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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

sparkplug reach

  • Thread starter Thread starter TokyoJoe
  • Start date Start date Mar 29, 2011
T

TokyoJoe

New Member
Mar 25, 2007
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0
Mar 29, 2011
#1
  • Mar 29, 2011
  • #1
How can I measure what the correct reach sparkplug should be?

Motor is a 420w (4.10 x 4.040 6.2 rods)
AFR 225 heads 58cc
 
J

junkyardwarrior

Well-Known Member
Jan 10, 2011
400
113
63
Mar 29, 2011
#2
  • Mar 29, 2011
  • #2
14mm thread, 3/4" reach.

Probably start with an Autolite 3924 or 3933 for a gas natural aspirated deal. 3933 is a race plug with trimmed strap.
 
T

TokyoJoe

New Member
Mar 25, 2007
179
5
0
Mar 29, 2011
#3
  • Mar 29, 2011
  • #3
I've got a set of ar3933's but they are a .750 reach plug. I pulled .50 reach plugs out of the motor, thats why I am asking how can I measure maximum reach or correct reach that I should be using?
 

tannerc91gt

This last 25% is foreign territory at this point
Founding Member
Nov 29, 1999
4,392
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234
Indiana
Mar 29, 2011
#4
  • Mar 29, 2011
  • #4
this is just thinking out loud here as i honestly dont know the legit way to do it but if your concern is piston contact couldnt you just clay them like you would when checking PVC and see if youre getting any contact? shouldnt do any damage to the piston if youre just hand turning it and you should be able to see how much you can get away with that way

id love to know the professional solution
 
T

TokyoJoe

New Member
Mar 25, 2007
179
5
0
Mar 30, 2011
#5
  • Mar 30, 2011
  • #5
thats exactly what I was thinking of trying but when you clay for PTV clearance the head is off...if you clay the plug it will just come off when you try to thread it into the chamber I would think. So I guess the correct way would be to pull the head then....?
 
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