Plugs - What a diff!
 

On the left is a Bosch W7DTC 3-electrode plug with about 5000 miles on it. On the right is an NGK BPR6ES (copper) with about 5000 miles on it. The Bosch showed some caked on carbon which you can't see here very well. The NGKs had no carbon on the electrodes at all. (the black on the NGK electrode is dirt/grime from removing).

Quite a difference , yes? The only other variables were that I replaced my rotor and cap when I installed the NGKs.

http://forums.pelicanparts.com/uploa...1125287055.jpg

Would you say that the main difference is a better spark due to new cap and rotor? Or are the single electrode plugs just a way better plug?

I use NGK's in every car I own. They are the best plug IMHO.

Mike

Re: Plugs - What a diff!
 

Unfortunately, from a design of experiments perspective you messed things up by replacing the cap and rotor, so there is no way to tell what the cause was. If the rotor and cap were worn, it could very likely have changed the spark to the level where it would cause what you see.

You can correct the problem though by cleaning up and regapping the Bosch plugs and putting them in for another 5000 miles, and THEN comparing them to the NGK's.

Back in the 80's when I used to work on the line, I couldn't tell you how many problem cars came in with ign problems. It would always boil down to people installing plat plugs. These cars were made for copper plugs. Install the Bosch Super plugs and you'll notice how good they work.

Excellent picture, thanks.

No prob.
I wouldn't normally change my plugs so often but since I have to do my smog test this week, I didn't want to take any chances.

Those two plugs have different heat ranges, right? that might have something to do with it. Maybe the one on the left was too cold. Anyone?

Good point about the heat ranges. In order for the comparison to be meaningful, both plugs have to be of comparable heat ranges.

Those plugs have the same heat range.

Mike

wow.

and NGK BP6ES is one step colder than plugs for rich carbs. Meaning I ran BP7&8 ES with CIS.