question about spark plug gap?

donkey_punch

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Jan 16, 2004

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northern****ingjersey

Sep 4, 2007

#1

• Sep 4, 2007

• #1

i bought a new set of plugs and wires. and they guy at the part store say that the motorcraft plugs that i bought were pre-gap. they were all between .50 and .55.
but then the ones that i took out of the car were at .35

so what should the gap be at? whats the stock gap, and would it make a difference since i have aluminum heads and a mild cam?

Thanks
Joe

 

blksn955.o

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Mar 15, 2002

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st.louis mo 314

Sep 4, 2007

#2

• Sep 4, 2007

• #2

55 or so is the stock gap for the stock plug.

I would kinda want to make sure the plug is for the alum. head...he may have assumed you just need a stock plug that will not work with alum. heads in most cases.

Most people run a 35 gap with a higher compression, boost, or bottle to help stop spark blow out.

 

juiced_94gt

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Mar 30, 2005

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Sep 4, 2007

#3

• Sep 4, 2007

• #3

stock is .054 My tuner told me to gap mine to .040 for my combo in the sig.

 

juiced_94gt

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Mar 30, 2005

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Southern California

Sep 4, 2007

#4

• Sep 4, 2007

• #4

blksn955.o said:

55 or so is the stock gap for the stock plug.

I would kinda want to make sure the plug is for the alum. head...he may have assumed you just need a stock plug that will not work with alum. heads in most cases.

Most people run a 35 gap with a higher compression, boost, or bottle to help stop spark blow out.

Click to expand...

Very true, sorry, my plugs are Autolite 3924's for the AFR's

 

donkey_punch

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northern****ingjersey

Sep 4, 2007

#5

• Sep 4, 2007

• #5

so is there a particular plug to use with AFR 165 heads?

thanks for the replys guys

 

95opal

5 Year Member

Nov 16, 2004

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Sep 4, 2007

#6

• Sep 4, 2007

• #6

donkey_punch said:

so is there a particular plug to use with AFR 165 heads?

thanks for the replys guys

Click to expand...

Autolite 3924's Seem to work for me.

 

blksn955.o

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st.louis mo 314

Sep 4, 2007

#7

• Sep 4, 2007

• #7

Alot of people have good luck with the autolite 3924's and such with alum. heads.

The plug diff. is that the stock plug is a tapper fit...look at were the threads end you will see an angle. That angle fits snug into the heads plug location. The alum. heads tend to need a gasket style plug. These plugs have a large flat area that has a "crunch" gasket or metal o-ring that seals it to the alum. head. Tapper fit plugs look like toothpics compared to the gasket style plugs that look like sumo wrestlers by comparo.

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Sep 4, 2007

#8

• Sep 4, 2007

• #8

I'd be sure to use antiseize with alum heads as well.

And yes, always check your gaps.

Good luck.

 

donkey_punch

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northern****ingjersey

Sep 5, 2007

#9

• Sep 5, 2007

• #9

thanks for the suggestion on the autolites

so i guess .35 is what i should gap them at?

and antiseize FTW. lol

thanks
Joe

 

Don 95Vert

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Oct 1, 1999

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Delaware, OH

Sep 5, 2007

#10

• Sep 5, 2007

• #10

We just today had a car on the dyno that was misfiring at higher RPMs. The plugs were brand new but we did not install them. We pulled them and gapped them at 0.035 - they were 0.055 and the problem went away.
Don