use a drill bit the correct size to make sure the gap is correct. Flat surface feeler gauges are ok, but a good drill bit set will have one in the range your looking for, and you will be able to get a better feel of how tight you are. If there is no gap between the spark plugs, the electricity never creates a spark to ignite the fuel = no run condition.
Our huge natural gas engines where I work use the 4 electrode spark plugs, only 3 times bigger and 2 per piston. Not sure why they would be less effective in an automotive engine?
I don't think it's the 4 ground design that's faulty, it's the Bosch name stamped on the side. They're terrible. They will misfire, you'll be making less power than with stock plugs... Their platinums' electrodes fall off (do the +4's use platinum electrodes?)... Avoid them like you would a rabid dog infested with plague carrying fleas.
amen, took out my bosch platinums that came with the car, and gained 60 hp. (it started running on all cyls). The platinum falls off as stated above, or it burns out.
Electricity takes the shortest ground possible. One one of them 4 electrode plugs, all the spark will do is ark to the nearest one, which will have the least resistance, therefore out of the 4 electrodes, 3 will rarely get a spark, and 1 will wear, until another is closer, and by then they will be covered in carbon.
Ok, heres the deal I sent someone to pic up my plugs (ac delco) and i'm not sure if they got pre gapped or not. The reason i'm thinking they didn't is because the engine is running as described in my above post.
1998 Mustang GT
You can't piss on what you can't catch.
