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  • Fox 5.0 Mustang Tech

Plug gap

  • Thread starter Thread starter FordGuy88
  • Start date Start date Oct 4, 2006
F

FordGuy88

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Nov 15, 2004
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Park Ridge, IL
Oct 4, 2006
#1
  • Oct 4, 2006
  • #1
What do the spark plugs have to be gaped to? I am running a regular old autolite 25.

Thanks
 
G

GTOreturns

Well-Known Member
Oct 1, 2003
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West Coast Best Coast
Oct 4, 2006
#2
  • Oct 4, 2006
  • #2
I think its 035 (35 thousants)
 
F

FordGuy88

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#3
  • Oct 4, 2006
  • #3
Thanks
 

TomCat

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#4
  • Oct 4, 2006
  • #4
Er, shouldn't it be .054"
 

Flavadave4

Active Member
Nov 28, 2003
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Utica, NY
Oct 4, 2006
#5
  • Oct 4, 2006
  • #5
I put new ones in the other day and read in the book that they were to be .054"
 
I

iwashmycar

20+ Year Stangneter
Apr 7, 2004
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Columbus, Ohio
Oct 4, 2006
#6
  • Oct 4, 2006
  • #6
.054"
 

HISSIN50

"How long does it take to get help in here?
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#7
  • Oct 4, 2006
  • #7
You might want to provide a year of stang and trim (if not stock. I.e., if you run a carb instead of EFI).

The 0.052-0.056" spec quoted above is correct for EFI aero foxes.

Good luck.
 
G

GTOreturns

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Oct 1, 2003
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#8
  • Oct 4, 2006
  • #8
mines a 93 fox and could swear its 035,,,sorry about that!
 

vristang

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Oct 4, 2006
#9
  • Oct 4, 2006
  • #9
My book says .05x

I know I have seen the .035" listed before, but can't remember where.


Anyone have a better memory than I do?






jason
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
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#10
  • Oct 4, 2006
  • #10
Jason, isnt the smaller gap for carbed foxes?
 
G

GTOreturns

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Oct 1, 2003
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#11
  • Oct 4, 2006
  • #11
OK,,here it is. 1989-90 is 044

and 1991-93 is 054,, sorry for the mix up fellas
 

HISSIN50

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#12
  • Oct 4, 2006
  • #12
GTOReturns said:
OK,,here it is. 1989-90 is 044

and 1991-93 is 054,, sorry for the mix up fellas
Click to expand...
Whenever one of these threads pops up and the specs are posted, I have to ask (some of us are wondering):

What was the source for this info?

Can anyone think of any reason/revisions to parts that would require the smaller plug gap for the years posted above?
 

vristang

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Oct 5, 2006
#13
  • Oct 5, 2006
  • #13
HISSIN50 said:
Jason, isnt the smaller gap for carbed foxes?
Click to expand...

What's a carb?


It very well could be.

I only have my Ford 1990 Shop Manual here, and can't find any plug gap specs. But I have .050" hand written on the front cover. Not sure where it came from though



If memory serves...

A bigger gap will be more likely to "blow out" at wot, but will provide better spark kernels at low rpms.

A smaller gap can help with cold starts as well.

I don't completely trust my memory on the above points, it has been a while since I considered plug gaps.

Can someone confirm or correct the above?



jason
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
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Oct 5, 2006
#14
  • Oct 5, 2006
  • #14
vristang said:
If memory serves...

A bigger gap will be more likely to "blow out" at wot, but will provide better spark kernels at low rpms.

A smaller gap can help with cold starts as well.

I don't completely trust my memory on the above points, it has been a while since I considered plug gaps.

Can someone confirm or correct the above?



jason
Click to expand...

Dem points you made sound good to me.

I read about them carb thingies once. Not sure on that.

I'm still just hung up on the differing plug gap specs offered on the forum. I think 5L5 and I [and maybe you too Jason] were wondering about it the other day on another thread. A TFI ignition is a TFI ignition.
 

TomCat

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Apr 19, 2005
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#15
  • Oct 5, 2006
  • #15
HISSIN50 said:
Dem points you made sound good to me.

I read about them carb thingies once. Not sure on that.

I'm still just hung up on the differing plug gap specs offered on the forum. I think 5L5 and I [and maybe you too Jason] were wondering about it the other day on another thread. A TFI ignition is a TFI ignition.
Click to expand...
When I worked with CSK, I noticed that in some cases spark plugs offered by two different manufacturers would list different gaps, even though they were going in the same engine. The autolites always came up as .054" for my stang, though.
 

jgfiveoh

New Member
May 8, 2006
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Oct 5, 2006
#16
  • Oct 5, 2006
  • #16
i think the turbocoupes and and svo's run a plug gap in the .030" range
 
G

GTOreturns

Well-Known Member
Oct 1, 2003
51
17
59
West Coast Best Coast
Oct 5, 2006
#17
  • Oct 5, 2006
  • #17
HISSIN50 said:
Whenever one of these threads pops up and the specs are posted, I have to ask (some of us are wondering):

What was the source for this info?

Can anyone think of any reason/revisions to parts that would require the smaller plug gap for the years posted above?
Click to expand...

Chiltons Ford Mustang 1989-93 Repair manual
Chapt 1 page 26
 
G

GTOreturns

Well-Known Member
Oct 1, 2003
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West Coast Best Coast
Oct 5, 2006
#18
  • Oct 5, 2006
  • #18
Interesting, thats what Chilton says.But the Official Mustang 5.0 Technical Reference & Performance handbook says that 1979-1986 used a 050 gap except the 1979's sold in California and the 1985 carbed 5.0. Then 1987-93 used 054 while the 93 Cobra used a 050. Even wierder is that a 1980 8 cylinder and a 1987-93 5.0 used the same Motocraft spark plug. ASF-42
 
2

2KsilverGT

Founding Member
Apr 27, 2001
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0
Collinsville Va
Oct 5, 2006
#19
  • Oct 5, 2006
  • #19
If you run a power adder you should run a smaller gap. Higher HP app's should run a smaller gap or if you have a aftermarket ignition system. Other wise the stock .050 ish gap should be more than adequate. I run a .034 personally but i'm runnin an aftermarket ignition, stroker motor and nitrous so every app will have a different gap.
 
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