why re-gap spark pluggs?

[JennaBear]

I have the TR55s and are gapped at .035. They were at .040 before the supercharger though. GM changed from .060 to .040, there was an advisory that went out with the change.

 

[danimalmax]

so how do i know what i should have them gapped at? .035? .040?

 

[Max]

unless you have a supercharger, turbocharger, or nitrous gap them at .040

 

[withac]

I put the NGK TR55's in my 5.3. I double checked the gap but all were at .040. As far as pressing the gapping tool against the center electrode to open up a gap I wouldn't do that regardless of it's size. You can slide the outer electrode through the hole with the larger part of the tool turned away from the plug. You can then gently pry down on the tool therebye lifting the outer electrode away from the center one therebye opening the gap.

 

[tybardy]

I put the NGK TR55's in my 5.3. I double checked the gap but all were at .040. As far as pressing the gapping tool against the center electrode to open up a gap I wouldn't do that regardless of it's size. You can slide the outer electrode through the hole with the larger part of the tool turned away from the plug. You can then gently pry down on the tool therebye lifting the outer electrode away from the center one therebye opening the gap.

thats the proper way of gapping a spark plugg, regardless of what type of plug you are gapping, you should never "wedge" something between the gap to open it up. if you are using the tool correctly, nothing should touch the electrode other the the act of measuring.

 

[road1will]

I think i may do my plugs today. I know they say they're fine til 100k miles, but i'd be curious to see if i see any change by re-gapping.

 

[tybardy]

the rear two will give you heart burn, but otherwise an easy project... just be carefull removing the boot as these ******* are particularly snugg, ive dont pluggs in several cars/trucks, these were the toughest to seperate plugg from wire i ever ran into. Yuo dont want to rip the wire, then your spending $70 on new wires

 

[withac]

I can NEVER remove all the old wires without ruining one, so I always to wires when I do plugs. I actually don't remember what I used, I think it was Bosch. Some people said they didn't like them but I saw at least a 2mpg increase with the new plugs and wires.

 

[tybardy]

2mpg increase is HUGE from just pluggs and wires

were your old pluggs all ****** up? did you go with a bigger dia. wire?

 

[withac]

2mpg increase is HUGE from just pluggs and wires

were your old pluggs all ****** up? did you go with a bigger dia. wire?

Same diameter wire. It had around 93 to 96K miles on it, I don't remember exactly. The old plugs had burned out considerably, I don't remember how much but it was a lot more than .040, big ol' gap.