plug gap measurements .054?

cool - I use the same exact gap as Kevin. It allows for a slightly weak ignition and gap erosion.

What do ya mean about vacuum diagnostics? Like how to do it, how to interpret, etc?

Good luck.
 
HISSIN50 said:
cool - I use the same exact gap as Kevin. It allows for a slightly weak ignition and gap erosion.

What do ya mean about vacuum diagnostics? Like how to do it, how to interpret, etc?

Good luck.

The Factory Engineers designed into their specs for gap errosion and if you have weak ignition parts, you should think of replacing the coil, plug wires, cap and rotor and you will be good to go!
 
Shaker, the arguable gain from slightly larger gaps are debateable IMHO. I have, as perhaps you also have, seen some dyno runs which reveal this (the trend to run the largest possible gap is one that might change at some point here, akin to too much timing advance).

I had no issues with running an 0.060 gap (did it when I got the car) but simple choose to do what I do. (I dont have a weak ignition and did not say I did. But some folks do and while mine works fine, most of the components have 150K miles on them). To each his own.

Since you say the gap erosion is figured into the specs, do you know how much erosion they factor for (over the life of a plug) and in what conditions that spec was related (specs are normally created for new motors with near a perfect efficiency balance. Most of our motors are not that way). So I guess we would need a new motor to extrapolate the specs.

Like I said, to each his own. :)
 
I wasnt trying to start an argument. Gap errosion was figured by the Engineers over the 30,000 Mile change period. I would bet most guys take better care of their Mustangs and do not go the entire 30,000 Miles before changing plugs, so that should more than make up for a motor that is broken in with a few miles.
 
Kevin -- I'll bet you it doesn't say .44-.46; but rather .044-.046". I think I'll win the bet. :)

Anywhere in the .044-.054" range ought to work just fine guys. If your ignition components are 'fresher' run it to the higher side. If they're more tired, run to the lower side. If possible, cut back the ground electrode on the plug (Dremel works fine) so you expose more of the plug tip -- allows a bit more of the spark to be exposed to the mixture.
 
89sleeper said:
Funny, under the hood of my 88GT and 89 Coupe, it says .44-.46

Not sure which book states that.

Maybe the earlier 5.0s had a smaller gap. Under the hood of my 92 GT it says .052 - .056, the Owners Manual says the same, and my Ford Service Manual also says the same.
 
Generally speaking -- the bigger, fatter spark you can generate in the cylinder, the better off you are. What that generally means is you should OPEN UP the gap until you find that it runs worse, then back off a bit - the bigger the gap, as long as the system has the energy to jump the gap, the bigger the spark. There isn't a one size fits all on this -- you can each experiment and see what works best. But you won't find too many folks below .045", and you won't find too many bigger than .060".
 
Michael Yount said:
Kevin -- I'll bet you it doesn't say .44-.46; but rather .044-.046". I think I'll win the bet. :)

Anywhere in the .044-.054" range ought to work just fine guys. If your ignition components are 'fresher' run it to the higher side. If they're more tired, run to the lower side. If possible, cut back the ground electrode on the plug (Dremel works fine) so you expose more of the plug tip -- allows a bit more of the spark to be exposed to the mixture.
You are correct.

You know what I meant.....;)