Spark plug specs ?? : rough idle when hot
09-22-2005, 11:09 PM
#1
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Spark plug specs ?? : rough idle when hot
Hi all.
I have been troubleshooting a rough idle problem on my '86 and I think it is due to plugwires. I searched and found this:
http://forums.corvetteforum.com/show...ot&forum_id=48
Where the original poster had the exact symptoms (smooth idle until the car warms to temp, then rough idle and a "miss") and he replaced almost everything but it turned out to be the wires.
Supporting this is that fact that I installed headers lately and some of the plug wires are VERY close to the tubes. And I found that even though I tried to route the wires well, after a few hundred miles, a couple of wires were touching the emissions tubing.
That's why I mentioned plug specs in the title. On a few of my cylinders (number 7 in particular) there is simply not enough room between the plug and the tube for a boot to fit. But if the sparkplugs were shorter, I could have clearance.
So my question is: How are spark plugs specified? I know there are different heat ranges, and internal and external lengths. But I don't know how to buy plugs that will work in an L98 and stick out of the heads less. It would be nice if somebody could just tell me which ones to buy, but since I will be replacing the heads in a few months, I want to learn how to figure it out myself. That way when I get the new heads installed (trickflow twisted wedge already bought and waiting) I will be able to get the reight plugs then
I have been troubleshooting a rough idle problem on my '86 and I think it is due to plugwires. I searched and found this:
http://forums.corvetteforum.com/show...ot&forum_id=48
Where the original poster had the exact symptoms (smooth idle until the car warms to temp, then rough idle and a "miss") and he replaced almost everything but it turned out to be the wires.
Supporting this is that fact that I installed headers lately and some of the plug wires are VERY close to the tubes. And I found that even though I tried to route the wires well, after a few hundred miles, a couple of wires were touching the emissions tubing.
That's why I mentioned plug specs in the title. On a few of my cylinders (number 7 in particular) there is simply not enough room between the plug and the tube for a boot to fit. But if the sparkplugs were shorter, I could have clearance.
So my question is: How are spark plugs specified? I know there are different heat ranges, and internal and external lengths. But I don't know how to buy plugs that will work in an L98 and stick out of the heads less. It would be nice if somebody could just tell me which ones to buy, but since I will be replacing the heads in a few months, I want to learn how to figure it out myself. That way when I get the new heads installed (trickflow twisted wedge already bought and waiting) I will be able to get the reight plugs then
09-26-2005, 04:30 PM
#3
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If you have steel heads - there are shorty plugs made by accel or holley. I am not sure which because it has been 2+ years since I changed heads.
My boots are also close but I use boot covers - Summit has a ceramic clothe boot cover that I use now.
My boots are also close but I use boot covers - Summit has a ceramic clothe boot cover that I use now.
09-26-2005, 08:02 PM
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Originally Posted by 85vet
If you have steel heads - there are shorty plugs made by accel or holley. I am not sure which because it has been 2+ years since I changed heads.
My boots are also close but I use boot covers - Summit has a ceramic clothe boot cover that I use now.
My boots are also close but I use boot covers - Summit has a ceramic clothe boot cover that I use now.
I didn't know they took different plugs, or I would have mentioned that.
