug gap in 1992, probably to increase the performance of the 5.0L. IMHO, opening the spark plug gap and bumping the timing in a 5.8L may or may not add a minor amount of pep, but at the cost of efficiency.
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Old 01-06-2011, 08:14 PM   #12
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did mine today too! didnt change the timing yet, but new wires, coil, plugs at .55, air filter, fuel filter.....my truck ran like an absolute BEAST afterwords!! Doesnt even drive like the same truck. 2 of the plugs i took out didnt even have the ceramic on them!! I can tell a HUGE difference gapping the mat .55 in stead of the .45 or so they were at!!
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Old 01-08-2011, 06:13 PM   #13
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I bought some bosch platinum plugs today and was told the gap should be .40. The old plugs were set at .44, it still runs like poop.
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Old 01-08-2011, 06:26 PM   #14
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Quote:
Originally Posted by earles113 View Post
I've done everything on the ignition upgrade, including 9mm Ford Racing plug wires, motorcraft platinum plugs, Motorcraft cap and rotor, and ignition coil.

I haven't done the 10* bump on the timing, and I probably won't. Not anytime soon. So what should I gap my plugs to? I know .55 is for the complete Six Litre tune up, but what should mine be? The same?

Help is greatly needed.
Spark Plug Gap 1.07-1.17 mm (0.042-0.046 inch) factory spec.
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Old 01-08-2011, 07:51 PM   #15
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Guys, guys, the best spark plugs for your Bronco 5.0L/5.8L is the cheapest copper spark plugs you can find, such as Autolite.

Platinum is a precious and rare metal which is used in spark plugs due to it's high corrosion resistance and longevity. On the other hand, Copper is by far a much better electrical conductor and, at about a buck apiece, you can afford to change them four to five times as often.

I wonder why Air Flow Research (AFR) recommends Autolite 3924 Copper Core Spark Plugs ($1.50 each) for my performance heads?

I am confident that your gaps of .44 and .55 are simple typos (thats about half an inch!) instead of the factory recommended .044 (forty four one-thousanths of an inch).
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Old 01-08-2011, 07:59 PM   #16
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Quote:
Originally Posted by Seattle FSB View Post
Guys, guys, the best spark plugs for your Bronco 5.0L/5.8L is the cheapest copper spark plugs you can find, such as Autolite.

Platinum is a precious and rare metal which is used in spark plugs due to it's high corrosion resistance and longevity. On the other hand, Copper is by far a much better electrical conductor and, at about a buck apiece, you can afford to change them four to five times as often.

I wonder why Air Flow Research (AFR) recommends Autolite 3924 copper Core Spark Plugs ($1.50 each) for my performance heads?

I am confident that your gaps of .44 and .55 are simple typos (thats about half an inch!) instead of the factory recommended .044 (forty four one-thousanths of an inch).
i run motorcraft spark plugs, just like what came factory.
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