1994 Spark Plug gap - ZR-1 Net Registry Forums

USAFPILOT · 04-18-2009

I see the manual says .05 ... is there any reason to do anything different? I went with the NGK Iridium TR551X #7164 plugs. The car is bone stock.

jonszr1 · 04-19-2009

i gap mine (ngks) at.45 thousand . my car seems to idle better at that gap vs 50thou..plus its what corey henderson who does my tuning said to do .he has tried tons of different things while tuning our cars and found that 45 thou works best .thats good enough for me

USAFPILOT · 04-19-2009

I'll tell you what....changing the gap to smaller isn't easy with the NGK...the things dont budge. I think they are going in with the .05. Any good techniques out there...i dont have a vice, and dont really want to tap it with a hammer or something.

Demps · 04-19-2009

My bet is you will experience some tip-in stumble at .05.

Ted

USAFPILOT · 04-19-2009

so if I want to reduce it to .045 how do I go about it without smashing the plug into something, a vice is the only thing I think tat will do it.

Demps · 04-19-2009

I personally use a medium-to-small set of channel locks.

USAFPILOT · 04-19-2009

I just used the base of my chop saw and some elbow grease...they are all in with the .045 gap. I have to say it is running smoother; and throttle response seems better as well; but I still think it will benefit from some new Fuel Injectors...so that is next. I know my secondary throttle linkage is one of the ones that is on backwards, and sometimes I think it could be smoother too...so I'll have to check that out once I am under the plenum. Another project to get to in my spare time, for which I have almost none.

That number 8 plug is a pita, but doable. Next time I will go get one of those magnets I almost bought that has an elbow on it...the straight pencil magnet just barely gets in there to suck it up.

Lithium grease in the plug socket is a good trick, works well.

I noticed the plugs that came out of it were AC Delco, maybe the original plugs, and they all look the same, so I think the engine is still running normally. The gap on those plugs was definitely .05 or more. Maybe that could explain the occasional miss I could feel in it.

Am I going to lose any power with the smaller plug gap, al I can infer is that a smaller gap increases the percentage the plug will not misfire etc. So I should be more likely to always have a spark...but the spark may have less energy to ignite fuel?

Ohh well....the seat of the pants feel I have right now is that the car is running and idleing better.

jonszr1 · 04-19-2009

no way you will lose power . the bigger gap of .50plus will cause some power lose due to missing and possible overheating of the coils

USAFPILOT · 04-19-2009

I was wondering if that was why I lost one coil already...Corey replaced it last November...we took the NASCAR approach and only changed the one vs all four. But I am thinking about doing the other 3.

04-18-2009	#1
USAFPILOT Join Date: Aug 2007 Location: Spring TX Posts: 1,348	1994 Spark Plug gap I see the manual says .05 ... is there any reason to do anything different? I went with the NGK Iridium TR551X #7164 plugs. The car is bone stock.

04-19-2009	#2
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: 1994 Spark Plug gap i gap mine (ngks) at.45 thousand . my car seems to idle better at that gap vs 50thou..plus its what corey henderson who does my tuning said to do .he has tried tons of different things while tuning our cars and found that 45 thou works best .thats good enough for me

04-19-2009	#3
USAFPILOT Join Date: Aug 2007 Location: Spring TX Posts: 1,348	Re: 1994 Spark Plug gap I'll tell you what....changing the gap to smaller isn't easy with the NGK...the things dont budge. I think they are going in with the .05. Any good techniques out there...i dont have a vice, and dont really want to tap it with a hammer or something.

04-19-2009	#4
Demps Join Date: Jan 2006 Location: Niceville Posts: 998	Re: 1994 Spark Plug gap My bet is you will experience some tip-in stumble at .05. Ted

04-19-2009	#5
USAFPILOT Join Date: Aug 2007 Location: Spring TX Posts: 1,348	Re: 1994 Spark Plug gap so if I want to reduce it to .045 how do I go about it without smashing the plug into something, a vice is the only thing I think tat will do it.

04-19-2009	#6
Demps Join Date: Jan 2006 Location: Niceville Posts: 998	Re: 1994 Spark Plug gap I personally use a medium-to-small set of channel locks.

04-19-2009	#7
USAFPILOT Join Date: Aug 2007 Location: Spring TX Posts: 1,348	Re: 1994 Spark Plug gap I just used the base of my chop saw and some elbow grease...they are all in with the .045 gap. I have to say it is running smoother; and throttle response seems better as well; but I still think it will benefit from some new Fuel Injectors...so that is next. I know my secondary throttle linkage is one of the ones that is on backwards, and sometimes I think it could be smoother too...so I'll have to check that out once I am under the plenum. Another project to get to in my spare time, for which I have almost none. That number 8 plug is a pita, but doable. Next time I will go get one of those magnets I almost bought that has an elbow on it...the straight pencil magnet just barely gets in there to suck it up. Lithium grease in the plug socket is a good trick, works well. I noticed the plugs that came out of it were AC Delco, maybe the original plugs, and they all look the same, so I think the engine is still running normally. The gap on those plugs was definitely .05 or more. Maybe that could explain the occasional miss I could feel in it. Am I going to lose any power with the smaller plug gap, al I can infer is that a smaller gap increases the percentage the plug will not misfire etc. So I should be more likely to always have a spark...but the spark may have less energy to ignite fuel? Ohh well....the seat of the pants feel I have right now is that the car is running and idleing better.

04-19-2009	#8
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: 1994 Spark Plug gap no way you will lose power . the bigger gap of .50plus will cause some power lose due to missing and possible overheating of the coils

04-19-2009	#9
USAFPILOT Join Date: Aug 2007 Location: Spring TX Posts: 1,348	Re: 1994 Spark Plug gap I was wondering if that was why I lost one coil already...Corey replaced it last November...we took the NASCAR approach and only changed the one vs all four. But I am thinking about doing the other 3.