spark gap 02' 5.7l

[johnfin]

Factory manual states .060 for the spark gap - modern replacement AC 41-110 shows .040 for a gap. Whats the deal? Most spark plug gappers dont go beyond .040

[redbird555]

Factory manual states .060 for the spark gap - modern replacement AC 41-110 shows .040 for a gap. Whats the deal? Most spark plug gappers dont go beyond .040

I usually gap at .050-.055 id go with that the gap is more suited to the output of the coil than the plug so id go with what the car recommends

[johnfin]

plugs change over the years - ie the new number. .050 would be in between, might go with that after I find a gapper that goes that far.

[redbird555]

yup pretty much every sets the gap in that .05-.055 range I use tr55 plug which come in at a .055 gap and I just recheck it and throw em in. as far as the gauge goes the autoparts stores all carry the little gauge that looks like a disk and goes on your key chain and it goes to .1 i believe

[SMWS6TA]

gap is also depends on the HP and if you are using FI or NO2.


Stock to mild power mods
Plug/Gap
TR5 (copper) - .38
TR55 (copper) - .40
TR5IX (iridium) - .40


For every 100 hp over stock added from boost, a cooler plug would be required to prevent pre-detonation:

TR-6 - .40



Stock LS1's seem to like the TR55's, even though the only difference between the TR5 and 55 is that the "5" is able to be set at a lower gap spacing but not recommended to exceed 0.40 while the "55" starts at about 0.38 but can be gaped to 0.60.

Purpose of the Metal

The metal in a spark plug serves a single basic purpose: to channel the electric energy from the plug wire through the spark plug so that it can be forced to the engine block in the form of a spark. Therefore, any metal that conducts electricity at all could potentially be used for a spark plug. The metal should also not get too hot; one of the main problems with some metals is that they overheat quickly, causing the electric charge itself to be compromised and the spark plug to not operate as smoothly.
Copper Spark Plugs

Copper spark plugs are generally considered to have the best performance of any spark plug type. This is potentially different from what advertising companies suggest, but the other metals are, unfortunately, not as conductive in general as copper is. Platinum and iridium plugs are more likely to overheat, which causes damage to the plug components and can compromise the delivery of the spark to the engine block.
Platinum and Iridium Plugs

Platinum and Iridium plugs perform at a lower level than copper spark plugs, because they are less conductive and they tend to overheat. However, the overall longevity of these two types of metal is better than copper plugs. In reality, copper has the best performance of all three and the worst longevity. Platinum has good longevity and the worst performance. Iridium has good longevity and a performance that is decent, which is why iridium plugs tend to be more expensive than any other type. Still, the difference between these plugs in terms of overall quality is minimal, as there is a trade off for each.
Most copper plugs need to be changed every 20,000 miles or so. Platinum and iridium plugs can often go for twice that before they require changing, but the overall performance will not be as good and you may have to deal with overheating of the plugs. This is potentially not worth the added cost of both platinum and iridium spark plugs, although the decision will depend upon your preference.

[Cold]

Yea I always gapped stock @ .055 and cam/no2 @ .035-.038

[pajeff02]

^^ Pretty much as stated. Different plug styles call for different gaps. My TR55's are set at .054" right now. I also utilize a set of feeler gauges rather than a plug gauge -- much more accurate imo.