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Unread 08-15-2013, 08:09 PM   #1
Gasman303
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Which spark plugs on 4.2l 6cyl?

Ok I just gathered my Team rush distributer upgrade kit along with Msd 6al ignition module and Howell tach filter

What spark plugs work best with this setup I'm going with?

4.2l, stock motor, T5 trans, howell efi

Thanks

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Unread 08-15-2013, 08:18 PM   #2
SCSEAJAYSEVEN
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I use Autolite/Motorcraft part # 985 in mine. Set the gap at .045 to start, you can play around with this setting. I once set mine at .050, that was too much. Currently I have them set about .042-.043. Seems to work fine at this setting.
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Unread 08-16-2013, 06:49 AM   #3
Neuner-9R
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Quote:
Originally Posted by SCSEAJAYSEVEN
I once set mine at .050, that was too much.
I thought about doing this. What do you mean by too much? Non effective or tearing up your dizzy?
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Unread 08-16-2013, 10:20 AM   #4
Gasman303
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I purchased Bosch platinum they are pre gapped .38 ill have to take it to .45 I guess?!
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Unread 08-16-2013, 10:35 AM   #5
RenoF250
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Quote:
Originally Posted by Gasman303 View Post
I purchased Bosch platinum they are pre gapped .38 ill have to take it to .45 I guess?!
You can leave them at .038. I am not much of a fan of the Bosch platinums myself. Fire them outside the engine next to a regular plug and you will see they make a puny little spark.
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Unread 08-16-2013, 10:37 AM   #6
Renegade82
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I'd be careful of the Bosch plugs. I know of two people who had their Bosch plugs come apart and cause major damage and Bosch wouldn't back up their product.

I currently am using the 985 autolite's.
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Unread 08-16-2013, 03:44 PM   #7
LumpyGrits
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Bosch plugs run on the cold side.
Time 2 on Autolite 985's. I run prem(91)fuel and found that .045" gap was best all around.
LG
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Unread 08-16-2013, 05:52 PM   #8
WindKnot
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I'm with Lumpy on this. Same set up. You're wasting your money on the Bosch or any platinum plug with your Jeep, IMO. Just a good ol' copper plug does fine.
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Unread 08-16-2013, 07:07 PM   #9
waterdowg
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I use plain Copper Champion Plugs in all the Jeeps that I have ever owned over the past 20 years.
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Unread 08-16-2013, 10:00 PM   #10
Renegade82
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Yep, I've run Champions as well. I used to get the resister ones to reduce engine static in the cb. I've been runnin' the 985's in more recent years but I never noticed much of a difference between the two, that I recall.
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