Which spark plug to use?
- Thread starter supraman72
- Start date
this week I finally got around to changing my plugs. Thought the ngk platiums that have been in for some time were finally getting tired. Car only has bolt ons. Decided to try the copper bcpr6es after hearing good things about them. Tried to gap them at .030, but I think the crappy gapper tool I used wasn't very accurate. Even though the car seems to run better, since I put them in the car has a periodic "bump" or odd pulse only at op. temp idle. Never does it any other time. Gotta be the gap I set doesn't it? Only thing is, did I go too low or not low enough? I'm about to go out and pull them all back out and recheck them with a better tool. If the idle was smoother with my old plugs, I'm thinking maybe I should open the gap a little.
IBoughtASupra;1830890 said:
No, It doesn't feel like a misfire.... It's hard to describe. It almost feels like a late power pulse or something. Nope stock ignitor & coil pack. Isn't the Ignitor mod something guys with the COP mod do? Maybe it has something to do with going from platinum to copper? Platinums didn't do it. :dunno:
Just actually pulled the plugs back out. The gaps were more accurate than I expected, except #6 plug was under .030... wonder if that was it?
Last edited:
Do you mean it dips down in RPM slightly and then comes back up? The igniter mod is to give it a better ground rather than going through the body points.
IBoughtASupra;1830927 said:
Well yea it feels like a lump or a bump in the idle, which makes the rpm drop very slightly and then come back up, and a slight pop or puff from the exhaust. Ah I see. Any idea why it didn't do this with the platinum plugs?
Turbo Habanero;1830989 said:
Those are coppers too I see. What plugs did you have previously? Did it stumble then too?
Turbo Habanero;1830989 said:
Also Use those same plugs at 22 psi, or 29 psi. I get the idle stumble, but I gapped 'em too close at .026, I want to go cold coppers and gap at .028. The higher the number the colder the plug... http://ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml Any high boosted folks have recommendations for plugs and gaps they use and swear by?
Went to autolites (cheaper throwaways) - over gapped the first time and it missed like a pig at 10psi . Changed oil and new autolites copper stock gap and now still slight miss here and there. The NGK platinum were better and next change plats back for me.